DC TO DC convertor with arduino

Hey, I've tried to build a DC to DC convertor using the arduino, based on the following schematic:

According to Wikipedia

Strangely my circuit doesn't follow this equation.The output voltage when I changed the frequency of the PWM, The inductor or the LOAD resistor.While it should be changed by the duty cycle

Moreover, I've used the following simulator to simulate this circuit and it was working the same as my circuit on a breadboard

http://www.falstad.com/circuit/

What am I doing wrong?

What am I doing wrong?

You are using real components instead of idealised components.

The load will affect the voltage because if it did not then you could draw an infinite amount of current from it which you can't due to things like magnetic saturation in the coil.

Getting switch mode regulators to work reliably calls for careful design. In particular, the inductor needs to have a high enough inductance to limit the ripple current to a reasonable value, it must not saturate at the peak current, and its resistive and magnetic losses must be low. The Arduino default PWM frequency is too low to make this easy and you really need to increase it, otherwise the inductor becomes unmanageably large.