I’ve put a higher resolution image of the hand-drawn schematic up now. In the comments below, Tima noticed a resistor in the video connected between Gate and Source of the MOSFET. This is a 10M ohm resistor which I added to protect the gate against stray voltage while I was assembling the breadboard – it’s not critical, can be included or left out.
The code listing (below) requires PWM.h - this comes from the library “PWM Frequency Library” which you’ll have to install.
Have a look at my video: Arduino PWM Tutorial #2 – How to Set PWM Frequency Accurately http://youtu.be/9JXGIeM3BSI