We have all had difficulty testing diodes in-circuit. Most DMM’s have a diode Vf function that measures forward drop, but what is the normal voltage drop? Analog VOM’s attempt to measure resistance of ...

To measure a zener diode’s breakdown voltage, you need a dc voltage source whose voltage exceeds that of the zener voltage. In Figure 1, resistor R SER provides voltage drop between V IN and V ZEN. In ...