This circuit was found in an old GE SCR manual. The SCR must be in accordance with the relay and transformer as well.
This simple intercom for home use was found in a 1979 publication. It can be easily mounted with...
This circuit was found in a Popular Electronics from the 90's. The CMOS integrated circuit used is...
This circuit was found in old Maxim documentation. Check the availability of the IC if you are...