File Name: ammeter construction and working .zip
Several electrical machines and panels are fitted on board so that the ship can sail from one port to another, safely and efficiently. The electrical machinery and system require scheduled maintenance and checks to avoid any kind of breakdown during sailing.
How does it measure the correct current flowing through the circuit. Most mechanical movements are based on the principle of. The construction of ammeter can be done in two ways like series and shunt. Moving magnet ammeters operate on essentially the same principle as. In this article, we shall study the principle, construction, and working of a potentiometer and its uses.
Ammeter and Voltmeter
An ammeter is an electrical measurement device apparatus which is used to measure the electric current in the electrical circuit. Requirements of Good Ammeter:. Necessity of Shunting for an Ammeter:. We know that an ammeter is used for measuring current. It is to be connected in series in the circuit for this purpose. If the resistance of ammeter is not very low but considerable, then, when it is connected in a circuit the effective resistance of the circuit will considerably increase. Due to the increase in the value of the effective resistance of the circuit the current in the circuit will decrease compared to the original current in the circuit which was to be measured.
Thus the decreased value of the current will be measured by the ammeter. In order to avoid this, the resistance of the ammeter should be very low. The effective resistance of the parallel combination is always smaller than the least value in the parallel combination. Hence a low-value resistance is connected in parallel across the galvanometer.
This process is known as shunting. Uses of a Shunt in an Ammeter:. Conversion of a Moving Coil Galvanometer into an Ammeter:. A sensitive moving coil galvanometer pivoted type is taken. To measure given the range of current a low resistance of suitable value is connected in parallel with it. Expression for the Value of a Shunt in an Ammeter:.
Let G be the resistance of the galvanometer coil. Let I g be the current required to give full-scale deflection in the galvanometer.
Let S be the resistance to be connected in parallel with the galvanometer coil so as to measure a maximum current I. Let I s be the current through the shunt. This is the expression for the low-value resistance which is to be connected in parallel with the galvanometer to convert it into an ammeter to measure the given current. A voltmeter is an electrical measurement device apparatus which is used to measure the potential difference in the electrical circuit.
Requirements of Good Voltmeter :. We know that a voltmeter is used to measure the potential difference between two points. It is to be connected in parallel for this purpose. If the resistance of the voltmeter is not very high it will divert a considerable current from the circuit through it, as a result, there will be a fall in potential difference.
Instead of measuring the actual potential difference this decreased potential difference will be measured by the voltmeter. In order to avoid this the resistance of the voltmeter should be very high i.
We know that the effective resistance of the series combination is always larger than the largest value in the series combination. Hence a large value resistance connected in series with the galvanometer to convert it into the voltmeter. Use of a High-Value Resistance in a Voltmeter:. Conversion of a Moving Coil Galvanometer into a Voltmeter:.
To measure given the range of potential difference a high resistance of suitable value is connected in series with it. Expression for Value of a Resistance in a Voltmeter:. Let R be the resistance to be connected in series with the galvanometer coil so as to measure a maximum potential difference V.
Let Is be the current through the shunt. This is the expression for the high-value resistance which is to be connected in series with galvanometer to convert it into a voltmeter to measure the given potential difference.
The range of measurement of current can be changed by changing the shunt resistance. The range of measurement of P. To measure a larger current, a shunt of smaller value is required.
To measure a larger P. Extremely low P.
Ammeter construction and working pdf file
We know that meter is an electronic device used to measure a particular quantity and it is associated with the measurement system. Similarly, the ammeter is nothing but ampere-meter used to measure ampere value. Here ampere is the unit of current and ammeter is used to measure current. There are two kinds of electric current namely AC and DC. AC changes the flow of current direction at regular intervals whereas the DC supplies the current in one direction.
In ammeter designs, external resistors added to extend the usable range of the movement are connected in parallel with the movement rather than in series as is the case for voltmeters. This is because we want to divide the measured current, not the measured voltage, going to the movement, and because current divider circuits are always formed by parallel resistances. Taking the same meter movement as the voltmeter example, we can see that it would make a very limited instrument by itself, full-scale deflection occurring at only 1 mA:. Whatever extended range provided by the parallel-connected resistors, we would have to represent graphically on the meter movement face. Knowing that the circuit formed by the movement and the shunt is of a parallel configuration, we know that the voltage across the movement, shunt, and test leads total must be the same:.
How Does an Ammeter Work?
Definition: The meter uses for measuring the current is known as the ammeter. The current is the flow of electrons whose unit is ampere. Hence the instrument which measures the flows of current in ampere is known as ampere meter or ammeter.
Current is the rate of flow of electric charge. If this electric charge flows only in one direction, then the resultant current is called Direct Current DC. The instrument, which is used to measure the Direct Current called DC ammeter. The parallel resistance, which is used in DC ammeter is also called shunt resistance or simply, shunt.
Electrical Academia. When the current in a circuit is substantially less than an ampere, its value is determined by the use of a milliammeter or micro-ammeter, which measures full-scale currents in milli-amperes or microamperes, respectively. The symbol for the ammeter is a circle with the enclosed letter A, as shown in the following figure. In the above figure, an ammeter is inserted into the path of a current, that is, in series, so as to carry the current being measured.
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