First, confirm the power parameter of the device, and then multiply it by the corresponding working time to calculate the power consumption of the camera.
W=p.t, take the camera DS-2CD3T45 as an example, the maximum power is 7W, working for 1 hour (equal to 3600 seconds), the power consumption is
W=p.t=7*1*3600=25200 Joule
25200/(3.6*10^6)=0.007 kWh
It can be seen that the power consumption per hour is about 0.007 kWh.
Note: The unit of W is Joule (the general unit is kilowatt-hour, commonly known as degree, which needs to be converted after calculation, 1 kilowatt hour = 1 degree = 3.6 multiplied by 10 to the 6th power of Joule)