We found this circuit in a 1956 Sylvania publication. It serves to monitor telegraph transmissions being placed next to the transmitter. The circuit is indicated for the range of 80 and 160 meters.
We found this circuit in an American publication from the 1990s. The triac must be equipped with a heat...
This TTL circuit uses LED indicators and must be powered by a voltage of 5 V. The capacitor...
This circuit uses an integrated CMOS having the frequency determined by the resistors and...