This circuit was obtained from Dutch documentation from 1964. The components are of the time, but current equivalents such as BC548 to BC108 can be used.
This circuit was found in National Semiconductor documentation from the 90s. The circuit uses two...
This bargraph circuit has already been explored in other versions in articles on this site. This is...
We found this circuit in a Popular Electronics of the 80s. The circuit can be made with almost any...