What is Cable in Electronics?
Cable
It is an insulated bundle of metal wires or threadlike fibres that carry electric current. They are widely used to distribute electric power and to transmit communication signals. They are also used to connect parts of computers and other electronic devices. Fiber optic cables have also been developed which transmit communications signals in the form of pulses of light. Most communications cables consist of conductors and insulation. Simple cables are made up of a single pair of insulated wires twisted together. Multiconductor cables such as telephone lines contain, hundreds or even thousands of conductors bound together. Submarie cables serve as a communication link between continents. In 1844 American painter and inventor Samuel F.B. Morse completed the first long distance telegraph cable in America.
Coaxial Cables
They are made up of special conductors called coaxials. A coaxial is a copper tube with a copper wire running through its centre. Insulation holds the wire in place. The tube and the wire have the same axis and are therefore called coaxials. A typical coaxial has about the same diameter as a pencil. Many telephone calls, especially long distance calls travel over coaxial cables. When used for telephone conversations coaxial work in pairs. One coaxial carries signals in one direction and the other carries signals in the other direction. Cable Television systems use coaxial cables to transmit TV programmes.
Cable Television
Television programmes transmitted to viewers via wires from the broadcasting station constitute a cable television system. Since their initial introduction in the 1970’s cable systems have become common in areas well enough populated to be financially feasible. By 1988, 50% of the US households subscribed to cable television. In recent years, there has been some use of fiber cables instead of conventional copper or aluminium cables. Channel selectors allow for reserving certain channels to subscribers who have paid extra for access.
Cable Railway or Cable Car
Railways running on aerial cables were invented in the later half of 17thcentury and early half od 18th century to move coal from coal mines to the harbours by crossing the hills and mountains. Now the cable railways are mostly used for ski resorts and other tourist attractions. The ccapacity of passenger units varies from chairs to cabins that can hold more than hundred passengers. The first street railway to run on underground cables was developed by Andrew Hallidie in the San Francisco (USA) in the year 1873. The complex cable systems were subject to breakdowns and need much energy. It was in the beginning of 19thcentury, electric street cars began to replace cable railways.
