the.com/solenoid
a coil of wire pretending it's a magnet only when electricity says so
on demandCurrent makes the magnetic field; cut it, field vanishes
car starterClicks your engine to life every cold morning
field insideMagnetic field stays nearly uniform along its core
named 1820sFrom Greek for channel-shaped, coined by André-Marie Ampère
valve dutyControls washing machine water and sprinkler flow electrically