两线制电流 温湿度变送器原理图，MSP1221的PWM和XTR115

PWM经过RC滤波产生电压,经过XTR115产生4-20mA电流输出,要点是XTR115的电压输入问题,自身为两线制,+5V输出提供不了较大电流,需要用DCDC,RC滤波采用钽电容和4.7k-4.9k的低温漂电阻能得到较高线形度,PWM输出为AVR单片机16位,模式15,不分频,PWM voltage generated through RC filter, after XTR115 have 4-20mA current output, the key points of the voltag

内容有：0欧姆电阻作用,LC,RC滤波电路设计,PCB铜箔厚度、线宽和电流表,Total_etch_path_manhattan,电学计算公式,华硕内部的PCB设计规范，大家可以看一下-Are: the role of 0-ohm resistors, LC, RC filter circuit design, PCB copper foil thickness, width and ammeter, Total_etch_path_manhattan, electrical calculati