Found in an old Popular Electronics this circuit is still current. The SCR can be of the 106 series and the relay according to the voltage used in the supply. The voltage can be 12 V.
The simple touch of the fingers on a sensor causes this circuit to drive a motor that goes into...
Motorola's MC1456 integrated circuit used in this application is not very common today. The...
This circuit of an old publication produces the insect-like noise that drives them away. The...