Put a current-carrying wire square across a magnetic field and the field pushes on it — the motor effect, and the reason anything electric spins. The push is $F = BIL$ (read aloud: F equals B I L): field strength, current, length of wire in the field. $B$ is measured in teslas — a one-tesla field pushes one newton on each metre of wire carrying one ampere. Every wire in this lesson sits square across its field, so the angle factor is 1 and stays out of the way.

The transformer is the other magnetic worker: two coils sharing one iron core, trading voltage by turns — $\dfrac{V_s}{V_p} = \dfrac{N_s}{N_p}$ (read aloud: V-s over V-p equals N-s over N-p; the subscripts are secondary and primary). The instinct that beats the trap: MORE turns sit on the side with MORE voltage, always.