[sdiy] Thevenin's and Norton's Theorems

[Ethan Duni]

These theorems are for conceptually replacing a larger circuit with an
equivalent model consisting of a source (either voltage or current) and a
resistance (or more generally an impedence). I believe the theorems
themselves say that this model is totally equivalent (as far as whatever you
hook to the output terminals is concerned) in the case that the circuit is
linear. They're generally used when you're worrying about connecting
circuits together, as they provide a simple, equivalent model of what one
circuit "looks like" to the other one. For example, you might want to match
the input impedence of one circuit to the output impedence of the one
feeding it, so no power is reflected. Then, you don't care that the first
circuit may actually consist of a whole bunch of components arranged in
whichever way, but only what total impedence is "seen" by the second
circuit.
----- Original Message -----
From: "Dustin Withers" <clockwork at softhome.net>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, April 02, 2003 7:49 PM
Subject: [sdiy] Thevenin's and Norton's Theorems


> Ok so I can build kits and read datasheets but I decided to increase my
> knowledge of electricity and since I haven't had a class in many years
I've
> forgotten all the theory.  Anyhow got a book and got through a fair amount
> of it until I got to this Thevenin's and Norton's theory along with
Voltage
> Deviders and Current Deviders.  I figured I won't get very far not
> understanding these theories, so what are they used for?  Are they used
just
> to figure out E-Out off of a tap between to resistors?  I'm sorry this
> question is so vague but I rather confused.  It seems to me you could just
> use Ohm's law to figure out what needs to be and what doesn't.  Am I
wrong?
>
> Thanks :)
>
> -dustin
>