Darren Reid wrote:
>
> Hmm. Did you build it straight from the app notes, or some other schematic?
> Can you point us to the schematic you used, somewhere on the web? The hiss
> might be from lack of a true ground...

Thanks for this (and thanks to Joshua too. The amp in question is part
of:
http://www.radiohc.org/Distributions/Dxers/dsratregen.html

Dominic
--

http://dominic.rivron.tripod.com

http://www.thehungersite.com

Hmm. Did you build it straight from the app notes, or some other schematic?
Can you point us to the schematic you used, somewhere on the web? The hiss
might be from lack of a true ground...

I'm new to the world of electronics myself. I have successfully built an
LM386 amp, though....I think I used a mish mash of app notes and general
opamp theory to come up with my schematic, and I didn't get any hum or
oscillation. I *did* get nasty clipping artifacts when I turned up the
volume on my guitar :)

I built it in an empty 10-pack diskette box, BTW. They make rather
convenient small project boxes.

-Darren

----- Original Message -----
From: "Dominic Rivron" <karen.rivron@...>
To: <Electronics_101@yahoogroups.com>
Sent: Monday, April 16, 2001 6:55 PM
Subject: [Electronics_101] LM386 amp


> I've just built an audio amplifier using an LM386, and found that though
> it amplifies, there is an annoying level of backgound hiss, irrespective
> of the volume setting or input. Also, it tends to oscillate at full
> volume. Can anyone offer any suggestions?
>
> regards
> Dominic Rivron
> --
>
> http://dominic.rivron.tripod.com
>
> http://www.thehungersite.com
>
>
> To unsubscribe from this group, send an email to:
> Electronics_101-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>

Hi all

Great site, and just about at my level being fairly new at this
game.  I am a pretty keen radio monitor on both VHF and UHF as well
as HF.  I am very keen to get my hands on a circuit for a RF preamp
for VHF,  I know they can be purchased ready made but this would be
my first project if I built it myself.  I got a circuit for a mast
head preamp from http://hem.passagen.se/sm0vpo/antennas/preamp-0.htm
but I would Idealy prefer one that I can use next to the radio.  Also
I have searched the catalogues for a transister BFY91 without
success, can another be used in its place?

If anyone has a circuit for a preamp or knows a site were I can get
one, or even a modification of the one I mentioned I would realy
appreciate the info.

Roger Harrison

If I'm not mistaken, there's a +15V gain on the LM386.... I think I read
this from National Semiconducter's PDF file on constructing sine wave
shapers...look on google, in the PDF file there's a couple of good
alternatives that don't suffer from the noise pickup.

Joshua

----
"I'm not a slave to a world that doesn't give a shit."
Pulse 8 - aim:jkerseyVCSO
http://www.goodtimetribe.com


----- Original Message -----
From: "Dominic Rivron" <karen.rivron@...>
To: <Electronics_101@yahoogroups.com>
Sent: Monday, April 16, 2001 4:55 PM
Subject: [Electronics_101] LM386 amp


> I've just built an audio amplifier using an LM386, and found that though
> it amplifies, there is an annoying level of backgound hiss, irrespective
> of the volume setting or input. Also, it tends to oscillate at full
> volume. Can anyone offer any suggestions?
>
> regards
> Dominic Rivron
> --
>
> http://dominic.rivron.tripod.com
>
> http://www.thehungersite.com
>
>
> To unsubscribe from this group, send an email to:
> Electronics_101-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

I've just built an audio amplifier using an LM386, and found that though
it amplifies, there is an annoying level of backgound hiss, irrespective
of the volume setting or input. Also, it tends to oscillate at full
volume. Can anyone offer any suggestions?

regards
Dominic Rivron
--

http://dominic.rivron.tripod.com

http://www.thehungersite.com

There are a lot of different ways to do this.  You can
spend a lot of money and not so much time, or a lot of
time and save some money.

PLCs (Programmable Logic Controllers) are well suited
for this sort of thing.  They will take in data from
your transducers and come equipped with all kinds of
switching relays and analog outputs.  Look at

automationdirect.com

If you are planning on making money off this venture
and can't afford to be screwing around with things
that don't work for whatever reason, that is the best
way to go.

Altenatively you could buy a microcontroller kit,
learn to program it and get some D/A converters for
your signals, but you will probably spend a bunch of
cash on that too.

I do data acquisition and control with a program
called LabVIEW, that runs on a PC.  It costs $3000 and
it lets you do all the PLC stuff, but with user
interfaces and a graphical programming language.

Omega.com is a good place for industrial transducers.

Another thought is to post to a hydroponics group.
They do exactly what you are doing but for hundreds of
acres of hothouse vegetables.
=]
Matt Hill

--- paksao@... wrote:
> Hi I am a new guy here and to electronics. But I'm
> hoping to learn
> enough to complete some projects I have in mind.
>
> I'm interested in setting up a system that will
> control a vivarium
> temperature humidity, lights pumps , etc and do it
> based not only on a
> schedule (ex mist 3 times a day) but also on the
> current conditions(
> ex too hot -> mist run fans,cut some lights). I know
> I have a long way
> to go before I could build it from scatch.  So the
> plan is to learn
> the individual pieces then put them together.
>
> some of the parts I need
>
> build a circuit to control a relay to turn on and
> off a light or pump.
> build a circuit to monitor and display temp
> build a circuit to monitor and display humidity
> build a circuit to monitor and store temp ( probably
> need a pic or pc)
> build a circuit to monitor and store humidity (
> probably need a pic or
> pc )
> ...
> ...
>
> Any suggestions on where to get started?
>
> I already have some basic soldering skills and
> programming skills but
> i need to do a lot more.
>
> Hope fully I can start to pick up some of what I
> need here
>
>
>


__________________________________________________
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Get email at your own domain with Yahoo! Mail.
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--- In Electronics_101@y..., justsuem@p... wrote:
> a friend of mine is looking for a weller 12 volt soldering iron and
> the serch hasnt turned up anything. if any one knows where to order
> on it would be a big help.   73  kb9yet

Check out http://www.mouser.com. I did a search using 'weller' and
'soldering iron' and there was a really big list of items. I don't
know if they have a 12 volt version. It would be worth checking out.
They also have a paper catalogue and a searchable cd-rom.

Hi I am a new guy here and to electronics. But I'm hoping to learn
enough to complete some projects I have in mind.

I'm interested in setting up a system that will control a vivarium
temperature humidity, lights pumps , etc and do it based not only on a
schedule (ex mist 3 times a day) but also on the current conditions(
ex too hot -> mist run fans,cut some lights). I know I have a long way
to go before I could build it from scatch.  So the plan is to learn
the individual pieces then put them together.

some of the parts I need

build a circuit to control a relay to turn on and off a light or pump.
build a circuit to monitor and display temp
build a circuit to monitor and display humidity
build a circuit to monitor and store temp ( probably need a pic or pc)
build a circuit to monitor and store humidity ( probably need a pic or
pc )
...
...

Any suggestions on where to get started?

I already have some basic soldering skills and programming skills but
i need to do a lot more.

Hope fully I can start to pick up some of what I need here

I didn't see an answer to this.  But, mail has been slow through my
server today.  so forgive me if this is a repeat.  "Rails" is a term
that refers to the power supply voltage, often times on a bipolar
power supply.  So, if you have a typical power supply designed for op
amps and such, it might supply +15 VDC and -15 VDC.  Some might
include +5 VDC is there are logic circuits.  These power supply
points are often called the "rails."
Larry Hendry

--- jpotter2@... wrote:
> What does "rails" mean?
>
> For example:
>
> "5V at the rails"
>
> "rail to rail amplifiers"
>
> "As for current delivery, most will do a few milli-amps, but
> typically not near the rails"
>
> "an opamp with a symmetric output swing at each rail"
>
> "as long as your supply rails were properly adjusted."
>
> "This pretty much slams the square right up to the rails"
>
> Thanks,
>
> JP


__________________________________________________
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Get email at your own domain with Yahoo! Mail.
http://personal.mail.yahoo.com/

a friend of mine is looking for a weller 12 volt soldering iron and
the serch hasnt turned up anything. if any one knows where to order
on it would be a big help.   73  kb9yet

>What does "rails" mean?
>
>For example:
>
>"5V at the rails"
>
>"rail to rail amplifiers"

Unless I'm mistaken (I'm still learning here), the rails are the
maximum and minimum voltages the amplifier can go to.  Whether it's
single ended or double ended (one transistor, or two doing push
pull), and what the supply DC voltage is will determine this.  Of
course, by the time you get to the 'rails' you've really distorted
your signal...but that's good, to me.  Many amplifiers are more
efficient and distort the least with lower outputs.  I like to turn
things up to eleven though.  But not for guitars.  Look at what your
DC supply voltage is, and that's probably the peak to peak output
voltage of the amplifier, though it can be less than that depending
on the circuit.  In fact, it probably will be.

But I may have no idea what I'm talking about.

-Tavys

What does "rails" mean?

For example:

"5V at the rails"

"rail to rail amplifiers"

"As for current delivery, most will do a few milli-amps, but
typically not near the rails"

"an opamp with a symmetric output swing at each rail"

"as long as your supply rails were properly adjusted."

"This pretty much slams the square right up to the rails"

Thanks,

JP

In a message dated 3/31/01 10:40:24 AM, Electronics_101@yahoogroups.com
writes:

<< I think you must choose a power resistor
which can be used at high watts, because you are
driving a motor.Good-luck.. >>

The power rating of the resistor is dependent on how much current the motor
draws during operation. There's usually a spike in the current when the motor
is first turned on, because it has to overcome inertia to start moving. But
this is the resistor in the charger, correct? If so, it might not even be
connected to the motor, and more likely is some sort of current limiting
resistor to control the charge rate of the battery.

Chris

Yes you must use the resistor having the same color
codes but you must be aware of the power passing over
the resistor. I think you must choose a power resistor
which can be used at high watts, because you are
driving a motor.Good-luck..
                             ERDEM


__________________________________________________
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Get email at your own domain with Yahoo! Mail.
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Check it out...

http://www3.ncsu.edu/ECE480/

I also put it in the "Bookmarks" section of egroups/Electronics_101
along w/ another link.

Dan - you might want to stick your circuit page over there as well.

See ya.

JP

the resistor should have a set of bands in a color pattern on it, just get
one that matches that color pattern and replace.

Joshua

----
"A meow massages the heart."
Pulse 8 - aim:jkerseyVCSO
http://www.goodtimetribe.com



----- Original Message -----
From: <justsuem@...>
To: <Electronics_101@yahoogroups.com>
Sent: Wednesday, March 28, 2001 12:42 PM
Subject: [Electronics_101] b&d charger schematics


> i have a black and decker 12v cordless drill and a resistor burnt out
> in the charger and i need to know what kind of resistor is needed. if
> anyone knows  what i need please get back to me.
>
>
>
> To unsubscribe from this group, send an email to:
> Electronics_101-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

i have a black and decker 12v cordless drill and a resistor burnt out
in the charger and i need to know what kind of resistor is needed. if
anyone knows  what i need please get back to me.

Hello everyone,

I have created a website, called the Public Electronics Circuit
Archive, where people can submit their own electronics circuits,
designs and ideas for others to look at, build, modify or redesign to
their heart's content.

No-one gets paid, anyone can use it, and every circuit and idea
becomes free-gratis public property, so everyone benefits.

The circuits will be categorised, (currently 13 categories from Audio
to Toys), and there is a public forum for electronics hints and tips
that spring to people's minds from time to time. I think it would be
a great addition to Ian's electronics list!

So, if you would like to take a look (no circuits yet - get
designing!!), please visit, http://www.publicelectronics.cjb.net

Thanks and Regards,

Dan Bartlett
Public Electronics Circuit Archive Webmaster

Hi Thomas, have been using EAGLE 4.01 light for quite some time. It is
excellent, with extensive
symbol libraries, together with DRAFTCAD from "http://www.illuminated.com.au",
[not available in lighy or demo], but I have never used the Circuit Board
part of any of them,
preferring to hardwire the one off jobs that I do from time to time, unless
I would do something from a kit that includes the printed circuit board as
well.

                                                                                         
Regards,
Steve

At 08:33 PM 3/22/01 +0000, you wrote:
>--- In Electronics_101@y..., erdem ulukan <erdemulukan@y...> wrote:
> > Dear Thomas,
> > You can use BOARDMAKER Program to convert schematics
> > to a circuit board. You must modify the board because
> > it doesn't work properly and can't give the right
> > answer. But it can give a design idea :)
> >
> >                        ******ERDEM*********
>Where can I get BoardMaker?
>
>I found software from http://www.cadsoft.de/http://www.cadsoftusa.com
>that has a program called Eagle CAD. It was free for/to hobbiest.
>Have you heard about/know anything about it?
>
>
>
>To unsubscribe from this group, send an email to:
>Electronics_101-unsubscribe@yahoogroups.com
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

--- In Electronics_101@y..., tipf_1@y... wrote:
> --- In Electronics_101@y..., "Thomas Lee Mullins" <tomleem@a...>
> wrote:
> > Is there a book on schematic symbols? I have schematics for a
> > TI-99/4A and trying to create a circuit board using software from
> > exprespcb (http://www.exprespcb.com [IIRC]).
>
> Yes, you can go into any radio shack and pick one up for about $5.
> Plus some ok basic electronic books.

Thanks for the information. They are also in the Radio Shack
catalogue (I didn't think of looking until you posted your message).
They might even have them at their web site (which is
http://www.radioshack.com) but I didn't think of looking there
until just now.

--- In Electronics_101@y..., erdem ulukan <erdemulukan@y...> wrote:
> Dear Thomas,
> You can use BOARDMAKER Program to convert schematics
> to a circuit board. You must modify the board because
> it doesn't work properly and can't give the right
> answer. But it can give a design idea :)
>
>                        ******ERDEM*********
Where can I get BoardMaker?

I found software from http://www.cadsoft.de/http://www.cadsoftusa.com
that has a program called Eagle CAD. It was free for/to hobbiest.
Have you heard about/know anything about it?

Dear Thomas,
You can use BOARDMAKER Program to convert schematics
to a circuit board. You must modify the board because
it doesn't work properly and can't give the right
answer. But it can give a design idea :)

                        ******ERDEM*********

--- Thomas Lee Mullins <tomleem@...> wrote:
> Is there software that can convert schematics to a
> circuit board
> design? I have some schematics that I want to see if
> I can make
> a circuit board from (perhaps to 'recreate' the
> device that
> schematics are of).
>
>


__________________________________________________
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Get email at your own domain with Yahoo! Mail.
http://personal.mail.yahoo.com/

So I'll just get right into it.  I'm currently on transistor
amplifiers.  We haven't gotten to push-pull stuff yet, or any IC
opamp stuff, so I'm sure my questions will be answered in class
later.  But I'm impatient.

If anyone here knows a bit more about this stuff please speak up.

If I understand this correctly, common emitter amplifiers are for
voltage gain, common collector amplifiers are for current gain and
impedence matching, and common base amplifiers are used for their low
input capacitance and therefore better frequency response.  So if I
string these together, I'd just end up with both voltage and current
gain with better low frequency response, right?

And for push pull stuff, do I need to have both positive and negative
power supply (with respect to ground) and use both npn and pnp
transistors or is there another way?  With single transistor common
emitter amplifier stuff I've done in lab so far I've seen the
waveform distortion of a sine wave amplified to cutoff voltage, so if
I put another common emitter in after this using the opposite
transistor type and opposite power supply, would I get distortion
spikes in the opposite direction?  I'm interested in perhaps making
my own audio effects circuits.  I've seen lots of schematics on line,
but not a lot of technical description to go with them.

That's all for now I guess.  More to come.

-Tavys

Hi, I just joined this group.  I was actually thinking of starting my
own, but I found this one.  I'm taking electronics classes and
 

Hi Tavys,

          Good to see you join. The groups a bit quite at the moment, so send as many people as you want this way, the more the merrier, And the more we will all learn........     Hope to hear from you shortly........

)O(  )O(  )O(  )O(  )O(  )O(  )O(  )O(  )O(  )O(  )O(  )O(  )O(  )O(  )O(  )O(

     The Sinister Dragon
        (Moderator)
 

Hey, Just becuase I'm EVIL,
     Doesn't make me a bad person......

Visit My sites at Geocities:
  Blood Mood - http://www.geocities.com/evil_trinity666/index.html
  Little Herbal - http://www.geocities.com/tanacetum_vulgare/index.html

Join my Egroup:
  Inverted Pentagram - http://www.egroups.com/group/Inverted_Pentagram
 

Hi, I just joined this group.  I was actually thinking of starting my
own, but I found this one.  I'm taking electronics classes and
learning a lot, but have found very little tutorial information
online that I find useful.  I figure that as I learn stuff perhaps I
could make tutorials and hopefully there's people on this list that
know more about stuff than me.  I've just gotten to common
emitter/collector/base circuits in my semiconductor theory class, and
I can't wait to get to ICs.

I'm on another list called 'benders' which is for people who are
interested in modifying toys (casio keyboards, speak and spells, etc)
to make sounds they were not intended to make.  I may direct some of
the people this way as some of the discussions on the list have gone
more into the area of theory than just simple modifications to toys.

So who all is here and what do you do with electronics?

-Tavys

--- In Electronics_101@y..., "Thomas Lee Mullins" <tomleem@a...>
wrote:
> Is there a book on schematic symbols? I have schematics for a
> TI-99/4A and trying to create a circuit board using software from
> exprespcb (http://www.exprespcb.com [IIRC]).

Yes, you can go into any radio shack and pick one up for about $5.
Plus some ok basic electronic books.

I'm glad to see some people joining and using the group. As you can
see, things arn't exactly super busy yet, but spread the word, I'm
sure we can get some discusion going, and thats what it's all about
after all.....    Hope to get the Electronics 101 web page up and
running very soon, will have a basic tute on electronics princables
and some link in general to electronics pages of intrest........
Will speak to you all soon I hope.......

           The Sinister Dragon.....
               (Moderator)

Is there software that can convert schematics to a circuit board
design? I have some schematics that I want to see if I can make
a circuit board from (perhaps to 'recreate' the device that
schematics are of).

Is there a book on schematic symbols? I have schematics for a
TI-99/4A and trying to create a circuit board using software from
exprespcb (http://www.exprespcb.com [IIRC]).