This document describes a wireless battery charger circuit that charges mobile devices without wires. It works on the principle of mutual inductance to transfer power from a transmitter coil to a receiver coil placed near it. The circuit uses common electronic components like resistors, capacitors, diodes, transistors and coils. To operate it, the circuit is constructed and powered on, then a mobile device with a receiver coil is placed near the transmitter coil to start charging the battery wirelessly. Advantages are not needing a separate charger and ability to charge anywhere. Applications include charging phones, cameras and medical devices. Limitations are some power loss and short effective range.

2. Contents
 Introduction.
 Working Principle.
 Circuit Diagram & Design.
 Operating Process.
 Advantages.
 Application.
 Limitations.

3. Introduction
Each phone will have its own
designed battery charger. Thus
the battery chargers are
required to carry everywhere to
keep the battery backup. Now
just think of a battery charger
that charges your obile
automatically. When you sit for
tea and place your mobile on
the table, it simply charges your
mobile. This article explains a
simple wireless battery charger
circuit that charges your mobile
when placed near the
transmitter. This circuit may be
used as wireless power transfer
circuit, wireless mobile charger
circuit, wireless battery charger
circuit, etc.

4. Working Principle
This circuit mainly works on the principle of
mutual inductance. Power is transferred from
transmitter to the receiver wirelessly based
on the principle of “inductive coupling”.

5. Circuit Diagram & Design
o Resistors
o Capacitors
o Diodes
o Voltage Regulator
o Copper Coil
o Transformers
o MOSFET
o LED

6. Operating Process
Initially, connect the circuit as shown in the circuit
diagram.
Switch on the supply.
Connect the battery charger at the output of the
circuit.
Place the receiver coil near the transmitter coil.
You can observe the charging of battery.

7. Advantages
 Usage of separate charger is eliminated.
 Phone can be charged anywhere and anytime.
 It does not require wire for charging.
 Easier than plug into power cable.

8. Application
 Wireless chargers can be used to charge mobiles, camera batteries,
Bluetooth headsets etc.
 This can also be used in applications like car battery charger with little
modification.
 This can also be used in medical devices.

9. Limitations
 Power is somewhat wasted due to mutual induction.
 It will work for very short distances only. If you want to use it
for long distances, then the number of inductor turns should be high.

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