This circuit activates a warning lamp when an incoming call is received. We found it in an 80s Hands-On Electronics. The diac and triac can be of any type.
This anti-ringing circuit was found in an English documentation from 1996. The integrated circuit is...
The figure shows how to increase the gain of the amplifier stage of the previous circuit. The...
This circuit uses unusual operational amplifiers, but equivalents can be tried. FETs can also be...