This test circuit for transformers connected to the power grid makes use of a variac. We found it in an old American documentation.
This circuit is intended to detect when current flows through the opening of a car door. The...
This low power metronome produces pulses in a small loudspeaker. Pule rate is adjusted by P1 and...
This circuit uses a 4020 counter that divides the frequency up to 210, being found in a former...