This is a circuit for receiving signals from the previous transmitter. The circuit uses a common phototransistor. It was found in the August 1984 issue of Radio Electronics magazine.
Using a piezoelectric sensor of the time, this circuit was found in the February 1994 issue of...
I found this circuit in an old English magazine from 1981, but it can still be assembled with some...
Only signals about 1 kHz can pass through this tuned circuit. The main component is a operational...