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An electric current is a flow of charged particles, ... (in amperes) can be calculated with the following equation: =, where Q is the electric charge ...
Equations for time-invariant AC circuits take the same form as Ohm's law. However, the variables are generalized to complex numbers and the current and voltage waveforms are complex exponentials. [29] In this approach, a voltage or current waveform takes the form Ae st, where t is time, s is a complex parameter, and A is a complex scalar
The neutral current can be determined by adding the three phase currents together as complex numbers and then converting from rectangular to polar co-ordinates. If the three-phase root mean square (RMS) currents are I L 1 {\displaystyle I_{L1}} , I L 2 {\displaystyle I_{L2}} , and I L 3 {\displaystyle I_{L3}} , the neutral RMS current is:
The current entering any junction is equal to the current leaving that junction. i 2 + i 3 = i 1 + i 4. This law, also called Kirchhoff's first law, or Kirchhoff's junction rule, states that, for any node (junction) in an electrical circuit, the sum of currents flowing into that node is equal to the sum of currents flowing out of that node; or equivalently:
The power losses in the wire are a product of the square of the current ( I ) and the resistance (R) of the wire, described by the formula: P w = I 2 R . {\displaystyle P_{\rm {w}}=I^{2}R\,.} This means that when transmitting a fixed power on a given wire, if the current is halved (i.e. the voltage is doubled), the power loss due to the wire's ...
In electromagnetism, current density is the amount of charge per unit time that flows through a unit area of a chosen cross section. [1] The current density vector is defined as a vector whose magnitude is the electric current per cross-sectional area at a given point in space, its direction being that of the motion of the positive charges at this point.
The most fundamental formula for Joule heating is the generalized power equation: = where P {\displaystyle P} is the power (energy per unit time) converted from electrical energy to thermal energy, I {\displaystyle I} is the current travelling through the resistor or other element,
The upper graph shows the current density as function of the overpotential η . The anodic and cathodic current densities are shown as j a and j c, respectively for α=α a =α c =0.5 and j 0 =1mAcm −2 (close to values for platinum and palladium). The lower graph shows the logarithmic plot for different values of α (Tafel plot).