Test a Diode with different equipment

How to test a diode with different equipment

These days, diode is one of the basic as well as popular electrical components widely used in almost every electronic device like television, mobile phones etc. apart from this, few people also use diodes for personalizing as well as repairing their and customer’s machines. Using a diode is very easy and so testing a diode is as easy as you think. To test a diode you do not need special skills as it is is much easier as the resistor testing. However you still need to know that how to do it else your wrong step during diode testing will surely waste your valuable time.

Diode terminal identification

Diode terminal identification

Different ways of testing a diode

Before diode testing, you need to identify its fault. A diode might be faulty in following four cases- showing error during operation in high voltage, opened, leaky or shorted. To check last three diode failure condition, you can use a digital multi meter. To test a diode, you can also use an analog multi-meter as they are much efficient in finding a fault in a diode as compared to digital multimeter.

Crystal-Diode Testing

Crystal-diode testing is one of the most common tests widely used to test a diode. In this testing, both ohmmeter and ammeter are used together. With the help of these two equipment, the measurements of reverse current, forward and back resistance can be measured easily. Using final results, one can easily test and compare the condition of a diode with the default, or you can say that manufacturer’s data sheets. In-circuit testing of diodes is another popular way of testing a diode.

Testing diode with an Ohmmeter

It is a very convenient way of testing a semiconductor diodes specially for zener diode. In this type of diode testing, you only need an ohmmeter. To test a LED (Light emitting diode) or a simple diode, firstly you need to determine and set the voltage with the help of the battery potential of an ohmmeter. After all this, you can easily measure back as well as forward resistance which is an important aspect in diode testing.

test a diode forward and riverse bias

test a diode forward and riverse bias

When you connect the anode and cathode with voltage and common of multimeter and turn the meter to Diode or DC voltage check. You will observe the following for working diode.

  • Voltage should be displayed when anode is connected to the voltage and cathode to the common.
  • Zero Voltage should be shown when cathode is connected with voltage and anode with common.

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Testing diode with multimeter

The very first step of this testing is to set the Multimeter meter at x1 ohms. By keeping reading in this range, you can check current leakage in both reverse as well as forward direction. This is also known as quick diode testing. Whether it’s a small signal diode or a large signal diode, the current always flows in one direction which also means that a diode has polarity (minus and plus). Now, connect your meter with the one side of the diode and record readings. No reading means, you need to change the testing side of the diode. Along with this, you can get resistance reading on the both side of a Schottky Diode.

test a diode with DMM

test a diode with DMM

You can rotate up to Resistance meter division and select the value up to the maximum Ω. After starting the method you must take a look on the ohm meter/Multi meter screen.

  • When you connect the anode with voltage and cathode with common, the resistance value must be zero.
  • When you connect the cathode with voltage and anode with common, the resistance value must be maximum or in some meters it may show infinity as well.

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Testing a diode would become a fun act if you use any of the above mentioned testing methods. The best part is that it can also save your lots of time.

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