Electrical Characterisitics The performance of a network using copper wires depends on the electrical characteristics of the cable used. Bits are framed by the Data Link and put over the Physical Layer's wires where they travel as electrical signals. If a node on a network is a few feet away from a hub, almost any wire will work if the connectors fit the equipment. The maximum length of a 'cable run' in 10Base-T Ethernet, without using repeaters, is 100 meters, a little more than 300 feet. Longer runs require appropriate wiring.
Capacitance is the ability, or capacity, of a circuit to store an electrical charge. Condensers & Capacitors are electrical components which derive from the Leyden Jar, which was discovered in the 1700's. Electricity was thought of as an invisible liquid which condensed and could be stored in such a jar. Now, we call these components Capacitors and they have use in electronics of many types. Anyone who has seen, or felt, the Condenser off an old Chevy's ignition system discharge, long after it's been removed from the distributor understands that these components can store quite a shock. Although Capacitance is desirable where it's needed, we don't want our Network Wires _storing_ a charge, since this would distort the pattern of bits in the signal. The metal alloys for Copper wire and dielectric properties of the insulators used in network cabling are chosen to control & _reduce_ capacitance in the circuits.
