# Thevenin voltage and resistance

1. Oct 22, 2009

### yoamocuy

1. The problem statement, all variables and given/known data
Calculate the Thevenin voltage Vt and the Thevenin resistance Rt.

2. Relevant equations
V=(Vt*R)/(Rt+R)

I=Vt/(Rt+R)

3. The attempt at a solution
I'm thinkin that my R is 1 ohm but I can't figure out how to simply the rest of the resistors to get Rt. If I can get Rt, then I can solve for Vt. Is my thinking correct or am I completely off? I've attached a picture of the diagram. Any input would be great, thanx.

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2. Oct 22, 2009

### vk6kro

The resistor across the battery is not part of the problem. Someone's little joke.

To get the Thevenin voltage, work out the open circuit voltage across the terminals a and b.

To get the Thevenin resistance, calculate the current that would flow if you short circuited the output. Then divide the Thevenin voltage by this current to get the Thevenin resistance.

Alternatively, you can "look" into the terminals and replace the battery with a short circuit. The resistance you "see" when you do this is the Thevenin resistance.