This circuit is the receiver for the transmitter from the previous project. We also found it in the Radio Electronics Experimenter magazine, 1989 issue.
This series and parallel sensor circuit was found in Popular Electronics from the 1990s. Any SCR...
This circuit was found in a 1973 documentation, being able to use any general purpose NPN...
This circuit was found in a 1974 documentation. The bipolar transistor can be the BC548 and at the...