Abstract: A gas-supply system includes a gas container filled with gas, a gas flow controller coupled to the gas container, and an operation device electrically connected to the gas flow controller. The gas-supply system further includes a buffer tank coupled to the gas flow controller and configured to receive the gas from the gas container via the gas flow controller. Furthermore, a pressure transducer disposed on the buffer tank and configured to generate a pressure signal to the operation device according to the pressure of the gas in the buffer tank. The operation device is configured to generate a control signal to the gas flow controller according the pressure signal, and the gas flow controller is configured to adjust the flow rate of the gas according to the control signal to keep the pressure of the gas in the buffer tank in a predetermined pressure range.