power supply for arduino

Good morning friends please need help for power supply to freeduino / sanguino as the available input voltage is DC 72 volts wants to stepdown to 5volts DC for freeduino or sanguino board the 72 volts is purely DC,thanks in advance.

I think the device you need is a DC-to-DC converter. Any with a maximum input voltage of 72V or more, an output voltage of 5V and an output current over, say, 200mA. DigiKey.com has a bunch to choose from starting at about $12.

Thankyou soooooomuch johnwasser,I will check it out.Can we hack the conventional mobile charger its input is 220v/110v and output is 5v by tinkering diodes is it correct.

in a nutshell its more complicated than that

nazeem: Can we hack the conventional mobile charger its input is 220v/110v and output is 5v by tinkering diodes is it correct.

If you have a 110V/220V AC switched-mode 5V power supply you may be able to use it.

In a switched-mode AC power supply the 110V/220V AC is first turned into DC at a fairly high voltage. You may be able to apply your 72VDC to the AC pins and have 5V come out. If it doesn't work one way, try swapping + and -.

thanks
johnwasser for your kind help,please check the image is this the same adaptor?please let me know can it be tinkered for DC input.

220px-SmSntWoIc.jpg

Looks like a switch-mode power supply. Try connecting your 72VDC supply to where the red wires are going.