# Need help with stepping down DC volts

I don't have much experience with electronics, I'm simply trying to get (at least what I think) is a fairly simple circuit running.

I've got a blower fan that I need to get running. It uses 12VDC at 4.3 amps. I've got a DC converter that converts 120VAC to 19VDC, but that's too high. I want to step down the voltage from the converter to around 12 volts DC, and I was thinking simply using a resistor might work, though I'm none too sure how the calculations are worked out. I tried an Ohm's law calculation and arrived at that I would need a 2ohm resistor for this, but I'm not sure.

• Suggest you buy a 24V to 12V converter module with an 8A rating approximately and an input range that includes 19V. A ~2$\Omega$ resistor would probably work but would get very hot - about 30W. – Spehro Pefhany Aug 2 '15 at 20:50
• @Spehro: If he's going to buy a converter, he might as well just get a 12 V power supply in the first place. – Olin Lathrop Aug 2 '15 at 21:16
• @OlinLathrop Yes, this is a good point. A good & safe power supply. – Spehro Pefhany Aug 2 '15 at 21:21
• Possible duplicate: electronics.stackexchange.com/questions/75448/… – The Photon Aug 2 '15 at 23:51