# Homework Help: Thevenin equivalent of resistor only circuit

1. Jun 25, 2014

### bpatyk2

1. The problem statement, all variables and given/known data
Find thevenin equivalent of resistor circuit

2. Relevant equations

3. The attempt at a solution
This may be a dumb question, but does a thevenin equivalent NEED to have a voltage source? On my final exam there was a question that asked for the thevenin equivalent of a circuit that was only resistors. Finding the thevenin resistance was no problem so I just put that resistance in series with a 0V voltage source. Can the thevenin equivalent be just a resistor?

2. Jun 25, 2014

### phinds

Hm ... I think in practical terms it's pretty meaningless to call a resistor network reduced down to one resistor a "Thevenin equivalent" but I suppose technically it is.

3. Jun 25, 2014

### bpatyk2

Yeah that's kinda why I don't see why that type of circuit would be used on an exam to ask for a thevenin equivalent circuit. If there was even one type of independent or dependent source involved i could see the point, but there was none.

4. Jun 26, 2014

### donpacino

The Thevian equivalent circuit is used for giving simple values to complex circuits.

There are many situations where you are going to find the equivalent resistance of a circuit using the thevian theorem, such as finding a circuits input resistance, output resistance, and load. In all of those cases, there will not be any voltage sources on the circuit.

5. Jun 26, 2014

### Su3liminal

I see your point. However, that is pretty common. Think of it as a circuit with 0 V (independent) source.

6. Jun 28, 2014

### Alpharup

Hey,thevinin voltage across which two point? Is it across a resistor? Or any resistor in the network?
I think the question lacks clarity