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Diode Curve Tracer for NI myDAQ

Introduction: Use NI myDAQ to plot the current-voltage (I-V) characteristic of a diode.

diode_curve_tracer.png

The input controls circled in red set the start, stop, and step values for the diode voltage. The measured value of a current shunt resistor is also required. Run the VI to measure and plot the diode current as a function of voltage.

Equipment Setup: An operational amplifier (op amp) and a resistor are required in addition to the NI myDAQ:

diode_curve_tracer_circuit.png

Theory of Operation: The op amp circuit uses negative feedback to drive whatever current is required by the diode to make its voltage VD match the desired voltage created by the myDAQ analog output. In this way the measurement points are equally spaced along the horizontal voltage axis. The diode current ID is the same as the current through the shunt resistor RD; the measured shunt voltage on the analog input divided by the measured shunt resistance yields the diode current.

Comments
em_engineering
Member
Member
on

the schematic is interesting to study but can u pls provide some document explaining all the details of the design... pls at least to help a beginner

phong87
Member
Member
on

missing daqmx clean task.vi, why? i have already installed daqmx 9.9.

MiguelGP
Member
Member
on

It doesn't work, in the new versions of MyDaq shows a error dev1 doens't exist.

I'm new user and I don't know how meke the changes that it requires to wotk properly.

Could any one help me with it.

Thanks

Alex8850
Member
Member
on

Thanks a lot! Excellent code, everything worked perfectly.

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