PORTABLE_TRANSISTOR_TESTER

Published:2009/7/11 4:22:00 Author:May | From:SeekIC

Go/no-go tester shows relative condition of NPN and PNP transistors, junction FETs, and dual-gate MOSFETs. Not suitable for checking audio or highpower RFtransistors. Crystal for upper range of HFspectrum is permanently wired; any HF crys-tal cut for fundamental-mode operation can be used. Rectified RF from oscillator is monitored on M1. S1 selects negative ground for testing N-ehdnnel FETs and NPN bipolars and provides positive ground for P-ehannel and PNP devices. If device is open, shomed, or extremely Ieaky, circuit wiII not oscillate and meter will not deflect. The higher the meter reading, the higher the gain of transistor at operating frequency. When testing MOSFETs that are not gate-protected, keep transistor Ieads shorted until device is in socket and replace short before re moving device. Diodes are 1N34A or equivalent.-D. DeMaw and C. Greene, A Pair of Handy Testers, QST, May 1973, p 24-27.



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