Here are some common types of DO meters:
* Electrochemical DO meters: These use a Clark-type electrode, which consists of a platinum cathode and a silver anode. The electrode measures the current generated by the reduction of oxygen at the cathode.
* Optical DO meters: These use fluorescence to measure dissolved oxygen. A fluorescent dye is excited by a light source, and the intensity of the emitted light is inversely proportional to the dissolved oxygen concentration.
* Membrane-covered DO meters: These use a membrane that selectively allows oxygen to pass through. The oxygen then reacts with a reagent, producing a measurable signal.
The choice of DO meter depends on the application and the required level of accuracy.
