Found in an American 1980s documentation, this circuit compares signals from two TTL sources, providing an output that depends on the frequency difference. The circuit can be used as a shield.
Two identical transformers can be used as a single improvised isolation transformer. The maximum...
This transmitter can send its signals from several kilometers away, depending only on the antenna...
This circuit was found in Radio Electronics magazine from January 1959. The power transistor must...