Positive half-circle current flow from the fire wire to the zero wire is the ultimate method
Positive half-circuit current flows from the fire wire to the zero line, the negative half-circuit current flows from the zero line to the fire wire, why use the test pen is always the fire wire bright
Measurement of the fire wire with a test pen is bright because the fire wire voltage to ground 220V, measurement, the fire wire through the resistance within the pen through the human body to ground, there will be a current flow, so it will be bright. The zero wire is zero volts to ground voltage, because the zero wire itself is connected to the earth, and you are in the earth isotropic, so there is no potential difference, the formation of current, so naturally not bright.
Why is the zero line zero, this is because it is grounded, the earth's potential is zero, so the natural zero line potential is zero. This is also the human body standing on the ground to grab the zero line will not be electrocuted.
Zero wire is the line leading from the neutral point of the transformer, it is the circuit after the fire wire to the electrical appliances, the zero wire will be grounded when it leads from the mid-point of the transformer, so you can think of the zero wire as the ground where the transformer is located in a distant location, and the ground in the home is the protective ground where your home is located. Because the earth is also resistive, sometimes the zero wire in the home can be electrically charged, but the voltage is so low that it is not dangerous.
Positive half-week fire wire potential higher than the zero line, negative half-week fire wire potential lower than the zero line, water flows down, the current is the same, here to correct a misunderstanding, many people think that the current can only be the positive pole to the negative pole, in fact, the current also flows from the potential of the high positive pole to the potential of the low positive pole!
said here that the potential, mention this question may not understand, do not understand can also be understood as voltage, in fact, is not the same concept, the voltage is the potential difference, assuming that the potential is the height, the voltage is the height difference, for example, there are two reservoirs in the mountains, a 100 metres (potential), a 150 metres (potential), then the difference in their heights (voltage) is 50 metres, if the two reservoirs are linked, the high water will flow to the lower one, if both are 150 metres (potential) it can't flow (voltage is zero), even if their heights (potentials) are high
