Skip to content
Electronic Circuits

DIY Hobby projects, diagram, schematic

Electronic Circuits

DIY Hobby projects, diagram, schematic

Ni-MH Ni-Cd Adjustable Constant Current Charger

electronicecircuits, November 30, 2010August 15, 2023
Ni-Cd Ni-MH Adjustable Constant Current Battery Charger

Ni-Cd Ni-MH Adjustable Constant Current Battery Charger Circuit

This is a Adjustable Constant Current Ni-MH or Ni-Cd battery charger circuit. It can be used to get a constant current power supply. Here is the schematic diagram of the circuit:

Ni-MH Ni-Cd Adjustable Constant Current Battery Charger circuit

PARTS LIST
R1100Ω
VR1500Ω Preset
C10.1µF
C20.01µF
D11N4001
Q1BC140
IC1LM317

This circuit can be adjusted to any value from a few milliamp to about 500mA. The max current is 500mA because it is the limit of the BC140 transistor in the current-limiting part of the circuit.

The input voltage has to be 5.25v above the required output voltage, because of 1.25v across the current-limiting section and Approximately 4v is dropped across the regulator.  The LM317 3-terminal regulator will need to be heatsinked.

LM317 pinout configuration

the LM series of regulator is suitable for this circuit because they have a voltage differential of 1.25v between “adj” and “out” terminals.

BC140 NPN transistor pinout

For example, to charge 4 Ni-Cad cells, just connect them to the output and adjust the 500Ω preset until the required charge-current is obtained. The charger will charge 4 Ni-Cad cells at the same current. But, don’t forget to turn off the charger before the cells are fully charged or the battery will be over-charged.

LM317 Regulator Adjustable Constant Current ChargerLM317 Adjustable Constant Current Ni-Cd Ni-MH  Battery Charger

Please send your ideas, which are very important for our success…

Electronic Circuits Battery ChargerPower Supply

Post navigation

Previous post
Next post

Comments (4)

  1. cerebro says:
    September 5, 2011 at 5:49 am

    muy buen diseño,gracias

    Reply
  2. Lahiru says:
    November 26, 2013 at 10:22 am

    Can I Use BC 547 instead of BC140? if not what Can I Use?????

    Reply
  3. Ramana Madishetty says:
    September 10, 2014 at 10:50 pm

    Hello,

    Very well explained.
    Need a suggestions. Can i replace Diode with 1n4007 and 0.001uf with 0.1uf? Hope there will be no big changes with capacitors. Sorry, Correct me if i am wrong.

    Reply will be appreciated 🙂

    Reply
  4. pauspam3 says:
    October 4, 2014 at 4:17 am

    Equivalent transistors can be found via a link on http://alltransistors.com/transistor.php?transistor=22314

    Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

  • Diagrams
  • Privacy Policy
  • Software
  • Contact

Recent Posts

  • LM317 CONSTANT CURRENT CALCULATOR
  • 5V buck converter – LM2576 simple DIY project
  • ICL7107 PANEL METER
  • Precision 1Hz clock generator circuit
  • Toggle to Momentary Switch Using 555 Monostable

Categories

  • Circuit Tutorials
  • Electronic Circuits
  • Electronic Software

AC Projects Alarm Circuits Amplifier Circuits Amplifiers Antenna Circuits Battery Charger Calculator software Circuit Designer Control Circuits Converter circuits Crossover Circuits Data Sheets Digital Circuits Electronic Switch Flasher Circuits Game Circuits IC Programmer IC Programming Indicator Circuits LED Circuits Light Circuits Logic Circuits Measuring Circuits Meter Circuits Microchip Motor Circuits Music Circuits Oscillator Circuits PCB Designer PIC Power Amplifier Power Guard Power Supply PreAmplifier Circuits Radio Circuits Regulator Circuits Regulator Diagrams Regulator Schematics RF Schematics Sensor Circuits Tester Circuits Timer Circuits Transmitter Circuits Tutorials Vacuum Tube

©2025 Electronic Circuits | WordPress Theme by SuperbThemes