In this DIY tutorial, we will demonstrate an Automatic NiMH (nickel-metal hydride) battery charger circuit. This NIMH is a secondary cell and a kind of rechargeable battery. It is modest and normal for AA cells available in numerous Capacity ranges. By implementing this battery charger we can supplant the conventional battery immediately.
Furthermore, a 7085 IC, two transistors, and a couple of discrete parts are the main components of this circuit. These components make it an exceptional, automatic, self-regulating, and automatic NiMH battery charger circuit.
The following schematic is a full automatic NiMH battery charger circuit. It is utilizing a positive integrated voltage regulator IC 7805. Moreover, the circuit provides a steady current to charge the batteries. Right now, the circuit is functioning as a charging indicator, so when the batteries become fully charged the LED will turn off.
Hardware Component
The following components are required to make Battery Charger Circuit
| S no | Component | Value | Qty |
|---|---|---|---|
| 1. | Voltage regulator IC | 7805 | 1 |
| 2. | LED | – | 1 |
| 3. | Transistors | S9014 | 2 |
| 4. | Resistor | 1K, 10K, 150K, 25, 33, 50, 100 Ω | 1 |
| 5. | Capacitor | 1000µF | 1 |
| 6. | Step down Transformer | 230V to 9V | 1 |
| 7. | Diode | 1N4001 | 5 |
| 8. | Switch | – | 1 |
| 9. | AC Power Supply | 230V | – |
LM7805 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 7805
Battery Charger Circuit
Working Explanation
The operation of the circuit is simple and easy to understand. The circuit can charge two NiMH rechargeable batteries one after another. This automatic NiMH Battery Charger has four distinctive current sources. For example 50mA, 100mA, 150mA, and 200mA. You can select any of these current sources with the help of the attached switch S. So you can pick the appropriate current source for your batteries. For instance, on the off chance that you need to charge 500mA NiMH rechargeable batteries you need to choose 50mA current. For 1000mAh NiMH batteries select 100mA, for 1500mAh select 150mA and for charge 2000mAh batteries select 200mA.
Applications and Uses
NiMH battery chargers utilize in the following areas:
- Use to Charge digital cameras and other electronic devices.
- Favorable for high-current-drain applications, to a great extent because of their lower internal resistance.
