How to get Thevenin Resistance of this circuit?

Question

I have the following circuit:

And i need to calculate the Thevenin Resistance.

when I shorted the source and removed the R5(Load resistor), I got

I thought the result was (R1 || R3) || (R2 || R4) since R1 and R3 are joined at both ends and the same happens with R2 and R4, then the reduction R1 || R3 and R2 || R4 were also in parallel, however this development did not give me the expected response.

The resistance you should get between points a,b is approximately 1.72kOhm.

How should I do it?

Answer 1

To see it better, redraw the circuit:

^{simulate this circuit – Schematic created using CircuitLab}

You should be able to write down the Thevenin resistance directly from that.

Answer 2

Guidance only:

In your greenish drawing: Color the bottom horizontal line to blue. Color to blue also every wire which is directly connected to the blue line. Consider the blue lines as one intermediate node and see what's between a and b.

If that doesn't help them fold the greenish drawing along the horizontal line between a and b and see then what's between a and b. Recall: the blue is a single node.

Answer 3

Steps to find thevenini equivalent circuit

1. Remove the load between point a and b
2. Short circuit the voltage source and or remove the current source in the open circuit
3. Calculate the R total
4. R total is equal to R thevenini