Calculate the input voltage

How is its input voltage calculated? If the input voltage of the rectifier bridge is a sine wave, then its voltage can be directly measured by the multimeter's AC file. Of course, if its waveform is unordered, then we can calculate it. The area of the space between the waveform and the X-axis, how to calculate this, there are two ways to establish a mathematical model of the area between its waveform and the X-axis, or the way of calculus is calculated by the formula, and we actually live Among them, especially in the field of power supply, the commonly used AC power is sine wave, so we do not explain in depth the calculation of other waveforms. Finally, the rectifier bridge itself is an energy-consuming original, which itself has a saturated voltage drop. That is, at full power load, there will be a voltage drop of 1.1V, which is only 0.5% loss for the input voltage of 220V. This value is very low and is generally ignored. Do you understand the output voltage of the rectifier bridge?