We found this solid-state relay circuit that can function as a shield in a Radio Electronics magazine from December 1989. The optocoupler is a phototransistor type.
We found this alarm in an English publication from 1978. Although the original power supply is 3...
This circuit used in photographic applications was found in the May 1971 issue of Radio...
This switching power supply is ideal for LCD multimeters that use 9 V batteries (which spend...