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 power supply was originally created for the CB16760E (Loudness System) but can be used in any...
Found in 1980s Electronic Engineering, this circuit uses common phototransistors as sensors. The...
This simple, unregulated power supply with an approximate 6 V output voltage can supply currents up to...