---
title: UnitElectricPotentialDifference
framework: foundation
role: symbol
role_heading: Class
path: foundation/unitelectricpotentialdifference
---

# UnitElectricPotentialDifference

A unit of measure for electric potential difference.

## Declaration

```swift
class UnitElectricPotentialDifference
```

## Overview

Overview You typically use instances of UnitElectricPotentialDifference to represent specific quantities of electric potential difference using the NSMeasurement class. Electric Potential Difference Electric potential difference is the amount of electric potential energy of a point charge at a point in space. The SI unit for electric potential difference is the volt (V), which is derived as the difference in electric potential energy between two points of a linear conductor when an electric current of one ampere dissipates one watt of power between those points (1V = 1W/1A). The UnitElectricPotentialDifference class defines its baseUnit() as volts, and provides the following units, which are initialized using UnitConverterLinear converters with the specified coefficients:  |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |

## Topics

### Accessing the Base Unit

- [baseUnit()](foundation/dimension/baseunit().md)

### Accessing Predefined Units

- [megavolts](foundation/unitelectricpotentialdifference/megavolts.md)
- [kilovolts](foundation/unitelectricpotentialdifference/kilovolts.md)
- [volts](foundation/unitelectricpotentialdifference/volts.md)
- [millivolts](foundation/unitelectricpotentialdifference/millivolts.md)
- [microvolts](foundation/unitelectricpotentialdifference/microvolts.md)

## Relationships

### Inherits From

- [Dimension](foundation/dimension.md)

### Conforms To

- [CVarArg](swift/cvararg.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [NSCoding](foundation/nscoding.md)
- [NSCopying](foundation/nscopying.md)
- [NSObjectProtocol](objectivec/nsobjectprotocol.md)
- [NSSecureCoding](foundation/nssecurecoding.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Electricity

- [UnitElectricCharge](foundation/unitelectriccharge.md)
- [UnitElectricCurrent](foundation/unitelectriccurrent.md)
- [UnitElectricResistance](foundation/unitelectricresistance.md)