With the circuit shown in the figure, it is possible to connect or disconnect a load controlled by the relay by touching the sensors X1 and X2.
We found this simple alarm circuit in a 1981 documentation. As we can see, it is a car alarm...
This small regulator was found in a Motorola 1968’s documentation. It is a current regulator using...
This low-pass filter with 741 op and symmetrical source was found in the August 1993 issue of...