Anyone used one of these?

Never used one.. but it says octopus. I recall this curve tracer that a navy tech showed me once. A couple of transformers and R's..

Google octopus curve tracer and maybe you'll end up building on of your own.

George H.

Tracker-

Thanks. I wouldn't have thought there was much to these things, especially since they rely on an external scope display. I'm just curious as to how useful they are compared to more common test kit.

All this ammouts to is a transformer, capacitor and resistor in a box. Just do a search for an Octopus component tester. Years ago it was of some use and may be today if you have a known good board and one you are testing.

Today there are much beter component testers out. For about $ 20 you can get the circuit board of a component tester that is much beter for testing components out of the circuit.

This ebay number is one of many of them.

Common commercial unit is the Huntron 'Tracker' with built-in display. Can be of some use on production test bench, but doesn't replace visual inspection and simple open/short or bias testing.

RL

Thanks Ralph.

Nice - but a bit pricey!

I keep a home made "octopus curve tracer" (two-lead type) on a dedicated scope for the past 30+ years.

Absolutely WOULD NOT be without it.

Instantaneously find one bad amp channel out of many, very quick checks of capacitance, inductance, resistance, diodes, fets, transistors, etc.

Once you get used to it and sort of "get it" as to what the device is telling you, it will make you a better, faster technician.

Mark Z.

And it's capable of testing these components at their intended working voltages and currents? This seems to be the main shortcoming with almost all the small battery powered testers.

Mine uses a 6.3v AC transformer so no attempt is made to operate devices under load.

mz

But you still find that exposes every form of damage you encounter in practice?

I never said "every form" but it is a powerful tool.

Like oscilloscopes.

Like multimeters.

Like an esr tester. (Even though the "curve tracer" can give a quick check of esr in many situations.)

It's usable in-circuit and once a person is proficient with it, can VERY often cut troubleshooting time dramatically. (Test current is resistance-limited, depends on exact schematic of the curve tracer. There are many variations.)

We all have our favorite tools and little tricks to help us in what we do.

This is just one more.

Mark Z.

A sample curve tracer "octopus" schematic.

mz

Thanks, Mark. I'll take a look on youtube see if I can find any tips on how to use these under practical conditions to take in-circuit measurements. I have more than enough scopes here with x-y/comp tester inputs.

Hence the jig on offer. Just add your own uncommited oscilloscope...

You won't want to hook it up and disconnect it every time you need to switch over.

RL

We used to make those out of a 6.3 volt transformer and a couple of resistors.

Later I figured out a neater one for caps. You need a 1 KHz square wave of 400 mV with as close to 350 ohms source impedance as possible.

I can check caps with it from about 0.47 uF all the way up. If you can manage to, have the 400 mV square wave ride on 200 mV DC and it will also automatically detect shorts.

It is way faster than any ESR meter out there, even the old Wonderbox. Once you learn how to read it that is. And it is easier to see than almost any analog or digital display.

One of these days I plan on doing a writeup on it but I want to get a bunch of pictures depicting the readings on good and bad caps of a bunch of different values.

Sounds like a useful addition to any test bench. I've probably already got a suitable transformer lying around waiting for just such a project. Plus no shortage of "uncommitted oscilloscopes." :)