Found in a Philips publication from the 1970s, this circuit uses a DO040, which is difficult to obtain today. The circuit is powered by 12 V on pins indicated in the diagram.
This control for 12 V drills was found in a 90s Elektor. The components are current, and Q1 can be...
Found in an old English publication, this circuit applies to the 240 V network, but can be changed to...
This circuit was found in a 90s Popular Electronics. With it, using a 4066, it is possible to...