Thevenin Equivalent Circuit

[Kimly]

voltage source= 20V

R1= 5 ohms
R2= 5 ohms
R3= 5 ohms

Find the Thevenin equivalent circuit for the network external to the resistor R

I have replaced R with an open circuit and so the voltage between the open circuit is 10V. Don't know how to go about from there.  Can anyone help me?

 

[Jerome Trent]

Thevenin Equivalent Circuit

The Thevenin Equivalent Circuit is a circuit composed of a voltage source and a series resistance that could replace our circuit and act the same as our circuit. This only applies to linear circuits. It does not work for non-linear circuits.

 
The first step is to remove the Load resistor and calculate the voltage at the open terminals where it was removed. R3 would have no voltage drop across it so we are simply calculating the voltage across R2. Since R1 and R2 are of equal value, it would divide our voltage in half giving us 10volts.

R1 = R2 = R3 = 5 ohms, source voltage = 20volts

Now we need to calculate the equivalent series resistance seen at the terminals where the load resistor was removed. To do this we replace any voltage source with a short. That would give us R1 in parallel with R2 which would give us 2.5 ohms. Then that combination in series with R3 would be 2.5 ohms plus 5 ohms giving us 7.5 ohms.

So our Thevenin Equivalent Circuit would be 10volts in series with 7.5 ohms.