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.
This circuit produces a loud sound in the speaker when water level reaches the sensor. The power...
This circuit should be used with low frequency signals only. The circuit is from a documentation from the...
This Signetics circuit uses a double 555 (556) to generate tone bursts at frequencies determined by...