A pneumatic solenoid valve is a switch for routing air to any pneumatic device, usually an actuator of some kind. A solenoid consists of a balanced or easily moveable core, which channels the gas to the appropriate port, coupled to a small linear solenoid. The valve allows a small current applied to the solenoid to switch a large amount of high pressure gas, typically at around 100 psi (7 bar, 0.7 MPa, 0.7 MN/m²).
Pneumatic solenoids may have one, two, or three output ports, and the requisite number of vents. The valves are commonly used to control a piston or other linear actuator.
The pneumatic solenoid is akin to a transistor, allowing a relatively small signal to control a large device. It is also the interface between electronic controllers and pneumatic systems.
The magnetic field inside a solenoid is given by B=μnl, where μ=4(3.14)E-7T, n is the number of loops per length.
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