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The resistance per wire length (Ω/m) of a heating element material is defined in ASTM and DIN standards. [2]: 2 [3] [4] In ASTM, wires greater than 0.127 mm in diameter are specified to be held within a tolerance of ±5% Ω/m and for thinner wires ±8% Ω/m.
Joule heating affects the whole electric conductor, unlike the Peltier effect which transfers heat from one electrical junction to another. Joule-heating or resistive-heating is used in many devices and industrial processes. The part that converts electricity into heat is called a heating element. Among the applications are:
Utility pole with electric lines (top) and telephone cables. Fixed telephone lines per 100 inhabitants, 1997–2007. Cross section of telephone cable of 1,800 twisted pairs, 1922. A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system. [1]
Nichrome, a non-magnetic 80/20 alloy of nickel and chromium, is the most common resistance wire for heating purposes because it has a high resistivity and resistance to oxidation at high temperatures, up to 1,400 °C (2,550 °F). When used as a heating element, resistance wire is usually wound into coils.
Telephone wiring is required between the telephone company's service entrance and locations throughout the home. Often a home will have telephone outlets in the kitchen, study, living room or bedrooms for convenience. Telephone company regulations may limit the total number of telephones that can be in use at one time. The telephone cabling ...
A positive-temperature-coefficient heating element (PTC heating element), or self-regulating heater, is an electrical resistance heater whose resistance increases significantly with temperature. The name self-regulating heater comes from the tendency of such heating elements to maintain a constant temperature when supplied by a given voltage.
On an ordinary two-wire telephone line, off-hook status is communicated to the telephone exchange by a resistance short across the pair. When an off-hook condition persists without dialing, for example because the handset has fallen off or the cable has been flooded, it is treated as a permanent loop or permanent signal .
Most modern electric heating devices use nichrome wire as the active element; the heating element, depicted on the right, uses nichrome wire supported by ceramic insulators. Alternatively, a heat pump can achieve around 150% – 600% efficiency for heating, or COP 1.5 - 6.0 Coefficient of performance , because it uses electric power only for ...