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Re: [Electronics_101] Re: Point me into the right direction please.

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  • 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 1 of 27 , Feb 1, 2005
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      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 2 of 27 , Feb 1, 2005
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        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 3 of 27 , Feb 1, 2005
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          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 4 of 27 , Feb 2, 2005
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            > > 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 5 of 27 , Feb 2, 2005
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              --- "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 6 of 27 , Feb 2, 2005
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                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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