Found in a 90s Elektor, this mixer makes use of integrated circuits of the time. The supply must be symmetrical at 15 V.
We found this circuit in a technical documentation from the 70s. It can be implemented with more...
We found this shield circuit in a 1991 technical documentation. The phototransistor can be...
This circuit was obtained from a Radio Electronics from October 1963. The 4 transistors must be...