This circuit is from an article in Radio Electronics magazine from October 1958. The circuit is for testing electrolytics that operate at high voltages depending on the source.
This circuit was found in old documentation and can be implemented with other operational...
Found ina 1970 American documentation this fast-reading circuit uses a photodiode. Transistors...
This circuit is from a publication from the 70s, but it can be assembled with any diac and a Triac...