In the figure we have one of the many options found in this section for an intercom using ordinary phones not in use. This was obtained in a Popular Electronics from the 90s.
This circuit tests quartz crystals of frequencies between 100 kHz and 10 MHz. The circuit is from...
We found this circuit at a January 1991 Modern Electronics. The magazine no longer exists, but the...
The ZN416E integrated circuit is uncommon today. It consists of a complete radio, like the one...