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笔者收集了大量剩余的齐纳二极管,某些型号已经淘汰,另一些标记已经看不清,为了测试其性能和好坏,特地制作齐纳二极管测试仪,其电路原理如附图所示。测试项目是检查齐纳管的极性和稳定电压。测试时,齐纳管有一恒定电流流过,在数字电压表(DVM)上可直接读出齐纳管的稳压值。一、测试单元TR2、D1、D2和 R1、R2组成恒流源。R2、TR2和测试端 SK2、SK1串联相接,TR2的集电极通过约7mA 的测试电流。在没有接入被测齐纳管时,电压表上读出的是电源电压:+33V 或+6V,由齐纳管的稳压值决定用哪个测试端。图中所示使用电源电压:+33V 测试;若用+6V 测试,数字电压表的正表笔应接至+6V 端。二、测试控制单元测试控制单元主要由 TR1、TR3等组成。TR1的e-b 极与 TR3的 c-e 极经 R6形成回路,+33V 直流电压经 TR1的 e-b 极、R6加至 TR3的集电极,为其提供集电极电源;反之,TR3又控制 TR1的通断,C1、R5分别为 TR3基极偏置电路的去耦电容和限流电阻。
I collected a large number of remaining Zener diodes, some models have been eliminated, others have not see the mark, in order to test its performance and good or bad, specially made Zener diode tester, the circuit as shown in the figure. The test item is to check the zener polarity and the steady voltage. During testing, the zener has a constant current flowing through it, and Zener’s regulation can be read directly on the digital voltmeter (DVM). First, the test unit TR2, D1, D2 and R1, R2 form a constant current source. R2, TR2 and the test terminal SK2, SK1 series connection, TR2 collector through the test current of about 7mA. In the absence of access to the zener under test, the voltmeter reads the supply voltage: + 33V or + 6V, Zener tube voltage regulation which test terminal. The figure shows the use of power supply voltage: +33 V test; +6 V test, the digital voltmeter positive pens should be connected to the +6 V terminal. Second, the test control unit test control unit mainly by the TR1, TR3 and other components. The eb pole of TR1 and the pole of TR3 form a loop through R6. The + 33V DC voltage passes through the eb pole of TR1 and R6 is added to the collector of TR3 to provide collector power. On the contrary, TR3 controls the on-off of TR1 and C1 , R5 are the decoupling capacitors and the current limiting resistor of the TR3 base bias circuit respectively.