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Transistor Tester

IP.com Disclosure Number: IPCOM000097945D
Original Publication Date: 1961-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Sommerfield, EH: AUTHOR

Abstract

The transistor tester receives either transistor T1 or T2, or both, for testing and connects them to a D.C. source through emitter and collector resistors R1 and R2 and indicating lamps L. Switch SW selectively connects the bases to ground through clamp diodes D1 and D2 or to the -3 or +3 volt terminals of the D.C. source through base resistors R3.

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Transistor Tester

The transistor tester receives either transistor T1 or T2, or both, for testing and connects them to a D.C. source through emitter and collector resistors R1 and R2 and indicating lamps L. Switch SW selectively connects the bases to ground through clamp diodes D1 and D2 or to the -3 or +3 volt terminals of the D.C. source through base resistors R3.

When SW is in the position shown, T1 should be off, and the resistance of the circuit is such that the lamp L is off. If T1 is shorted, L goes on.

When SW is reversed, the base of T1 is forwardly biased and T1 turns on. If T1 has adequate gain, sufficient current flows to light L. If T1 has insufficient gain or is open, L remains off. The two circuits are similar, being arranged for PNP and NPN transistors, respectively.

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