Current Sense Resistor

The Vektrex Current Sense Resistor (VCSR) provides simple and accurate current verification to 44A. It converts current to a voltage that may be measured with the SMU digitizer or with a digitizing multimeter. The VCSR’s low inductance minimizes overshoot errors that can occur when standard shunts are used with fast rise-time current waveforms. The VCSR’s low temperature coefficient allows accurate measurement even at high current levels.

The current sense resistor is an important tool when making MDCP (mean differential continuous pulse) UVC LED measurements

Current Sense Resistor P/N VCSR-0.05

The VCSR is easy to place in-line in the load circuit (ideally near the load). Convenient mounting flanges allow it to be permanently secured in a test station. Current connections are via banana jack connectors and the voltage output signal is available on a BNC connector.

Vektrex Current Sense Resistor used to verify 1A current pulse. Shown with Vektrex Control Panel Software Application.

Using the appropriate VCSR and Vektrex developed Control Panel Software Application it is easy to verify current accuracy in all LED/Laser drive modes including DC, Constant Current, Pulsed Current, CW, QCW. When using a calibrated current sense resistor, simply click on the Use Shunt Resistance box in the Control Panel Digitizer Settings tab and enter the VCSR’s calibration value. Digitizer captures and statistics are then scaled in amps instead of volts.

Measure Small Current Details With Accuracy

Vektrex current sense resistor accurately measures ~0.4% pulse overshoot

By connecting the VCSR inline with a digitizing voltmeter, it is possible to view and measure fine detail in the current waveform. Small distortions at the top of the waveform and recovery from overshoot is easily detected and measured.

The device is a 1A LED. To measure the pulse overshoot, a 1ms pulse was generated using Vektrex SMU Part Number: PSMU–PRF-5-50us. The 0.4% overshoot is measured using Vektrex current sense resistor part number VCSR-0.1. Note the recovery time may also be measured. Vektrex developed Control Panel software application controls the instrumentation and graphically portrays the pulse shape. Control Panel data is also exportable and may be imported into a database or other applications for use.