Found in American documentation from the 90s, this circuit keeps the high beam on for a time determined by the trimpot adjustment. The relay is sensitive 12 V.
This transmitter modulator amplifier for the 11-meter band (CB) was published in Radio Electronics...
This oscillator, which operates from 2 V, was found in the June 1993 issue of Radio Electronics magazine....
This amplifier for electrometer can work with currents of 0.1 pA in a band of 1 Hz. The circuit is...