describe

The handheld micro dissolved oxygen analyzer uses a membrane-type dissolved oxygen sensor, which includes a gold cathode and a ring-shaped silver anode at the bottom, along with a thin semipermeable membrane. The membrane, spread over the sensor, isolates the electrodes from the external environment while allowing gas penetration. During operation, the sensor's base is filled with an electrolyte solution containing a small amount of surfactant to enhance wetting. When a polarization voltage is applied to the electrodes of the polarographic sensor, oxygen penetrates the membrane, reacts at the cathode, and generates an electrical current. The current flowing through the electrodes is directly proportional to the oxygen concentration, maintaining a linear relationship between current and oxygen levels under constant temperature conditions.