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Re: Point me into the right direction please.

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  • rtstofer
    Knowing how individual components function is important but, as you point out, that doesn t create a circuit. The most important thing to know is that, for
    Message 1 of 27 , Jan 31, 2005
      Knowing how individual components function is important but, as you
      point out, that doesn't create a circuit. The most important thing
      to know is that, for all practical purposes, every circuit has
      already been designed. Now, I can hear the negative feedback
      starting but for the most part it is true. At least at this level...

      My approach to engineering has always been to copy someone else's
      work. And, since I believe everything has already been done, all I
      have to do is find it - Google is my best friend. Datasheets,
      application notes - all available free from the manufacturers.

      There are many tutorials on the Internet - this is far better than
      when I went to school. The four function calculator was state-of-
      the-art.

      Take your LED flasher example. You can look for 555 timer circuits
      on the internet. A single 555 will make one LED flash. What should
      the second do? Turn on when the first turns off? Well, any single
      transistor inverter will do that. Voila' Two flashing LEDs.

      Start simple, get one LED to flash using the 555. Then, get a
      2N2222 transistor or most any NPN device. Connect the emitter to
      ground, connect a 1K ohm resistor between your power supply and the
      anode of the LED (the long lead) and connect the cathode of the LED
      (the lead near the flatted edge) to the collector lead of the
      transistor. Now, connect a 1K resistor between the output of the
      555 and the base of the 2N2222. That's it. A simple inverter.
      Assuming you have a 5V power supply the LED will light up. It won't
      be very bright because the 1K resistor in series with the LED is too
      large. But, it will work.

      All complex systems are built with simple building blocks. Each
      block has an input and an output and performs some function on the
      way by. And, at some point, the math gets hairy. But that is a 4th
      year problem, not something to worry about today. Ohm's law and the
      equations for capacitor voltage/current and inductor voltage/current
      will get you by for quite a while. Study Kirchoff's Law and
      Thevinin equivalent circuits and you are on your way. A few
      simultaneous linear equations will help analyze most simple circuits
      but things get out of hand pretty quickly when you start handling
      tuned circuits and such. And signal processing is a mathematical
      exercise for those so inclined.

      Get any of the electronics experimeter kits you can find at Radio
      Shack. These will be easy circuits and you can play with them until
      you are comfortable.

      Heck, I just did a Google search for Kirchoff's Law and Thevinin
      circuits and came up with dozens of sites with explanations. It's
      all out there! And it has all been done before... Mostly...




      --- In Electronics_101@yahoogroups.com, "mahan" <mahan@r...> wrote:
      > Hello everyone:
      >
      > I am interested in getting into the field of electronics. I
      have
      > tried to read many books which all start off by explaining the
      math and
      > equations and describing what each little component does and how
      it fits
      > into the equation. I understand the equations, but I do not
      understand how
      > we go from an equation to a PCB full of components which all work
      together
      > to perform one or more functions. I have heard the water flow
      theory over
      > and over again, but the water flow theory doesn't explain what
      happens when
      > the main pipe branches out to 100 different lines which each
      perform their
      > own function. I have some schematic simulator programs which I
      have messed
      > around with, but what good does that do me when I do not
      understand the
      > basis of how everything is working together?
      >
      > Currently I am reading a book titled "How electricity
      works". I am
      > on chapter 2 which is explaining different laws and relations but
      I feel
      > like I'm starting to drift away from what they are trying to
      explain. I
      > understand the math; I was in calculus and advanced chemistry at
      my last
      > college I attended. But I don't understand how the math falls into
      a
      > circuit. For example I want to design a circuit with 2 LED's that
      blink. I
      > know I need a power source and 2 LED's but I am lost after that. I
      am going
      > to start an Electronics Technologist program in a year; it is for
      a 3 year
      > diploma and then 2 more years at a university to get my BS. I am
      doing this
      > so I can get some real hands on training and experience, rather
      than
      > studying theory as an EE. Please help me and shed some light on to
      my
      > problem. Any and all advice would be much appreciated and I thank
      everyone
      > who has read this long email.
      >
      > A lost person
      > Mahan M ... :)
    • Stefan Trethan
      ... Well, you know, in your city you have a huge waterflow system. Similar to a PCB. The waterflow is ok, but not 100% applicable. To make a PCB you basically
      Message 2 of 27 , Feb 1, 2005
        On Tue, 1 Feb 2005 00:59:59 -0500, mahan <mahan@...> wrote:

        >
        > Hello everyone:
        >
        > I am interested in getting into the field of electronics. I have
        > tried to read many books which all start off by explaining the math and
        > equations and describing what each little component does and how it fits
        > into the equation. I understand the equations, but I do not understand
        > how
        > we go from an equation to a PCB full of components which all work
        > together
        > to perform one or more functions. I have heard the water flow theory over
        > and over again, but the water flow theory doesn't explain what happens
        > when
        > the main pipe branches out to 100 different lines which each perform
        > their
        > own function. I have some schematic simulator programs which I have
        > messed
        > around with, but what good does that do me when I do not understand the
        > basis of how everything is working together?
        >

        Well, you know, in your city you have a huge waterflow system. Similar to
        a PCB.

        The waterflow is ok, but not 100% applicable.

        To make a PCB you basically just piece together many, many of those small
        circuits you know.



        > Currently I am reading a book titled "How electricity works". I am
        > on chapter 2 which is explaining different laws and relations but I feel
        > like I'm starting to drift away from what they are trying to explain. I
        > understand the math; I was in calculus and advanced chemistry at my last
        > college I attended. But I don't understand how the math falls into a
        > circuit. For example I want to design a circuit with 2 LED's that blink.

        > I
        > know I need a power source and 2 LED's but I am lost after that. I am
        > going
        > to start an Electronics Technologist program in a year; it is for a 3
        > year
        > diploma and then 2 more years at a university to get my BS. I am doing
        > this
        > so I can get some real hands on training and experience, rather than
        > studying theory as an EE. Please help me and shed some light on to my
        > problem. Any and all advice would be much appreciated and I thank
        > everyone
        > who has read this long email.
        >
        > A lost person
        > Mahan M ... :)


        Hands on experience is a good idea.
        Now, we do not invent every circuit ourselves (Although i have "invented"
        the bridge rectifier when i was very, very little without knowing someone
        did it before me ;-)). Mostly we just take well known circuits and modify
        them.

        For your two leds, there are many possibilities. For example, we can use
        two "switches" (transistors for example) to switch them on/off
        alternately. Also, we could generate a AC voltage with the right
        frequency, and drive one with the positive amplitude and one with the
        negative.

        But in real life most of us would simple enter "astable multivibrator" in
        google ;-).
        Probably we know different possbilities, and want to use certain parts, so
        we enter "astable multivibrator with npn" or "astable multivibrator with
        555".
        You can also enter "Led blinker" if you have no idea what you need.

        You need experience to design your own circuits, which you gain by
        understanding circuits someone else designed. You also need to learn what
        each component does. (And i mean what it does in circuit not what happens
        internally).
        Also, you can't expect to be able to put together a oscilloscope as first
        project, you will have to start with small things.

        ST
      • Leon Heller
        ... From: mahan To: Sent: Tuesday, February 01, 2005 5:59 AM Subject: [Electronics_101] Point me into
        Message 3 of 27 , Feb 1, 2005
          ----- Original Message -----
          From: "mahan" <mahan@...>
          To: <Electronics_101@yahoogroups.com>
          Sent: Tuesday, February 01, 2005 5:59 AM
          Subject: [Electronics_101] Point me into the right direction please.


          >
          > Hello everyone:
          >
          > I am interested in getting into the field of electronics. I have
          > tried to read many books which all start off by explaining the math and
          > equations and describing what each little component does and how it fits
          > into the equation. I understand the equations, but I do not understand how
          > we go from an equation to a PCB full of components which all work together
          > to perform one or more functions. I have heard the water flow theory over
          > and over again, but the water flow theory doesn't explain what happens
          > when
          > the main pipe branches out to 100 different lines which each perform their
          > own function. I have some schematic simulator programs which I have messed
          > around with, but what good does that do me when I do not understand the
          > basis of how everything is working together?
          >
          > Currently I am reading a book titled "How electricity works". I am
          > on chapter 2 which is explaining different laws and relations but I feel
          > like I'm starting to drift away from what they are trying to explain. I
          > understand the math; I was in calculus and advanced chemistry at my last
          > college I attended. But I don't understand how the math falls into a
          > circuit. For example I want to design a circuit with 2 LED's that blink. I
          > know I need a power source and 2 LED's but I am lost after that. I am
          > going
          > to start an Electronics Technologist program in a year; it is for a 3 year
          > diploma and then 2 more years at a university to get my BS. I am doing
          > this
          > so I can get some real hands on training and experience, rather than
          > studying theory as an EE. Please help me and shed some light on to my
          > problem. Any and all advice would be much appreciated and I thank everyone
          > who has read this long email.

          The best way to learn is to buy a few components, some tools, and a
          multimeter, and build a few simple circuits and get them working.

          Leon



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        • upand_at_them
          Hi Mahan, I know exactly how you feel. I went through the same thing when I started learning electronics. And I m still learning. I bought so many
          Message 4 of 27 , Feb 1, 2005
            Hi Mahan,

            I know exactly how you feel. I went through the same thing when I
            started learning electronics. And I'm still learning. I bought so
            many "beginning electronics" books and was frustrated after working
            through them, because I still didn't "get" it.

            What really helps - and what the other guys have said - is to start
            building small circuits. You really do have to get your hands dirty
            for it to make sense. Get a breadboard, some basic components, and
            batteries. Build something simple, flash some LEDs, use transistors
            to switch LEDs, use transistors to control the brightness, and then
            try changing component values (or even components) to see what
            happens.

            It's true that nearly all circuits really have already been built and
            you'll only be making small changes. But once you start playing
            around with some of your own circuits, you'll understand how and why
            things work the way they do. And then you'll use these basic
            building blocks and know "hey, I need to put a capacitor here" or "I
            need to increase the size of this resistor". And before you know it
            you'll be making the circuits that YOU want to build.

            So start building stuff, have fun, and ask questions.

            Mike
          • Abdul Kerim FAHME
            ... have ... math and ... it fits ... understand how ... together ... theory over ... happens when ... perform their ... have messed ... understand the ...
            Message 5 of 27 , Feb 1, 2005
              --- In Electronics_101@yahoogroups.com, "mahan" <mahan@r...> wrote:
              > Hello everyone:
              >
              > I am interested in getting into the field of electronics. I
              have
              > tried to read many books which all start off by explaining the
              math and
              > equations and describing what each little component does and how
              it fits
              > into the equation. I understand the equations, but I do not
              understand how
              > we go from an equation to a PCB full of components which all work
              together
              > to perform one or more functions. I have heard the water flow
              theory over
              > and over again, but the water flow theory doesn't explain what
              happens when
              > the main pipe branches out to 100 different lines which each
              perform their
              > own function. I have some schematic simulator programs which I
              have messed
              > around with, but what good does that do me when I do not
              understand the
              > basis of how everything is working together?
              >
              > Currently I am reading a book titled "How electricity
              works". I am
              > on chapter 2 which is explaining different laws and relations but
              I feel
              > like I'm starting to drift away from what they are trying to
              explain. I
              > understand the math; I was in calculus and advanced chemistry at
              my last
              > college I attended. But I don't understand how the math falls into
              a
              > circuit. For example I want to design a circuit with 2 LED's that
              blink. I
              > know I need a power source and 2 LED's but I am lost after that. I
              am going
              > to start an Electronics Technologist program in a year; it is for
              a 3 year
              > diploma and then 2 more years at a university to get my BS. I am
              doing this
              > so I can get some real hands on training and experience, rather
              than
              > studying theory as an EE. Please help me and shed some light on to
              my
              > problem. Any and all advice would be much appreciated and I thank
              everyone
              > who has read this long email.
              >
              > A lost person
              > Mahan M ... :)
              -
              -
              -
              You remind me when I lived your situation about 30 years ago :)
              Me too, I started from almost zero (even financially) though I had a
              rather good background as yours in math and electronic theories.

              My first serious project (for sell!) happened to be also a simple
              flip-flop circuit :) but instead of leds I had to drive two sets of
              light bubbles (each 500W on 220V/50Hz) using two triacs. It took me
              about two months (since I didn't have yet an oscilloscope) to build,
              rebuild the circuit with repeated calculations (voltages and
              currents) to discover at the end that the polarity of the supply
              electrolytic capacitor was by mistake connected in reverse :(
              Therefore for weeks I was working with highly non-filtered DC supply
              while thinking it is well regulated! I knew then that till I found a
              way to buy a suitable oscilloscope it would hard for me to see
              easily any new mistakes to quickly correct them. Even today I
              believe that minor mistakes are likely present in any design step.
              And only the ones that don't design by themselves... don't make
              mistakes neither :))

              The minimum lab would be a low cost oscilloscope, a multi DC supply,
              a rather precision multimeter and perhaps a wave generator (up to
              200KHz). If you have time you can build first the DC supply you
              might probably need in your future experiments and of course a
              simple wave generator for audio circuits in the least.

              I personally liked, in my first years, to build what I was able to
              analyse theorically only. But to know that my analysis was right I
              tried to modify a circuit to a small extent and saw if my calculated
              prediction fits the new results. Otherwise I knew that somewhere in
              my analysis I missed something; in the hypothesis and/or in solving
              the equations. Year after year, I saw myself designing my own ideas!

              So every time the circuit you experiment doesn't work, be glad,
              because you have now something to think of hence to learn. And if
              you really like electronics you will surely find the cause in a way
              or another... in a day or months (as I did!). That's all what you
              need to be a professional someday... by starting in really trusting
              yourself!
            • Hermod Pedersen
              ... The Electronic Project Builder s Reference by Josef Bernard is a great starter. Being a novice that was the first book making some sort of sense in
              Message 6 of 27 , Feb 1, 2005
                At 06:34 2005-02-01 +0000, you wrote:
                > Currently I am reading a book titled "How electricity works". I am
                >on chapter 2 which is explaining different laws and relations but I feel
                >like I'm starting to drift away from what they are trying to explain. I
                >understand the math; I was in calculus and advanced chemistry at my last
                >college I attended. But I don't understand how the math falls into a
                >circuit.

                "The Electronic Project Builder's Reference" by Josef Bernard is a great
                starter. Being a novice that was the first book making some sort of sense
                in designing and modifying circuits. Out of print, but a Amazon search
                should give you some used alternatives. That's how I got my copy, after
                having gotten tired of repeatedly borrowing it from the library

                - - - - - - - - - - - - - - - - - - - - - - - -
                Hermod Pedersen, HCDX Web Editor
                <http://www.hard-core-dx.com/>
              • drbillpmt@aol.com
                Hi Mahan, Your problem is familiar. I ve taught numerous people electronics over the years and the best advice I can give you is as follows: 1. Get a
                Message 7 of 27 , Feb 1, 2005
                  Hi Mahan,
                   
                  Your problem is familiar. I've taught numerous people electronics over the years and the best advice I can give you is as follows:
                   
                  1.    Get a breadboard device such as is available from Radio Shack. This is a plastic grid that you can push the leads of various electronic parts into to create circuits. The best part of this is that you can re-use all of the parts and the circuit requires no soldering. You will need a power supply to energize the circuits. Radio Shack carries small power supplies, ready built, that provide regulated 12 Volts DC. This is a good place to start.
                   
                  2.    Component sources are only limited by your imagination. You can strip a lot of parts from old TV chassis. This is what a lot of people I taught did. Surplus is another good place but many are rip-off artists so be careful!  Radio Shack has bundles of resistors in decade values fro little money. Don';t buy transistors, IC's, etc. from them - they get an arm and a leg for them.
                   
                  3. Once you have a few parts, build circuits over and over to experiment with. That is the only way to learn and gives a lot of pleasure when they work, and lots of experience troubleshooting when they don't.
                   
                  4. Don't try to learn without building as it won't stick. You can calculate forever, but only by building and experimenting can you reinforce what books tell you. There are many sources for circuits you can try. There is a series of books you can get that show literally thousands of circuits. They are called Encyclopedia of Electronic Circuits. I've been in electronics all of my life and still keep them around for ideas. Radio Shack has little booklets with circuits also.
                   
                  5.    Don't get the idea that I own stock in Radio Shack, it is sort of a universal parts house for experimenters. One of the things NOT TO DO is buy kits and build them. The only thing you learn is to follow directions and solder.
                   
                  Hope this has been of some help to you. I can't imagine starting over at this point in my life since I had my first amateur radio license when I was a sub-teen and I'm 74 now, and still at it every day designing and building medical equipment.
                   
                  If you would like to e-mail me, I'll try to help you out where I can.
                   
                  Dr. Bill Biagioli
                  Florence, SC
                • Roy J. Tellason
                  ... Even that s making things too complicated... ... Nah. If you wire up one LED and resistor so that it s on when the output of the 555 is grounded, then
                  Message 8 of 27 , Feb 1, 2005
                    On Tuesday 01 February 2005 02:31 am, rtstofer wrote:

                    > Take your LED flasher example. You can look for 555 timer circuits
                    > on the internet. A single 555 will make one LED flash. What should
                    > the second do? Turn on when the first turns off? Well, any single
                    > transistor inverter will do that. Voila' Two flashing LEDs.

                    Even that's making things too complicated...

                    > Start simple, get one LED to flash using the 555. Then, get a
                    > 2N2222 transistor or most any NPN device. Connect the emitter to
                    > ground, connect a 1K ohm resistor between your power supply and the
                    > anode of the LED (the long lead) and connect the cathode of the LED
                    > (the lead near the flatted edge) to the collector lead of the
                    > transistor. Now, connect a 1K resistor between the output of the
                    > 555 and the base of the 2N2222. That's it. A simple inverter.
                    > Assuming you have a 5V power supply the LED will light up. It won't
                    > be very bright because the 1K resistor in series with the LED is too
                    > large. But, it will work.

                    Nah. If you wire up one LED and resistor so that it's on when the output of
                    the 555 is grounded, then wire up another one so that it's on when the
                    output is high, you don't need the transistor inverter!
                  • Roy J. Tellason
                    ... I think this is probably the best advice. I ve been messing with this stuff for darn near 40 years now, and I m *still* doing that, sometimes. :-)
                    Message 9 of 27 , Feb 1, 2005
                      On Tuesday 01 February 2005 03:03 am, Stefan Trethan wrote:

                      > You need experience to design your own circuits, which you gain by
                      > understanding circuits someone else designed. You also need to learn what
                      > each component does. (And i mean what it does in circuit not what happens
                      > internally).

                      I think this is probably the best advice. I've been messing with this stuff
                      for darn near 40 years now, and I'm *still* doing that, sometimes. :-)
                    • Roy J. Tellason
                      ... I wouldn t even say that regulated is necessary to start with, and in many cases, unless you re working with logic chips or something of that sort that
                      Message 10 of 27 , Feb 1, 2005
                        On Tuesday 01 February 2005 12:26 pm, drbillpmt@... wrote:
                        > Hi Mahan,
                        >
                        > Your problem is familiar. I've taught numerous people electronics over the
                        > years and the best advice I can give you is as follows:
                        >
                        > 1. Get a breadboard device such as is available from Radio Shack. This
                        > is a plastic grid that you can push the leads of various electronic parts
                        > into to create circuits. The best part of this is that you can re-use all
                        > of the parts and the circuit requires no soldering. You will need a power
                        > supply to energize the circuits. Radio Shack carries small power supplies,
                        > ready built, that provide regulated 12 Volts DC. This is a good place to
                        > start.

                        I wouldn't even say that regulated is necessary to start with, and in many
                        cases, unless you're working with logic chips or something of that sort that
                        needs it. My most-used power supply is a transformer salvaged out of
                        something or other, a bridge rectiifier, and a couple of caps, mounted
                        into a minibox with a power switch, an LED, and a terminal strip.

                        > 2. Component sources are only limited by your imagination. You can
                        > strip a lot of parts from old TV chassis. This is what a lot of people I
                        > taught did. Surplus is another good place but many are rip-off artists so
                        > be careful! Radio Shack has bundles of resistors in decade values fro
                        > little money. Don';t buy transistors, IC's, etc. from them - they get an
                        > arm and a leg for them.

                        And their solid-state stuff often leaves a lot to be desired in terms of
                        meeting the specs. I have a curve tracer, and on testing some of the
                        unmarked parts that they at one time sold as being roughly equivalent to
                        2N2222, I was finding breakdown voltages of around 6-8V in most cases!

                        I've scrapped a LOT of stuff over the years. My comment on that is that the
                        older the stuff is, the more usable parts are going to be had from it. Too
                        much these days is specialized chips, surface mount, and similar nonsense.
                        It's probably easy enough to ask around for "electronic junk" and then scrap
                        stuff out...

                        > 3. Once you have a few parts, build circuits over and over to experiment
                        > with. That is the only way to learn and gives a lot of pleasure when they
                        > work, and lots of experience troubleshooting when they don't.

                        Yep. Although troubleshooting something that doesn't work can be *REAL*
                        frustrating when you're inexperienced.

                        > 4. Don't try to learn without building as it won't stick. You can calculate
                        > forever, but only by building and experimenting can you reinforce what
                        > books tell you. There are many sources for circuits you can try. There is a
                        > series of books you can get that show literally thousands of circuits.
                        > They are called Encyclopedia of Electronic Circuits. I've been in
                        > electronics all of my life and still keep them around for ideas. Radio
                        > Shack has little booklets with circuits also.

                        Yes.

                        > 5. Don't get the idea that I own stock in Radio Shack, it is sort of a
                        > universal parts house for experimenters. One of the things NOT TO DO is
                        > buy kits and build them. The only thing you learn is to follow directions
                        > and solder.

                        And _maybe_ troubleshoot when it doesn't work right off. :-)

                        > Hope this has been of some help to you. I can't imagine starting over at
                        > this point in my life since I had my first amateur radio license when I was
                        > a sub-teen and I'm 74 now, and still at it every day designing and building
                        > medical equipment.

                        Now there's an area where I haven't done anything (yet?)...

                        > If you would like to e-mail me, I'll try to help you out where I can.

                        I think this is a lot of what this list is all about, wouldn't you agree?
                      • brewski922
                        If you have a local trade/vocational school stop by and talk to the electronics instructor. I m sure he can or has some good books and projects to start with.
                        Message 11 of 27 , Feb 1, 2005
                          If you have a local trade/vocational school stop by and talk to the
                          electronics instructor. I'm sure he can or has some good books and
                          projects to start with. Or you might just enroll in a Electronics 101.
                          You would be supprised how much you could learn talking to that
                          instructor at an Outback over a couple of beers and steak.

                          --- In Electronics_101@yahoogroups.com, "mahan" <mahan@r...> wrote:
                          > Hello everyone:
                          >
                          > I am interested in getting into the field of electronics. I
                          have
                          > tried to read many books which all start off by explaining the math
                          and
                          > equations and describing what each little component does and how it
                          fits
                          > into the equation. I understand the equations, but I do not
                          understand how
                          > we go from an equation to a PCB full of components which all work
                          together
                          > to perform one or more functions. I have heard the water flow
                          theory over
                          > and over again, but the water flow theory doesn't explain what
                          happens when
                          > the main pipe branches out to 100 different lines which each
                          perform their
                          > own function. I have some schematic simulator programs which I have
                          messed
                          > around with, but what good does that do me when I do not understand
                          the
                          > basis of how everything is working together?
                          >
                          > Currently I am reading a book titled "How electricity works".
                          I am
                          > on chapter 2 which is explaining different laws and relations but I
                          feel
                          > like I'm starting to drift away from what they are trying to
                          explain. I
                          > understand the math; I was in calculus and advanced chemistry at my
                          last
                          > college I attended. But I don't understand how the math falls into a
                          > circuit. For example I want to design a circuit with 2 LED's that
                          blink. I
                          > know I need a power source and 2 LED's but I am lost after that. I
                          am going
                          > to start an Electronics Technologist program in a year; it is for a
                          3 year
                          > diploma and then 2 more years at a university to get my BS. I am
                          doing this
                          > so I can get some real hands on training and experience, rather than
                          > studying theory as an EE. Please help me and shed some light on to
                          my
                          > problem. Any and all advice would be much appreciated and I thank
                          everyone
                          > who has read this long email.
                          >
                          > A lost person
                          > Mahan M ... :)
                        • rtstofer
                          ... circuits ... should ... single ... the ... LED ... won t ... too ... output of ... when the ... I knew somebody would come back with that. And, of course,
                          Message 12 of 27 , Feb 1, 2005
                            --- In Electronics_101@yahoogroups.com, "Roy J. Tellason"
                            <rtellason@b...> wrote:
                            > On Tuesday 01 February 2005 02:31 am, rtstofer wrote:
                            >
                            > > Take your LED flasher example. You can look for 555 timer
                            circuits
                            > > on the internet. A single 555 will make one LED flash. What
                            should
                            > > the second do? Turn on when the first turns off? Well, any
                            single
                            > > transistor inverter will do that. Voila' Two flashing LEDs.
                            >
                            > Even that's making things too complicated...
                            >
                            > > Start simple, get one LED to flash using the 555. Then, get a
                            > > 2N2222 transistor or most any NPN device. Connect the emitter to
                            > > ground, connect a 1K ohm resistor between your power supply and
                            the
                            > > anode of the LED (the long lead) and connect the cathode of the
                            LED
                            > > (the lead near the flatted edge) to the collector lead of the
                            > > transistor. Now, connect a 1K resistor between the output of the
                            > > 555 and the base of the 2N2222. That's it. A simple inverter.
                            > > Assuming you have a 5V power supply the LED will light up. It
                            won't
                            > > be very bright because the 1K resistor in series with the LED is
                            too
                            > > large. But, it will work.
                            >
                            > Nah. If you wire up one LED and resistor so that it's on when the
                            output of
                            > the 555 is grounded, then wire up another one so that it's on
                            when the
                            > output is high, you don't need the transistor inverter!

                            I knew somebody would come back with that. And, of course, it is
                            true because of the active pull-up of the 555. It won't work for
                            every device but it will work for the 555.

                            The thing is, building the inverter is worth the effort.
                          • rtstofer
                            For components including grab bags, try www.jameco.com. I have been buying from them off and on for 20 years. Digikey is probably my favorite source -
                            Message 13 of 27 , Feb 1, 2005
                              For components including grab bags, try www.jameco.com. I have been
                              buying from them off and on for 20 years. Digikey is probably my
                              favorite source - www.digikey.com. They have an enormous selection.

                              I started getting serious about this stuff around 1969. I was never
                              interested in analog (still no real interest) but when I found out
                              what I could do with RTL logic circuits my curiosity picked up and
                              away it went. I have played with this stuff for more than 50 years
                              including my formative years building Heathkit stuff and I still
                              have the VOM, oscilloscope, freq counter, power supply and probably
                              a few other odds and ends. Too bad they got out of the business.


                              --- In Electronics_101@yahoogroups.com, "rtstofer" <rstofer@p...>
                              wrote:
                              >
                              > --- In Electronics_101@yahoogroups.com, "Roy J. Tellason"
                              > <rtellason@b...> wrote:
                              > > On Tuesday 01 February 2005 02:31 am, rtstofer wrote:
                              > >
                              > > > Take your LED flasher example. You can look for 555 timer
                              > circuits
                              > > > on the internet. A single 555 will make one LED flash. What
                              > should
                              > > > the second do? Turn on when the first turns off? Well, any
                              > single
                              > > > transistor inverter will do that. Voila' Two flashing LEDs.
                              > >
                              > > Even that's making things too complicated...
                              > >
                              > > > Start simple, get one LED to flash using the 555. Then, get a
                              > > > 2N2222 transistor or most any NPN device. Connect the emitter
                              to
                              > > > ground, connect a 1K ohm resistor between your power supply
                              and
                              > the
                              > > > anode of the LED (the long lead) and connect the cathode of
                              the
                              > LED
                              > > > (the lead near the flatted edge) to the collector lead of the
                              > > > transistor. Now, connect a 1K resistor between the output of
                              the
                              > > > 555 and the base of the 2N2222. That's it. A simple inverter.
                              > > > Assuming you have a 5V power supply the LED will light up. It
                              > won't
                              > > > be very bright because the 1K resistor in series with the LED
                              is
                              > too
                              > > > large. But, it will work.
                              > >
                              > > Nah. If you wire up one LED and resistor so that it's on when
                              the
                              > output of
                              > > the 555 is grounded, then wire up another one so that it's on
                              > when the
                              > > output is high, you don't need the transistor inverter!
                              >
                              > I knew somebody would come back with that. And, of course, it is
                              > true because of the active pull-up of the 555. It won't work for
                              > every device but it will work for the 555.
                              >
                              > The thing is, building the inverter is worth the effort.
                            • Stefan Trethan
                              Reading all the great replys you got i want to add one thing. Additionally to the solderless breadboard simply get a old PC power supply. It has 5V,12V, the
                              Message 14 of 27 , Feb 1, 2005
                                Reading all the great replys you got i want to add one thing.

                                Additionally to the solderless breadboard simply get a old PC power supply.

                                It has 5V,12V, the two negative, sometimes 3.3V.
                                Most even have good overload protection.


                                The amount of stuff i learned with a solderless breadboard and a PC PSU
                                fitted below it doesn't fit in any book. Make custom leads for your meter
                                so they directly fit into the breadboard. (You won't have 4mm system at
                                the beginning anyway).

                                If you have the money, get a scope. How much it would have helped me back
                                then....

                                Also, i have once written a list of basic parts you need for someone who
                                asked, i think it is in the files section.


                                ST
                              • Roy J. Tellason
                                ... Indeed they do. I ve used both companies, and have no complaints about either of them. ... I am! ... OTOH, I can remember a number of fun and
                                Message 15 of 27 , Feb 1, 2005
                                  On Tuesday 01 February 2005 02:02 pm, rtstofer wrote:
                                  > For components including grab bags, try www.jameco.com. I have been
                                  > buying from them off and on for 20 years. Digikey is probably my
                                  > favorite source - www.digikey.com. They have an enormous selection.

                                  Indeed they do. I've used both companies, and have no complaints about
                                  either of them.

                                  > I started getting serious about this stuff around 1969. I was never
                                  > interested in analog (still no real interest)

                                  I am!

                                  > but when I found out what I could do with RTL logic circuits my curiosity
                                  > picked up and away it went.

                                  OTOH, I can remember a number of fun and interesting projects that used those
                                  parts. Are they still around at all anywhere?

                                  > I have played with this stuff for more than 50 years including my formative
                                  > years building Heathkit stuff and I still have the VOM, oscilloscope, freq
                                  > counter, power supply and probably a few other odds and ends. Too bad they
                                  > got out of the business.

                                  I guess the market just wasn't there any more like it used to be, or
                                  something.
                                • Stefan Trethan
                                  On Tue, 1 Feb 2005 14:27:00 -0500, Roy J. Tellason ... The computer games were invented. ST
                                  Message 16 of 27 , Feb 1, 2005
                                    On Tue, 1 Feb 2005 14:27:00 -0500, Roy J. Tellason
                                    <rtellason@...> wrote:

                                    >
                                    > I guess the market just wasn't there any more like it used to be, or
                                    > something.


                                    The computer games were invented.

                                    ST
                                  • Roy J. Tellason
                                    ... To this I will add that most of these supplies need some minimum load on them to work properly. The best setup I ve seen (and I unfortunately can t
                                    Message 17 of 27 , Feb 1, 2005
                                      On Tuesday 01 February 2005 02:16 pm, Stefan Trethan wrote:
                                      > Reading all the great replys you got i want to add one thing.
                                      >
                                      > Additionally to the solderless breadboard simply get a old PC power supply.
                                      >
                                      > It has 5V,12V, the two negative, sometimes 3.3V.
                                      > Most even have good overload protection.

                                      To this I will add that most of these supplies need some minimum load on them
                                      to work properly. The best setup I've seen (and I unfortunately can't
                                      remember where I saw it) had a 10 ohm 10 watt resistor wired into the unit
                                      across the +5V output and mounted on the case in such a way that the airflow
                                      from the fan would go right across it, keeping it cool.

                                      The other thing that site did was to remove the wires coming out and mount
                                      sets of binding posts in the case, using only those for output.

                                      I would also add a caution here that anybody who is inexperienced with this
                                      stuff be real careful about sticking your hands inside of that box,
                                      especially with power applied -- there are parts in there with 300V+ on them!

                                      I don't know if anything earlier than an ATX supply would have 3.3V on an
                                      output, though I suppose it's possible. AT-type supplies should be
                                      available for next to nothing anyway, since not all that many people are
                                      using such stuff any more.

                                      And how about using old PC cases for projects?

                                      <...>

                                      > If you have the money, get a scope. How much it would have helped me back
                                      > then....

                                      Yes. For a beginner nothing fancy is needed, though it helps if it's DC
                                      coupled and calibrated, as compared to the old AC couple audio-only stuff I
                                      used way back when. (Which was still better than nothing.)

                                      > Also, i have once written a list of basic parts you need for someone who
                                      > asked, i think it is in the files section.

                                      One of the advantages of scrapping out a lot of stuff -- you get a fair amount
                                      of stuff that's _used in the industry_, rather than a complete inventory
                                      with parts in it that'll never get used. :-)
                                    • Stefan Trethan
                                      On Tue, 1 Feb 2005 14:33:16 -0500, Roy J. Tellason ... I simply used a 12V 10W (or so) car bulb acros 5V, worked well and need no cooling. ... Yes, 5 or 6 4mm
                                      Message 18 of 27 , Feb 1, 2005
                                        On Tue, 1 Feb 2005 14:33:16 -0500, Roy J. Tellason
                                        <rtellason@...> wrote:

                                        >
                                        > To this I will add that most of these supplies need some minimum load on
                                        > them
                                        > to work properly. The best setup I've seen (and I unfortunately can't
                                        > remember where I saw it) had a 10 ohm 10 watt resistor wired into the
                                        > unit
                                        > across the +5V output and mounted on the case in such a way that the
                                        > airflow
                                        > from the fan would go right across it, keeping it cool.

                                        I simply used a 12V 10W (or so) car bulb acros 5V, worked well and need no
                                        cooling.


                                        > The other thing that site did was to remove the wires coming out and
                                        > mount
                                        > sets of binding posts in the case, using only those for output.

                                        Yes, 5 or 6 4mm terminals with "screw down wire clamp" mechanism are great
                                        here, you simply clamp wires which go to the breadboard.

                                        > I would also add a caution here that anybody who is inexperienced with
                                        > this
                                        > stuff be real careful about sticking your hands inside of that box,
                                        > especially with power applied -- there are parts in there with 300V+ on
                                        > them!

                                        agreed. Don't mess around with switchmode supplies for a long, long time,
                                        they are much more dangerous than normal line voltage, also because they
                                        have parts that store the high voltage.

                                        > I don't know if anything earlier than an ATX supply would have 3.3V on an
                                        > output, though I suppose it's possible. AT-type supplies should be
                                        > available for next to nothing anyway, since not all that many people are
                                        > using such stuff any more.

                                        I have seen 3V3 on few non-atx supplies, but rare.

                                        > And how about using old PC cases for projects?
                                        > <...>

                                        too big, too...


                                        > One of the advantages of scrapping out a lot of stuff -- you get a fair
                                        > amount
                                        > of stuff that's _used in the industry_, rather than a complete inventory
                                        > with parts in it that'll never get used.

                                        Well, i only agree partially. I do not believe one can get by with only
                                        scrapped parts. With the component prices, i do not see the value in a
                                        resistor with clipped leads which need soldered extensions to work in the
                                        breadboard. It just can get tedious to hunt for used parts at times,
                                        especially if you try to copy web-schematics, at the beginning you don't
                                        know what to substitute with.
                                        Too often the industry uses solutions you have not much use for.

                                        I suggest buying the cheap parts, and desoldering the expensive ones. Not
                                        too tedious and not too expensive.. well.. that's what i did anyway..

                                        ST
                                      • rtstofer
                                        ... been ... selection. ... about ... never ... curiosity ... that used those ... I haven t seen RTL or DTL in years and years. I think by the early 70s TTL
                                        Message 19 of 27 , Feb 1, 2005
                                          --- In Electronics_101@yahoogroups.com, "Roy J. Tellason"
                                          <rtellason@b...> wrote:
                                          > On Tuesday 01 February 2005 02:02 pm, rtstofer wrote:
                                          > > For components including grab bags, try www.jameco.com. I have
                                          been
                                          > > buying from them off and on for 20 years. Digikey is probably my
                                          > > favorite source - www.digikey.com. They have an enormous
                                          selection.
                                          >
                                          > Indeed they do. I've used both companies, and have no complaints
                                          about
                                          > either of them.
                                          >
                                          > > I started getting serious about this stuff around 1969. I was
                                          never
                                          > > interested in analog (still no real interest)
                                          >
                                          > I am!
                                          >
                                          > > but when I found out what I could do with RTL logic circuits my
                                          curiosity
                                          > > picked up and away it went.
                                          >
                                          > OTOH, I can remember a number of fun and interesting projects
                                          that used those
                                          > parts. Are they still around at all anywhere?

                                          I haven't seen RTL or DTL in years and years. I think by the early
                                          70s TTL had taken over the world because it reduced the issues of
                                          fan-in, fan-out and rise-times. But I still have one of my first
                                          books on the topic - "Logic Design With Integrated Circuits" by
                                          William E Wickes published by John Wiley and Sons 1968. It is still
                                          the first thing I reach for when I want to do minimization -
                                          something of a lost art given the size of CPLDs and FPGAs.

                                          >
                                          > > I have played with this stuff for more than 50 years including
                                          my formative
                                          > > years building Heathkit stuff and I still have the VOM,
                                          oscilloscope, freq
                                          > > counter, power supply and probably a few other odds and ends.
                                          Too bad they
                                          > > got out of the business.
                                          >
                                          > I guess the market just wasn't there any more like it used to be,
                                          or
                                          > something.

                                          No, I believe their big market was stereo equipment. The Japanese
                                          pretty much own this market and you don't have to put it together.
                                          I don't know if there is enough of an increase in the number of
                                          people interested in electronics to drive a kit based test equipment
                                          market or not. There is so much used equipment on eBay.
                                        • One Two
                                          My suggestion to becoming a good electrical person is to have a good understanding of physics. This may seem absurd but I know it to be the best. Understand
                                          Message 20 of 27 , Feb 1, 2005
                                            My suggestion to becoming a good electrical person is
                                            to have a good understanding of physics. This may seem
                                            absurd but I know it to be the best. Understand things
                                            liek the electric feild, and even things like Newton's
                                            Laws. Electronics, for the most part, is nothing but a
                                            simple explotation of electrical physics... the
                                            electric feild, capacitors and inductors.
                                          • Roy J. Tellason
                                            ... Good idea, though I guess you need a socket then, and if the bulb burns out you lose your minimum load, though I don t guess that s likely to happen that
                                            Message 21 of 27 , Feb 1, 2005
                                              On Tuesday 01 February 2005 02:47 pm, Stefan Trethan wrote:

                                              > I simply used a 12V 10W (or so) car bulb acros 5V, worked well and need no
                                              > cooling.

                                              Good idea, though I guess you need a socket then, and if the bulb burns out
                                              you lose your minimum load, though I don't guess that's likely to happen
                                              that soon running off the +5...

                                              <...>

                                              > > And how about using old PC cases for projects?
                                              > > <...>
                                              >
                                              > too big, too...

                                              Depends on how ambitious your project it. :-) Perhaps those low-profile
                                              cases would be more useful. I know that i use the PS from one of those for a
                                              lot of testing purposes, it's *much* smaller than the usual size.

                                              > > One of the advantages of scrapping out a lot of stuff -- you get a fair
                                              > > amount of stuff that's _used in the industry_, rather than a complete
                                              > > inventory with parts in it that'll never get used.
                                              >
                                              > Well, i only agree partially.

                                              I expected no different. :-)

                                              > I do not believe one can get by with only scrapped parts.

                                              I didn't mean to imply that you could. But it can go a long way, for casual
                                              messing around.

                                              > With the component prices, i do not see the value in a resistor with clipped
                                              > leads which need soldered extensions to work in the breadboard.

                                              None of them are *that* short!

                                              > It just can get tedious to hunt for used parts at times, especially if you
                                              > try to copy web-schematics, at the beginning you don't know what to
                                              > substitute with.

                                              Depends on how well organized your salvage is. I'm not as well organized as I
                                              used to be, but I have a *lot* of parts in small boxes, etc. and which are
                                              listed in a card file. Goes all the way back to 1977!

                                              > Too often the industry uses solutions you have not much use for.

                                              Too true.

                                              > I suggest buying the cheap parts, and desoldering the expensive ones. Not
                                              > too tedious and not too expensive.. well.. that's what i did anyway..

                                              Whatever works. Which is going to be somewhat different for everyone.
                                            • Roy J. Tellason
                                              ... I suspect that a lot of the hobby-type projects that used these were because they were available in the surplus market... ... I think it was 1970 I first
                                              Message 22 of 27 , Feb 1, 2005
                                                On Tuesday 01 February 2005 03:32 pm, rtstofer wrote:

                                                > > > but when I found out what I could do with RTL logic circuits my
                                                > > > curiosity picked up and away it went.
                                                > >
                                                > > OTOH, I can remember a number of fun and interesting projects
                                                > > that used those parts. Are they still around at all anywhere?
                                                >
                                                > I haven't seen RTL or DTL in years and years.

                                                I suspect that a lot of the hobby-type projects that used these were because
                                                they were available in the surplus market...

                                                > I think by the early 70s TTL had taken over the world because it reduced the
                                                > issues of fan-in, fan-out and rise-times.

                                                I think it was 1970 I first ran into it.

                                                > But I still have one of my first books on the topic - "Logic Design With
                                                > Integrated Circuits" by William E Wickes published by John Wiley and Sons
                                                > 1968. It is still the first thing I reach for when I want to do
                                                > minimization - something of a lost art given the size of CPLDs and FPGAs.

                                                A lot of the simpler tricks that used to be pretty common are a lost art any
                                                more, they don't teach it in the tech schools and colleges, and the folks
                                                coming into the field just aren't aware of a lot of this stuff.

                                                <...>

                                                [Heathkit...]

                                                > No, I believe their big market was stereo equipment.

                                                Really? That's interesting. I was actually in a couple of their stores, way
                                                back when, looking for employment. One was in NYC and one was in Frazier,
                                                PA. I honestly don't recall what was in those stores, it was so darn long
                                                ago, and I can't remember the last time I saw one of their catalogs...

                                                > The Japanese pretty much own this market and you don't have to put it
                                                > together.

                                                Yep, and for TVs and such the Koreans and even China is making some
                                                nontrivial inroads. There almost isn't much of a domestic electronics
                                                industry any more, at least not for consumer stuff.

                                                > I don't know if there is enough of an increase in the number of
                                                > people interested in electronics to drive a kit based test equipment
                                                > market or not. There is so much used equipment on eBay.

                                                Yes. I suspect that used stuff was always out there, but it sure is easier
                                                to find it these days.
                                              • Stefan Trethan
                                                On Tue, 1 Feb 2005 23:35:53 -0500, Roy J. Tellason ... Nah i simply soldered wires to it, which held it in place under the 4mm terminals. A 12V bulb at 5V
                                                Message 23 of 27 , Feb 1, 2005
                                                  On Tue, 1 Feb 2005 23:35:53 -0500, Roy J. Tellason
                                                  <rtellason@...> wrote:

                                                  >
                                                  > On Tuesday 01 February 2005 02:47 pm, Stefan Trethan wrote:
                                                  >
                                                  >> I simply used a 12V 10W (or so) car bulb acros 5V, worked well and need
                                                  >> no
                                                  >> cooling.
                                                  >
                                                  > Good idea, though I guess you need a socket then, and if the bulb burns
                                                  > out
                                                  > you lose your minimum load, though I don't guess that's likely to happen
                                                  > that soon running off the +5...

                                                  Nah i simply soldered wires to it, which held it in place under the 4mm
                                                  terminals.
                                                  A 12V bulb at 5V isn't going to burn out while we are still here ;-).



                                                  >
                                                  >> With the component prices, i do not see the value in a resistor with
                                                  >> clipped
                                                  >> leads which need soldered extensions to work in the breadboard.
                                                  >
                                                  > None of them are *that* short!

                                                  Well, that depends on your breadboarding preferrence.
                                                  There is the "flat" type and the "3D" type.
                                                  Some prefer to lay down the parts and wires flat like on a pcb (or solder
                                                  breadboard) and some prefer to make big loops that stick up in the air.
                                                  With a used resistor you are limited to the pitch it was used with (or
                                                  close). A new resistor goes anywhere from 100mil to what? 2000mil or so.
                                                  That means i need much less wires because the resistor goes directly from
                                                  e.g. IC pin to IC pin.
                                                  If you are worried about shorts you can slide lengths of wire isolation on
                                                  the component legs.(but i never had a destructive short.)

                                                  >
                                                  >> It just can get tedious to hunt for used parts at times, especially if
                                                  >> you
                                                  >> try to copy web-schematics, at the beginning you don't know what to
                                                  >> substitute with.
                                                  >
                                                  > Depends on how well organized your salvage is. I'm not as well
                                                  > organized as I
                                                  > used to be, but I have a *lot* of parts in small boxes, etc. and which
                                                  > are
                                                  > listed in a card file. Goes all the way back to 1977!

                                                  That might be, but i can not have as many small boxes as my parts
                                                  supplier. Even if i could, there are some parts i use which i __KNOW__ are
                                                  in no PCB i have or know where to find.
                                                  I just don't want to be restricted that much on the component side.
                                                  Also, having to make a differnt footprint for many different versions of
                                                  the same components isn't worth the saving for me, i like a bit of
                                                  consistency.

                                                  > Whatever works. Which is going to be somewhat different for everyone.
                                                  >
                                                  Like everything.

                                                  ST
                                                • Mario Lopez
                                                  ... As my teachers said, to be an engineer all you have to do is copy, but ALWAYS knowing what you re copying. ______________________________________________
                                                  Message 24 of 27 , Feb 2, 2005
                                                    > > You need experience to design your own circuits,
                                                    > which you gain by
                                                    > > understanding circuits someone else designed. You
                                                    > also need to learn what
                                                    > > each component does. (And i mean what it does in
                                                    > circuit not what happens
                                                    > > internally).


                                                    As my teachers said, to be an engineer all you have to
                                                    do is copy, but ALWAYS knowing what you're copying.



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                                                  • Mario Lopez
                                                    ... On Tuesday 01 February 2005 12:26 pm, ... Shack, it is sort of a ... the things NOT TO DO is ... is to follow directions ... off. :-) When i was
                                                    Message 25 of 27 , Feb 2, 2005
                                                      --- "Roy J. Tellason" <rtellason@...> wrote:


                                                      ---------------------------------
                                                      On Tuesday 01 February 2005 12:26 pm,
                                                      drbillpmt@... wrote:

                                                      >>> 5. Don't get the idea that I own stock in Radio
                                                      Shack, it is sort of a
                                                      >>> universal parts house for experimenters. One of
                                                      the things NOT TO DO is
                                                      >>> buy kits and build them. The only thing you learn
                                                      is to follow directions
                                                      >>> and solder.

                                                      >And _maybe_ troubleshoot when it doesn't work right
                                                      off. :-)


                                                      When i was younger, I built some kits. If the circuit
                                                      did not work, my only mean was suddelndly switch off
                                                      the power supply and inspect the circuit. I couldn't
                                                      have done more, because with no knowledge and no tools
                                                      (only a digital multimeter, but i had no idea where to
                                                      measure) its almost impossible to start testing the circuit.



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                                                    • Stefan Trethan
                                                      On Wed, 2 Feb 2005 17:27:33 +0100 (CET), Mario Lopez ... too right, the kits are often badly described. The do not usually break the task
                                                      Message 26 of 27 , Feb 2, 2005
                                                        On Wed, 2 Feb 2005 17:27:33 +0100 (CET), Mario Lopez <linked82@...>
                                                        wrote:

                                                        >
                                                        > When i was younger, I built some kits. If the circuit
                                                        > did not work, my only mean was suddelndly switch off
                                                        > the power supply and inspect the circuit. I couldn't
                                                        > have done more, because with no knowledge and no tools
                                                        > (only a digital multimeter, but i had no idea where to
                                                        > measure) its almost impossible to start testing the circuit.


                                                        too right, the kits are often badly described. The do not usually break
                                                        the task up in tiny
                                                        pieces and let you debug them.

                                                        The exception is experimenting kits. I got a really good one which was
                                                        very nice.
                                                        I didn't understand all circuits (like the radio receiver) then, but i did
                                                        understand the function
                                                        of each component because it was very well described (water model) and
                                                        when using a diode the first time, they really used _ONLY_ the diode, and
                                                        just what was needed to see it work.
                                                        I think those kits are meant for a certain age, if one starts older they
                                                        may be too basic.
                                                        (Can't hurt, can it?)

                                                        You never know, maybe, if i'd gotten a chemistry kit back then and not an
                                                        electronics kit i might not be writing here.. not likely but you never
                                                        know, those things are powerful....

                                                        Thinking about it, i got something similar to a chemistry kit, and didn't
                                                        even remember at first, so hey, not all that life-deciding....

                                                        ST
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