Products > Test Equipment
So what do you do when you need a modern transistor curve tracer?
chilternview:
There is a big difference between simple curve tracers (think Tek 576, which was designed in the 60's) and the semiconductor parameter analysers like the 4145 and subsequent models which are really a collection of SMUs and the ability to sweep and graph the results.
The latter can be used for characterising all manner of things from a simple diode to a optocoupler to a complete functional block. They are certainly not commonly used by amateurs, but if you have one it's surprising how often you find yourself powering it up and checking if a device really does what its spec sheet says.
And yes you can buy them still, but they are not (and never were) cheap: https://www.keysight.com/gb/en/products/parameter-device-analyzers-curve-tracer.html
alm:
--- Quote from: chilternview on February 21, 2023, 06:25:17 pm ---And yes you can buy them still, but they are not (and never were) cheap: https://www.keysight.com/gb/en/products/parameter-device-analyzers-curve-tracer.html
--- End quote ---
Neither where the "simple" curve tracers like the Tek 576 back when they were new. According to TekWiki, the 576 sold for about $17k in 2022 dollars in 1969, and $40k in 2022 dollars in 1990. I highly doubt many hobbyists have them. Now of course both used curve tracers (if you can find a working one) and old used semiconducter parameter analysers like the HP 414x series are within the reach of some hobbyists.
Martin72:
This is the point.
Tracers are unpopular not because they are no longer needed, but because they are simply expensive.
A few years ago, we (the company) had the problem of being taken in by fake goods.
BUZ84...A classic that we need again and again for older projects.
It turned out that one batch already broke down at about 280V, instead of at 800V, as stated in the data sheet.
You can't get that out with a simple diodentest or an Atlas DCA75 or similar with low voltage.
For a "simple" (I had to smile earlier) TEK576 with its test voltages up to 1500V, this is not an issue.
Unfortunately, we didn't have that, we solved it differently.
timeandfrequency:
Hi Martin72,
--- Quote from: Martin72 on February 21, 2023, 11:21:21 pm ---[...]
It turned out that one batch already broke down at about 280V, instead of at 800V, as stated in the data sheet.
You can't get that out with a simple diodentest or an Atlas DCA75 or similar with low voltage.
For a "simple" (I had to smile earlier) TEK576 with its test voltages up to 1500V, this is not an issue.
Unfortunately, we didn't have that, we solved it differently.
--- End quote ---
For very basic breakdown voltage test of transistors and diodes (up to 1000VDC), this small device makes the job. It's handy and lightweight.
User manual here.
mbrennwa:
Looks like I was missing out by not looking at this forum more often. Anyway, here's my curvetracer: https://pypsucurvetrace.readthedocs.io
PyPSUcurvetrace takes a somewhat different approach than most other curve-tracer projects that require some specific hardware / board to work. PyPSUcurvetrace is a software toolbox that controls programmable power supplies to set and read the voltages and currents at the DUT. This means you can make a curve tracer from PSUs that are available off the shelf, and you choose the PSU units that suit your application: small transistors, power transistors, vacuum tubes, etc.
The PSUs don't need to be expensive "high end". For example, two RIDEN 6006P units can be had for about $300 or less, and will make for a very decent curve tracer setup!
PyPSUcurvetrace also allows controlling the temperature of the DUT during curve tracing. I attached an example of an IRFP150 power FET measured at 30°C, 50°C and 70°C.
PyPSUcurvetrace not only allows measurement of the curves, but also has post-processing tools for high-quality curve plotting and to determine the DUT parameters from the raw data files (e.g., bias voltage/current for a given operating point, gain parameter, output conductance). More tools like curve matching/pairing of parts are in the works...
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