以下是上海四達電子SDT-21C數字萬用表的產品中英文介紹：

上海四達電子SDT-21C數字萬用表是一款功能豐富、性能可靠的測量工具，廣泛應用于電子電氣維修、工業(yè)檢測、實驗室測量等多種領域。它采用2000計數的LCD顯示屏，能夠清晰地顯示測量數據。該萬用表具備雙注入測試功能，可精準測量直流/交流電壓、直流電流、電阻、溫度以及進行二極管測試和連續(xù)性測試。其直流電壓測量范圍可達600V，精度為±(0.5%+5)；交流電壓測量范圍同樣為600V，精度為±(1%+5)。在電流測量方面，直流電流和交流電流的測量范圍均為200μA/200mA，直流電流精度為±(1.5%+2)，交流電流精度為±(1.8%+2)。電阻測量范圍為20MΩ，其中小于1MΩ時精度為±(0.8%+5)，大于等于1MΩ時精度為±(2%+5)。溫度測量范圍為-40-752℉/-40-400℃，不同溫度區(qū)間精度略有不同。

此外，SDT-21C還具備低電量指示功能，方便用戶及時更換電池，確保測量工作的順利進行。自動量程設計讓操作更加便捷，背光功能則在光線較暗的環(huán)境中也能保證清晰讀數。該萬用表的電源為兩節(jié)AAA 1.5V電池，LCD尺寸為61.6x26.2mm，產品尺寸為140x85x34mm，凈重僅180g，便于攜帶和操作。其安全等級為CATⅢ 600V，能夠為使用者提供可靠的安全保障。標準配件包括電池、測試筆、說明書、吸塑卡以及K型熱電偶。

The SDT-21C digital multimeter from Shanghai Sida Electronic Instrument Co., Ltd. is a versatile and reliable measuring tool, widely used in electronic and electrical repair, industrial inspection, laboratory measurement, and other fields. It features a 2000-count LCD display that clearly shows measurement data. This multimeter is equipped with a dual-injection testing function, capable of accurately measuring direct/alternating current voltage, direct current, resistance, temperature, as well as performing diode testing and continuity testing. The measurement range for direct current voltage reaches 600V with an accuracy of ±(0.5%+5), and for alternating current voltage, the range is also 600V with an accuracy of ±(1%+5). In terms of current measurement, both direct and alternating current have a range of 200μA/200mA, with direct current accuracy at ±(1.5%+2) and alternating current accuracy at ±(1.8%+2). The resistance measurement range is 20MΩ, with an accuracy of ±(0.8%+5) for values less than 1MΩ and ±(2%+5) for values greater than or equal to 1MΩ. The temperature measurement range is -40-752℉/-40-400℃, with varying accuracy levels depending on the temperature range.

Moreover, the SDT-21C has a low battery indicator, which allows users to replace the batteries in time to ensure the smooth progress of measurement work. The auto-ranging design makes operation more convenient, and the backlight function ensures clear readings even in low-light environments. Powered by two AAA 1.5V batteries, this multimeter has an LCD size of 61.6x26.2mm, product dimensions of 140x85x34mm, and a net weight of only 180g, making it easy to carry and operate. With a safety rating of CATⅢ 600V, it provides reliable safety protection for users. Standard accessories include batteries, test leads, a manual, a blister card, and a K-type thermocouple.