This circuit for musical instruments was found in a 90’s Elektor. The circuit still applies, as the components used can still be obtained with some ease.
This circuit is from the 1993 Motorola Linear Interface Circuits. The source does not have to be...
This range is normally used in marine communications as indicated in the 1989 documentation. The...
This shield circuit is from a 1968s Motorola documentation. The relay is according to the supply...