This simple circuit is a continuity test that, in addition to testing resistors, can also test other components. Power is provided by batteries and the LED can be of any color.
This circuit is quite old, from 1964, but can still be mounted with BC558 transistors. The circuit is...
This circuit is from a 1965 General Electric manual. It uses components from the time that admit...
This system of sequential lights for shop windows, discotheques, stores, does not use integrated...