By following the instructions from this article one can make its own portable phone charger circuit similar to one you can get at shop .
It is an excellent idea to keep your phone charged when you are out or travelling.
These chargers range in size from tiny ones that fit in your pocket to larger ones that have the capacity to power several devices.
They can also charge smartwatches, iPads, phones and even headphones
Components for Power Bank Circuit:
7.4V 2600mAh Li-ion Battery: The mobile phone bank circuit is powered by a 7.4V 2600mAh Li-ion battery.
It generates 8.2V when fully charged.
7805 Voltage Regulator IC: The IC 7805 is a widely used linear voltage regulator integrated circuit that is used to control voltage.
The main purpose of this circuit is to reduce the Li-ion batteries 8.2V output to a steady 5V.
How to Build:
Parts List:
| Category | Component | Quantity |
|---|---|---|
| Semiconductors | IC 7805 Voltage Regulator | 1 |
| Power Source | Li-ion Battery 7.4V | 1 |
| Electronics | Mobile USB Port for Charging | 1 |
- Connect the Li-ion batteries positive connection to the 7805 input Vin.
- Join the Li-ion batteries negative terminal to the circuits common ground.
- Now the IC 7805 output Vout pin is steady for 5V.
- Use wires to connect the 7805 output to the USB ports positive terminals.
- Connect the 7805 ICs ground pin to the USB ports negative terminal.
- Attach the positive and negative USB port terminals to the correct mobile phone charging cable terminals.
- The USB ports must to be made to provide the standard 5V output for mobile phone device charging.
- Protection components like fuses or overvoltage protection circuits must be included depending on the design.
- Monitoring devices that show the batteries condition or the charging process like LEDs or voltage indicators should also be included.
In general, the circuit uses the 7805 voltage regulator to step down the 8.2V or 8.4V from the Li-ion battery to a steady 5V output which is then sent to USB ports for charging smartphones or other smart devices while traveling outside.
Functioning with standard mobile device charging standards is thus guaranteed.
Components for Recharging the Power Bank Battery at Home:
9V AC to DC Adapter: This adapter is used to convert the mains electricity into a stable 9V DC power source for the circuit.
Zener Diode 9V: The Zener diode is used to fix the base of the TIP35 transistor providing a stable reference voltage.
In this circuit a 9V zener diode is used.
TIP35 Transistor : The TIP35 is installed as an emitter follower.
In this configuration the emitter follows the base voltage minus the diode forward voltage drop.
Connection Details:
Parts List:
| Category | Component | Quantity |
|---|---|---|
| Resistor | 100Ω 1W Resistor | 1 |
| Semiconductors | TIP35 Transistor | 1 |
| Zener Diode 9V 1W | 1 | |
| Power Source | Li-ion Battery 7.4V | 1 |
- Connect the zener diodes anode to the 9V AC to DC positive terminal adapter.
- Fix the zener diodes cathode to the circuits common ground.
- Wire the zener diodes cathode to the TIP35 transistors base pin.
- Connect the TIP35 transistors emitter pin to the common ground.
- Join the TIP35 transistors collector pin to the Li-ion power bank batteries positive terminal.
- Make sure the Li-ion batteries negative terminal is connected to the ground.
- Feedback mechanisms like resistors or sensors are used to monitor the charging process and control the charging current depending on once needs.
Formulas and Calculations:
Following are few essential factors while using a power bank to charge a mobile phone battery.
Below are simple formula with an explanation:
Charging Time = Battery Capacity / Charging Current
where,
- The charging time (t) is the time needed to fully charge the battery of a mobile phone.
- Battery Capacity (C) which normally appears in milliampere hours (mAh) or ampere hours (Ah) is the capacity of the mobile phone battery.
- Usually expressed in milliamperes (mA) or amperes (A) the charging current (I) is the current that the power bank supplies to charge the battery of a mobile phone.
Example Calculation:
Assume that you have a 3000 mAh cell phone battery and that your power bank provides 1000 mA of charging current.
Charging Time = 3000 mAh / 1000 mA
Charging Time = 3 hours
Therefore, in this situation using a power bank with a 1000 mA charging current to charge the mobile phone battery from 0% to 100% can take about three hours.
Remember that this is only a rough estimate and that real charging periods can change based on the circuits charging efficiency the batteries initial condition and changes in charging current over time.
Circuit Working:
The circuit receives a steady 9V DC input from the 9V AC to DC adaptor.
The zener diode maintains the TIP35 transistors base voltage at a steady 9V less the forward voltage drop which comes out to be about 8.6V at the base.
The output voltage of the TIP35 transistor in emitter follower voltage regulation mode is then around 0.6V lower than the base voltage.
For charging the 7.4V Li-ion power bank battery the output voltage thereafter drops to about 8.4V.
Both the battery and the TIP35 transistors emitter share a common ground and the Li-ion battery is connected to the transistors collector pin.
This simple power bank battery recharger circuit allows for the controlled charging of the Li-ion power bank battery at home using a 9V AC to DC adapter.
When the battery is completely charged it is placed outside power bank which offers a practical means of charging cell phones in an emergency.
Conclusion:
If difficult calculations are avoided a general audience will find the information in this Simple Power Bank Circuit for Charging Mobile Phones easier to understand.
Since most customers are more worried about safe charging methods.
It highlights the user friendly already built module options that can be used to save time and even prevent frustration.
There is less danger and it is easier to read and remember shorter explanations.
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