How do you know when a rectifier is bad?

Answer 1

(1) A basic check of a simple electrical rectifier (diode) requires the application of an ohm meter (an electrical resistance measurement device). A digital ohm meter (digital multimeter or DMM) is easier to use than the conventional dial (analog) type of meter. (2) The rectifier must be disconnected from the circuit to be assured of an effective test. (3) Measure the resistance of the rectifier from one terminal to the next. (4) Switch the meter test leads to measure the rectifier in the opposite direction. Do not to touch the electrical conducting parts of the meter leads or the terminals of the rectifier with your fingers or you may cause a false measurement. (5) Usually an effective rectifier has at least a 10 to 1 ratio of resistance as measured one direction versus the other.