TDS Water Quality Tester HT66F004 Characteristics ► Flash MCU : HT66F004, 20-pin SOP package ► TDS, Conductivity, Celsius and Fahrenheit temperature measurement function ► LED backlight ► Temperature, TDS calibration ► Temperature compensation ► Temperature measuring range : 0 ~ 70°C ► TDS measuring range : 0 ~ 4500 ppm ► TDS Accuracy : ±2 (TDS < 2000 ppm) Application Areas ► Industrial Water, Water Purifiers, Swimming Pool Water, Running Water etc. 2015 Holtek New Product Presentation E07 Block Diagram I/O LED Backlight 3V SCOM MCU HT66F004 A/D LCD 4×9 NTC NTC Sensor I/O A/D SW-PB TDS Measuring probe Application Circuit LCD Display 3V Power LCD 4x9 Master Key Temperature, TDS Measuring Circuit HT66F004 Master MCU Function Keys 2015 Holtek New Product Presentation E07