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.
This circuit can be used with 5 to 15 V sources and the zener diode must be chosen according to...
This semi-proportional temperature control was found in old American documentation. The components are...
The main feature of this circuit is that it provides a sine waveform signal. In this circuit, the...