Can diodes be properly checked while in the circuit or with power on?

When checking diodes, it is important to consider the method used to ensure accurate readings. The assertion that diodes can be properly checked while in the circuit or with power on is generally accurate because certain digital multimeters (DMMs) are equipped to perform a diode test under these conditions.

When using a DMM's diode testing function, the meter applies a small forward bias to test the diode, allowing it to measure its forward voltage drop. This can be done without disconnecting the diode from the circuit, as the DMM can often differentiate between the diode and other circuit components by applying a small voltage and measuring the current flow.

However, care must be taken, as performing a diode test while the circuit is powered can lead to misleading results if there are other components that influence the readings. It is also crucial to avoid testing in high-power or sensitive circuits where other voltages could interfere.

While the answer posits that diodes can be tested with the power on, it’s also important to consult specific equipment guidelines and understand the circuit conditions to ensure accurate readings.