# Super P & Thevenins

Discussion in 'General Electronics Chat' started by Pinky Ringz, Nov 12, 2009.

1. ### Pinky Ringz Thread Starter New Member

Oct 4, 2009
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I am a first year electrical student and the only classed I missed so far (had a funeral to attend) was the one where they introduced Thevenin's Theorem. Can someone explain to me what I am trying to do when I have to "Thevenize" a circuit? I've been going through the motions but don't know why i'm shorting power sources and parallelling resistors and stuff.

Super P i'm just not really clear on. If someone could dumb it down for me I'm sure it will "click"!

Thanks for your help if you can!

2. ### hgmjr Moderator

Jan 28, 2005
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By super P, are you referring to superposition?

hgmjr

3. ### Pinky Ringz Thread Starter New Member

Oct 4, 2009
6
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yeah, my instructor just calls it super-p but super position is what i was referring too.....i'm looking for a quick rundown if possible..an overview you might say of the theory behind it....I would post a question from class to rip apart but i thought i would ask for an overview first...like a basic rundown on it or whatever...thanks!

4. ### KL7AJ AAC Fanatic!

Nov 4, 2008
2,043
292

Here's the Superposition Theorem in one easy sentence:

"At any point in time, at any location in a circuit, one and only one voltage may exist."

Though this seems so obvious that it doesn't need statiing (a truism of the first degree) the implications of this are profound. Without superposition, we would not be able to transmit complex waveforms over a wire....or through space, for that matter.

Eric

5. ### Pinky Ringz Thread Starter New Member

Oct 4, 2009
6
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So THAT'S what i'm trying to find out....thanks!!

6. ### KL7AJ AAC Fanatic!

Nov 4, 2008
2,043
292

No problem! Your bill is in the mail.

7. ### hobbyist Distinguished Member

Aug 10, 2008
773
62
Thevenizing a circuit.

You are making a equivavalent circuit using one voltage source and one impedance to act with the same function as the entire network. (only linear networks allowed)

Simple example.

2 resistor voltage divider, each with 10K ohms. across a 10 volt battery.
Find an equivalent voltage for the voltage that is measured between these 2 resistors.

Thevenizing means

The voltage measured would be 5V.
So the tevenin voltage is 5V.

Then the parrallel combination of the two 10K ohm resistors, would be 5K ohms.
So your thevenin resistance is 5K ohms.

So now you draw up a circuit with a 5V. source in series with a 5K ohm resistor,

and this represents the entire network function, as you took the physical measurements.