Found in a 1970s American documentation, this circuit uses components from the era that can eventually be replaced by modern equivalents. The power supply must be symmetrical.
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...