This circuit indicates when the voltage of a 12 V battery is low. With changes, for example, the zener, the circuit can be used to monitor other voltages.
This circuit is from 80s documentation, using still common CMOS components. The display is 7...
This circuit was obtained in an English magazine from 1979, but it can be easily assembled with...
Found in Electronics Now, this circuit generates signals for testing like a signal injector. The...