Square DC ammeter 84C4-A DC ammeter refers to a meter used to measure the intensity of current in a DC circuit. When it is necessary to measure a large current, a low resistance with a certain resistance value can be connected in parallel at the two input terminals to expand the range. The zero point of its scale is usually placed at the extreme left of the scale.
In the magnetoelectric measuring mechanism, because the wire of the movable coil is very thin, and the current also passes through the hairspring, the allowed current is very small, about several microamperes to several hundred microamperes, so its practical value is very small. . According to the principle that the parallel circuit has a shunt effect, in practice to measure a large current, a shunt resistor must be added. Therefore, the DC ammeter is usually composed of a magnetoelectric measuring mechanism and a shunt resistor in parallel. Because the magnetoelectric ammeter can only measure DC current, it is also called DC ammeter.
The selection of common DC ammeter is the same as that of DC voltmeter. If a shunt is used, the shunt must be used with the ammeter. The wiring of the DC ammeter is polar. The positive pole of the power source (the pole where the current flows out) must be connected to the ﹢ terminal of the ammeter, and the ﹣ terminal of the ammeter is connected to the negative pole of the power source (the pole into which the current flows). When the polarity of the DC meter is not clear, the voltage and current can be reduced and temporarily connected with a DC voltage regulator. When the pointer is in the correct direction, the wiring is correct. In the opposite direction, the positive and negative electrodes (﹢, ﹣) can be reversed and connected.
The DC ammeter can be divided into ammeter, milliamp meter and microamp meter according to the range, which are respectively represented by the symbols A, mA and uA.
Embedded installation on ships, locomotives, power stations, mining metallurgy, petrochemicals or other mobile electrical equipment and devices to measure DC current or voltage. It can also be used as a secondary meter for converting non-electricity to electric energy.