This FM receiver tuning step circuit was found in a 1960 documentation. No information about the coils is given, but the FI used at the time was 10.8 MHz.
This voltage-controlled oscillator or VCO has rectangular and triangular signal outputs. The...
This circuit was obtained from a 1965 Radio Electronics. The semiconductors used admit modern...
This Hall sensor circuit is intended to isolate an audio signal applied through a coil. The...