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# How can I get the graphic of the a resistor-diode circuit’s ID-VD graph?

I have tried the following but I am not sure if it is correct or not. How can I be sure?

• So you are using a circuit simulator to do the DC sweep I-V curve tracing. Your curve looks OK. Of course you can prove it by an experiment using real components. I did that a couple of weeks ago. I used the following equipment (1) manual push button adjustable PSU, with fine steps of mV, (2) two cheap multi-meters to measure the voltage across the diode, and current of order 0.1mA and 0.1mV. So I took discrete manual I, V readings and use Excel to plot the I-V curve. The following two pictures show the setup and results / to continue, … – tlfong01 Jan 6 at 12:50
• Sorry, I cannot show the pictures as comments. So I am uploading them as an answer. Please let me know if you wish to know more details. – tlfong01 Jan 6 at 12:53
• 1@CanberkÖzçelik: How to do an IV curve for real. – JRE Jan 6 at 12:59

One thing that is obvious is that you have negative numbers in your plot. That is to say, your forward current is negative when it should be positive. In real life, that would mean you have your ammeter connected backwards. I don’t know what you need to do differently in Proteus.

As for the shape of the curve, you can compare your current/voltage plot to the current/voltage plot given in the datasheet of the 1N4007.

The problem here is that your plot goes from 0 to about 500 milliamperes and the one in the datasheet goes from 10 milliamperes to 10 amperes – and the datasheet plot uses a logarithmic representaion for the current. The range of your plot would be down in the bottom left corner of the datasheet plot.

You could run your simulation over the same voltage range as the datasheet and see if they match. Remember that the datasheet uses a semi-log graph. That’ll make a visual comparison look wrong unless Proteus can also do semi-log plots.

You’ll probably find it easier to do spot checks against the datasheet curve – pick a voltage, read the current, compare to your own plot in Proteus.

I checked a few points from your plot and the datasheet:

It looks to me like your curve may be a little off. Simulators use models of the parts, and they may not be exactly correct in all cases. There’s also the question of how accurate my measurements are from the plots in your post and from the datasheet.

For comparison, here’s a current/voltage plot I made of a 1N4007 diode using a program I wrote together with a little bit of hardware and an Arduino:

You can see the typical exponential current curve of a diode quite clearly.

The current my little toy IV tracer can produce is (quite) limited, so the voltage only goes up to about 640 millivolts. That’s right – my gadget generates a current and measures the resulting voltage. Most IV tracers sweep the voltage and measure the current. What can I say – I’m weird.

640 millivolts from the datasheet should be about 15 milliamperes of current. My plot says 3.9 milliamperes at 640 millivolts.

Question

How to plot the I-V curve of a diode?

Setup

Results

I am testing a tunnel. The current reading are too small to show clearly on only one continuous curve. So I am plotting three separate curves:

(1) before negative resistance region,

(2) negative resistance region,

(3) after negative resistance region.

I also used the python matPlotLib plotting package to plot a single tunnel diode I-V curve, as shown below.