Found in an American publication from 1968, this circuit can be made based on a TIP42 that must be mounted on a heat sink. The transformer is 25 V with a current of 3 to 4 A.
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...