This circuit was found in 80's Popular Electronics. The components used are common and the number of indication channels (LEDs) can be changed.
Developed by Philips this 60's circuit uses a transistor of the time, but the configuration holds true for...
This independently charged circuit was found in a 1969 EEE. The operational amplifier supports a...
This power control circuit was found in an article in the June 1995 Electronis Now magazine. The...