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A Huntron Tracker is a neat piece of test equipment manufactured by a company called Huntron. It sweeps a voltage signal across a component under test and measures the resulting current flow, it then displays a graph of the voltage vs. current on an oscilloscope-like display. If, for instance, you were testing a diode by applying a sine wave voltage to it, the current would be zero for all negative values up to approximatly positive 0.7v, where the current would switch from zero to maximum (a short circuit). Transistors, capacitors, inductors, FETs, diodes, and just about any other passive components can be tested in this manner.

Now, if you shop around, an oscilloscope can be had from eBay for $50 total cost ($25 for the scope, $25 for shipping). If you don't want to shop around then $75 is an easy price to find, or you may already own an oscilloscope. An oscilloscope is a much more versitile instrument than a Huntron Tracker, a much better investment, especially since a low end used Tracker usually goes for $200 on eBay - EXCEPT that the oscilloscope doesn't do the current/voltage sweeping trick that the Tracker is famous for.

So here is my circuit for building my own version of what the Huntron Tracker does using my $50 oscilloscope in X/Y mode. First you need something that looks roughly like a sine wave. What I found is that a wall-wart that puts out AC makes a rough approximation of a sine wave and works very nicely for our needs - find one in the 3v to 12v range.

If there is no connection between the red and black probes, a horizontal trace will be shown (no voltage drop across resistor R for vertical deflection, full sine wave across the X axis. If the probes are shorted together, the full sine is across resistor R for full vertical deflection and there is no horizontal deflection. If there is resistance between the probes then a proportionally diagonal line will appear.

The alternate method is just a reversal of the connectors, instead of the center of the BNCs forming a common node, the outsides form a common node. Polarity of the image is obviously reversed as well. I couldn't come up with an arrangement whereby both of the probes could be (mostly) standard oscilloscope probes connected to their respective BNCs. In the top method the Y axis probe could be a probe attached to the Y axis BNC with a connection spliced into the center line of the probe or between the BNC junction, and in the bottom method it is the X axis probe that could be connectec directly to the scopes BNC connectors. (basically I don't have any spare BNCs laying around and don't want to butcher my only pair of oscilloscope probes, guess I'll just have to be patient).

I've seen more complex versions of this circuit which I do not in fact believe to work. This is original work created by, if you re-post it without permission you will be killed and eaten.

This web site is is in no way affiliated with Huntron or the Huntron Tracker - fair use is made of trademarks - prosecutors will be violated.

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