Current is measured with the help of an ammeter. Current is the flow of electrons whose unit is ampere. So it can be said that the instrument that measures the flow of current in ampere units is, therefore, an ammeter.
The standard ammeter has no internal resistance. But in reality, the emitter has little internal resistance. The range of the emitter depends on this resistance.
Series connection is to be given in the ammeter circuit. All the electrons flowing in the circuit flow through the ammeter. Due to its internal resistance, it causes voltage drop and some power loss.
Ammeter Power Loss
Ammeter meter resistance RA, Current I flowing in ammeter If so, Power loss Ww= I2RA Watt So the lower the resistance of the emitter, the lower the power loss.
Types of Ammeter
- Moving Iron Ammeter
- Attraction Ammeter
- Repulsion Ammeter
- Moving Coil Ammeter
- Parmanent Magnet Ammeter
- Dynamo Meter Ammeter
- Moving Magnet Ammeter
- Hot Wire Ammeter
- Electrostatic Ammeter
- Induction Ammeter
- Rectifier Ammeter
- Digital Ammeter
- Clamp Ammeter
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Moving Iron Ammeter
The current flows through the moving coil of the moving iron ammeter. As a result of this current flow, the deposited iron is attracted. With the help of A.C. And D.C. Both can be measured.
Moving Coil Ammeter
In this ammeter, the current is measured by the deflection of the moving coil between the permanent magnets.
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Permanent Magnet Moving Coil
Permanent magnets use in this meter into which the coils place. Deflection is found in this coil with the flow of electrons. With permanent magnet moving coil ammeter only DC. Can be measured.
Dynamo Meter Ammeter
With the help of A.C. And D.C. Both can be measured. Its accuracy is relatively good.
Moving Magnet Ammeter
In this meter, the coil attaches to the meter case and the permanent magnet rotates the indicator cut. This meter can measure much more current than a moving coil meter.
Hot Wire Ammeter
In this meter current flows through a wire, in which the wire is heated and stretched. The accuracy of this meter is low and it takes a long time to get the measurement.
With the help of this meter, the current measure by rectifying the AC with a permanent magnet moving coil.
The text of the digital emitter is available on the digital display. These meters provide many subtle values.
The clamp emitter can measure current without an electrical connection to the conductive wire. It is possible to measure many high-quality currents.
Basically, current flows through the moving coil of the emitter, resulting in deflection and meter reading. But not much current can flow through these coils. For this, a register attaches to the parallel of the ammeter. This register calls an ammeter shunt. The ammeter shunt meter attaches to the case. The meter shows the value of the meter current relative to the ammeter shunt.
Effect of Temperature in Ammeter
The ammeter is very sensitive to ambient temperature. Its lessons are more or less as the temperature changes. To reduce this error, swamping resistance connect to the meter series. The temperature coefficient of this swamping resistance is zero.