A vacuum gauge is a device used to measure the pressure in a vacuum system. It helps determine how much air or gas has been removed from a sealed environment, indicating the quality of the vacuum. These gauges are essential in various applications, including laboratories, manufacturing, and HVAC systems. There are different types of vacuum gauges, such as mechanical gauges, electronic gauges, and capacitance manometers. Each type operates on different principles and is suitable for specific pressure ranges. Accurate measurements are crucial for processes like chemical reactions and packaging, where maintaining a proper vacuum is vital for efficiency and safety.