Found in a Hands On Electronics from the 80's this circuit allows the reading of low resistances in a common multimeter. The circuit consists of a constant current source.
I found this circuit in a 1980 documentation, but it can be easily assembled with BC548...
We found this alarm in an English publication from 1978. Although the original power supply is 3...
Found in old documentation, this circuit can use modern equivalent components. The signal has good...