This circuit was found in the January 1989 issue of Radio Electronics magazine. The circuit sends audio signals by modulating a low-frequency carrier through the power grid.
The simple optical intercom we show is from a 1995 documentation. The LEDs can be infrared or...
This circuit is suggested by Texas Instruments in old documentation. The components depend on the...
This circuit was found in a Popular Electronics documentation from the 90s. It is possible to switch...