[TriEmbed] Transistor as switch

Glen Smith mrglenasmith at gmail.com
Mon Jun 15 19:09:39 CDT 2015


Brian,

I think there is value in starting with the wimpy transistor to control
some small stuff, then moving to the darlington pair transistor to control
some bigger current draws, (Simplified, a Darlington pair is a transistor
controlled by another transistor) then use one motor to turn another motor
and watch what happens to the terminals of the driven motor - you just made
a generator. Which is all well and good, but what does it do to that poor
darlington pair transistor that is always expecting a positive voltage from
here to there? Because when the transistor turns off, the motor keeps
spinning for a bit and generates a reverse voltage. So now you add a
snubber diode that will take care of that, and it just so happens that the
next step up the ladder is a MOSFET, which usually takes care of the
reverse or transient voltage protection for you, and can handle higher
currents for bigger loads.

The book may not cover it, but you can still mention it as an option.

Glen

On Mon, Jun 15, 2015 at 7:51 PM, Grawburg via TriEmbed <
triembed at triembed.org> wrote:

> Pedantic?   When I post questions I expect some answers will be short and
> some will be longer. I'm also quite able to take the occasional, "you
> should know the answer...think".
>
> I want information, and analogies (although I've never cut a sweet gum
> tree) are often more helpful than a more technical explanation.
> Pedantic?  Not a chance.  :-)
>
>
> Brian
>
>
> -----Original Message-----
> > From: "Pete Soper via TriEmbed" <triembed at triembed.org>
> > To: triembed at triembed.org
> > Date: 06/15/15 07:27 PM
> > Subject: Re: [TriEmbed] Transistor as switch
> >
> > OK, this came across very pedantic. Sorry, Brian! There have got to be
> > better analogies out there, and I've now established the benchmark for
> > crap in this regard.
>
>
>
>
>
>
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