Pressure & Compound Gauge

Compound Gauge - is a device that can display both positive and negative (vacuum) pressures. You need to use a compound gauge when you are measuring a system that is exerting both positive and negative pressure on the gauge. Gauges are designed to measure specific types of pressure, so if you pick a simple pressure or vacuum gauge for a system that requires a compound gauge, the gauge will most likely be damaged. The exertion of negative pressure on a pressure gauge will cause damage, and likewise the exertion of positive pressure on a vacuum gauge will also damage the gauge.