# Thevenin voltage

1. Jul 14, 2006

### esmeco

I was wondering,how do we calculate the thevenin resistance in a circuit with a load resistor?Do we remove the load?How do we calculate the voltage at the load terminals?

2. Jul 14, 2006

### leright

Well, there are a couple of ways you can calculate the thevenin resistance. The formal way would be to replace the load with an open and then calculate the output voltage there and then to replace the load with a short and then calculate the output current there. The ratio of the calculated V/I is the thevenin resistance.

You can also remove all voltage sources and current sources (short voltage sources and open current sources and then determine the thevenin resistance. You would remove the load resistance.

3. Jul 15, 2006

### rbj

you can compute the thevenin voltage and thevenin resistance by applying two different and known load resistances to the output terminals. often one of those loads is an infinite resistance (then the output voltage is the thevenin voltage), but it doesn't have to be.