An ammeter is an electrical instrument for measuring the magnitude and direction of current. It is divided into two types: DC ammeter and AC ammeter. The commonly used ammeter is a magnetoelectric ammeter, and its main components are a permanent magnet and a movable coil. When the measured current flows through the coil, it will be deflected by the torque of the magnetic field.
The magnitude of the current of the ammeter is reflected by the deflection angle, which can be read by the position of the pointer fixed on the coil on the dial. Because the deflection angle is proportional to the current, the scale on the dial is uniform. When the measured current exceeds the range of the ammeter, the deflection of the pointer will exceed the limit of the scale. Not only the current value cannot be read, but the pointer will bend. When the current is too large, the coil may even be burnt due to excessive Joule heat. Off. Therefore, the range that each meter can measure has a certain limit, which is the meter's range (or full-scale current). Due to the different measurement needs, the ammeter is divided into three types: ampere meter, milliamp meter and microammeter. In the measurement of the induction cooker, an ammeter is usually used.
What is a DC ammeter?
DC ammeter is an instrument used to measure the current in a DC circuit. Its meter head structure adopts a magnetoelectric type. The main parameters are: ①range, that is, full-scale current value; ②internal resistance, usually the internal resistance of a DC ammeter is very small to reduce the voltage drop on the ammeter; ③accuracy level, the accuracy level of the DC ammeter is divided into 0.1, There are 7 levels of 0.2, 0.5, 1.0, 1.5, 2.5, and 5.0. The smaller the level, the higher the accuracy of the ammeter.
What is an AC ammeter?
There are many types of AC ammeters, including electromagnetic (moving iron), magnetoelectric, electric, digital, etc. The common appearance is shown in the figure.
The principle of the electromagnetic meter is: when the coil is energized with current, the energized coil generates a magnetic field, exerting a magnetic force on the iron sheet, forcing the shaft to drive the hairspring to rotate. When the resistance moment produced by the balance spring is balanced with the attractive moment of the magnetic field to the iron sheet, the pointer points out the value of the current. Since the coil is energized to attract the iron piece to deflect the pointer, the angle is proportional to the square of the current flowing through the coil, so the scale is not uniform. In addition, since the direction of energization in the coil does not affect the direction of pointer deflection, it can be used for both AC and DC.
Is the ammeter using electrical appliances?
Ammeter is a measuring tool. It is only used in the measurement, so it should not be included in the electrical appliances. If it is an ammeter connected in series in a consumer (such as in the circuit of a motor), it is just a measuring tool (I just understand it this way). From another perspective, if the ammeter is connected in series to the motor circuit (or other electrical appliances), and the measurement data is displayed during work, then the power is consumed (although it is weak: but also consumes the power, otherwise the pointer Or numbers cannot be displayed).
If it is said that since it consumes electricity, it should be the use of electrical appliances. This understanding is also the use of electrical appliances. As with the clamp meter that is usually used, it is only a temporary measurement when stuck in the circuit. In this state, the ammeter can only be understood as a measuring tool. This can only be seen from the perspective of the problem. My understanding is that the ammeter is only a measurement tool. It's not about electrical appliances.