DIODE_AND_FET_LEAKAGE

Published:2009/7/11 1:44:00 Author:May | From:SeekIC

FET under test is connected with 22k resistor as source follower, with capacitor C across input from gate to ground. Leakage of FET charges capacitor at rate directly proportional to leakage and inversely proportional to capacitance. With 0.01 μF for C, each volt of change across C indicates stored charge of 10-8 coulomb. This can be interpreted as current in amperes if time for voltage on capacitor to rise 1 V is measured with stopwatch or timer while watching voltmeter. To test diode, connect as shown by dashed line and use good FET in circuit as shown. Article gives design equations; if voltage across C rises 1 V in 38.7 s, leakage current is 0.258 nA.-D. Dilatush, Leakage Testing of Diode and JFETs, EDNMagazine, May 5, 1973, p 72-73.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Basic_Circuit/DIODE_AND_FET_LEAKAGE.html

Print this Page | Comments | Reading(3)