2 Automatic 12V NiCd Charger

This is a very cheap NiCd charger with overvoltage control. The charger is very similar to Ni-Cd charger version 1 , but much simplified and specifically designed for 12V NiCd. The charger have current and voltage control.
-Charging current is around 100mA but you can change it using the formula : (Vd1 - 0.7) / R2; where Vd1 is voltage of zener D1.
-Cutoff voltage is limited to Vd2 - 0.7; where Vd2 is voltage of zener D2
charger schematic
Part List:
R1 - 2.7 kilo ohms 1/4w
R2 - 56 ohms 1W
D1 - 1N4735A or any 6.2V zener diode
D2 - 1N5244B or any 6.2V zener diode
D3 - 1N4001 or similar diode
Q1 - 9013, 2N2222 or similar NPN transistor
Q2 - 2N3440 or similar NPN transistor
9013 or  2N2222 pinouts
2N3440 pinout
Other NiCd Chargers:


  1. Yes thank you immensely for this site,it is very much appreciated.
    I dont see any were i can leave a donation
    Thank you very much
    Kind regards

  2. Hello, I see 24V DC supply on the scematic... is this what requires a 12V charger? I'm very new to electronics and have a drill tool labeled 9.6V and its charger labeled 12V 500mA 6VA. The charger is dead and I thought I could use a spare 12V 1000mA 12VA adaptor if it is possible and relevant. It would be a good training and very useful to get the drill back to work. Would anyone be kind enough to tip me, please?