Method of measuring the quality of transistors with a multimeter
Firstly, connect the multimeter to the test diode terminal. Use the red probe of the multimeter to touch one of the pins of the transistor, and use the other probe of the multimeter to test the remaining pins until the following result is obtained:
1. If the black probe of a transistor is connected to one of its pins and the other two pins are both conducting with a voltage display when measured with a red probe, then this transistor is a PNP transistor, and the pin connected to the black probe is the base B of the transistor. When tested using the above method, if the voltage of the red probe of a multimeter connected to one of its pins is slightly higher, then this pin is the emitter E of the transistor, and the remaining pin with a lower voltage is the collector C.
2. If the red probe of a transistor is connected to one of its pins and the other two pins are both conducting with a voltage display when measured with a black probe, then this transistor is an NPN transistor, and the pin connected to the red probe is the base B of the transistor. When tested using the above method, if the voltage of the black probe of a multimeter connected to one of its pins is slightly higher, then this pin is the emitter E of the transistor, and the remaining pin with a lower voltage is the collector C.
Another method is to use the hFE gear for judgment. After determining the base and transistor type of the transistor, insert the base of the transistor into the Lu value measurement hole according to the position of the base and the transistor type, and insert the other two pins into any two of the remaining three measurement holes. Observe the size of the data on the display screen, find the collector and emitter of the transistor, exchange positions, and then measure again. Observe the value on the display screen, repeat the measurement four times, and compare and observe. The maximum value measured is the current amplification factor of the transistor, which corresponds to the collector and emitter electrodes of the transistor.
