This powerful transmitter for the 27 MHz band was found in a Japanese publication from 1961. The circuit is powered by battery and has the details of the coils given next to the diagram.
This interesting circuit suggested by Motorola increases the duration of a pulse produced from the...
This Radio Electronics circuit, in an 80's edition, decodes the 67 kHz signal used at the time to...
Found in a Maxim publication from the 90s, this circuit generates signals from 10 to 25 kHz with a...