Wet linear cartridge valve solenoid coil amps current set of short straight line current is also applicable. Ring current can be seen as composed of many small pieces of line currents, each with a short straight line current in amperes current setting is to determine the ring current magnetic induction on the central axis direction.
Stacking up to get the ring current magnetic induction on the central axis line direction, the linear current amp is a basic set, you can set the ring current amp current amps set by the straight line is a straight line to export the current amp is set for the linear movement of the charge also applies to the magnetic field, when the current direction and direction of movement of positive charge the same, with the negative charge movement in the opposite direction. Charged case, the coil to form a corresponding threaded cartridge valve thrust to its principle of work and running.