Found in a 90’s HAM Radio, this circuit is used for an optical communications system or even audio transmission by optical fiber. The components are common.
We found this circuit in an 80's Radio Electronics. The circuit uses a PTC sensor and an LED...
In this circuit a 12 V lamp or LED blinks with the music signal applied to the input. R depends on...
Using a period sensor, this circuit was found in the February 1986 issue of Radio Electronics...