Working Principle: The Diaphragm Type Level Switch is a level switch detecting an object to be measured, through utilizing the pressure change affected by level rise and fall in a pipe. As level rises, air pressure inside a pipe gets higher. When the measuring face of diaphragm falls under the air pressure, the diaphragm presses a micro switch, thus turning it on. In turn, as the level descends and the air pressure inside the detection pipe gets lower, the output contact will return to the initial condition.