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Introduction
There are two ways to measure electricity: current with an ammeter and voltage with a voltmeter. These devices are employed in electric circuits; however, the ammeter is more useful for measuring current flow. The voltmeter is more useful for measuring voltage or emf across two points in an electric circuit.
What is the Difference between an Ammeter and a Voltmeter?
Voltmeter | Ammeter |
Voltmeters are devices that are used to determine the potential difference (in volts) between two locations in an electrical circuit A voltmeter’s internal electrical resistance should be extremely high A perfect voltmeter has no resistance When determining the potential difference between two points, the voltmeter must be linked in parallel with the points being measured Voltmeters are schematically represented as a circle with a V within By connecting a very high resistance in series with the galvanometer, a voltmeter may be built | Ammeters are used to determine the amount of electricity (in amps) passing through a cable in an electrical circuit An ammeter’s internal electrical resistance should be very low A zero-resistance ammeter is an ideal ammeter When determining the current flow between two points, the ammeter must be linked in series with the two points Ammeters are schematically represented as a circle with the letter A within |
Ammeter
When connected in series with the circuit to be tested, the ammeter is used to measure a small amount of current, and measures in ampere or milliamperes. Uses of ammeters include the following:
- This gadget is readily available in labs and industries in various ranges
- It is beneficial to monitor the current flow through the home and its electrical devices
- It is also extensively used in businesses with a manufacturing or instrumentation background
- Additionally, the ammeter may be used with a thermocouple to determine the temperature
- Electricians use this gadget to inspect circuits in companies and homes for defects
Voltmeter
The voltmeter is linked in parallel with the electric circuit to determine the potential. The uses of the voltmeter are the following:
- Voltmeters are often used in electrical circuits and hardware to provide exact measurements
- It monitors the voltage while ensuring the circuit’s integrity and safety and the integrity and safety of its components
- It is also useful in the circuit for debugging and therefore for confirming the presence of the requisite voltage at its ideal value
- Voltmeters are also used with cathode ray tubes to verify that findings and measurements are accurate
- It is advantageous in laboratories for experimentation and testing
The result is shown in milliamperes when the ammeter is connected in series with the circuit to be tested.
A voltmeter is connected to an electric circuit to determine the potential. Both devices have the same connection polarity, with the negative potential connected to the supply’s negative polarity and the positive terminal connected to the supply’s positive polarity.
Conversion of Galvanometer into Ammeter and Voltmeter
A galvanometer is an extremely sensitive device that is used to measure current. It converts easily to an ammeter and voltmeter.
Conversion of Galvanometer into Ammeter
Ammeters are used to determine the current flowing through an electrical circuit. The ammeter’s resistance must be low enough to not affect the current going through it. Thus, an ammeter is connected in series to the circuit to measure the current.
A galvanometer may be turned into an ammeter by connecting it parallel with low resistance. This extremely low resistance is called shunt resistance S. The scale is now calibrated in amperes, and the shunt resistance values determine the ammeter’s range.
Thus, the galvanometer’s deflection indicates the amount of current I flowing through the circuit (ammeter).
Because the shunt resistance is extremely low and the ratio S/Rg is likewise rather modest. This implies that Rg is also modest, i.e., the ammeter’s resistance is very low. Thus, when we connect an ammeter in series, the ammeter has no discernible effect on the resistance or current in the circuit. The resistance of an ideal ammeter must be equal to zero. As a result, the ammeter value is always smaller than the current flowing through the circuit. Let It be the ideal ammeter-measured current, and Actual be the actual ammeter-measured current in the circuit.
Significant Points
- An ammeter is a low-resistance instrument that is constantly linked in series with the measuring circuit
- A zero-resistance ammeter is an ideal ammeter
- To double the range of an ammeter by n, the value of the paralleled shunt resistance is S =G/ (n-1)
Converting a Galvanometer to a Voltmeter
Voltmeters are instruments used to determine the potential difference between any two sites in electrical circuits. It should not take current from the circuit since this will modify the value of the potential difference being monitored.
Voltmeters must have high resistance and, when linked in parallel, they must not draw a significant current to accurately show the genuine potential difference.
Thus a galvanometer can be converted to a voltmeter by connecting a high resistance in series with it.
Significant points
- A voltmeter is a high resistance instrument connected in parallel to the circuit element whose potential difference is to be determined
- The resistance of an ideal voltmeter is infinite
- To expand the voltmeter range by n times, the resistance in series with the galvanometer should be R = (n-1) G
Conclusion
Both the voltmeter and the ammeter are electrical instruments used to measure two distinct properties in an electrical circuit. Voltmeters are used to determine the potential difference between two locations in an electrical or electronic circuit; on the other hand, ammeters quantify the flow of current in a closed circuit. Both of these may be effectively made analogously using a galvanometer.
