A pressure switch is a device that detects pressure levels in a system and activates or deactivates electrical circuits based on those levels. It is commonly used in various applications, such as HVAC systems, water pumps, and industrial machinery, to ensure safe and efficient operation. When the pressure reaches a predetermined set point, the switch triggers a response, such as turning on a pump or shutting off a compressor. These switches can be mechanical or electronic, and they come in different types, including differential pressure switches and vacuum switches. They are essential for maintaining proper pressure levels, preventing equipment damage, and ensuring safety in various processes.