Found in a 1968 EEE, this switch controls a high-power load from an audio signal. The current is determined by the type of SCR.
This filter has a cutoff frequency of 0.026 Hz given by R and C. These components can be...
In the figure we have a way of receiving ultrasonic signals of a single frequency using a PLL 567....
Using integrated circuits from the time, we found this audio compressor in an English publication from...