1, work: W=Fs (definition of work)

W- work, F- force, s- distance

Work refers to the product of the distance s that an object moves under the action of force F.

2. Power: P=W/t (definition of power)

In order to show the speed of work, time is used to divide the work.

Power refers to how much work an object has done in a unit time. By P=W/t=F*s/t=Fv, this is a mathematical operation without much physical meaning, which is generally used for operation.

3, the meaning of power:

(1) Physical meaning: a physical quantity indicating the working speed of an object.

(2) Physical definition: The work done per unit time is called power. Power is a physical quantity, indicating the speed at which an object does work.

Extended data:

1, there are four ways to measure power:

(1) diode detection power method;

(2) Equivalent thermal power consumption detection method;

(3) TRMS/DC conversion detection power method;

(4) Logarithmic amplification detection power method.

2, the reasons for the power:

The input terminal of switching power supply usually adopts a rectifier and filter circuit composed of rectifier diode and filter capacitor, and the 220V AC input commercial power is directly connected to the capacitor for filtering to obtain a smoother DC voltage.

The rectifier and filter circuit composed of rectifier diode and filter capacitor is a combination of nonlinear elements and energy storage elements. Although the waveform Vi of AC input mains voltage is sinusoidal, the conduction angle of the rectifier element is less than 180o, generally only about 60, which causes the waveform of input AC current to be seriously distorted and pulse-like.