This 3-tube receiver is from a 1924 publication. The circuit has 3 supply voltages and a high-impedance headphone output.
This circuit is from General Electric documentation from 1970. The transistors can be of...
The S-meter is a signal strength meter used in communication receivers. This circuit was found in...
This 5.1 MHz circuit was found in a 1980s documentation. The frequency is given by the crystal and...