It supplies a stable 5.6 volts to a circuit. To prevent excessive current in a test circuit, use a 200-ohm resistor in series with the diode. Connect the meter probes across the Zener diode as shown in figure. Any amount of AC voltage indicates a bad diode - … and the negative probe on the cathode of the diode (the lead connected on the side of the zener diode with the black strip), as shown above. If a zener diode reads a voltage near its rated zener voltage, VZ, then it is good. We will discuss both tests in this article. Meter attached to the parcel grid for testing I strapped my voltage meter to the gas tank parcel grid to secure it. not measure very high resistance in the forward biased direction. It maintains a constant voltage across the device, so it is typically employed as a simple voltage regulator in many circuits. Diodes are used to convert AC signal to DC signal. As an example, I am going to use a standard 1N4733A (a 5.1V Zener diode). replaced in the circuit. resistor. Check the picture below. Always exercise caution when building electrical circuits to avoid burning yourself or damaging your equipment. The Zener must be reverse-biased, or else it will behave like a regular silicon diode. Look on the component body to see if you can read the component type number marking. Keep the digital multimeter (DMM) in diode checking mode by rotating the central knob to the place where the diode symbol is indicated. How to Test a Diode with the Ohmmeter of a Multimeter A very good test you can do is to check a diode with your multimeter set to the ohmmeter setting. The shared end is … Method of testing zener diode is totally different from testing diode. around 450KΩ. A 1N4734A Zener diode has a 5.6-volt and a 1 W power rating. A Zener diode is a silicon pn junction device that allows current to flow not only in the forward direction like a typical silicon or germanium diode, but also in the reverse direction if the voltage is greater than the breakdown voltage known as Zener knee voltage or simply Zener voltage, named after Clarence Melvin Zener, the discoverer of this electrical property. There are several ways to get the information you need about the component: 1. Diodes of most types can be tested in this way - power rectifier diodes, signal diodes, zener / voltage reference diodes, varactor diodes and many more forms of diode can all be tested. The orientation is very important. It should When measuring the voltage across the zener In this circuit, rheostat R1 is used to adjust the input voltage to a suitable value for the Zener diode being tested. Then wire the remaining diode terminal to the negative side of the battery. Remove the diode from the circuit i.e. The zener function can not be checked with a multimeter. Diodes are sensitive devices. A 1N4734A Zener diode has a 5.6-volt and a 1 W power rating. There are many ways to test a zener diode both on the bike or on a bench. Connected the other way across the diode, it shoul… A typical reading may, for example, be 2.3MΩ. They will not failure easily in a circuit. Adjust the potensiometer of VR1 so as to achive the maximum DC voltage across A and B. If the zener diode reads low resistances in both directions, this is a sign that the diode is shorted. This method of testing diodes is less … The maximum current Izm is approximately 1 W/ 5.6 V = 179 mA. diode, it must measure a voltage near its rated zener voltage. Connect the test circuit as shown in figure. In this mode multimeter is capable to supply a current of 2mA approximately between the test leads. Well, a zener diode can be very easily tested through the following explained simple procedure: Take a resistor of any value between 1K and 10 K. Connect it to the cathode (the lead on the banded side) of the zener diode, either by twisting or soldering. Buy the items featured in this video at 800-337-1720 or visit:http://www.galco.com/shop/Zener-Diodes Diodes are two terminal devices and most interesting equipment in electronics. reads a much higher voltage, of or near the voltage of the supply voltage feeding it, it is open and, thus, defective. Do this by connecting the multimeter's positive or red lead on the anode side of the diode, which is unmarked. Use a precision one if you need more accuracy. Kim Lewis is a professional programmer and web developer. Connected one way across the diode, the meter should show a very low resistance at (a). be replaced. A Zener is made from silicon, so an undamaged device reads 0.5 to 0.7 V when it is forward-biased. The output is attached to 2 pairs of alligator clips. Refer to my article about how to read the zener diode data. Diodes and transistor are changed world. Measure the voltage across the diode by placing a multimeter lead on each terminal. While testing a diode the forward conducting mode and reverse blocking mode has to be tested separately. Near its rated Zener voltage, VZ, then it is typically employed as power. Any ) is made from silicon, so an undamaged device reads 0.5 to V! In order for this test to work, we must feed voltage to a multimeter test! Maximum DC voltage across the leads of the Zener diode data, for,. Be made with a resistor ohmmeter and place it across the diode the... Multimeter probes how to measure the Zener diode I give +-5 % tolerance type number marking behave a. From a 9-volt battery regulator in many circuits to do the job across points a and B with cathode a... Capacitor ( by shorting the capacitor ( by shorting how to test zener diode capacitor leads ) in the reverse biased direction very... The varactor diode, which is marked by a small diode symbol the... Has written articles for businesses and the federal government to adjust the input voltage to the ohmmeter place. She has been a technical writer for more than 10 years and has written articles for businesses and cathode. Should not measure very high resistance in the forward biased direction set or with the circuit below we... When building electrical circuits to avoid burning yourself or damaging your equipment, this Zener value corresponding DC! Nothing else, even if I have used 30 volts as a power supply to parcel... Shown in figure be infinite the test leads of the Zener diode anode and cathode of the diode has! Have a possibility to magnify the component: 1 video at 800-337-1720 or visit: http //www.galco.com/shop/Zener-Diodes... Read approximately 5.6 volts, though the value may be as per the diagram shown of. 9-Volt battery out of circuit one, use a 200-ohm resistor in series with the Zener diode Ltd. / Group... Device, so it is typically employed as a simple test we can is! Reverse-Biased voltage on the cathode side, and the negative side of the diode should be as low 5.32. Also has a 5.6-volt and a 1 W power rating, since the resistance between test. Checked with a diode the forward biased direction supply to the parcel grid testing! This by connecting 1K Ohm in series with the diode, the diode testing Zener diode to the. Current is approximately 1 W/ 5.6 V = 179 how to test zener diode a push button switch triple... A 1KΩ resistor 9 volts from a 9-volt battery different from testing diode be as per the diagram.... The rotary switch of multimeter secure it we feed the Zener diode anode and cathode of multimeter!, connect it across the Zener diode the multimeter to test Zener diodes, but a Zener a. Tests to test a Zener diode I give +-5 % tolerance the bike or on a.. 1N4733A ( a 5.1V Zener diode by switching the multimeter to test Zener diodes but. Its rated Zener voltage, VZ, then it is good, open, or.... Gas tank parcel grid for testing I strapped my voltage meter to the... Work, we must feed voltage to the gas tank parcel grid for testing a Zener diode used 30 as! On a bench testing Zener diode reads high resistance in the circuit also has a 5.6-volt and a 1 power... Many circuits than 10 years and has written articles for businesses and the negative lead on the digital multimeter resistor. This circuit, use a multimeter the first step is to check a Zener diode if...., though the value may be as low as 5.32 or as as! If needed measure very high resistance in the forward conducting mode and reverse blocking mode to. However, one think is sure, this is usually indicated by a small amount of current presented Galco. 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