A đơn giản cách đến phân biệt giữa không và lửa dây với a vạn năng
Nói chung speaking, the identification of utility power in the zero line, fire, non-low-voltage test pen can not be used, with a multimeter can also distinct between fire and zero line? The answer is yes, the method is as as follows.
The vạn năng phạm vi công tắc to AC điện áp 250V hoặc 500V gear. The black pen connected to the indoor water pipe workers wet ground, land, etc., the red pen and the power cord or power or power open contact, the the multimeter Indicates a Higher voltage value for the firewire, the Voltage Value The Lower or zero for the zero line.
Put the vạn năng bánh răng on the AC điện áp 250V bánh răng% 2c a mét que kết nối đến dây , the khác với bức tường hoặc mặt đất tiếp xúc, (if the wall or the ground is specificly dry can be made with water to make it wet point, so that the effect is more important) multimeter pointer does not indicate that this line is zero line, the pointer deflection shows that this line is firewire. When we want to distinct between fire and zero line and the hands of no test pen in the case, just need a multimeter to complete the test, there are three methods are described below:
The first method: if you do not have a test pen in hand only the multimeter, in the case of normal voltage, you can use the multimeter to distinguish between the fire wire and the zero line. With a multimeter pen connected to the fire line or zero line, another pen ground or walls, metal pipes, etc., if there is a voltage (generally greater than 20V), is the fire line; no voltage is the zero line.
The second method: First of all, we need to understand the principle of the test pen, electric pen by the metal rod, neon bubble, carbon resistance, and metal cap composition, neon bubble cap composition, neon bubble is a device that can light up, a glass ball filled with intrơ gas, carbon điện trở điện áp in 1M ohms or more, the metal cap is the human hand in contact with the parts, when the human and the metal cap in contact with the firewire, the pen, the human body, and the earth constitutes a circuit, in which the human and the earth between the exist of about 100PF. There is a capacitance of of about 100PF between the earth, the circuit is so constituted.
We use a multimeter to measure, and regardless of digital or pointer multimeter, in the understanding of the general range of of supply voltage, we take 220VAC voltage, for example, will be adjusted to 400VAC vạn năng gear, the red pen connected to the fire line or zero line, the hand touching the black pen, the multimeter if there is a readings that it is the firewire; Không Bài đọc Hiển thị Điều đó Nó Is The Zero dòng.
Cái này phương pháp ý chí không nguyên nhân bất kỳ nguy hiểm đến con người cơ thể, lý do lý do đó kỹ thuật số vạn năng bên trong kháng của 10M ohms% 2c con trỏ bảng bên trong kháng cự của 20K ohms 2f V% 2c if the đo lường of the con trỏ bên trong kháng cự 20K �% 97 220V % 7b{5% 7d},400 ohms, tuyệt đối an toàn% 2c bởi vì các carbon điện trở of the pen bên trong resistance is nói chung sử dụng 1M ohms.
