A machine is a set of mechanisms consisting of various machine elements such as gears, bearings and shafts in order to convert any type of energy into another energy, to do a job or to create an effect by using a certain power. Electronic or organic devices that do not have any mechanical parts are also called machines. Machines have been developed to assist or completely replace human or animal power in the performance of a particular job or the performance of a physical function. They cover a wide range of devices, from simple machines such as levers, inclined planes, and spinning wheels to very complex systems such as a modern automobile. Machines can operate by converting thermal, chemical, nuclear or electrical energy into mechanical energy or vice versa, or they can only function to transmit or adapt forces and motion. All machines have input and output equipment and adaptation or conversion and transfer equipment. Machines that take input energies (input) from natural sources such as wind, river, coal, oil or uranium and convert this energy into mechanical energy are called primary motors. Windmills, water wheels, turbines, steam engines and internal combustion engines are the primary drivers.