60's crystal radio (CB22171E)

Found in an English publication from the 1960s, this circuit uses period components, including the commercial grade coil.

Diode Comparator (CB14051E)
This sensitive photo-diode circuit with output compatible with TTL logic was found in a 1972 RCA...
Tone Transmitter (CB24673E)
This circuit can send signals in both the VHF and FMN bands with a range of a few tens of meters. The...
VCR Video detector (CB20897E)
This circuit was found in a Popular Electronics from the 80s. It is possible to control a relay...