说明：  TINA下绘制的用电压互感器采集220v电压信号的隔离放大电路。前级利用2mA/2mA电压互感器采样，将电压放大至0~3V。
(TINA drawn under the acquisition with a voltage transformer 220v voltage signal isolation amplifier. Pre-sampling using 2mA/2mA voltage transformer, the voltage is amplified to 0 ~ 3V.)