30.4.2 Basic Operation of the 200 µA Source

The primary application of the 200 µA current source is to remove the DC offset so that the signal to be measured is within the ADC module’s input range. Figure 30-3 shows a typical signal to be measured: an AC signal with a DC offset. This class of current source can be used to create a positive shift with an external resistor. The following examples show the basic configurations for shifting the input voltage and the required calculations. The equations in Equation 30-2 are used for positive voltage shift calculations.