This circuit consists of a stereo audio compressor. We found it in Radio Electronics magazine from October 1968. The circuit uses an opto-coupler made with a neon lamp and LDR.
In the figure we have the typical configuration of a sinusoidal audio oscillator with twin-T. The...
This circuit was found in a 1969 US documentation. It provides a signal that can be externally...
We found this adapter in a 1970s American documentation on instrumentation. It is suitable for analog...