Page 17 - Curriculum Visions Dynamic Book

electron: a tiny, negatively charged particle that is part of an atom. The flow of electrons through a solid material such as a wire produces an electric current.
ion: an atom, or group of atoms, that has gained or lost one or more electrons and so developed an electrical charge.
 Looking through the inside of a large electrical
motor. The copper wire carries the electrical current that generates the magnetic field that, in turn, causes the drive shaft of the motor to turn.
Copper in printed circuits
A printed circuit is made from a
rigid baseboard of insulating material with conductors stuck to its surfaces.
To make a printed circuit, a sheet of copper foil is stuck to both sides of the baseboard. The copper foil is then sprayed with a film of light-sensitive (silver-based) material. A mask is made up of the connections that are required and placed on the film. The film is then exposed to light and the board put into
a photographic developer, which removes all undeveloped parts of the film.
Next the board is placed in an acid solution that dissolves away all parts of the copper not protected by the developed film. This leaves behind the pattern of connections on the board, ready for the electrical components to be added.
 A printed circuit board showing the conducting circuit of fine copper connecting the wide variety of electronic devices.
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