This humidity sensor indicates the different levels of conduction of the sensors through an LED bar. The circuit is from Popular Electronics and must be powered by cells or battery.
This variable gain circuit for analog video signals was found in a 90s Linear Technology...
In the figure we show how to connect a power MOSFET to the output of a CMOS function to control a power...
This receiver using a FET appeared in a November 1957 Radio Electronics magazine. It is one of the...