Zener diodes are useful components in electronics their main characteristic is their working voltage however this voltage is not printed in the diode body this video will show you how to measure the Zener voltage this is the Zener diode symbol the cathode is identified by a black mark in the diode body checking the voltage rating is easy we will need a battery or power supply a 1 kilo ohm resistor the Zener diode and a multimeter the voltage of your battery or power supply must be larger than the voltage rating of the diode since we don't know this voltage it is convenient to use a variable power supply let's now perform the test with some senior diodes I have here a variable power supply these are the test leads of the power supply and the multimeter these are the test leads of the multimeter and let's connect us the diagram says the positive of the power supply or battery goes to the 1 kilo ohm resistor and the other side of the resistor will go to the center diode to the cathode that is the side that has the black band in this same point we will connect the positive of the multimeter in the other side of the diode we need to connect the negative of the power supply and the negative of the multimeter we can see that the multimeter reads the same voltage as that of the power supply if we increase the voltage the voltage across the center also increases we need to increase the voltage further until the Zener voltage is not varying okay we have six volts applied and the Zener voltage reads five point 64 volts if we increase the voltage even more this value does not move this means that this Zener diode has a voltage of 5.65 volts the nominal voltage of this Center is 5 point 6 volts however there is a tolerance in the Zener diodes and the real voltage is 5 point 65 volts let's try with another diode from the same batch this is also a single diode of five point six volts but let's test the real world - of this diode we know have voltage of 5 point 70 volts a little bit more than the former dial again this is because of the tolerance of the dials let me check with another dial this has a nominal voltage of 12 volts let's see the real voltage we need to increase the voltage of the power supply there you have it the voltage is not increasing we are at more than 15 volts and the center voltage is 12 point tilting volts