This circuit is from the 80's but uses common components today. The relay is voltage sensitive according to the power supply used. Transistors may be general purpose types.
This circuit allows the detection of RF signals using the lowest range of direct currents of a...
The MC496 integrated circuit used in this application is not common today. Motorola's circuit...
This window comparator circuit was found in a Popular Electronics from the 90s. The circuit has a...