This circuit was found in a 1945 publication. The circuit was stated to be part of a walk talkie. Note that, as it is a portable assembly, it was powered by batteries. The jack was for microphone insertion.
This circuit is from a 90s Popular Electronics. It appears elsewhere on this site. Q1 can be any...
This circuit works as a booster operating with signals from 1 to 30MHz. The gain is between 1 and...
This timer circuit was found in a 1980s American documentation. Transistors and SCR support modern...