An electromagnetic coil is an electrical conductor such as a wire in the shape of a coil, spiral or helix. Electromagnetic coils are used in electrical engineering, in applications where electric currents interact with magnetic fields, in devices such as inductors, electromagnets, transformers, and sensor coils.
Causes of lower back spasms. Back spasms can be the result of injuries to the muscles, tendons, and ligaments in the back or it can be related to more serious medical conditions. Heavy lifting is a common cause of back spasms. Any activity that puts excessive strain on the muscles and ligaments in the lower back can cause an injury.
1 If you're in poor physical condition, constant strain on your back may cause painful muscle spasms.  Bulging or ruptured disks. Disks act as cushions between the bones (vertebrae) in your spine. The soft material inside a disk can bulge or rupture and press on a nerve.