The 141A Absolute Vacuum / Pressure Switch offers fast, accurate, and reliable protection for vacuum equipment and processes. Designed for applications where a DC signal output is not required, the 141A provides relay outputs that are readily interfaced with alarms, valve actuators, computers, process controllers, or other protection devices. Based on the well-known MKS Baratron® capacitance manometer principle of operation, the 141A senses the deflection of a diaphragm due to applied pressure, providing a switched output when pressure exceeds the chosen set point. An LED provides visual ''above set point'' indication, and facilitates adjustment of the set point. The dual electrode sensor is an all-metal, all-welded design, thus exposing only corrosion-resistant Inconel to the process gases.