Found in a 1924 book by Gernsback, this circuit uses a double variable capacitor, a component not very common at the time. Listening was done on a loudspeaker at the time.
This 2 meter (144 MHz) preamplifier is intended for use with portable transceivers. The...
This circuit was found in a 1970s RCA publication. Transistors support modern equivalent types....
The circuit presented is from the Motorola Linear Databook of 1990. The integrated circuit is a...