有關 - the concept of voltage drop 既diagram 應該點畫? 只係圖唔識

Draw a horizontal line of 0V first. Then above this line draw a section of downward inclined line starting with 220V with gentle slope to indicate the voltage drop at the elect cable. Afterwards, draw a another section of downward inclined line with deep slope to indicate the voltage drop of the household equipment. Finally, draw a section of downward inclined gentle slope line to indicate the voltage drop at the return path, until it intersect with the horizontal line of 0V.