A pressure switch, which is also commonly referred to as a discharge switch, is an electronic circuit switch used in electrical applications to regulate the flow of a liquid such as aqueous humor or a gas. A pressure switch is generally made of two to five components depending upon the application it is used for. A pressure switch consists of a sensing device, an output filter, a control circuit and a battery. The output filter prevents excessive flow of aqueous humor and excessive discharge of gaseous wastes; the control circuit allows the operator to control the operating pressure and the flow of aqueous humor; and the battery powers the output filter and the control circuit during operation.
There are different types of pressure switches available in the market. These switches can be of various designs including mechanical, electrical and hybrid. All of these switches work on the same basic principle of opening and closing the conductive path. However, because of their very different operating principle, each and every type of these electrical switches has its own unique features, advantages and limitations. An electrical switch operates on the following basic operating principle:
All pressure switches function according to this very basic principle. Therefore, all switches have three basic parts which are the sensing element, the filter and the battery. The sensing element is placed at the point where the flow of aqueous or gaseous waste is expected to occur. The filter is placed at the end of the supply line where it absorbs any excess gas or liquid; the battery is placed at the working area where it stores energy when the switch is in operation and ensures that the electric current flows through the supply line.