Metal detector receiver (CB22457E)

Found at Popular Electronics this receiver is used with a transmitter for quadrature-coil signals.

Telephone Call Sign (CB16888E)
The presented circuit activates a relay when a telephone call occurs. The relay can be used to...
SIDAC Gas Stove Lighter (CB12544E)
SIDACs are not yet common components in power applications that involve voltage tripping. However,...
Optical Isolator and AC Trigger Power Switch (CB12414E)
This solid-state relay (SSR) or shield was found in a 1995 Electronics Now. The transistor can be...