Hello, friends, I hope all of you are having fun in your life. In today’s tutorial, we will explain what is ammeter. in 1820 Hans Christian oersted who belonged to Denmark discovered the relationship among current, magnetic field and physical forces (gravitation, electromagnetism, weak interaction, and strong interaction). He performed an experiment for this relationship he saw that the needle of compass moved towards north when current flows in nearing the wire. For current measurement, he used a tangent galvanometer.
In electrical and electronic engineering there is numerous meter are used like voltmeter for voltage measurement, ohmmeter for resistance measurement. In today’s post, we will have a look at ammeter its working, construction, applications and some other related parameter. So let’s get started with what is ammeter.
What is ammeter
- The ammeter is also known as ampere meter and used for measurement of electric current and the unit of the current measured by this meter is ampere so it also called ampere meter.
- the ampere meters used to find the small value of currents like mas, the ammeter used before the 19th century was only used in different laboratories since their working operation depends on the magnetic field of the earth.
- After the nineteenth century, some improvements were made in these meters and now they can be used at any location with higher accuracy.
Difference between ammeter and galvanometer
- Now we compare ammeter and galvanometer and will observe what is the difference between these two meters.
- A galvanometer is used to find a very small amount of current passing through the circuit and ammeter used to find a larger ampere current.
- For the working of a galvanometer, there is a need of a magnetic field and while in ammeter there is no need of a magnetic field.
- The accuracy of the galvanometer is larger than the ammeter and ammeter is less accurate.
- Due to larger accuracy galvanometer can find a small amount of variation in current.
- A galvanometer can use only for direct current measurement while ammeter can be used for both direct current and alternating current measurements.
- A galvanometer is used in bridge circuits for measurement of current and ammeter is used in electrical circuits.
- A galvanometer is a mechanical instrument while the ammeter is both electric and mechanical.
Difference between ammeter and voltmeter
- It used for the measurement of current.
- Its resistance value is less as compare to the voltmeter.
- In-circuit it linked in series.
- This meter is more accurate than the voltmeter.
- Its range can not be varied.
- It used to find the value of voltmeter in any circuit.
- Its resistance value is high than the ammeter.
- It linked in parallel combination in the circuit for voltage measurement.
- Its accuracy is less than the ammeter.
- Its range can be varied.
Why is an ammeter connected in series and a voltmeter in parallel in a circuit?
- The ammeter is used to find the value of current in circuitry for accurate measurement of current it should pass through the ammeter.
- So it arranges in series in a circuit. If we place it in parallel and its resistance is also less so all current will flow through it and can damage this meter because we know that current always follows less resistance path.
- so it always preferred to connect in series for current measurements.
- while the resistance of voltmeter is high so if we place it in series then there will be less amount of current will flow through the circuit due to this it uses in parallel to measure the voltage across any element.
How to use Ammeter
- There some steps you must follow to use ammeter all these steps are mentioned here with the detailed.
- for current measurement, we discuss it should be connected in series, first of all, you should create your circuit for which you have to use an ammeter.
- break the circuit where you want to measure current for this remove the wire at your desired location.
- than attached red lead of ammeter to the positive terminal and black lead on the grounded terminal of the ammeter.
- after that place ammeter in a circuit for which you are going to measure the current positive red lead of meter should be attached to the positive terminal of a battery.
- and connect the black leads to the point that is closed to the negative terminal of the battery. If these connections are not right then meter can be damaged.
Types of ammeter
- now we discuss the types of ammeter that are listed here with the detailed.
- moving coil ammeter
- digital ammeter
- electrodynamic ammeter
- hotwire ammeter
- integrating ammeter
- moving iron ammeter
- moving magnet ammeter
Moving coil ammeter
- this meter is also called d’arsonval galvanometer or we can say d’arsonval galvanometer is known as moving coil ammeter.
- it measures the current through the magnetic deflection this mete has coil when current passes through that coil it rotates in a magnetic field.
- the currently used ammeter is designed by Edward Weston and has 2 spiral spring for restoring force.
- the gap among the core of iron and permanent magnet poles allows the movement of a meter needle directly proportional to the current.
- the scale of this meter is linear. This meter has the ability to measure both direct and alternating current.
- the coil of this meter move between the permanent magnet poles. When the current flows through the coil it moves in between poles of the magnet.
- the movement or deflection is directly proportional to the current flowing through the meter or coil.
Moving magnet ammeter
- this is also used to measure the value of both dc and ac currents. This meter consists of a coil that is placed among the poles of a permanent magnet.
- after the movement of current through the coil, it shows some variation in its position the variation in coil position is directly proportional to the current flowing through the meter.
- it can also find the value of alternating and direct current passing through the circuit.
- its accuracy is larger than the moving coil meter and permanent magnet ammeter.
- its main feature is that there is no need of separate calibration for both ac and dc measurements.
Moving iron ammeter
- this meter used an iron piece that shows some deflection when a force exerted on this iron by the fix coil wire.
- this meter first was manufactured by Friedrich Drexler in 1884 who was an engineer of Austria.
- this meter has the ability to measure both direct and alternating current accurately. The iron piece of this meter comprises on the moving vane connected with the pointer and the second vane that is fixed and coil surrounds these vanes.
- when either direct current or alternating current flows through the coil it indued the field in both fields both fixed and moving vane the direction of the field is opposite to each other so these vanes repel one another.
- the moving vane moves opposite to the force applied by the helical spring and the deflection in moving iron meter is directly proportional to the square of the current.
- when the high value of current flows through the ammeter it can cause serious problems for a meter to avoid such problems a resistance is connected in parallel to the ammeter this resistance is known as ammeter shunt.
- if in any certain current flows through the circuit then the most part of current will flow through the shunt resistance and will not damage the meter.
Effect of temperature on Ammeter
- the ammeter is a sensitive instrument that can get affected by the environmental temperature. The alteration in temperature value also varies the measured value of current or readings.
- the effect of temperature can be minimized by using the resistance called swamping resistance and have zero value of temperature coefficient.
- in-circuit it attached in series with the ammeter.
That is a complete post on ammeter I have mentioned each and everything related to ammeter if you have any questions about this post asks in comments. Thanks for reading. See you in the next tutorial.