The current meter refers to the instrument that uses the current in the interchange and DC circuit.In the circuit diagram, the symbol of the current meter is circular A.The current value is "An" or "A as the standard unit.
Current table model
The model of the current meter can reflect the purpose, function and principle of the instrument.The composition of the installation instrument (also known as the panel instrument) model is as follows: The first digit of the shape is compiled according to the maximum size of the panel shape of the meter, and the second code of the shape is compiled according to the shell size of the instrument.The series code is compiled by a series of instrument working principles, such as: the magnetic appliance system code C, electromagnetic system code T, electric system code D, induction system number G, rectification system code L, static electrical system code Q, electronics electronics, electronicsThe name of the department is Z, etc.
Number of current meters
First look at the range of the current meter, which is generally marked on the dial.After confirming the most squarely, how many ampels can connect the positive and negative wiring column of the current meter and observe the position of the pointer to read the number.In addition, you must choose a current current meter with a suitable range.You can try it first. If the pointer swing is not obvious, change the table with a small range.If the pointer swings a large angle, change to a large table.Generally, pointers are left and right in the middle of the dial, and the readings are more appropriate.
The working principle of the current meter
The current meter is made of a magnetic field in the magnetic field.There is an permanent magnet inside the current meter, which generates a magnetic field between the pole. There is a coil in the magnetic field. There is a scarf spring on each ends of the coil. A wiring column connects to the current meter.There is a pointer at the front end of the current meter.When the current is too long, the current is cut through the spring and the shaft through the magnetic field and the current. Therefore, the effect of the magnetic field force will cause the coil to be deflected, and the rotation and pointer deflection will be driven.Because the size of the magnetic field force increases with the current, the deflection of the pointer can be observed to observe the size of the current.
The difference between the current and the voltage meter
The current meter is converted from a small -range current meter with a small resistance.Its internal resistance is very small. In the case of poor strictness, it can be considered that there is no resistance and has no hindrance to the current.The voltage table is converted from a small -range current meter with a large resistance.Its internal resistance is very large.In the case of an approximate situation in the circuit, the current can be seen as 0.
How to use the current meter
The first point: First of all, we need to prepare a current meter. The current meter should be correctly connected on the circuit to work normally.Then be sure to connect the line in a way in the "+" level and "-" level.In addition, it should be noted that the measured current must not exceed the range of the current meter. When connecting the current meter, you must not directly connect the current meter to the positive and negative poles of the power supply.The second point: The working environment of the current meter must also clarify the working environment of the current meter when connecting the current meter.The operating temperature of the current meter should be between minus 10 ° C and 50 ° C. At the same time, when using the current meter, you must pay attention to no corrosive gases around.Do not use it where rain and snow erosion.Also pay attention to its measurement current between 50mA-5A.The measurement method should be communicated.The working current should be between 100V-220V.

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