In this circuit of an American documentation of the 90s, when the light is cut, we have the production of a pulsating tone. R3 determines the trigger sensitivity.
This circuit is from an Electronics Now from August 1995. The triac is according to the load that...
This configuration is from an old integrated circuit manual. The circuit can be applied to modern...
August 2016 - It can be obtained from Mouser Electronics thenew broadband ADCs ADS127L01 from...