Voltage is the amount of pressure required to move an electric charge (electrons) from one point to another in an electrical circuit. Voltage is also known as “electrical potential difference”, “electric tension” or “electric pressure”, it is the difference in electric potential of two points in an electric circuit. Voltage is denoted by the symbol “V”, and Voltage is measured in the unit “Volt”. One volt is equal to one joule of energy per coulomb of charge. A “Voltmeter” measures the voltage between two points in a system.
Properties of Voltage
Some properties of Voltage are listed below:
- Its SI unit is volt(V).
- In Equations and circuit diagrams, it is represented by symbol “V”.
- It defines the electric potential difference between two points in an electrical circuit.
- It is a scalar quantity.
- It has magnitude but it does not have a specific direction.
- It describes the magnitude of potential difference between two points but it does not indicate the direction of current flow in a circuit.
- Various sources, like batteries, generators, power supplies, and photovoltaic cells can generate it.
Formula of Voltage
In terms of static electric feild,mathematically voltage is defined as the amount of work done(W) to move an electrical charge(Q).
Voltage(V)=Work done(W)/Charge(Q)
In terms of Ohm’s law, the voltage is deined by the product of resistance of the conductor and current flowing through it.
Voltage(V) = I * R
where,
I stands for current flowing in amperes (A).
R stands for resistance in ohms (Ω).
Types of Voltage
Voltage is classified into two types based on the direction and magnitude of current flowing:
- AC(Alternating Current) voltage
- DC(Direct Current) voltage
DC(Direct Current) Voltage
DC(Direct Current) voltage maintains a constant direction and the electricity flows in a certain direction.The direct current voltage may be a constant voltage or a pulsating voltage. If it is an constant voltage, then the magnitude of voltage does not change with respect to time, while if it is an pulsating voltage, the magnitude changes with respect to time. It is mainly used in battery devices, smartphones, laptops, and electric vehicles (EVs).
AC(Alternating Current) Voltage
AC voltage alternates the voltage direction periodically,it changes from positive to negative and from negative to positive, and the direction of the current also periodically changes accordingly.The magnitude of the voltage changes continuously and direction also changes periodically. It is mainly used in household appliances, lighting systems, and electronic devices.
How to Measure Voltage?
There are several ways to measure voltage that are mentioned below.
Measure Voltage Using Voltmeter
Voltage between two points in a system can be measured by using a Voltmeter.Voltmeter is used to measure the voltage of an Alternating Current (AC) circuits or Direct Current (DC) circuits.The voltmeter connected across the two points measures the voltage drop between them when the current flows through the circuit.
There are two types of Voltmeters:
- Analog Voltmeter
- Digital Voltmeter
Analog Voltmeter
Analog voltmeters provide continuous readings and are suitable for measuring both AC and DC voltages. Analog voltmeter has a pointer or needle to indicate the voltage on a scale. They have a moving coil or moving iron design.Due to digital voltmeter,these days analog voltmeter is less common usage.
Digital Voltmeter
Digital voltmeter contains voltage readings as numerical values on a digital screen. They are more accurate and easier to read than compared to analog voltmeters. The digital multimeter measures and displays the voltage readings on an LCD screen in the form of digits.The main advantage of using digital voltmeter is we can measure both direct voltage and alternating voltage with the same device just by changing the meter settings such as ac voltage and dc voltage.
Examples on Voltage
Voltage plays an important role in some electrical circuits and electrical applications:
Here are few examples how voltage is used in daily-life applications:
- Car batteries like electric cars have voltage around 350 volts.
- Normal AA alkaline battery have voltage of 1.5 Volts.
- High voltage transmission lines carry voltages of 100,000 volts or more volts.
- Cell phone battery like lithium battery contains voltage around 3.7 volts charge.
- USB ports on computers and chargers typically provide a voltage of 5 volts.
FAQs on Voltage
1. What is Voltage and its Units?
Voltage is the amount of work done(pressure) required to move a unit charge from one point to another point in an electric circuit.The SI unit of Voltage is Volt(V).One volt is equal to one joule of energy per coulomb of charge.
2. How Voltage is measured?
Voltage between two points in a system can be measured by using a Voltmeter.Voltmeter is used to measure the voltage of an Alternating Current (AC) circuits or Direct Current (DC) circuits.
3. How Voltage is created?
Voltage is created by a difference in electric charge between two points. It can be generated by various means, which include batteries, generators, and power supplies,these create an electric potential difference.