This 2-quadrant modulator circuit was found in the May 1988 issue of Radio Electronics magazine. The CA3080 is an OTA operational amplifier.
This was a very popular instrument in the workshops of the 60s and 70s. It was a "top of the line"...
The idea is simple: using a flashlight to cut your TV commercials triggers a relay that turns off...
This circuit is from a Popular Electronics from the 90s. The integrated circuit admits equivalents...