How to test a Zener diode, and how they work

How to test a Zener diode, and how Zener diodes work See rectifier diode

Summary: Learn how Zener diodes work, and how to test them with a multimeter.

Zener diodes work a little different than rectifier diodes in that they will conduct with reversed bias voltage applied at a set voltage level.

These diodes act as an open circuit from the output-in, until a strict specified reverse bias voltage is reached.

At this point, once the threshold is reached, the diode conducts allowing current to pass through.

	Zener diodes are commonly used to regulate voltage in circuit and external power supplies. The testing of Zener diodes requires a variable dc power supply. In this circuit, the variable power supply is used to adjust the input voltage to a suitable value for the Zener diode being tested. Zener diode testing circuit Resistor R1 limits the current through the diode. With the Zener diode connected as shown in the above figure, no current will flow until the voltage across the diode is equal to the Zener voltage, sometimes referred to as the avalanche voltage. When this happens, the current will flow through the diode at the supplied voltage. If the diode is connected in the opposite direction, current will flow at a low voltage, usually less than 1 volt. Current flow at a low voltage in both directions indicates that the Zener diode is defective. A typical Zener diode See more how-to articles