Here is a handy zener diode tester which tests zener diodes with a Digital Multimeter with breakdown voltages extending up to 120 volts.

The circuit presented here is compact and handy for measuring the voltage rating of a Zener diode instantly. To check a Zener diode, it is connected across a DC power supply with a suitable resistor ...

The 1N4004 diode rectifies the unloaded voltage while the 2.2 uF capacitor flattens it to reach the rate of 150 VDC. 1N4004 provides high forward surge current capability, guaranteed high temperature ...

Diode D1 and capacitor C3 forms the output rectifier and filter circuit. If possible, try to replace D1 with a UF4001 fast diode for better efficiency. Zener diode D2 sets the output voltage to near ...