I am designing a wireless charger for my cellphone, Where my Primary coil is energised with 1.5V and 0.3A, Where I have used a transistor to turn it on and off at a frequency of 1Mhz. In the secondary coil I got a peak to peak voltage of 32V and Vavg of 0.8V, Which I later rectified using a resistor and capacitor in parallel and I achieved a Vavg of 5.8V and the current in Microamps.

Since the current was insufficient to charge my cellphone,How can i improve the current in secondary Coil. Note: My primary coil had 40 turns Secondary coil had 20 turns.

The distance between primary and secondary coil is less than 1cm


simulate this circuit – Schematic created using CircuitLab


1 Answer 1


The key for making this work is resonance. You need to make a primary resonant circuit (i.e. pure LC). Then you need to feed it AC at teh resonant frequency, not just any frequency. Third is you need a secondary resonant circuit that is tuned to the primary. Then it will work.

But beware, currents in both primary and secondary will be large. That's the whole point of making it resonant. You'll need to tune the frequency of the feeding power to be just off resonance (but close). Experiment and you'll lean a lot. These are only the basics.


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