This NiCd battery charger circuit is very simple but it has a current and voltage limiting.
Lamp L1 will light brightly and the LED will be out when the nicd battery is low and being charged, but the LED will be bright and the light dim whenever the nicad battery is nearly ready. Li should be a bulb that is rated for the current you want (usually the battery capacity divided by 10). Diode D1 must be no less than 1 A, and Zl is a 1-W zener diode with a voltage in accordance with the full-charge battery voltage minus 1.5 V. Right after the nicad battery has been fully charged, the NiCd charger circuit will float it at around battery capacity divided by 100 mA.
