This circuit was found in a 90’s EDN. The components used are still common and the sensors can have their quantity increased. The supply voltage is according to the relay.
This circuit of an old publication produces the insect-like noise that drives them away. The...
Found in American documentation this circuit uses transistors of the time. The circuit can be made...
G This neon lamp indicator was suggested by General Electric in 1970 documentation. Virtually any neon...