First things first, I don't usually write articles like this and I am writing this article only to showcase a battery charging circuit me and my friends made for a college project.
The circuit is designed to charge 3 NiCd batteries of 1000 mAh each but can be modified to be set at any battery voltage and the circuit can be used for any battery type.
Components:
The circuit is designed to charge 3 NiCd batteries of 1000 mAh each but can be modified to be set at any battery voltage and the circuit can be used for any battery type.
Components:
- 230 V to 9 V Transformer (Or 110 V; depends on the AC Mains voltage where you live)
- Bridge rectifier. We used one similar to 4 1N4007 diodes but you can use any that you find.
- 470 microF, 50 V capacitor which is used as a filter.
- LM7805 Voltage regulator.
- LM741 op amp x3
- BC547B NPN Transistor
- 1 kiloOhm Resistor x5
- 1.2 kiloOhm Resistor x2
- 2.7 kiloOhm Resistor
- 2 LEDs (1 red and 1 green)
The voltage at the node connecting R1, R2 and the U1 op amp is ~3.64 V which is the full voltage of the battery.
This circuit is designed in such a way that the current going into the battery getting charged decreases when the voltage increases and the current gets automatically cut-off at 3.64 V.
Most of the charging current going into the battery comes from the emitter of the NPN Transistor.
For high and low battery indication, 2 LM741 op amps are used as comparators. The D1 LED is green, indicating full charge and the D2 LED is red indicating low charge.
In the circuit diagram, the +5 V voltage source is the equivalent of the circuit containing transformer, bridge rectifier, capacitor and LM7805 Voltage Regulator.
Link to .asc file to access circuit in LTSpice: https://drive.google.com/file/d/0BwawuPAjHYZSdmNCM3lVclA1RkU/view?usp=sharing
I also want to tell you about two of my friends' blogs who are in the same college as me.
Maitrey Mehta: infotechpundit.blogspot.com
+Shreyas Patel : spatels.blogspot.com
That's it for this article guys! I may write some more articles similar to this displaying my college projects. Feel free to write any comments/suggestions/questions in the comments section below. Keep reading! :D
