In the figure we have the way to obtain 500 gain from a FET. FETs can be BF245 or MPF102. The circuit is from the 1977 National Semiconductor FET Data Book. Power supply depends on the application.
With this circuit it is possible to control an operational amplifier so that it switches an input...
This circuit consists of a traditional amplifier version with complementary output using BD series...
This circuit was obtained from a Texas Instruments 1985 document. The circuit is powered by 1.5 V...