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Radians

<^< Measuring Angles | Course Index | Examples: Radians >^>

In electrical circuits, angles are measured in either degrees or radians (both of which are strictly dimensionless units). You will no doubt, already be familiar with angular measure in degrees where one complete circular revolution is equivalent to an angular change of 360°. The alternative method of measuring angles, the radian, is defined somewhat differently. It is the angle subtended at the centre of a circle by an arc having length which is equal to the radius of the circle.

It is often necessary to convert from radians to degrees, and vice versa. A complete circular revolution is equivalent to a rotation of 360° or 2π radians (note that π is approximately equal to 3.142). Thus one radian is equivalent to 360/2π degrees (or approximately 57.3°). The following rules should assist you when it is necessary to convert angles expressed in degrees to radians and vice versa:

1 To convert from degrees to radians, divide by 57.3

2 To convert from radians to degrees, multiply by 57.3

<^< Measuring Angles | Course index | Examples: Radians >^>