In this circuit the LED lights up when the voltage drops below the value set in the trimpot. The transistors can be the BC548. The circuit is from a 1999 American publication.
With this circuit that we found in documentation from 1989, it is possible to transform an...
This circuit was found in Signalite documentation from the 1960s. The circuit uses a pulse...
This circuit with RTD sensor was found in the Radio Electronics magazine of April 1992. At the...