This circuit is from 1980s documentation. The maximum operating frequency is 3.5 MHz. The current of the LED can be from 0 to 100 mA. The integrated circuits used are from that time.
This circuit uses one of the first comercial transistor and is from a 1958’s magazine. Tone...
This circuit is intended to indicate the operation of transmitters with powers above 5 W. The...
Emitt This crystal-controlled oscillator can generate signals from 100 kHz to over 30MHz. The...