This circuit was found in Philips documentation from 1967. The components are of the time, being transistors like BCY38 for TR1, BC108 for TR3, and others depending on currents.
This circuit uses a 7-segment display to indicate the logic level of a test circuit. The power...
With the circuit shown, we have an excellent level for the signal obtained from an electret...
The integrated circuit used in this project is an old voltage comparator, since the configuration was...