This two-tube circuit, one being a double, was found in Radio Electronics magazine from July 1958. The distance to the microphone depends on noise and losses. The cable must be shielded.
This circuit was found in old documentation, but the setting applies to any operational. Resistors...
We adapt this circuit of Radio Electronics - March 1990. The magazine no more exists, but the...
The circuit of the figure consists of a motor timer that can delay drives for up to 15 minutes....