Answer to Question #138731 in Electrical Engineering for Carlo Beeker

Question

How and where would you install a zener diode? Also what size.

Answer 1

The main purpose of a Zener diode is to maintain a constant voltage on the load when the input voltage and load current change.

When a plus is applied to the anode and a minus to the cathode, the Zener diode behaves like a normal diode.

As a rule, calculations recommend taking the minimum input voltage 1.5 times higher than the stabilization voltage. When a plus is applied to the cathode and a minus to the anode, i.e. it is turned on in the opposite direction, the characteristic of the Zener diode, the dependence of the current through it on the applied voltage, also changes dramatically. This is clearly seen in the form of the reverse branch of the characteristic.

If the Zener diode is small and the leads are thin, then this is a low power with a stabilization current of 3 to 20 mA. If the case is slightly larger and the terminals are thicker, then this is the average power and stabilization current up to 90 mA. Well, a powerful Zener diode has a large size and can be installed on the radiator. It has a stabilization current of up to an ampere and higher.