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 excellent wireless microphone circuit for the varicap-modulated FM band came out in...
This amplifier obtained from Signetics documentation can operate with signals ranging from the...
This circuit is from Radio Electronics from April 1987. The circuit is powered with voltages that...