Identification and detection of transistor 3

A woman uses a black probe to connect to one pin and a red probe to connect to the other two pins. When both resistance values are measured to be low, the black probe is connected to the base of an NPN transistor.

(2) The method of identifying the collector electrode. The collector can be determined based on the principle that the forward current amplification factor of a transistor is greater than the reverse current amplification factor. Using a multimeter with a resistance range of R × 100 or R × lk, hold the probes tightly with both hands and connect the two probes to the other two pins of the tube. Use your tongue to contact the base of the tube and use human resistance to achieve bias. Observe the magnitude of the pointer deflection of the multimeter, then swap the two probes and measure the resistance value or pointer deflection amplitude in the same way. Compare the magnitude of two readings. For PNP type transistors, for the one with a smaller resistance value (larger deflection amplitude), the pin connected to the red probe is the collector. For NPN transistors with low resistance (large deflection), the pin connected to the black probe is the collector. After determining the base and collector, the remaining pin must be the emitter.transistor

There is a simple method to distinguish the collector electrode, which is to place the multimeter in the R × lOk range after the base electrode is determined (NPN transistor), measure the other two electrodes except for the known base electrode, and observe the amplitude of the pointer swing. Then replace the probe and measure again, subject to the obvious swing of the probe. The electrode connected to the black probe is the emitter (PNP tube is the opposite). However, this method has certain limitations, which means that it is ineffective for some transistor.

In addition, the function of measuring the amplification factor port with a multimeter, i.e. hI; E range, can be used to distinguish between the collector electrode, base electrode, and emitter electrode, because when the electrode of the transistor is correctly inserted, its Lu value can be effectively displayed. Otherwise, it will display very small values or cannot be displayed normally. This can be read out according to the c, b, and e marked next to the socket.transistor