Low-tension coil

A low-tension coil is an electrical device used to create a spark across the points of an ignitor on early-1900s gasoline engines, generally flywheel engines, hit-and-miss engines, and other engines of that era. In modern electronic terms, a low-tension coil is simply a large inductor, an electrical device that stores energy for brief periods. The term "low tension" was the terminology of the day used to differentiate it from the term "high tension" and generally meant "low voltage" (tension) as opposed to "high voltage" (tension). High-tension coils produce high voltages, generally meant to produce a spark across a spark plug.