This circuit was found in an article in Radio Electronics magazine. The issue is from July 1992 and the circuit uses components that are common today.
The indicator instrument of this transistor tester, from an Argentine publication of the 1970s,...
This circuit was obtained from a Philips documentation from 1970. It can be built on modern...
This circuit was obtained in 1974. It serves to indicate the tuning of stations on a common...