Overview
Imagine you’re on a camping trip, far from power outlets, but your phone’s battery is running low. You wish you had a way to charge it using the USB port on your power bank. That’s where the USB Powered Mobile Phone Battery Charger Circuit comes in handy.
In today’s tutorial, we are going to make a “USB Powered Mobile Phone Battery Charger Circuit” using Transistors.
This simple circuit delivers a steady 4.7 volts for mobile phone charging. A standard USB port provides 5 volts DC at 100mA, ample for slower phone charging. Most phone batteries are rated around 3.6 volts with capacities ranging from 1000 to 1300 mAh, typically comprising three NiMH or lithium cells rated at 1.2 volts each. Faster charging typically demands 4.5 volts at 300-500 mA.
However, slower charging is often better for battery health and efficiency. This circuit ensures a stable 4.7-volt output suitable for slow charging. Transistor Q1 manages the regulated output, and various NPN transistors like CL100, BD139, or TIP122 can be used. Zener diode D2 stabilizes the output voltage, while D1 guards against supply polarity issues.
For assembly, connect a red wire to pin 1 and a black wire to pin 4 of the USB plug for easy polarity identification. Then, link the output to a compatible charger pin for connection to the phone. Once assembled, plug the USB into a socket and check the circuit’s output. If the voltage is correct and the polarity is right, it’s ready to charge your phone.
Hardware Components
To make this Mobile Phone Battery Charger Circuit, you’ll need the following hardware components to get started:
| S.no | Components | Value | Qty |
|---|---|---|---|
| 1 | Transistors | Q1 = BD139 | 1 |
| 2 | Diodes | D1 = 1N4001 D2 = 4.7V – 1/2W | 1 |
| 3 | Non-Polar Capacitors | C1 = 16V – 100uF | 1 |
| 4 | Resistors | R1 = 560R – 1/2W | 1 |
Schematic
If the polarity is incorrect, it will destroy the mobile battery. So take extreme care.
Applications
- Creating a portable and compact mobile phone charger for travel or emergencies, powered by USB sources such as power banks, laptops, or car chargers.
Conclusion
The USB Powered Mobile Phone Battery Charger Circuit offers a practical and accessible solution for DIY enthusiasts and electronics hobbyists seeking to create a reliable charging system for mobile phones
