How arises electrical voltage?
Voltage supply can occur in many different ways. The main reason why voltage may occur is by the energy that comes from different sources. By magnetic and mechanical action In a copper-wire that moves between the poles of a magnet, there will be created voltage. For example, magnetic energy is converted to electrical energy. Such rotating (moving) sources is called generators. So you have: the alternator that supplies DC, bicycle magneto that AC supplies and alternators from cars and power plants that supplies three phase voltage. This principle was discovered by the British physicist Faraday around 1830. He also discovered the 'Faraday cage'. Example The dynamo of a bicycle. If you place the wheel of the dynamo against the tire and you turn the wheel of the bicycle then there arise voltage in the magneto and that provides power to the bicycle lamps that can now can give light. Heat operation Two different metals, for example iron and constantan, are welded to each other on on...