This circuit uses a 7-segment display to indicate the logic level of a test circuit. The power supply is made with 5 V that can come from the analyzed circuit itself.
This circuit was obtained from an English magazine from 1979, but can be easily assembled...
This circuit is from a Linear datasheet. The circuit provides a 5 m voltage with 40 mA from an AA...
The circuit presented is suggested by Mullard (Philips) in an old manual. The circuit uses a...