This TTL circuit is from a Radio Electronics magazine from November 1983. The circuit drives a set of LEDs. The integrated circuit used is a BCD to decimal decoder.
This circuit uses reed switches as sensors. We found it in a 1992 documentation. A float at a...
One of the problems with analog multimeters is the non-linearity of the resistance scale. This...
I found this circuit in an old English magazine from 1979, but it can be easily assembled with...