Buck Converter & Arduino

Description:
The Buck converter is a step-down DC/DC converter in power electronics.
http://en.wikipedia.org/wiki/Buck_converter

Applications: 

- Battery charger (mobile, radio, ....) 

- Control load

Schematic: 

Components:
- Transistor
- Inductance
- Capacitor
- Diode
- Arduino (controller)
- Power source

In protoboard:

Arduino code:

The first code is like a motor speed code. 

Code 1

The second code use the delay for the on period  and off period.

Graphics whit the oscillogram:

* The real power source is a 8V DC.

Graphics with code 1, Transistor switching (Green), Output voltage (Red)  

Graphics with code 2, Transistor switching (Red), Output voltage (Green)