Why can't I measure the polarity of alternating current with a multimeter?
Alternating current is a current whose magnitude and direction change periodically. There is no polarity, only frequency. The frequency of alternating current in my country is 50 Hz, that is, the current changes back and forth 50 times per second, and the direction changes 100 times. This problem itself has a problem.
Why can't a multimeter measure the polarity of an alternating current?
The so-called alternating current means that the polarity changes alternately, and the change speed is very fast. Whether it is a pointer type or a digital multimeter, it cannot reflect the instantaneous polarity. Its polarity is the number of times it changes per unit time. Frequency, the unit is Hertz, which is the unit of physics named in honor of the physicist Mr. Hertz.
The polarity of this power supply changes alternately, and it is impossible to measure its polarity with a general multimeter. If it is necessary to know the polarity at a certain moment, that is, the simplest method of its instantaneous polarity, it needs to be specially used to observe the alternating current. Or an electronic instrument oscilloscope for DC pulses.
The direction of alternating current changes at any time, regardless of polarity. If you measure the live wire and the zero wire, you can turn the multimeter to the highest level of AC voltage, hold the black test lead with one hand, and use the red test lead to detect the wire. In addition, some digital multimeters are equipped with a test pen function, which can be used for some common measurement work.
