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.
Found in Motorola documentation from the 90's, this circuit has a high input impedance. The power...
This circuit from a National Semiconductor manual from the 1980s shows how to use the LM388, a...
This circuit was obtained in a 1977 Radio Handbook. The transistor is from the era and the coils...