What is electrical voltage, and what types are there?

What is electrical voltage?

Also known as electric tension, voltage is measured in volts (V) and represents the force that drives electrons through a conductor. Clearly speaking, it’s the ‘pressure’ that pushes electrical current.

Voltage is present in countless aspects of our daily lives—from household outlets powering appliances to advanced circuits used in medical technology, telecommunications, and industrial automation. It’s also vital in lighting systems, heating, and electronic devices like smartphones and computers.

In the transport sector, voltage plays a key role in electric vehicles, which rely on high-voltage batteries. Within electric distribution grids, proper voltage regulation is essential for ensuring efficient and safe power supply, allowing electricity to reach homes and industries effectively.

To meet different needs, there are several types of voltage, categorised by their origin and application.

Types of electrical voltage

Alternating current (AC) voltage

AC voltage is the most commonly used type of voltage in power grids. Its main characteristic is that it periodically reverses direction. This voltage is generated by alternators and is widely used in homes, industries, and businesses.

One of its major advantages is the ability to be transmitted over long distances with minimal energy loss. Furthermore, it can also be easily transformed to different voltage levels as needed using electrical transformers.

Typical AC voltage levels vary by region. In Europe and much of the world, the standard is 230 V at 50 Hz, while the United States and some other countries use 120 V at 60 Hz.

Direct current (DC) voltage

Direct current (DC) voltage is essential for electronic devices, as it provides a stable and unidirectional flow of electrons. This way, their proper function is ensured. Devices like computers, smartphones, and appliances with sensitive circuits depend on DC power to avoid malfunctions.

Since most power systems generate AC, many devices require the use of power supplies and rectifiers to convert it into DC. These components eliminate fluctuations and stabilise the voltage. This process is critical for battery chargers, solar energy systems, and industrial equipment that requires a reliable energy supply.

Contact voltage

Contact voltage occurs when a metal structure or part of an electrical device becomes energised due to insulation failure or faulty connections. This poses a serious safety risk, as touching an energised surface can result in an electric shock and potentially severe injury.

To prevent such incidents, it's essential to perform regular inspections, maintain proper insulation, and use safety systems like residual current devices and grounding connections.