This simple sensitive circuit was suggested in a July 1992 Radio Electronics issue. The relay is a double-contact changeover relay. Sensitivity adjustment is made at R2.
This circuit activates a machine to dry hands (fan and heater) when the sensor detects the...
The operational used is like the 741. The circuit is from the datasheet and the formula that...
The second order filter shown in the figure is suggested by Texas Instruments, based on the TL081...