+ \begin{align*}
+ F=qE \tag{$E$ = strength} \\
+ W=q_{\operatorname{point}}\Delta V \tag{in field or points} \\
+ F=k{{q_1q_2}\over r^2}\tag{force between $q_{1,2}$} \\
+ E=k{Q \over r^2} \tag{$r=||EQ||$} \\
+ F=BInl \tag{force on a coil} \\
+ \Phi = B_{\perp}A\tag{magnetic flux} \\
+ \mathcal{E} = -N{{\Delta \Phi}\over{\Delta t}} \tag{induced emf} \\
+ {V_p \over V_s}={N_p \over N_s}={I_s \over I_p} \tag{xfmr coil ratios} \\
+ \end{align*}