The **PCE-WO2-10** is an industrial-grade dissolved oxygen (DO) meter designed for precise liquid analysis. Its internal architecture relies on several critical electronic components to convert chemical reactions into digital readings. --- ### Core Electronic Components | Component | Function | Description | | :--- | :--- | :--- | | **Galvanic Sensor** | Data Acquisition | Uses a lead anode and silver cathode to generate a small voltage proportional to oxygen concentration. | | **Microprocessor** | Logic & Processing | A low-power 8-bit or 16-bit MCU that calculates DO values based on temperature and atmospheric pressure. | | **ADC (Analog-Digital Converter)** | Signal Conversion | Converts the continuous millivolt signal from the sensor into digital data for the microprocessor. | | **NTC Thermistor** | Temp Compensation | Measures liquid temperature to adjust DO readings (ATC), as oxygen solubility is temperature-dependent. | | **LCD Display** | User Interface | A multi-line segment display with integrated backlighting for showing DO (mg/L or %), temperature, and battery status. | --- ### Functional Circuitry Breakdown ### 1. The Measurement Circuit The sensor operates on a polarographic or galvanic principle. In the PCE-WO2-10, the electronics must provide a stable bias (if polarographic) or a high-impedance input to read the micro-ampere current generated by the oxygen reduction at the cathode. ### 2. Automatic Temperature Compensation (ATC) Electronics in this device include a dedicated compensation bridge. Because the membrane permeability and oxygen solubility change with temperature, the microprocessor applies a polynomial algorithm to the raw signal based on the input from the internal temperature sensor. ### 3. Power Management * **Voltage Regulator:** Ensures the sensitive analog components receive a stable voltage, preventing battery fluctuations from affecting measurement accuracy. * **Auto-Power Off:** A timing circuit that cuts power to the LCD and MCU after inactivity to preserve the internal battery. ### 4. Calibration Memory (EEPROM) The device includes non-volatile memory (EEPROM) that stores calibration constants. This allows the unit to "remember" its 100% air saturation calibration even after the batteries are removed. --- ### Technical Specifications Summary | Feature | Specification | | :--- | :--- | | **Power Source** | 4 x 1.5V AAA Batteries | | **Output Type** | Digital LCD | | **Operating Frequency** | High-speed sampling (approx. 1 second refresh) | | **Sensor Connection** | Specialized multi-pin screw connector (low noise) |