This circuit is from an American manual from 1975. The transistors are types of the time, but equivalents can be used, as well as the relay that can be according to the supply voltage.
This circuit was found in 80's Popular Electronics. The components used are common and the number of...
This 10-step voltage indicator was obtained from a 1980s publication. The circuit is based on an...
This circuit was found in an old Electronic Design used to apply digital signals to an analog...