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Fw: [DPRG] emitter/collector/base

Subject: Fw: [DPRG] emitter/collector/base
From: R. Bickle rbickle at swbell.net
Date: Fri Jul 27 10:20:47 CDT 2001

I agree with Dave here.

I love the "Art of Electronics" book, It's my electronics bible. However I
think some of the more basic references will be more beneficial to you now.
A little time spent now understanding the basics of passive devices,
transistor theory, and possibly 3 terminal regulators will save you loads of
frustration and confusion later on.

If enough people are interested, I would be glad to help with transistor
theory and such after one of the meetings.

Rick Bickle


-----Original Message-----
>From: dprglist-admin at dprg.org [mailto:dprglist-admin at dprg.org]On Behalf
Of David Peterson
Sent: Thursday, July 26, 2001 5:05 PM
To: Mike McCarty; montgomery f. tidwell
Cc: Dallas Personal Robotics Group
Subject: Re: Fw: [DPRG] emitter/collector/base


Actually the LM2940 is supposed to be a LDO drop in replacement for the
780x, just as easy to use. Supply a voltage just 0.5 volts above the
required, add caps on the input and output in a similar manner as you would
on a 780x and you've got a basic regualted supply capable of the same
currents, but dropping out at a lower required  voltage. Spec sheets at
http://www.national.com/pf/LM/LM2940.html
And Montgomery, you really should check out the link I posted earlier with
elementary electronics info at
http://www.botic.com/rutherfordrobotics/electronics/index.html and click the
transistor box from the electronics menu. More info can be had through
Forest Mimms books at Radio Shack or through one huge tome I love called the
Art of Electronics by Horowitz and Hill. A transistor has many uses and
possibilities, so it's a bit much to try and cover in an email. You can get
away with one supply on a robot, if individual components (motors) don't
pull heavy amounts of current.

David P
http://www.geocities.com/robodave2000/
----- Original Message -----
>From: "Mike McCarty" <jmccarty at ssd.usa.alcatel.com>
To: "montgomery f. tidwell" <mtidwell at practicalmatters.com>
Cc: "Dallas Personal Robotics Group" <dprglist at dprg.org>
Sent: Thursday, July 26, 2001 12:54 PM
Subject: Re: Fw: [DPRG] emitter/collector/base


> On Thu, 26 Jul 2001, montgomery f. tidwell wrote:
>
> > Howdy,
> >
> > well, i still don't know how emitter/collector/base relate to input/
> > output/ground.
> >
> > however, what i have gleaned is: (a) if the pins are labeled e/c/b, it's
> > not the part that i want/need, and (b) a1015/nte290a is not a power
> > regulator (or not one that meets my needs)
> >
> > so, for my needs i just need to go out and get a lm7805, or lm2940,
> > correct?
>
> The terms Emitter, Collector, and Base relate to transistors. A
> transistor is a basic electronics device.
>
> What you want/need is not a transistor, you need a voltage regulator.
> The integrated voltage regulators have *many* transistors inside them,
> all made from one crystal.
>
> The LM7805 needs at least 2.5V more on the input than on the output.
> Since the LM7805 regulates to 5V, it needs a minimum of 7.5V on the
> input at all times. Since you say that you cannot guarantee that, an
> LM7805 does not satisfy your needs.
>
> Using the LM2940 is not simple, and I would not recommend it for a
> neophyte. It isn't all that difficult, but requires much more support
> circuitry than the LM7805, including some specialized parts.
>
> I suggest, as have others, that you reconsider having the motors run by
> the same batteries as the control electronics package. Then you could
> guarantee the 7.5V needed by the LM7805, which is very easy to use. In
> fact, you probably could use an LM78L05, which is a smaller device and
> easier to mount.
>
> Mike
> --
> char *p="char
*p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
> This message made from 100% recycled bits.
> I can explain it for you, but I can't understand it for you.
> I don't speak for Alcatel      <- They make me say that.
>
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