HII. I want to do what this person is doing http://www.instructables.com/id/I-need-your-help.-INDUCTION/
seems awesome.. I want to generate 120 kHz with Arduino, but how do i do that.
Read the intructable so you can get some more info on what i want to accomplish.
maybe you could change the pwm frequency and use that, i dont remember how though.
I would imagine this is a task best left to the analog domain, not the digital domain. Whatever you produce would be a poor substitute for an AC waveform, and limited in terms of available frequencies.
That said, the DC square wave mentioned in the instructable can just be a PWM output set to a 50% duty cycle at the right frequency.
Google found these and several others:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1195922336
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1152547089
You don't actually need anything else but a square wave to drive the coil as the resonance will turn it into a sin wave. That instructables circuit doesn't need to two 10R resistors across the supply just put the other end of the coil to ground and switch between + and ground with the transistors. Derive the square wave from either the Arduino or the NE555 as shown. You will get about 200V across the coil with a 5V supply when you hit resonance. Tune for resonance by adjusting the capacitor and tweaking the frequency.
Can i convert the output of arduino into AC then power the coil.. Anyone have an easy tutorial for a DC to Ac circuit.... thanks.
Just treat it like a motor changing direction very quickly, that is send the current down the coil one way and then send it down the other. Use a H bridge circuit, just like a motor.
Cool, thanks
Im gonna simply build the timer circuit if you could help me a little bit.
what is this capacitor
http://www.instructables.com/file/FCNJSR1FA190GHT/
heres the original page,,,, http://www.instructables.com/id/S9K5298FA190GHW/
thanks you so much for all your help.
in uF 
18 the number 1K the number of zeros
so you have 18,000 pF
that is :-
18nF
or
0.018uF
Im wondering in a 0.01 cap. will work... any advice?
Im wondering in a 0.01 cap. will work
The capacitor is used to resonate the coil, if you change the value you have to either change the inductor value or change the excitation frequency.