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.
In this circuit, the current capacity doubles, but is still of the order of microamps. The...
We found this oscillator in an integrated circuit manual from the 90's. The circuit shows how to...
This regulator can be controlled by a logic signal. The circuit is from an Electronics Now from...