Hello,
There is something I don’t get about power and energy.
If I got it right, power is expressed in Watts or Joules ans energy is in Watts.hours.
So if I buy à power supply rated at let’s say 700W. Does that mean (assuming, for the sake of the argument 100% efficiency and 100% load) it also consumes 700Wh ? And also that 700W is it’s maximum power output ?
In: 2
Energy is Power multiplied by Time.
Power just describes how fast energy is beeing used – the rate of energy usage.
Unit of power is 1W that is the same as 1 joule per second (J/s).
Unit of energy is W*s, same as 1 Joule.
In electricity consumption we use Wh because of convince, so that numbers are smaller.
1 Watt-hour = 3600 Watt-seconds = 3600 Joules.
Because there’s 3600 seconds in a hour.
If you have a device that uses constantly 100W of power, then after one hour it will consume 100Wh, after 2 hours 200Wh, after 24h – 100W*24h = 2400Wh.
Regarding power supplies – that is the maximum power they can draw from wall socket and pass on to whatever device it supplies. Connected device will use the amount of power it needs, no more. If device at this moment needs just 100W, it will use just 100W through power supply, regardless of rated maximum power. But if device will need 800W at some moment, that will exceed what power supply can deliver and it will shut off it’s output to protect itself.
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