This circuit is from Motorola's 1990 Linear Databook. We can implement it with other operational amplifier. The power supply must be symmetrical.
This circuit locks when the sensors are opened. The relay can be 6 or 12 V depending on the power...
This is a conventional differentiator configuration with operational amplifier. In principle any...
This circuit should be used with low frequency signals only. The circuit is from a documentation from the...