实现二分压电路的经典方法是使用两只阻值相等的电阻器。如果使用精度为1％的电阻器,则二分压器的输出电压精度为2％。对于大多数应用来说,这一精度经济实惠,足以满足所需。但是,当你需要极高的精度时,这种方法就需要相应精密的电阻器,因而可能需要增加成本。给仪表放大器加上反馈回路,便可获得一个二分压电路,而且具有缓冲输出的好处(图1)。这一电路的工作原理很简单。该仪表放大器具有单位增益的特点, The classic way to implement a two-voltage divider circuit is to use two resistors of equal value. The output voltage resolution of the second divider is 2% if a 1% accuracy resistor is used. For most applications, this accuracy is affordable enough to meet your needs. However, when you need extremely high accuracy, this method requires a corresponding precision resistor, which may require additional costs. Adding a feedback loop to the instrumentation amplifier will result in a two-voltage divider circuit with the benefit of buffered output (Figure 1). The working principle of this circuit is very simple. The instrumentation amplifier has the characteristics of unity gain,