This sensitive circuit for triggering relays was found in an old English publication. It works with alternating signals applied to its input. Transistors are general purpose types.
This sophisticated alarm with traditional components was found in an ancient American...
This circuit is from a Fairchild digital clock module shown in the March 1977 issue of Radio...
This circuit was obtained in a Radio Shack documentation from 1977. It can be used as a multimedia...