Search results
Results from the WOW.Com Content Network
Frequency and voltage supplied to most premises by country. Mains electricity by country includes a list of countries and territories, with the plugs, voltages and frequencies they commonly use for providing electrical power to low voltage appliances, equipment, and lighting typically found in homes and offices.
The blinking of non-incandescent city lights is shown in this motion-blurred long exposure. The AC nature of the mains power is revealed by the dashed appearance of the traces of moving lights. In an electric circuit, instantaneous power is the time rate of flow of energy past a given point of the circuit.
Electric power quality is the degree to which the voltage, frequency, and waveform of a power supply system conform to established specifications. Good power quality can be defined as a steady supply voltage that stays within the prescribed range, steady AC frequency close to the rated value, and smooth voltage curve waveform (which resembles a sine wave).
For example, if the load power factor were as low as 0.7, the apparent power would be 1.4 times the real power used by the load. Line current in the circuit would also be 1.4 times the current required at 1.0 power factor, so the losses in the circuit would be doubled (since they are proportional to the square of the current).
[citation needed] Until about 1880, the paradigm for AC power transmission from a high voltage supply to a low voltage load was a series circuit. [citation needed] Open-core transformers with a ratio near 1:1 were connected with their primaries in series to allow use of a high voltage for transmission while presenting a low voltage to the lamps.
# Hz = frequency in hertz (alternating current (AC)) AC supplies are usually single-phase (1φ) except where marked three-phase (3φ). Conductors: overhead line or; conductor rail, usually a third rail to one side of the running rails. Conductor rail can be: top contact: oldest, least safe, most affected by ice, snow, rain and leaves.
An external power supply, AC adapter or power brick, is a power supply located in the load's AC power cord that plugs into a wall outlet; a wall wart is an external supply integrated with the outlet plug itself. These are popular in consumer electronics because of their safety; the hazardous 120 or 240 volt main current is transformed down to a ...
(Also used: 1 A 2 × 1 Ω.) [5] The watt was defined as equal to 10 7 units of power in the practical system of units. [10] The "international units" were dominant from 1909 until 1948. After the 9th General Conference on Weights and Measures in 1948, the international watt was redefined from practical units to absolute units (i.e., using only ...