This circuit converts a high voltage into a frequency using an optical coupler. The transistor can be 2N2646 and the coupler admits equivalent. The circuit is from a 1974 publication.
We found this circuit in Ferranti's 1974 transistor manual. Transistors are general-purpose types...
This circuit was found in a Dutch documentation from 1970. The circuit makes use of semiconductors that...
The scratching noise is quite unpleasant for those who pass the sound of vinyl records to other...