Solenoids, a type of electromagnet generating a uniform magnetic field when an electric current is passed through it, have applications in many different types of industries. In engineering, they refer to a variety of devices that convert energy into linear motion for use in solenoid valves and solenoid switches. As part of an actuator assembly it incorporates a sliding ferromagnetic plunger inside the coil. Without electrical power, the plunger extends for part of its length outside the coil; applying electrical power pulls the plunger into the coil to operate an electrical switch.
The most common examples include automotive solenoids used to interlock the gearbox drive selectors, activate security bolts and locks, control air-conditioning systems. Joysticks used for machinery control and gaming often use solenoid technology to control pneumatics. A solenoid is also very important in the medical field where medical equipment has to be very precise and accurate. Dosing devices like dialysis machines use solenoids to control the flow of medicine that goes into a person's blood stream.
Testing the load/displacement characteristics of solenoids is an important aspect of quality control testing. Mecmesins software-controlled force and torque testers reliably and accurately measure solenoids over the whole stroke of the plunger.