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# UnitElectricPotentialDifference

A unit of measure for electric potential difference.

```
class UnitElectricPotentialDifference
```

## Overview

You typically use instances of [`UnitElectricPotentialDifference`](/documentation/Foundation/UnitElectricPotentialDifference) to represent specific quantities of electric potential difference using the [`NSMeasurement`](/documentation/Foundation/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`](/documentation/Foundation/UnitElectricPotentialDifference) class defines its [`baseUnit()`](/documentation/Foundation/Dimension/baseUnit()) as [`volts`](/documentation/Foundation/UnitElectricPotentialDifference/volts), and provides the following units, which are initialized using [`UnitConverterLinear`](/documentation/Foundation/UnitConverterLinear) converters with the specified coefficients:

|Name      |Method                                                                                            |Symbol|Coefficient|
|----------|--------------------------------------------------------------------------------------------------|------|-----------|
|Megavolts |``doc://com.apple.foundation/documentation/Foundation/UnitElectricPotentialDifference/megavolts`` |MV    |`1000000.0`|
|Kilovolts |``doc://com.apple.foundation/documentation/Foundation/UnitElectricPotentialDifference/kilovolts`` |kV    |`1000.0`   |
|Volts     |``doc://com.apple.foundation/documentation/Foundation/UnitElectricPotentialDifference/volts``     |V     |`1.0`      |
|Millivolts|``doc://com.apple.foundation/documentation/Foundation/UnitElectricPotentialDifference/millivolts``|mV    |`0.001`    |
|Microvolts|``doc://com.apple.foundation/documentation/Foundation/UnitElectricPotentialDifference/microvolts``|µV    |`0.000001` |

## Topics

### Accessing the Base Unit

[`+  baseUnit`](/documentation/Foundation/Dimension/baseUnit())

Returns the base unit.

### Accessing Predefined Units

[`megavolts`](/documentation/Foundation/UnitElectricPotentialDifference/megavolts)

The megavolts unit of electric potential difference.

[`kilovolts`](/documentation/Foundation/UnitElectricPotentialDifference/kilovolts)

The kilovolts unit of electric potential difference.

[`volts`](/documentation/Foundation/UnitElectricPotentialDifference/volts)

The volts unit of electric potential difference.

[`millivolts`](/documentation/Foundation/UnitElectricPotentialDifference/millivolts)

The millivolts unit of electric potential difference.

[`microvolts`](/documentation/Foundation/UnitElectricPotentialDifference/microvolts)

The microvolts unit of electric potential difference.

## Relationships

### Conforms To

[`CustomDebugStringConvertible`](/documentation/Swift/CustomDebugStringConvertible)

[`Sendable`](/documentation/Swift/Sendable)

[`CVarArg`](/documentation/Swift/CVarArg)

[`NSCoding`](/documentation/Foundation/NSCoding)

[`Hashable`](/documentation/Swift/Hashable)

[`NSSecureCoding`](/documentation/Foundation/NSSecureCoding)

[`NSCopying`](/documentation/Foundation/NSCopying)

[`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible)

[`Equatable`](/documentation/Swift/Equatable)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol)

### Inherits From

[`Dimension`](/documentation/Foundation/Dimension)

---

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