The cut-off frequency of the circuit shown in the figure is 750 Hz, with the components used. The circuit applies to almost any operational amplifier and the power supply must be symmetrical.
This traditional sensor configuration with LDR was found in a 2001 documentation. The integrated circuit...
This circuit is from an 80's Radio Electronics. It triggers a load powered by the power grid from...
This circuit was found in February 1976, Radio Electronics magazine. The circuit is powered by 12 V...