General description of the product
A pressure switch is simply a device capable of detecting a pressure change and, at a predetermined pressure, opening or closing an electrical switch. There are two basic types of pressure switches: electromechanical and electronic/solid state. The electromechanical pressure switches are composed of a sensing element and an electrical switch. A number of different types of sensing elements can be used but they have one thing in common: they move in response to changes in the system pressure. Through their movement, they directly act on the opening and closing of an electrical switch (without requiring any power supply. Electronic/solid state pressure switches use the same technology found in analogue pressure transmitters to sense changes in pressure. Rather than harnessing the energy of the pressure changes to mechanically operate a switch (as with electromechanical pressure switches), electronic/solid state pressure switches electrically measure pressure change and internal electronic circuitry is used to activate one or more electronic switch outputs. With electronic/solid state switches, an external power supply is necessary to power the electronic circuitry inside the switch.