How to test Igbt by multimeter

Hello, this is Bing. I’m glad you’re interested in learning how to test an IGBT using a multimeter. An IGBT (Insulated Gate Bipolar Transistor) is a type of semiconductor device that can switch high voltages and currents. It is widely used in applications such as power electronics, motor drives, and inverters. Testing an IGBT is important to ensure its proper functioning and avoid any damage or failure.

There are different methods to test an IGBT using a multimeter, depending on the type of multimeter you have. You can use either an analog multimeter or a digital multimeter. In this article, I will explain how to test an IGBT using both types of multimeters.

Before you start testing, you need to prepare the following:

• A multimeter that can measure resistance and diode voltage drop. Make sure the multimeter is calibrated and has a battery voltage of less than 20V.
• An IGBT that you want to test. You can find the part number and the pin configuration of the IGBT from the datasheet or the diagram on the device. The IGBT has three pins: collector ©, emitter (E), and gate (G).
• A pair of test leads or probes that can connect the multimeter to the IGBT pins.
• A conductive foam or a wire that can short-circuit the IGBT pins.

The basic steps to test an IGBT using a multimeter are as follows:

1. Turn off and disconnect the power supply to the circuit or device that contains the IGBT. This is to prevent any electric shock or damage to the IGBT or the multimeter.
2. Remove the IGBT from the circuit or device. You may need to unscrew or unplug the IGBT from the board or the socket.
3. Short-circuit the three pins of the IGBT using the conductive foam or the wire. This is to discharge any residual charge or voltage in the IGBT and ensure accuracy in the testing.
4. Identify the pins of the IGBT using the datasheet or the diagram. You can also use the multimeter to identify the pins by measuring the resistance between the pins. The gate pin will have a very high resistance compared to the other two pins.
5. Set the multimeter to the appropriate mode. You can use either the diode test mode or the resistance mode (ohmmeter) to test the IGBT. The diode test mode will measure the voltage drop across the IGBT, while the resistance mode will measure the resistance of the IGBT.
6. Connect the multimeter leads to the IGBT pins. Depending on the type of multimeter and the mode you are using, you may need to connect the leads in different ways. I will explain the details in the following sections.
7. Observe the multimeter reading. The reading will indicate whether the IGBT is good or bad. A good IGBT will show a certain value in one direction and a different value in the opposite direction. A bad IGBT will show either a very low value or a very high value in both directions.

How to Test an IGBT Using an Analog Multimeter

An analog multimeter is a type of multimeter that uses a pointer and a scale to display the measurement. To test an IGBT using an analog multimeter, you need to set the multimeter to the Rx1k range and follow these steps:

1. Connect the black probe of the multimeter to the collector pin © of the IGBT and the red probe to the emitter pin (E). The pointer on the multimeter should be at zero.
2. Touch the gate pin (G) and the collector pin © with your fingers at the same time. This will turn on the IGBT and make it conduct. The pointer on the multimeter should move to the right and show a low resistance value (a few ohms).
3. Reverse the probes and repeat the steps. The pointer on the multimeter should be at zero again.
4. Swap the probes and repeat the steps. The pointer on the multimeter should be at infinity (very high resistance) in both directions.

If the multimeter shows the above results, the IGBT is good. If the multimeter shows a low resistance value in both directions, the IGBT is shorted. If the multimeter shows a high resistance value in both directions, the IGBT is open.

How to Test an IGBT Using a Digital Multimeter

A digital multimeter is a type of multimeter that uses a digital display to show the measurement. To test an IGBT using a digital multimeter, you need to set the multimeter to the diode test mode and follow these steps:

1. Connect the positive lead (red probe) of the multimeter to the collector pin © of the IGBT and the negative lead (black probe) to the emitter pin (E). The multimeter should show a voltage drop around 0.6 to 0.7 volts. This is the forward voltage drop of the IGBT.
2. Reverse the leads and repeat the step. The multimeter should show an open circuit or a very high resistance value. This is the reverse voltage drop of the IGBT.
3. Swap the leads and repeat the steps. The multimeter should show the same results as before.

If the multimeter shows the above results, the IGBT is good. If the multimeter shows a low voltage drop or a low resistance value in both directions, the IGBT is shorted. If the multimeter shows a high voltage drop or a high resistance value in both directions, the IGBT is open.

I hope this article has helped you understand how to test an IGBT using a multimeter. If you want to learn more about IGBTs and their applications, you can check out these websites.