This is a special charger you can carry with you to charge your phone anywhere, even without a plug.
It uses a regular AA or AAA battery just like the ones for your remote control.
Inside, it has a part that takes the weak battery power and turns it into strong power for your phone.
However, keep in mind that a single AA or AAA battery will not charge your phone for very long.
Circuit Working:
Parts List:
| Category | Component | Quantity |
|---|---|---|
| Resistor | 50Ω 3W | 1 |
| Capacitors | Electrolytic 470µF | 1 |
| Electrolytic 2200µF | 1 | |
| Semiconductors | Transistor TIP31 | 1 |
| Diode 1N4001 | 1 | |
| Zener diode 5.1V | 1 | |
| Others | Coil Inductor | 1 |
| Cell phone charging connector | 1 |
To charge a cell phone, the charger output must exceed 4V and deliver a maximum current of 500mA.
This charger circuit boosts the voltage from a 1.5V AA or AAA battery to 5V DC meeting the cell phones charging requirements.
The circuit comprises a simple oscillator, rectifier, and voltage regulator similar to the joule thief circuit.
The feedback winding, F consists of 5 turns of #30 AWG magnetic wire while the main winding, P comprises 6 turns of #24 AWG wire.
A 5.1V zener diode and a 2200uF capacitor regulate the output voltage to ensure proper charging.
The winding specifications are not crucial, you can experiment with different turn counts.
If the charger does not output any power try reversing the winding connection.
However, it is worth noting that this setup may only charge the mobile phone battery for a short period as the 1.5V batteries power capacity is much lower than that of the phones battery.
Formulas:
The above circuit explains, a BJT feedback oscillator that makes use of a center tapped transformer is called a colpitts oscillator.
Oscillation Frequency:
f = 1 / (2 * π * √(L * Ceq))
where,
- In hertz Hz, f represents the oscillation frequency.
- L is the transformer primary windings total inductance expressed in henrys H.
- Ceq, which is the two capacitors equivalent capacitance in farads F is determined by:
Ceq = (C1 * C2) / (C1 + C2)
Extra Information
One kind of feedback oscillator that makes use of a center tapped transformer is the colpitts oscillator.
There are other configurations as well, such as hartley and clapp oscillators.
Trade offs between variables including component availability, amplitude and frequency stability are common in practical circuit design.
How to Build:
To build a Simple Cell Phone Charger Circuit using 1.5V Battery follow the below mentioned connections steps:
- Connect the positive terminal of the battery to one end of the coil inductor.
- Connect the other end of the coil inductor to the collector of the NPN transistor TIP31.
- Connect the emitter of the transistor to the negative terminal of the battery.
- Connect a diode to the collector of transistor with the cathode connected to the positive terminal of the cell phone connector output.
- Connect the base of the transistor to the feedback winding.
- Connect a resistor 50Ω 3W between the base of the transistor and the positive terminal of the battery.
- Connect the 5.1V zener diode across the output terminal which is used for charging the mobile phones.
- Connect a capacitor 2200uF across the output terminal which goes to the cell phone connector.
Important Note:
- This circuit involves high frequency oscillations and can be challenging to get working correctly.
- Exercise caution and ensure you have the necessary skills and knowledge before attempting to build it.
Conclusion:
A cell phone charger circuit using a 1.5V battery offers a portable and efficient way to charge your phone while on the move.
By utilizing a boost converter, this circuit can step up the voltage from a standard battery to the 5V needed for USB charging.
This compact and versatile solution is ideal for situations where access to a wall outlet is limited providing a reliable power source for keeping your mobile phone charged and ready to use.
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