Found in an English publication in 1969, this circuit has a 600 kHz pass band. Ferranti's transistors support modern equivalents.
This TTL circuit was found in the December 1990 issue of Radio Electronics magazine. The circuit has...
Found in an Electronics World of 1968 this circuit can use any SCR and diodes depending on the...
Placed near a telegraphic transmitter (CW) and with a small antenna or pickup, it reproduces the...