This photoelectric sensor that triggers a relay was found in an English book from 1989. The transistor is a general-purpose type, and the integrated circuit consists of an operational amplifier.
In the figure we have a simple signal tracer circuit to be coupled to the volume control of an AM...
This circuit was found in documentation from the 90s, using components from that time. The...
This circuit, obtained from old documentation, allows the recovery of sulfated batteries. The...