how to test a transformer with an ohmmeter?

To test a transformer with an ohmmeter, first ensure the transformer is disconnected from any power source. Set the ohmmeter to the resistance measurement mode. Measure the resistance across the primary winding terminals and then across the secondary winding terminals. A normal reading indicates continuity, while an infinite reading suggests an open circuit. Additionally, check for short circuits by measuring between the windings and the core; any low resistance indicates a fault.