What should a good diode read when tested?

A good diode should read continuity in one direction only when tested. This behavior is due to the fundamental function of diodes, which are semiconductor devices designed to allow current to flow in one direction while blocking it in the opposite direction.

When a diode is tested with a multimeter, a forward-biased condition is created by applying the positive lead to the anode and the negative lead to the cathode, allowing current to flow, which shows continuity. In reverse-bias, where the leads are connected the opposite way, the diode should not conduct current, resulting in no continuity. This characteristic confirms the diode is functioning properly and is not shorted or open.

Options suggesting no continuity, continuity in both directions, or a short circuit do not align with the expected functional behavior of a diode. A reading of no continuity would indicate an open circuit, which usually suggests the diode is faulty. Continuity in both directions would suggest a short, meaning the diode is defective, and a short circuit would also signal a failure in the diode's integrity and ability to control the direction of current flow.