I am a bit confused with this circuit.I uploaded the circuit as you can see I already removed the resistance where I need to calculate the thevenin resistance. I know how to find the Thevenin voltage. Our mission is to find the Thevenin equivalent circuit at R1 resistance.
I know how to find the Thevenin voltage but if I don't understand how to find the Thevenin resistance. Let is remove the voltage sources:
As you can see I already removed the R1 resistance and named the nodes A and B. I know that the R7 and R3 in series connection.But I don't understand what to do with R6 R4 and R2 they are in star connection. My quenstion it is useful to use star-delta transformation ? If yes how to do it properly?
Edit: I want this circuit to be reduced to this:
As I mentioned above I know how to find voltage I need the Rth and star-delta transformation is little confusing.