AC voltage
Electricity whose magnitude and direction of voltage change with time is called alternating current, such as 220V AC for civil use and 380V for industrial use.
The AC voltage changes its polarity alternately with time, that is to say, when any pole is grounded, the voltage of the other pole changes continuously from high to low, from positive to negative, even if there is no ground loop at both ends. works fine.
Generally, the voltage of the DC circuit that we are exposed to on a daily basis is low and below the safe voltage, so there is no danger to personal safety. Therefore, the DC circuit does not need to be grounded. Alternating current is a current and voltage whose magnitude and direction change periodically. The most commonly used is sinusoidal alternating current, such as daily mains.
