This circuit was found in documentation from the 1980s. The integrated circuit is from the time and the voltage depends on the desired power, and the component's datasheet should be consulted.
This circuit controls a heating element with voltage from 6 to 30 V and current up to 3 A from...
We found this Vox in a 1969 Motorola documentation. Transistors support modern equivalents and the SCR can...
Found in a 90s Elektor, this mixer makes use of integrated circuits of the time. The supply must be...