let us suppose i have a device whoose rating is 12v, 0.3A and my supply is of 24V. For the device to work should i limit current to 0.3A by connecting a resistor of 80 ohm or should i limit the voltage by converting 24v to 12v?

limit current or voltage for a device? (noob)

Paul_B April 26, 2014, 8:45am 3

Use a switchmode regulator.

Plenty available on eBay.