This circuit was found in a 90’s 303 Circuits. The components are from the period and the heating system depends on the resistive element.
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...