This simple tester was found in a Popular Electronics from the 90s. The circuit is powered by two 9 V batteries since it requires a symmetrical source.
Found in RCA documentation two years 70, this circuit triggers an incandescent lamp at dusk. The...
Found in Popular Electronics from the 90s, this circuit is based on a PLL567 and employs high-end or...
This circuit was obtained in an English publication of 1977. The operational is of the type with...