Electricity: measuring and testing – Measuring – testing – or sensing electricity – per se – With rotor
Patent
1987-06-18
1989-01-31
Eisenzopf, Reinhard J.
Electricity: measuring and testing
Measuring, testing, or sensing electricity, per se
With rotor
324158D, 324 73R, 324158R, G01R 3122
Patent
active
048018783
ABSTRACT:
An in-circuit test device and method for testing transistors which are connected to various components on a printed circuit board. The present invention uses a fully automated system which provides a constant emitter current to bias the transistor to a predetermined level and prevents the transistor from going into saturation due to variations in the gain of different transistors. The collector lead and base lead are maintained at approximately ground potential so that the collector emitter voltage drop is maintained above the saturation voltage for transistors since the base emitter junction is biased by a constant emitter current placed in the emitter lead. Transistor gain is determined from the difference in two separate d.c. emitter currents which eliminates the effects of parallel impedence paths resulting from other components connected to the transistor on the printed circuit board. An operational amplifier having a feedback resistance is used so that the output voltage is directly proportional to the current flowing through the base of the transistor.
REFERENCES:
patent: 3430152 (1969-02-01), Walsh
patent: 4135153 (1979-01-01), Stone
patent: 4142150 (1979-02-01), Morrow et al.
Simpson; "Build and In-Circuit Transistor Tester"; Electronics Australia; Apr., 1977; vol. 39, No. 1; pp. 37-39.
Hojak; "Automatic Measurement of Transistor Beta"; Electronics; Dec. 4, 1959; pp. 114-115.
Graeme; "Accurate Transistor Tests Can Be Made Inexpensively"; Electronics; Feb. 28, 1972; pp. 84-89.
Hewlett-Packard Company, "3253A Operating and Serivce Manual," (HP part number 03253-90001), Section 3, p. 11.
Crook David T.
Peiffer Ronald J.
Cochran William W.
Eisenzopf Reinhard J.
Hewlett--Packard Company
Nguyen Vinh P.
LandOfFree
In-circuit transistor beta test and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with In-circuit transistor beta test and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and In-circuit transistor beta test and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-179454