Based on a 555, this 80's American documentation circuit detects the voltage of a battery and can then disconnect the charger. The transistor may be a general purpose type.
This circuit uses common diodes as sensors, triggering when the temperature rises by touch,...
Simple timers can be designed using inverters or any other gate that can be connected as inverter. Figure...
This circuit was found in the 1987 Radio Electronics magazine. The components used are integrated...