v-i curve tracer? waiting for the best answerer


i want to build this simple v-i curve tracer circuit at the page..

http://freecircuitdiagram.com/2008/09/06/voltage-currentvi-curve-tracer/

on the same page, they have shown different traces of diodes,capacitors, transistors...

what i am thinking is that if i connect this tracer to the pins of any ic, would this damage the ic or show v-i trace of that ic or of  those two pirticular pins to which i connected the probes?

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orksecurity6 years ago
Analog ICs or digital ICs?

The canonical solution is to plug the chip into a circuit which is designed to use it and see if it runs, and continues to run after it warms up. Heck, that's what we used to do with tubes and transistors -- plug it into an oscillator circuit and see if it beeps, preferably at something close to the right frequency.

For analog, if you're feeling paranoid you can trace the response curves -- but that' requires something much more complicated than a multimeter, and a lot more attention to detail than you will usually want to worry about unless you're manufacturing chips. If you insist on doing this, you'll want something like a recording digital 'scope linked to a programmable sweep generator.

For digital: What the manufacturers do is -- KNOWING what the intended behavior of the chip is -- hook it up to a test pattern generator which exercises its inputs and checks the outputs against expectations. There are some cute techniques for making that more effective for complicated chips -- IBM has some patents in that area. But the whole point of digital is to abstract away analog details, and almost nobody but the guys designing the internals of the chip every looks at digital circuitry that way.

All of that's for testing chips in isolation. For fixing home electronics: Power up the device, attack it with an oscilloscope to see what signal is getting where, possibly poke a finger around looking for a chip which is hotter than you think it should be and/or try spraying circuit cooler at warm components (since temperature-sensitive failures are not uncommon) until you find one which restores normal operation when chilled... Except for that last, you generally really can't go in blind; you need to have at least some sense of what the circuit is intended to do before you stand much chance of fixing it.
It will damage the IC !!! Don't
+1. At best, you won't get any interesting information out of it, at worst you may cook the chip.
hussainb (author)  orksecurity6 years ago
ok.. actually i saw two pcb test equipments recently and in them, there is a v-i tracer, the ground probe gets connected to the ground pin of the ic and the live one gets moved on every other pin... the user views the v-i trace made and gets to know if the ic is working or not... so i was just thinking of doing the same
For some ICs that may be appropriate and useful. For most, I don't see how it could be... and my degree claims I'm an EE.
hussainb (author)  orksecurity6 years ago
i have tested mostly every series of ics including rams, micros, analog devices,
maybe you would like to visit their website

http://www.abielectronics.co.uk/Products/BoardMaster8000.php

ya i know its too advanced for me to duplicate but just wanted to make the most basic thing only to use as an equivalent to a multimeter for testing purposes..

if you know any better ways to find faults in ICs please can you share it,maybe i could tryout some repair on my home electronics, i am fairly new in electronics, want to see if i create more faults or repair faults