Author Topic: Transistor curve tracing in this century  (Read 4143 times)

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Offline mcovington

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Transistor curve tracing in this century
« on: December 15, 2019, 09:20:47 pm »
I have my trusty Tek 575, which helps hold my house down when it's windy, but...

I would have thought that in this day and age, a transistor curve tracer would be a device that connects to a PC by USB, using the PC to do all the curve plotting.

I don't see those.  I still see curve tracers that connect to oscilloscopes, or look like oscilloscopes, and are very expensive.

What am I missing?  Why does the kind of curve tracer that I imagine not actually exist?  Should I get started designing one?
 

Offline Grandchuck

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Re: Transistor curve tracing in this century
« Reply #1 on: December 15, 2019, 09:39:22 pm »
I have one of these and it works very well:

https://www.peakelec.co.uk/resources/dca75.html
 
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Online Gyro

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Re: Transistor curve tracing in this century
« Reply #2 on: December 15, 2019, 09:44:41 pm »
+1  Great little tool (especially if you can get someone to 3D print their bench stand design for you).
« Last Edit: December 15, 2019, 09:46:44 pm by Gyro »
Regards, Chris

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Offline Someone

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Re: Transistor curve tracing in this century
« Reply #3 on: December 15, 2019, 10:05:07 pm »
I would have thought that in this day and age, a transistor curve tracer would be a device that connects to a PC by USB, using the PC to do all the curve plotting.

I don't see those.  I still see curve tracers that connect to oscilloscopes, or look like oscilloscopes, and are very expensive.

What am I missing?  Why does the kind of curve tracer that I imagine not actually exist?
Its now called a dual channel SMU, they usually come with example curve tracing software to get you started.
 

Online Cerebus

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Re: Transistor curve tracing in this century
« Reply #4 on: December 15, 2019, 10:10:56 pm »
The phrase you're looking for, in current equipment, is "Semiconductor Device Parameter Analyzer" or something similar.

Which will lead you to something like the Keysight B1500A Semiconductor Device Parameter Analyzer/Semiconductor Characterization System Mainframe



If Sir needs to ask "how much?", Sir can't afford it.  :)

The thing that separates something like that from something like the baby Peak analyser is range. The B1500A specs cover current source/measurement ranges of 0.1 fA - 1A, and 0.5uV - 200V voltage source/measure, with a 200 MS/s sampling rate for investigating pulsed parameters. The Peak goes up to 10V and 15.5 mA and doesn't specify a minimum current - the highest zener voltage you can characterise with it is 9V.

The difficulty in designing a useful curve tracer equivalent that would connect to as PC via USB is choosing the ranges to cover. If you want to cover only small signal devices (i.e. omitting what we might characterise as 'power' devices') you probably want a pair of USB computer controlled source/measure units that can handle say 50V and 500mA and have mV and sub-uA measurement resolution respectively - which implies something on the order of 20 bit resolution which is non-trivial to achieve in practice.

Oh, and ideally you want to be able to source and sink current, which means your SMU design would need to operate in at least 2 quadrants.
« Last Edit: December 15, 2019, 10:24:17 pm by Cerebus »
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Offline David Hess

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Re: Transistor curve tracing in this century
« Reply #5 on: December 15, 2019, 10:47:42 pm »
I just have a Tektronix 7CT1N but it sure has been handy.

Syscomp Design makes a USB curve tracer among other USB instruments:

https://www.syscompdesign.com/product/ctr-201/
 
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Offline Shock

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Re: Transistor curve tracing in this century
« Reply #6 on: December 16, 2019, 08:36:14 am »
There are simple audio card curve tracers as well, look hard enough and probably free ones. I think the advantage of the old Tek models is the large power supplies, plus testing two devices at once and having various test fittings on those specific models. If you want a cheap component tester the Chinese AVR ones are dirt cheap and you can also buy the octopus kits as well.

One of the personal distinctions for me is I don't want to necessarily test just low voltages devices. The Tek 576 seems to be one of the more desirable vintage models and covers low voltage, 1nA per division and comes with a 1.5kV anode supply that powers up to 220W or 20A. For this reason you can test small devices right up to large devices. It's easy to make DIY test fittings as well as it uses banana style sockets and if you DIY an external heater supply it makes an ideal tube tester.

Tektronix has an old "Measurment Concepts" book which is a good introduction for anyone who hasn't seen it, that along with the manuals of course.

I have an old Tek 576 in the restore queue so one day (clenched fist).

« Last Edit: December 16, 2019, 08:41:39 am by Shock »
Soldering/Rework: Pace ADS200, Pace MBT350
Multimeters: Fluke 189, 87V, 117, 112   >>> WANTED STUFF <<<
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Offline 001

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Re: Transistor curve tracing in this century
« Reply #7 on: December 16, 2019, 11:00:28 am »

Tektronix has an old "Measurment Concepts" book which is a good introduction for anyone who hasn't seen it, that along with the manuals of course.
 

Can You link me?  :-//
 

Offline fcb

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Re: Transistor curve tracing in this century
« Reply #8 on: December 16, 2019, 01:40:08 pm »
+1 for the Peak Electornics DCA75. However it will only go to 10-12V and a few mA.
https://electron.plus Power Analysers, VI Signature Testers, Voltage References, Picoammeters, Curve Tracers.
 

Online Johnny10

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Re: Transistor curve tracing in this century
« Reply #9 on: December 16, 2019, 02:13:16 pm »
I haven't followed it properly but Dos4ever uTracer tube curve tracer has a Lab Note for turning it into transistor curve tracer.

Check out Ronald's site, lots of great information in the Lab Notebook.

The uTracer was my first DIY electronics project!

« Last Edit: December 16, 2019, 03:11:08 pm by Johnny10 »
Tektronix TDS7104, DMM4050, HP 3561A, HP 35665, Tek 2465A, HP8903B, DSA602A, Tek 7854, 7834, HP3457A, Tek 575, 576, 577 Curve Tracers, Datron 4000, Datron 4000A, uTracer, HP5335A, EIP534B 20GHz Frequency Counter, TrueTime Rubidium, Sencore LC102, Tek TG506, TG501, SG503, HP 8568B
 


Offline exe

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Re: Transistor curve tracing in this century
« Reply #11 on: December 16, 2019, 03:19:38 pm »
I use analog discovery + a few resistors + external PSU. Before that I used siggen and an oscilloscope. An SMU would be cool, but they are very pricey. The cheapest one I saw was $1k.
 

Offline Zucca

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Re: Transistor curve tracing in this century
« Reply #12 on: December 16, 2019, 03:24:06 pm »
An SMU would be cool, but they are very pricey. The cheapest one I saw was $1k.

This.
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Can't love what you don't know. Zucca
 

Offline all_repair

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Re: Transistor curve tracing in this century
« Reply #13 on: December 16, 2019, 03:29:48 pm »
Wait 6 month or a year, a Chinese ham already selling a kit version for a curve tracer +/-28V 500mA version with PC that has preloaded curve of some of the device from their datasheet to be compared with what being captured.  I already have a locky_z curve tracer, so waiting for the next iteration of  this kit version with higher voltage and current range.
« Last Edit: December 16, 2019, 03:31:23 pm by all_repair »
 

Offline 10101

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Re: Transistor curve tracing in this century
« Reply #14 on: December 16, 2019, 04:20:01 pm »
There's always the diy route xD

"I do not think there is any thrill that can go through the human heart like that felt by the inventor as he sees some creation of the brain unfolding to success... such emotions make a man forget food, sleep, friends, love, everything."  Nikola Tesla
 

Offline DaJMasta

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Re: Transistor curve tracing in this century
« Reply #15 on: December 16, 2019, 05:05:00 pm »
You can get older mainframe based SMUs at somewhat more reasonable prices, and while they are not frequent, something like a U2722A can go under the radar for most SMU purchasers and go for a bit less (not the same name/model recognition as the Keithleys, for example) while being compact and having good performance.

If you have a bench supply and a load (resistors and a meter or electronic), you can get all the same data, it's just a matter of the software (or graph paper) that actually generates the curve.

Alternatively, you can get or build a relatively simple device that uses a sig gen and a scope to give you a curve tracer, there have been a number of projects described in other sections of the forum, but I think they're available as kits/fully assembled on ebay and others, and there are lots of designs that can be used.
 

Offline tmbinc

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Re: Transistor curve tracing in this century
« Reply #16 on: December 16, 2019, 05:32:10 pm »
Was about to say - I have a U2722A and I'm reasonably happy with it. Not that I have used it as much as I had planned to but I have a number of "shelved" projects (that I'll un-shelve, one day!) that need this.

Obligatory board images.
 
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Offline Shock

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Re: Transistor curve tracing in this century
« Reply #17 on: December 16, 2019, 07:39:56 pm »
Can You link me?  :-//

http://w140.com/tekwiki/wiki/Concepts_Series
Semiconductor Device Measurements
http://w140.com/tekwiki/images/a/a0/062-1009-00.pdf

If you are interested in the Tek 576, similar to the HP journals they also cover products in the magazines.
http://w140.com/tekwiki/wiki/Tektronix_Magazines
The Tek 576 was introduced in Vol. 1 No. 1, Feb 1969 of Tekscope.
http://w140.com/tekwiki/images/7/76/Tekscope_1969_V1_N1_Feb_1969.pdf

As a side note these with inflation would be $14K instruments today.

Soldering/Rework: Pace ADS200, Pace MBT350
Multimeters: Fluke 189, 87V, 117, 112   >>> WANTED STUFF <<<
Oszilloskopen: Lecroy 9314, Phillips PM3065, Tektronix 2215a, 314
 

Online TimFox

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Re: Transistor curve tracing in this century
« Reply #18 on: December 16, 2019, 08:27:29 pm »
I just have a Tektronix 7CT1N but it sure has been handy.

Syscomp Design makes a USB curve tracer among other USB instruments:

https://www.syscompdesign.com/product/ctr-201/

The Syscomp unit looks interesting, but it has been discontinued..
They advise me that a replacement is expected in 2020.
Do you know what the price was before discontuance?
 

Offline fcb

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Re: Transistor curve tracing in this century
« Reply #19 on: December 16, 2019, 10:04:36 pm »
Here's a project I am finishing at the moment.

It is a small dual channel SMU we call "SMUSB" - basically a low-cost 2 channel SMU.  Video was shot in April 2019 and I've just switched it from private to public.

This describes the various prototypes we went through with the project.

https://youtu.be/KkDIATgGuxI

« Last Edit: December 16, 2019, 10:33:21 pm by fcb »
https://electron.plus Power Analysers, VI Signature Testers, Voltage References, Picoammeters, Curve Tracers.
 
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Offline David Hess

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Re: Transistor curve tracing in this century
« Reply #20 on: December 17, 2019, 12:47:40 am »
I just have a Tektronix 7CT1N but it sure has been handy.

Syscomp Design makes a USB curve tracer among other USB instruments:

https://www.syscompdesign.com/product/ctr-201/

The Syscomp unit looks interesting, but it has been discontinued..
They advise me that a replacement is expected in 2020.
Do you know what the price was before discontuance?

It was like $400 so not exactly cheap.
 

Offline rodpp

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Re: Transistor curve tracing in this century
« Reply #21 on: December 17, 2019, 05:06:37 pm »
I just have a Tektronix 7CT1N but it sure has been handy.

Syscomp Design makes a USB curve tracer among other USB instruments:

https://www.syscompdesign.com/product/ctr-201/

The Syscomp unit looks interesting, but it has been discontinued..
They advise me that a replacement is expected in 2020.
Do you know what the price was before discontuance?

It was like $400 so not exactly cheap.

If its test voltage/current range were similar to the Tektronix boat anchors, that price would be great. But definitely, it is not.
 

Offline jonpaul

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Re: Transistor curve tracing in this century
« Reply #22 on: December 19, 2019, 02:01:34 pm »
Hi there, I have had TEK 577, somewhat smaller than 576 but similar.

My lab has a 576 in perfect condition with all test fixtures and printed manual.  Very useful and essential for power electronics work.  The 7CT1N and similaire TM 500 CT plug-in are rare and hard to use.

I Suggest to Look at Ham Radio Fleas.

To build one, Search DIY articles in 1960s....1980s consumer electronics magazines like Popular Electronics, Radio Electronics and ham radio magazines like QST and 73.


Just the ramblings of an old retired EE


Jon
Jean-Paul (EE 1968, the Internet Dinosaur)
 
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Online RoGeorge

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Re: Transistor curve tracing in this century
« Reply #23 on: December 19, 2019, 03:08:50 pm »
My question is why would one need curve tracer, other than for didactic purposes?

I needed one only once, while I was trying to find out if an optical sensor from a very old punch cards reader is in fact a photodiode or a phototransistor.  Ended up improvising a curve tracer with a simple coil (transformer) that was laying around, a signal generator and the humble Rigol DS1054Z in XY mode.  Conclusions were not so obvious, but the device looked more like a phototransistor on the curve tracer.  The decisive tests, thought was while looking at the chip's die under microscope, it looked like a disc circled by a ring, so a phototransistor layout.

What would be the nowadays typical use for curve tracer?
« Last Edit: December 19, 2019, 03:11:40 pm by RoGeorge »
 

Online Johnny10

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Re: Transistor curve tracing in this century
« Reply #24 on: December 19, 2019, 04:17:54 pm »
Because they are just so damn cool !
Tektronix TDS7104, DMM4050, HP 3561A, HP 35665, Tek 2465A, HP8903B, DSA602A, Tek 7854, 7834, HP3457A, Tek 575, 576, 577 Curve Tracers, Datron 4000, Datron 4000A, uTracer, HP5335A, EIP534B 20GHz Frequency Counter, TrueTime Rubidium, Sencore LC102, Tek TG506, TG501, SG503, HP 8568B
 
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