This circuit was presented in a January 1990 Radio Electronics magazine article as part of a home theater sound effects system. It consists of a 3 kHz high-pass filter.
This is a MOSFET version of a grid dip meter for frequencies between 1.8 MHz and 150 MHz,...
This circuit has a sensitivity of 2uW. We found it in documentation from the 1980s. The integrated...
The sensors in this circuit are photodiodes with filters. The circuit is suggested by the National...