The integrated circuit used in this detector is uncommon today. We found it in a documentation from the 70s. Detection is done by an optical camera with LEDs and a photo sensor.
Suitable for operation with high impedance microphones, this circuit was found in American...
Analog Devives EVAL AD5941 Electrochemical Evaluation Board This board provided by Mouser...
When the power is turned on, the output of this circuit goes to the “1“ logic level by a time...