Machine

A machine is any mechanical or electrical device that transmits or modifies energy to perform or assist in the performance of tasks. It normally requires an input as a trigger, and transmits the modified energy to an output, which performs the desired task.

Mechanical mechanisms and machines have been in steady use to amplify the abilities of human beings since before written records were available. The primary difference between simple tools and simple mechanisms or machines is a power source and a somewhat independent operation. The term machine generally applies to an assembly of parts operating together to perform work. Generally these devices increase intensity of applied force, changing direction of force, or changing one form of motion or energy into another.

The mechanical advantage of a machine is the ratio between the resistance or load, and the force required to overcome it, although this ratio is not entirely accurate as force is required to overcome friction, as well. To compensate for this, mechanical advantage is calculated as the ratio between the distance moved by the force applied, and the distance moved by the resistance.

Efficiency of a machine is the degree or percentage to which a machine accomplishes the work it could do without the restrictions of friction.

Modern power tools, automated machine tools, and human operated power machinery complicate this definition greatly. Machines used to transform heat or other energy into mechanical energy are known as engines.

Simple machines or mechanical components

• Bearing
• Driveshaft
• Gear
• Lever
• Screw
• Spring
• Wedge
• Winch

Clock

• Atomic clock
• chronometer
• Pendulum clock
• Quartz clock

Compressors and Pumps

• Archimedes screw
• Eductor-jet pump
• Hydraulic ram
• Tuyau
• Vacuum pump

Internal combustion engine

• Gasoline engine
• Diesel engine
• Four-stroke cycle
• Two-stroke cycle
• Wankel engine

External combustion engine

• Steam engine
• Stirling engine

Turbine

• Gas turbine
• Jet engine
• Steam turbine
• Water turbine
• Wind generator, Windmill (Air turbine)

Computing machines

• Calculator
• Analog computer
• Digital computer
• Turing machine

Automated machines

Biological machines

• Virus, Bacterium
• Cell (biology)
• Plant and animal
• Human being
• The mind - controversially

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