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 uses a 455 kHz IF coil and is suitable for SSB listening on a standard receiver. It...
An interesting timer is shown in the figure, using one of the 4 NAND gates of the integrated 4001....
Found in a 1964 Electronic Design this circuit makes use of components of the era. The output is 2 V...