This sensitive circuit was found in the June 1995 Electronics Now magazine. R1 can be from 10k to 1M depending on the desired sensitivity. Power is supplied by the relay.
This is the traditional unregulated power supply configuration with full wave rectification. For currents...
Home automation systems are becoming smarter and more connected with the launch of every new...
This simple circuit has its trigger point set in the trimpot. The transistor can be any general...