01 July 2016 User ReviewCheck your delivery options:
Inductive charging or wireless charging is a convenient method to charge your smart phones without any wires. As you switch on the charging circuit, you can see that smartphone gets charging up. Wireless charging makes use of electromagnetic field to transfer energy from your charging circuit to the smartphone. Charging circuit consist of an oscillator, switching circuit and a primary coil. Oscillator will generate oscillations which will be a square wave. MOSFET (IRFP 240) can be used as switching unit. It’s a three terminal device (drain source and gate). By controlling the gate voltage, current flow through the coil can be controlled. Now, IC 555 timer starts to work as an Astable Multivibrator. An Astable multivibrator, often called a free-running multivibrator, is a rectangular-wave generating circuit. As timer IC gets the required power supply, it produces square wave at the 3rd pin. An Astable multivibrator can be produced by adding resistors and a capacitor to the basic timer IC, as illustrated in circuit. The timing during which the output is either high or low is determined by the externally connected two resistors (R47, R48) and a capacitor (C20).The period of the square wave is described by the equations:
T (on) = (0.69) (R47+R48) (C20)
Mutual induction is the basic principle behind wireless charging. Amount of mutual inductance depends on the relative positioning of both the coils. If the coils are nearer to each other, most of the flux generated by the primary coil will interact with the secondary coil. Hence a high voltage will be induced in secondary coil. If the coils are farther apart, amount of flux linkage will be less and voltage induced art secondary coil will be less.