Hello everyone,

I am working on a project where I need to analyze the IV characteristics of several diodes to make sure they work properly. I have a vector signal analyzer (HP89410, very old) with two channels, which I am trying to use so far to just get the IV characteristics of a simple LED connected in series to a resistor. The problem is I cannot think of how I can get a current vs voltage plot.

Does anyone have any input on how to get IV characteristics using this vector analyzer or by another method? I would like something more sophisticated than using a voltmeter and an amneter and collecting data manually.

 

Hello there,

Well, simply put, if you had a computer voltmeter and ammeter and computer signal generator, you could program a ramp of current through the diode and take readings with the voltmeter (and optional ammeter). That would give you the characteristic curve at that one ambient temperature.

 

You are talking about a Curve Tracer which generates a current ramp and plots the DUT voltage versus current. Those can be purchased.

To build your own you need a function generator to generate a current ramp (voltage ramp through a resistor) and an oscilloscope in its X-Y mode (or two A/D converters) to measure the diode voltage versus current for that ramp. (The current can be displayed by measuring the voltage across a resistor in series with the diode using a differential amplifier or with a current-probe.)

 

For diodes and other low voltage devices:
http://www.cappels.org/dproj/CURVE_TRACER/CURVE_TRACER_MANUAL.html