A simple method to measure the voltage value of Zener diode

    Zener diodes are widely used. Here is a simple method to accurately measure the voltage value of Zener diodes: As shown in Figure 1-1①, to measure the voltage value of Zener diodes below 15V, two 9V batteries can be used and taped together with sealing tape. Four output terminals are left. Connect one output terminal (one positive and one negative) of each battery with a 4.5K resistor, and the other two output terminals can be used for testing. 

　　Test method: Set the multimeter to 25V DC. Connect the two test leads to the test terminals of the battery respectively, and the multimeter will display the series voltage of the two batteries (18V). Contact the positive and negative poles of the Zener diode to be tested to the positive and negative poles of the test leads respectively. The voltage value displayed by the multimeter is the voltage value of the Zener diode. If the voltage displayed by the multimeter does not change, it means that the voltage value of the Zener diode is higher than the battery voltage or the internal circuit is broken. If the voltage displayed by the multimeter is much lower than the predicted value and close to 0V, it means that the Zener diode is short-circuited and damaged, or the polarity is connected incorrectly. You can change the polarity and test again. The voltage regulator value is greater than 15V. You can increase the number of batteries and resistors, or assemble according to Figure 1-1②, connect the multimeter and the voltage regulator first. Adjust the voltage range of the multimeter from high to low, and test several times. 

　　Since the test current of the above two circuits is below the working current of the voltage regulator, the voltage regulator diode will not be damaged. However, when testing according to Figure 1-1②, the human body should not touch the live parts. After each measurement, discharge the capacitor before the next measurement.