Consider a coil of \(N\) windings in which there is a current \(i\). This current causes the coil to produce a magnetic field, and the flux of this field through each winding of the coil is \(\Phi_B\). The total flux through all \(N\) windings is then \(N \Phi_B\). We define the inductance of the coil (symbol \(L\)) as the total flux divided by the current that produces it:
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