koaksikaapeli

Koaksikaapeli, often referred to as coaxial cable, is a type of electrical cable with an inner conductor surrounded by an insulating layer, an outer conductor, and a protective outer sheath. This construction allows it to carry radio frequency signals with minimal loss. The name "coaxial" refers to the fact that the inner conductor and the outer conductor share the same geometric axis.

The primary function of the coaxial cable's design is to shield the signal from external electromagnetic interference and to prevent the signal from radiating out of the cable. The insulating layer, typically made of polyethylene or Teflon, maintains a precise distance between the inner conductor and the outer conductor, which is crucial for the cable's electrical characteristics, particularly its impedance. The outer conductor, usually a braided copper mesh or a solid metal tube, acts as the ground and the shield. The outer sheath protects the entire assembly from physical damage and environmental factors.

Koaksikaapeli is widely used for transmitting television signals, both from antennas to televisions and in cable television systems. It is also employed in radio and telecommunications, for connecting antennas to transmitters and receivers, and in networking, particularly in older Ethernet standards like 10BASE2 and 10BASE5. The characteristic impedance of coaxial cables is a key parameter, with common values being 50 ohms and 75 ohms, chosen based on the application.