This old 4-channel circuit was found in the December 1994 Electronics Now magazine. The circuit uses a 556 as a modulator. Note the code programming key.
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...