If you plug a device in a 240v socket and the output is 12v 10 Watts, what is the power used in amps. Do you simply divide the end wattage by the original voltage (240)?
Larry
Plendo said
06:43 PM Nov 26, 2015
HI Larry, the age old formula applies. Watts = Volts * Amps, so the output is 10 watts = 12 volts * 0.83 Amps. It would be reasonable to assume that a 240v to 12v power supply would be about 80% efficient thus your input would be about 12.5 Watts ((10/80)*100), thus your input current would be about 0.052 Amps (12.5/240).
I hope this helps.
oldtrack123 said
08:55 PM Nov 26, 2015
Hi
As Plendo has said the POWER used will be around 1O to 20% higher due to the conversion losses in the converter .
BUT the actual AMPs drawn could be up to 50% more. as most converters have a poor power factor, often given as PF 0.xx
deverall11 said
10:34 AM Nov 28, 2015
Thanks to all that replied. Larry
D and D said
10:28 PM Nov 28, 2015
This would have to be the shortest electrical related thread on the forum I reckon.
Dave
KFT said
11:00 PM Nov 28, 2015
Don't jinx us please Dave
Frank
mjt57 said
01:35 PM Nov 29, 2015
Yep, the last thing that you want is a short in an electrical thread...
Bruce and Bev said
05:40 PM Dec 3, 2015
Oh Martin - what a bright spark you are with your "short" comment LOL !!
I have a question regarding power drain.
If you plug a device in a 240v socket and the output is 12v 10 Watts, what is the power used in amps. Do you simply divide the end wattage by the original voltage (240)?
Larry
HI Larry, the age old formula applies. Watts = Volts * Amps, so the output is 10 watts = 12 volts * 0.83 Amps. It would be reasonable to assume that a 240v to 12v power supply would be about 80% efficient thus your input would be about 12.5 Watts ((10/80)*100), thus your input current would be about 0.052 Amps (12.5/240).
I hope this helps.
Hi
As Plendo has said the POWER used will be around 1O to 20% higher due to the conversion losses in the converter .
BUT the actual AMPs drawn could be up to 50% more. as most converters have a poor power factor, often given as PF 0.xx

Dave
Frank