This circuit was found in a 90’s EDN. The components used are still common and the sensors can have their quantity increased. The supply voltage is according to the relay.
We found this code key or coded keyboard in a publication from the 90s. The circuit uses...
Two operational are used on this triangular-rectangular oscillator suggested by Motorola in its...
This circuit can be used in a power grid remote control project with the coil according to the...