A mechanical linear actuator is a device which produces precise straight-line movement, position & force driven usually by an electric motor.

Conversion from motorised rotary input can be achieved by using a leadscrew or ball screw for example. Generally, this involves rotating part of the mechanism to facilitate a linear movement of the screw shaft.

There are other ways of producing linear movement in a linear actuator, such as a motor driven belt attached to a carriage with accompanying guideways and bearings etc.

A typical example of an electric linear actuator is shown below.

A typical example of an electric belt driven linear actuator with carriage is shown below.