Thermistor & Heater , Standardized limit switches are industrial control components manufactured with a variety of operator types, including lever, roller plunger, and whisker type. Limit switches may be directly mechanically operated by the motion of the operating lever.

may be used to indicate proximity of a magnet mounted on some moving part. Proximity switches operate by the disturbance of an electromagnetic field, by capacitance, or by sensing a magnetic field., Limit switches are used in a variety of applications and environments because of their ruggedness, ease of installation, and reliability of operation. Thermistor & Heater  determine the presence, passing, positioning, and end of travel of an object.