Thevenin's equivalent of wheatstone bridge

[Parparelis]

Hi guys, I tried to calculate the Vos and Isc and both of them are zero..so the Thevenin's resistance is 0/0=undefined. How do I calculate the resistance when Vos/Isc fails,such like the wheatstone bridge?

 

[NascentOxygen]

The Thévenin voltage will be 0V. To measure R you could apply a voltage to the terminals and measure the current that flows in.

To calculate R you short-circuit its source and determine the resistance seen looking in at the trrminals.