IGBT will be exposed in the maintenance of switching power supply, so how to measure the quality of IGBT with Multimeter? There are three steps to measure the quality of IGBT with a multimeter:

l. To judge the polarity, first set the multimeter to R × 1K 。 When measuring with a multimeter, if the resistance between one pole and other poles is infinite, and the resistance between this pole and other poles is still infinite after changing the probe, it is judged that this pole is grid (g). The other two poles are measured with a multimeter. If the measured resistance is infinite, the measured resistance is small after changing the probe. When the resistance value is small, it is judged that the red probe is connected to the collector (c) and the black probe is connected to the emitter (E).

2. To judge whether it is good or bad, set the multimeter to R × In 10kq gear, connect the black probe to the collector (c) of IGBT and the red probe to the hair time pole (E) of IGBT. At this time, the pointer of the multimeter is at infinity. Touch the grid (g) and collector (c) with your fingers at the same time. At this time, the IGBT is triggered to be turned on, and the pointer of the multimeter swings to the direction with smaller resistance value, and can stand at a certain position. Then touch the grid (g) and emitter (E) with your fingers at the same time. At this time, the IGBT is blocked and the pointer of the multimeter returns to its original position. At this time, it can be judged that IGBT is good.

3. Note: any pointer multimeter can be used to detect IGBT. When judging whether IGBT is good or bad, be sure to set the multimeter to R × IOK gear, because R × The internal battery voltage of the multimeter below ikq is too low, so the IGBT cannot be turned on when detecting whether it is good or bad, and the quality of IGBT cannot be judged. This method can also be used to detect the quality of power field effect transistor (p-MOSFET).