Using a digital multimeter to measure a triode
(1) Use the diode setting of a digital multimeter to measure the type and base b of the triode. When judging, the triode can be regarded as a back-to-back PN junction, as shown in Figure 2.1. According to the method of judging diodes, one of the poles can be judged to be the common positive pole or the common negative pole, and this pole is the base b. For NPN type tubes, the base is the common positive electrode; for PNP type tubes, it is the common negative electrode. Therefore, by determining whether the base is a common positive electrode or a common negative electrode, you can know whether the transistor under test is an NPN or PNP type transistor.
(2) Judgment of the emitter e and collector c. Use a multimeter to measure the β (HFE) value and judge the emitter e and collector c. Turn the gear to the MFE base and insert it into the hole of the corresponding type. Insert the pins into the c and e holes respectively to observe the data. Then reverse the pins in the c and e holes and look at the data. The larger value indicates the tube. The feet are inserted correctly.
(3) Determine the quality of the transistor. During the test, use a multimeter to measure the diode's gear position and test whether the forward and reverse biases of the transistor's emitter junction and collector junction are normal. A normal transistor is good, otherwise the transistor has been damaged. If the common b pole cannot be found during the measurement, the triode is also a bad tube. Set it to the ohm level and remember the numbers of the three legs to measure the resistance. The values are different and you can tell based on whether they are conducting or not.
Transistor, whose full name is semiconductor triode, is also called bipolar transistor and transistor. It is a semiconductor device that controls current. Its function is to amplify weak signals into larger amplitude electrical signals. It is also used as a contactless switch. The transistor is one of the basic components of semiconductors. It has the function of current amplification and is the core component of electronic circuits. The transistor is made of two PN junctions that are very close to each other on a semiconductor substrate. The two PN junctions divide the entire semiconductor into three parts. The middle part is the base area, and the two sides are the emitter area and the collector area. The arrangement is PNP and NPN.
