1, method one:
(1) the triode smooth light rectified square side facing themselves, three pins down, hold in hand.
(2) from left to right three pins are E, B, C.
(3) E represents the emitter, B represents the base, C represents the collector.
2, method two:
The table is set to 1K block, the black pen connected to any one foot, do not move, the red pen to measure the other two feet, when measured the other two feet of resistance in 10K or so, this time, the black pen is connected to the b level, and then use the 10K block to measure the other two feet, positive and negative measurements, when measured in the resistance value of about 1,000K, the red is e, and the last is c, which is the NPN-type! The PNP type can be measured in reverse.
3, method three:
If it is a low-power transistor, there is an extremely simple method, you call the three feet inserted into the multimeter to measure the transistor holes, gear in the magnification of that gear, when the pointer in the tens of hundreds of times or so, you look at the multimeter measuring holes corresponding to the EBC feet, high-power tubes, EC feet of the resistance of the resistance of the infinite EB resistance is greater than the EB resistance, when the red pen does not move, the red pen will not move, the red pen will not move, the red pen will not move, the red pen will not move, the red pen will not move, the red pen will not move, the red pen will not move. Resistance, when the red pen does not move, the black pen to measure the other two feet smaller resistance value, the tube for the PNP-type, the red pen corresponds to the B-pole, the resistance of small black pen corresponds to the E-pole, when the black pen does not move, the red pen to measure the other two feet smaller, the tube for the NPN-type, at this time, the black pen corresponds to the B-pole, the resistance of small is the red pen corresponds to the E-pole. Measurement method is the same as the size of the power tube, small power tube is used 1K ohm gear, high-power tube is used 1 ohm gear.
Two, chip transistor components how to determine the good and bad
Using the unidirectional conductivity of the PN junction within the transistor, check the PN junction between the poles of the positive and negative resistance, if the difference is greater than that of the tube is good, if the positive and negative resistance is large, indicating that there is a break inside the tube or a PN junction performance is not good. If the positive and negative resistance are small, it means that the tube is shorted between poles or breakdown.
Because the emitter and collector of the transistor are correctly connected when β is large (the meter needle swing is large), the reverse connection β is much smaller. Therefore, assume a collector first, and connect it with an ohm gear, (for a PNP-type tube, the emitter is connected to the black meter pointer, and the collector is connected to the red meter pointer).
Measurement, hand pinch (or connect with a 100KΩ resistor) the base and the assumed collector, the two poles can not be contacted, if the pointer swing is large, and the two poles are adjusted to the pointer after the pointer swing is small, it is shown that the assumption is the correct collector, so as to determine the collector and the emitter.