This configuration that appears in other points of this section was obtained in a 90’s Popular Electronics. The circuit can be applied to other operational ones.
This circuit was found in an EDN from the 90s. The circuit employs a double 555 and uses the...
This circuit was obtained from a 1977 magazine, but can still be mounted using BC548 for TR1 and...
This indicator makes use of an LM339 voltage comparator circuit that contains 4 internal...