Electrical voltage is a quantity that expresses the electric potential difference between two points within an electric field. Voltage is the potential energy per unit charge and is described in the International System of Units (SI) as Volt (V). It can be mathematically defined as follows:

Here:

• V: Voltage (V),
• E_P: Potential energy (J),
• q: Electric charge (C)

Using a formula, the potential energy is defined with the charges and the distance between them.

^{Electric Charges}

Here:

• k: 8.98 x 10⁹, Coulomb's constant (Nm²/C²),
• EP: Potential energy (J),
• q1, q2: Electric charges (C),
• r: Distance between the two charges (m)

These are expressed in the given context.

^{Potential Difference at Point A}

The potential difference at point A can be determined using the following formula.

Meaning of Voltage

Voltage represents the potential energy gained or lost by an electric charge as it moves between two points in an electric field. If there is voltage in an electrical circuit, it indicates the presence of a force that causes charges to flow, known as electric current.

Source and Measurement

Voltage is typically generated by an electrical energy source such as a battery or a generator. It is measured using a voltmeter. The voltmeter is connected between the points being measured in the circuit and displays the potential difference between these points.

Types of Voltage

Direct Voltage (DC Voltage): The potential difference is constant over time. For example, the voltage from a battery is expressed as direct voltage.

Alternating Voltage (AC Voltage): The potential difference changes periodically over time. For example, the electrical grid voltage used in our homes is expressed as alternating voltage. In Turkey, the electrical grid operates at 220 V AC voltage and 50 Hz frequency.

^{Types of Voltage}

Voltage Levels

Electrical energy is transmitted, distributed, and used at various voltage levels depending on different needs. Voltage levels are typically determined by the system's design, the equipment used, and the distance of energy transfer. Below is an explanation of voltage levels with general classifications:

• Low Voltage (LV): These are voltage levels up to 1000 volts (1 kV).
• Applications: Residential and commercial applications (230/400 V), small businesses and offices, electrical appliances, and lighting systems.
• Example: Outlet voltage used in homes (e.g., 220 V in Turkey).
• Medium Voltage (MV): These are voltage levels ranging from 1 kV to 34.5 kV.
• Applications: Electrical distribution systems (energy transfer to cities), industrial facilities, factories, high-power motors, and generators.
• Example: 10 kV, 15 kV, 33 kV.
• High Voltage (HV): These are voltage levels ranging from 34.5 kV to 154 kV.
• Applications: Electrical transmission lines (energy transfer between cities and regions), high-power industrial facilities, and long-distance energy transport applications.
• Example: 66 kV, 110 kV.
• Extra High Voltage (EHV): These are voltage levels above 154 kV.
• Applications: International electricity transmission systems, large industrial facilities, and energy projects.
• Example: 400 kV, 500 kV.