McLeod Gauge (Low Pressure Gauge) MQC Video Notes By Shubham Kola

Mcleod Gauge consists of measuring capillary, bulb, side glass, piston and cylinder arrangement which containing mercury. Initially mercury is released up to cut off point and unknown pressure is allow to accommodate build and capillary. In second step, mercury by piston and cylinder arrangement is raised to such a pressure that it reaches up to reference point in side glass at same time gas is compressed in capillary which is measured by height h. this gauge is used to measure very low pressure. its works on principle of boyle's law.