What is Volt? Things You Didn’t Know About Voltage

If you’ve been through basic education programs, the term “volt” may not be entirely unfamiliar to you. You may have also noticed the letter V on electrical devices. Volt is a unit widely used in subjects such as Physics, Technology, and Engineering, especially in calculations related to electricity. So, what exactly is a volt?

Understanding Voltage

Volt is the Vietnamese name for the unit “Volt” and is symbolized by the letter V. It is used to measure electric potential difference and electromotive force in the SI system. This unit is named after Alessandro Volta, an Italian physicist who discovered voltage.

A volt is defined as the electric potential difference between two points on a conductor when a current of 1A flows through it with a power of 1W. It can also be understood as the difference in electrical potential between two parallel infinite planes separated by 1m.

When the voltage increases, the current flowing through the circuit also increases. This is the voltage value commonly seen by consumers, such as 120V or 240V.

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Determining Voltage

The voltage is determined to be 1V when a current of 1A flows through a circuit with a power of 1W. For example, a regular hairdryer has a maximum power of 1000W. If it is used with the standard voltage of 220V, the maximum current consumed would be 1000/220 = 4.5A.

Voltage Measuring Instrument: Voltmeter

Volt is one of the units of measurement used in voltmeters. A voltmeter is a commonly used tool in today’s life. It is used to measure the potential difference or voltage between different points in an electrical circuit. The symbol for the voltmeter instrument is also based on the unit for measuring voltage.

You can think of a voltmeter as an electrical device used to measure the potential difference between two points in a circuit. It can be seen in circuit diagrams as V.

Types of Voltmeters

Currently, there are several types of voltmeters available, including iron voltmeters, induction voltmeters, electrostatic voltmeters, permanent magnet voltmeters, rectifier voltmeters, and digital voltmeters.

When connected to a circuit, a voltmeter extracts a portion of the electrical energy to determine the voltage magnitude. The level of energy extraction is determined by the voltmeter’s resistance at that particular scale. The resistance must be sufficiently high to avoid disturbing the circuit being measured.

In the past, when voltmeters had high resistance, people would often create lamp voltmeters. These were circuit amplifiers that used electronic lamps or transistors to ensure that the resistor could reach tens of megaohms. However, with the advancement and widespread use of microprocessor technology, the measurement scales of universal meters today meet the required standards.

Construction of a Voltmeter

A voltmeter consists of a sensitive ammeter connected in parallel with a high-resistance resistor. The resistance inside the voltmeter must be high. When tested, it will attract a certain amount of current in the circuit, which interrupts its operation. Voltmeters often use electronic display indicators on the surface of the instrument.

Typically, laboratory voltmeters have a maximum range of 1000-3000V. Most voltmeters have different measurement scales. Laboratory voltmeters are generally suitable for standard requirements because the voltage measured is at an average level.

The Working Principle of a Voltmeter

To operate, a voltmeter must be connected in parallel with the device you want to measure the voltage of. A voltmeter inherently has a relatively high voltage value. Therefore, if connected in parallel, the potential difference is practically non-existent, meaning the circuit will be open. The potential difference between the voltmeter and the source will be almost the same.

In theory, to have an ideal voltmeter, an infinite resistor must be present to attract zero current. If done this way, the phenomenon of energy loss during the process will not occur. However, in reality, this does not happen because there is no material that can withstand prolonged and infinite resistance.

Applications of Voltmeter

Voltmeters are used to measure the voltage difference between two points in a circuit without affecting or changing the voltage. They play a crucial role in measuring voltage in various applications.

Some of the applications of voltmeters include troubleshooting faulty fans or electrical appliances. By using a voltmeter, you can check the voltage in the fan and socket to identify the problem. If the voltage is not sufficient, it’s possible that the socket is damaged. Additionally, you can use a voltmeter to determine the state of a battery, such as whether it is charged or discharged, or to measure the voltage of car batteries when they are not in use.

Voltmeters are indispensable measuring instruments in daily life and in fields such as physics, chemistry, and technology. We hope that the information shared above provides a better understanding of voltage.