What does the first stage of a regulator do with the pressure from the cylinder?

The first stage of a regulator is designed to reduce the high pressure from the cylinder to an intermediate pressure that can be more easily managed and used by the diver. When you open your scuba tank, it contains gas at a very high pressure, which is not suitable for breathing directly. The first stage takes this high-pressure gas and reduces it to a level that is safe for human consumption, while still allowing the flow of gas as needed during the dive.

This intermediate pressure is then delivered to the second stage of the regulator, which further reduces it to ambient pressure right before the diver inhales. The intermediate pressure provides a steady and sufficient supply of gas, allowing for a comfortable breathing experience underwater. Therefore, the first stage plays a critical role in the safe use of the gas supplied from the diving cylinder.