A pulse that reverses field direction partway through its cycle, so it induces current twice, on the swing out and on the swing back. A pulse that stays in one direction is monophasic (unipolar); one that reverses is biphasic (bipolar).
Also known as: Monophasic / Biphasic
A real field pulse over time. The height of the pulse is its amplitude, how strong the field gets, separate from how often the pulse repeats. After the pulse the coil rings, a fast shrinking oscillation at the coil's natural frequency; the time from one ring peak to the next is one cycle of that ring frequency. A coil driven at its natural frequency takes up energy most efficiently, which is resonance.
