KV

Kilovolt (symbol kV) is a unit of electric potential difference or electromotive force equal to 1,000 volts. It is formed from the SI unit volt (V) using the SI prefix kilo, and it is not a base unit itself. The kilovolt is commonly used in electrical engineering and power systems to express large voltages.

One kilovolt equals 1,000 volts, and the volt is defined as one joule of energy per coulomb of charge. In practical terms, a potential difference of 1 kV moving an electron would impart about 1 keV of energy to that electron (in non-relativistic terms), making kilovolts a central quantity in high-energy and high-voltage applications such as X-ray tubes and particle accelerators.

In power transmission and distribution, kilovolts are used to denote the voltage levels of transmission lines and equipment. Common values include 11 kV, 33 kV, 110 kV, 220 kV, and 400 kV, reflecting a balance between reduced current for lower losses and the insulation requirements of higher voltages. Equipment such as transformers, switchgear, and insulators are rated in kV to indicate their voltage handling capability.

In radiography, kilovolts are used to describe the maximum accelerating voltage of X-ray tubes; this setting, often referred to as kVp (kilovolt peak), influences the energy spectrum and penetrating power of the X-rays, though the actual photon energy distribution depends on several factors in the generator and tube design.

Safety considerations are paramount at kilovolt levels, as insulation, clearance, and shielding requirements increase with voltage. Kilovolt values are a standard shorthand in engineering practice for high-voltage systems, distinct from the volt used for everyday electrical measurements.

See also: volt, kilovolt-peak, electronvolt.