To measure the reverse leakage current of a diode being tested, the PXIe-4133 outputs a negative voltage to reverse bias the diode under test and returns simultaneous measurements of both the bias voltage across the diode and the leakage current through the diode. The leakage current can be measured with input ranges of 1 µA, 10 µA, and 100 µA. The bias voltage is programmable up to 100 V in the 1 µA and 10 µA ranges, and up to 20 V in the 100 µA range.

Refer to the examples included with the NI-4133 Driver software for an example of this operating mode.

Noise Rejection

A common source of unwanted noise for sensitive current measurements is current induced into wiring or test fixtures by external circuits, often at harmonics of the local power line frequency. You can reject noise at these frequencies by averaging samples over an integer number of power line cycles.

In Single Point Per Pulse mode, set the measurement time to a multiple of 20 ms (with 50 Hz power frequency) or 16.666 ms (with 60 Hz power frequency). In Waveform mode, take an average of samples over equivalent periods.