Tension

Electric voltage is a quantity that represents the electric potential difference between two points in an electric field. Voltage is defined as the potential energy per unit charge, and its unit in the SI system is the volt (V). Mathematically, it can be defined as:

Where:

V: Voltage (V),

E_P: Potential energy (J),

q: Electric charge (C)

are expressed.

Potential energy is defined by a formula that depends on the charges and the distance between them.

Electric Charges

Where:

k: 8.98 × 10⁹, Coulomb’s constant (N·m² / C²),

E_P: Potential energy (J),

q₁, q₂: Electric charges (C),

r: Distance between the two charges (m)

are expressed.

Potential Difference at Point A

The potential difference at point A can be found 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 electric circuit, it indicates the presence of a force that causes charges to flow.

Source and Measurement

Voltage is typically generated by sources such as batteries and generators. Voltage is measured using a voltmeter, which is connected between the two points in the circuit and indicates the potential difference between them.

Types of Voltage

Direct Voltage (DC Voltage): The potential difference remains constant over time; for example, the voltage of a battery is expressed as direct voltage.

Alternating Voltage (AC Voltage): The potential difference varies periodically over time; for example, the voltage of the electrical grid in homes is expressed as alternating voltage. In Türkiye, the electrical grid operates at 220 V AC and 50 Hz frequency.

Types of Voltage

Voltage Levels

Electrical energy is transmitted, distributed, and utilized at various voltage levels depending on different requirements. Voltage levels are generally determined based on the system design, the equipment used, and the distance of energy transmission. Below are the general classifications of voltage levels:

• Low Voltage (LV): Voltage levels of 1000 volts (1 kV) and below.
• • Applications: Residential and commercial uses (230/400 V), small businesses and offices, electrical appliances and lighting systems.
  • Example: Outlet voltage in homes (for example, 220 V in Türkiye).
• Middle Voltage (MV): Voltage levels between 1 kV and 34.5 kV.
• • Applications: Electrical distribution systems (energy transmission to cities), industrial facilities, factories, high-power motors and generators.
  • Example: Values such as 10 kV, 15 kV, and 33 kV.
• High Voltage (HV): Voltage levels between 34.5 kV and 154 kV.
• • Applications: Electrical transmission lines (energy transfer between cities and regions), high-power industrial facilities, long-distance energy transmission applications.
  • Example: 66 kV, 110 kV.
• Extra High Voltage (EHV): Voltage levels above 154 kV.
• • Applications: International electrical transmission systems, large industrial facilities and energy projects.
  • Example: 400 kV, 500 kV.