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A passive component is one that does not have the ability to change its properties like a semiconductor, but performs a basic electrical function due to its construction and materials. There five types:

Capacitors
These are energy storage devices. They have layers of insulating material called a dielectric sandwiched between layers of conductor, and electrons build up at the layer junctions.
Resistors
These limit current in a circuit, useful for changing voltage. Most are made by mixing graphite powder and clay, with the resistance determined by the clay/carbon ratio. Some are also made by coiling a wire tightly, basically creating a really long path to limit current flow (These were the first type made.)
Inductors
These are coils of wire that store energy in the form of a magnetic field. The inductance is directly proportional to the radius of the coil and number of turns.
Transformers
These are square or round rings made of stacks of sheet metal that are wrapped in wire, using the magnetic field created to convert voltage. There is a wire for source current and a wire for the output current, with the number of windings on each length of wire determining the voltage conversion.
Fuses
These are protection devices that burn out or change their physical characteristics when the current in the line goes above a preset limit. A fuse can have a simple metal strip that melts, or be made from polymeric positive-temperature-coefficient material that changes from conductive to non-conductive when heated by excess current. The latter is referred to as a resettable fuse, as it goes back to a conductive state once it cools down.

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