Difference Between Ammeter and Voltmeter: Definitions, Applications, Sample Questions

Difference Between Ammeter and Voltmeter Overview

Electrical devices known as voltmeters and ammeters are both used to measure two distinct factors in an electric circuit. Voltmeters are used to detect potential differences between two points in electrical or electronic circuits, whereas ammeters are used to measure current flow in closed circuits quantitatively. Practically, a galvanometer can be used to produce analogue versions of both of them. An electromechanical device called a galvanometer is used to determine if there is or is not current flowing through an electric circuit. It functions like a voltmeter when a very high resistance is connected in series with the galvanometer. On the other hand, it behaves like an ammeter when a modest resistance is connected in parallel with the galvanometer.

Tabular Difference Between Ammeter and Voltmeter

The measurement of voltage and the flow of current are done using voltmeters and ammeters, respectively. The way these two devices are used differs significantly. To learn more about the distinctions between an ammeter and a voltmeter, see the table below.

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What is Ammeter?

This term was created using the ampere metre. The measurement tool used in electrical equipment is called an ammeter. It is used to gauge how much current is moving through the circuit. It measures with great accuracy. Even at milli- or micro-amperes, the ammeter can measure very small currents. Ammeter is connected in series to the measuring circuit in order to measure the current. This is so that the circuit's entire current can flow through it. The ammeter is used to measure a little amount of current, and the result is shown in milliamperes when it is connected in series with the circuit that has to be tested to flow the circuit's complete current through it.

Applications of Ammeter

1. This equipment is conveniently offered in laboratories and enterprises with various ranges.
2. For the house's electrical equipment, it is useful to measure the current flow.
3. It is also commonly used by businesses with a manufacturing and instrumentation foundation.
4. The thermocouple and ammeter work well together to measure temperature.
5. This tool is used by electricians to inspect the circuit problems in homes and offices.

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What is Voltmeter?

In electrical instruments, the voltmeter is a component that is frequently used to measure voltage. It has a parallel connection to the electrical circuit whose potential is being determined. The positive terminal of the voltmeter is connected to the positive polarity of the supply, while the negative terminal is connected to the negative polarity, just as the ammeter. To measure the potential, a parallel connection between the voltmeter and the electrical circuit is made.

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Applications of Voltmeter

1. A voltmeter is frequently used in electrical circuitry and hardware to do the incredibly accurate measurement.
2. It measures the voltage while taking into account the circuit's and its components' security and safety.
3. It can also be used to debug the circuit and confirm that the ideal amount of required voltage is present.
4. To guarantee the correctness of the findings and measurements, the cathode ray tubes are also used with the voltmeter.
5. It is helpful in laboratories for testing and experimentation.

Key Difference between Ammeter and Voltmeter

Following are the key differences between ammeter and voltmeter.

1. A voltmeter detects the potential difference between any two points in an electrical circuit, whereas an ammeter monitors the tiny value that flows through a circuit.
2. The ammeter's resistance is little. So that the entire circuit's current flows through it. However, the voltmeter's internal resistance is extremely low, ensuring that the circuit's current does not interfere with the voltmeter's measurement.
3. The voltmeter is linked in parallel with the circuit, whereas the ammeter is connected in series with the circuit to measure the total current. The parallel circuit's potential difference stays constant throughout. It is therefore connected in parallel with the sites whose voltage is to be measured in order to measure the precise value of the potential difference.
4. Compared to a voltmeter, an ammeter is more accurate.
5. While the measurement range of an ammeter cannot be altered, that of a voltmeter can be increased or decreased by altering the value of resistance.

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Important Questions 

Question 1- What is a differential voltmeter?

Solution- The differential voltmeter is a type of voltmeter that is useful for determining the voltage difference between known and unidentified sources. Potentiometer voltmeter is another name for this gadget. This is because it uses a similar operating system to a potentiometer. It is divided into two types based on AC or DC: AC differential voltmeter and DC differential.

Question 2- What is digital voltmeter?

Solution- The device that can be used to measure the electrical potential difference between two places in a circuit is a digital voltmeter. Direct current or alternating current may be present in this situation. Pulse generator, gating, counting clock pulses, analogue to digital conversion, and latching are the five functional components of a digital voltmeter.

Question 3- What are the different types of voltmeter?

Solution- Following are the different types of voltmeter based on their construction.

1. Induction Type Voltmeter
2. Electrostatic Type Voltmeter
3. Digital Voltmeter
4. Permanent Magnet Moving Coil Voltmeter
5. Moving Iron Voltmeter
6. Electro Dynamometer Type Voltmeter
7. Rectifier Type Voltmeter

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Question 4- What are the readings of the voltmeter and ammeter in the following circuit?

Solution- In the above diagram, the net resistance of the resistors connected in parallel is,

1/RP = 1/100 + 1/100 

1/RP = 2/100 = 1/50

RP = 50

This is connected in series with another resistor of 100, therefore the net resistance is:

Req = 100 + 50 

Req = 150

I = V/R

I = 6/150

I = 0.04 A   (Reading of Ammeter)

Now, V = IR

V = 0.04 100 

V = 4 V      (Reading of Voltmeter)

Ques. Find the reading of the voltmeter in the circuit given below.

Ans. In the circuit shown above, the net resistance is,

Req = 300  

I = V / Req  

I = 30 / 300 = 0.1 A

Now, reading of voltmeter (V) = IR

V = 0.1 125 

V = 12.5 V

entiometer Voltmeter."

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