The ammeter is connected in the charging circuit between the battery and generator to show how much current is f flowing to the battery during the charging: and how much current is flowing from the battery during the discharging. The ammeter is fitted on the instrument panel in front of the driver. It is used in most of the vehicles. however, an indicator lamp is also used in some vehicles to indicate whether or not the generator is charging the battery.
The figure shows the simplified diagram of a car ammeter. It consists of a pivoted vane to which a needle is attached, a permanent magnet and a heavy conductor. The needle moves on a graduated scale, one side of which indicates charging current and the other side discharging current. At the center, zero is marked. When the needle points zero, no current flows to or from m the battery, the pivoted vane is held between the two poles of the permanent magnet when the current flows to the battery, needle swings to “charge” side.
When the current flows from the battery, the needle swings to “discharge side. When the current flows in any side, it passes through the conductor. The magnetic field forces the vane to move. The stronger the current, the farther the van moves. Therefore, the needle swings on the scale point in the amount of current flowing through.
Watch the video below to know how to use an Ammeter?
History Of Ammeter
In 1820, the relation between physical forces, electric current and magnetic fields was first noticed by Hans Christian orsted who observed a compass needle was deflected from pointing towards North when a current flowed in an adjacent wire. Then the tangent galvanometer was firstly used to measure currents using this effect, where the restoring force causes returning the pointer to the zero position was achieved by Earth’s magnetic field. This made this instrument usable only when aligned with the Earth’s field. The sensitivity of the instrument was increased by using some additional turns of wire to multiply the effect the instruments were called “multipliers”.
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