Most digital meters used in the field will require a separate external battery to test a diode?

When testing a diode using a digital multimeter, it is essential to understand that most meters require a certain voltage to forward-bias the diode for accurate measurement. Typically, digital meters have a built-in test circuit that provides this necessary voltage, allowing the device to determine if the diode is functioning correctly.

However, in some cases, particularly with certain types of diodes or when the meter’s internal battery is low, an external power source may be needed to ensure the correct testing conditions. This can lead to the assumption that an external battery is necessary.

The assertion in the question is that most digital meters will indeed need a separate external battery to test a diode, which aligns with the concept that in specific situations, an external power source can be required for a comprehensive test in the field, particularly for diodes that exhibit higher forward voltage drops or when working in scenarios where the meter's functionality may be compromised.

While some meters might be capable of testing diodes without needing an external power source, it is often a practical approach in field conditions to have a separate battery available. Therefore, recognizing that certain instances can necessitate this requirement supports that the answer is true.