This circuit makes use of an integrated LM2907. The circuit is from an old documentation being applied to cars that still used platinum, common at the time.
The transistors in this 1978 circuit can be BC548 and 1N4148 diodes. The electrolytic capacitors can be...
This shield circuit is suggested by Texas Instruments and can employ almost any optical coupler...
This circuit was found in an American documentation from the 90s. It consists of a variable with a...