i am using Zener Diode SMAZ30 and i am measuring its impedence at test current 25 mA. The impedence should be less then 15 ohm but every time i am getting a higher impedence because zener heats up too much.
I tried to turn off power supply very rapidly to avoid heating but the minimum value i got through was 35 ohm.
The method i used is zener diode and a resistor of 1K in series. I took 2 zener voltage values 1 at 26 mA and the 2nd at 24 mA and then used the following formula.
Zzt = Vz@26mA-Vz@24mA
26mA-24mA
Do you know any good method to measure its impedence ????