Quote:
Originally Posted by kalee20
Argus's method is good in that the transistor's operation is stabilised, but it does need some means of determining the actual (AC) base current to work out hfe.
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There is no requirement at all to identify the actual value of the hfe and it has no value for the application. The circuit was intended to simply illuminate
differences in the behavior of two transistor specimens. Even the base bias resistors were chosen to be a little higher range than usual to help indicate possible different leakage properties. The purpose is not to measure hfe, but to see if two different transistors have near identical static & large signal dynamic electrical properties..or not.The collector current was kept at a modest value to avoid any significant thermal effects, none noticed during testing.