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.
The presented circuit has a stabilization with the LM313. The components used are uncommon, such...
This circuit makes use of a transconductance operational amplifier. It generates signals with TTL...
In the figure we have two typical configurations of voltage regulators with protection against short...