We found this tube receiver in a 1950s Japanese publication. The circuit uses 5 tubes and has an RF amplifier stage for greater sensitivity. The power supply is not shown on the circuit.
The frequency of this circuit, that makes use of a tunnel diode as an active element, depends on...
This circuit uses a sensitive reed relay to control external loads. The time delay is given by the...
This circuit uses the 741 Operational Amplifier to drive two LEDs. The LEDs indicate the signal of...