# what is the use of ultrafast diodes in wireless battery charger ckt

Instructable

I am working on a wireless charger that uses a ZVS Driver circuit for the transmitting end. This is its circuit diagram:

I have attached the instructable where this came from. Wireless Power Charger here

• Your attempt to experiment with mark-up is appreciated, but as a result your question now is a mess and it has little by way of further effort in asking an actual question. This will not help you get good answers. Generally the answer and length of it reflects the effort you put in your question. – Asmyldof Oct 31 '15 at 6:53

If you used "normal" diodes you would find that the oscillator would be a very poor performer - frequency would be massively lower and efficiency would be terrible. It comes down to the parameter of a diode known as "reverse recovery time" ($t_{rr}$).
If you looked at a "normal" diode like the 1N400x series you would find that it's $t_{rr}$ is in the order of 30 us.
$t_{rr}$ basically tells you that for 30 us after the polarity of the voltage across the device has changed from forward conducting to reverse biased, the diode will not instantly block but takes 30 us. LINK: -