The easiest way to check, whether the transistor is not damaged, – This bidirectional measurement of the voltage drop on the connectors “The base-emitter” and “the base-collector”. This tester performs both tasks, which are somewhat limited, but sufficient for most household applications. The electrical circuit of the tester is shown in Fig.. 1.
Despite the simple construction, the device allows you to measure the collector current depending on the set base current (two meanings: 10 and 100 ICA), and also determine the magnitude of the voltage drop on the line “The base-emitter”. Collector voltage with a conversion factor of about 1 mV / 1 mA. voltage UBE measured directly on the BE connector. Switch W1 allows you to change the polarization of the voltage, which apply to the tested transistor depending on the structure of the transistor (p-n-p or n-p-n). Using switch W2, voltage measurement is selected for connector EB or KB. It is proposed to mount the tester on the board., the assembly diagram of which is shown in Fig.. 2.
The tester is equipped with two bases for low power transistors (P1 and P2), made from standard – gold-plated IDC connectors and three universal Z1..3 connectors, to which high power transistors can be connected. Supply voltage must be 9 AT. The millivoltmeter with indicator must be connected to terminals Z4 and Z5.