A linear actuator is an actuator that creates motion in a straight line, in contrast to the circular motion of a conventional electric motor. You can get here Solenoid electromagnet with Operating Voltage of 12V DC which is employed for locking and unlocking doors, windows, etc in a DIY project.

Linear actuators are used in machine tools and industrial machinery, in computer peripherals such as disk drives and printers, in valves and dampers, and in many other places where linear motion is required. Hydraulic or pneumatic cylinders inherently produce linear motion. Many other mechanisms are used to generate linear motion from a rotating motor.