= Inductance
{title2=$L$}
{wiki}
<Inductance> relates <electric currents> to the <magnetic flux linkage> they produce. For a single linear coil with fixed geometry and magnetic response, its <self-inductance> $L$ is the constant in
$$
\Lambda=LI.
$$
Here $\Lambda$ is <magnetic flux linkage> from the coil's own <electric current> $I$. The <SI> unit of <inductance> is the <henry (unit)>. Knowing <inductance> lets us predict the induced <electromotive force> when <electric current> changes, and the <magnetic energy> stored by an <inductor>. https://openstax.org/books/university-physics-volume-2/pages/14-2-self-inductance-and-inductors[OpenStax University Physics 2, §14.2: self-inductance and inductors]{ref}.
For example, a coil of <self-inductance> $0.5\,\mathrm H$ carrying <electric current> $3\,\mathrm A$ has <magnetic flux linkage> $1.5\,\mathrm{Wb}$. If its $100$ turns link the same <magnetic flux>, each turn has <magnetic flux> $0.015\,\mathrm{Wb}$. Keeping the geometry and magnetic response fixed while doubling <electric current> doubles <magnetic flux linkage> and quadruples the <inductor>'s <magnetic energy>.
The comparison with <capacitance> is useful: a linear <capacitor> has $Q=CV$ and stores <capacitor energy> $CV^2/2$ in its <electric field>, whereas a linear <inductor> has $\Lambda=LI$ and stores <magnetic energy> $LI^2/2$ in its <magnetic field>. The <RLC circuit> brings both forms of <energy> storage together.
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