Programmable Output Resistance With an NI SMU

Updated May 8, 2023

Reported In

Hardware

  • PXI Source Measure Unit
  • PXIe-4154
  • PXIe-4137
  • PXIe-4139
  • PXIe-4141
  • PXIe-4143
  • PXIe-4145

Issue Details

What is the function of the programmable output resistor in an NI Source Measure Unit (SMU)?

Solution

Programming a positive output resistance allows you to simulate the output resistance of a non-ideal voltage source, such as a battery. The output resistance of a battery varies based on the type, age, charge, etc., and will cause a voltage drop at the output. You can program a positive output resistance with the SMU to reproduce this behavior and simulate the behavior of a battery.

These modules can also be programmed for negative output resistance.  This is valuable when remote sense connections cannot be connected directly to the DUT (Figure 1). This results in a series resistance between the remote sense connections and the DUT, which causes a voltage drop. You can program the output resistance to a negative value to nullify the effects of the voltage drop between the remote sense connections and the DUT.
 

Figure 1.

The supported programmable resistance ranges and accuracy values can be found in the specifications document for each module.

Additional Information

You can configure your SMU's output resistance in LabVIEW with the niDCPower Configure Output Resistance.vi