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 configuration, from the 1977 National Semiconductor FET Databook, can be applied to other...
This circuit is from a 1972 German magazine Funkshau. The circuit can use BC548 transistors...
This circuit amplifies RF signals up to more than 100MHz and can be used as a booster in...