# Can oscilloscope somehow be used as curve tracer?

#### NuLED

Jan 7, 2012
294
http://en.wikipedia.org/wiki/Semiconductor_curve_tracer

I just came across this.

So, it looks like the curve tracer graphs I current versus V voltage (with the voltage varying across time).

With an oscilloscope, my understanding is that it only graphs (displays) voltage over time.

Is it possible to somehow use it in a tracer mode?

For example, if you indirectly measure current by using voltage (I think that's how an Ammeter works right?) and introduce a varying voltage by another means, you can then get the data from Channel 1 for the input voltage, and Channel 2 as the indirect current measure (also voltage).

I guess the challenge is to graph the two against each other; I don't have an oscilloscope but wonder if the captured data can be downloaded to a computer and graphed there using a spreadsheet or maybe a basic C program to parse the data?

#### duke37

Jan 9, 2011
5,364
I have a scope but rarely use it and have never made a curve tracer.

The scope has an amplifier which alters the height of the spot (Y deflection)

The scope has a timebase which moves the spot across the screen (X deflection).

To curve trace these two must be correlated.
Some scopes have an X input and some scopes have an X output. You will need to find out what your scope does and connect appropriate X circuitry

#### NuLED

Jan 7, 2012
294
I don't have a scope. Just wondering about the possibilities. Maybe might try to get an analog scope off ebay one day to help me understand the fundamentals better.

#### wannabegeek

Aug 17, 2011
133
I've done it with an old Tektronix scope 20Mhz...it has to have an X and Y mode and external trigger wouldn't hurt...as I recall at least...I've only used it once for a physics lab...the Frank Hertz Experiment, a classic proof of quantized energy states.

Don't buy an old analog scope off of Ebay...None of the calibrated ones will be fairly priced and the rest are junk...I researched this years ago....same for Geiger counters.

I ended up finding an ooooold 2Mhz Tektronix sitting in a junk pile took it home and it works....worth every penny I spent.... ( it totally sux )....Buy a Rigol 10Mhz for $350 and do the firmware hack that takes it up to 100Mhz...Otherwise spend$1000.

#### eKretz

Apr 8, 2013
251
Look up Octopus circuits. I'm not sure if you can get all the info a real curve tracer will give you, but it's similar and will give a function check at least.

#### eKretz

Apr 8, 2013
251
Lol, that guy cracks me up with his choice of project housings. Did you see the chili one?

Edit: maybe it was a different guy; I was looking for it and couldn't find it. It was defo another ham guy though.

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#### eKretz

Apr 8, 2013
251
Made one of these the other day, worked out pretty good.

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