Transistor Curve Tracer kit on ebay

[drakke]

Hello,

http://www.ebay.com/itm/141138017533

Is this worthwhile?
I was considering using it to explore the behavior of various semiconductors.

Thanks.

[rdl]

Noppe

Consider this one ...
http://www.syscompdesign.com/CTR-101_ep_60-1.html

Best regards,
gazelle

Lol, that's a whole order of magnitude beyond apples vs. oranges.

[drakke]

I also saw this:

http://www.changpuak.ch/electronics/Curve_Tracer_advanced.php

Not a kit, just a schematic.

[Fraser]

I bought the built earlier version from Thailand as it was so cheap. Works fine and is an interpretation of an Elektor design. Cr*p it is not. I bought this newer ready built revision but have yet to play with it.

You do get what you pay for, but cheap does not always mean no good. The unit comes with a schematic so can be easily modified to meet individual needs. Its basic but it works.

The built version is here:

http://www.ebay.com/itm/Power-Transistor-Curve-Tracer-adapter-XY-Oscilloscopes-NPN-PNP-Vce-10V/140547987228?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D29384%26meid%3D8f4b0b82c46a48f98457355e541117ce%26pid%3D100005%26rk%3D2%26rkt%3D5%26mehot%3Dag%26sd%3D141138017533&rt=nc

Cheap as chips 

I attach the original Elektor article plus the early version of this Thai offering.

Aurora

[drakke]

I attach the original Elektor article plus the early version of this Thai offering.

Aurora

Thanks.

[ion]

If you have a scope and function generator, you can always use them to make a simple curve tracer:

[Fraser]

Also,

If wishing to look at semiconductor characteristics and I-V plots you could consider the Peak DCA75 PRO version at around £105 from the OEM in the UK. I ordered one today as they have a good reputation.

http://www.peakelec.co.uk/acatalog/dca75-dca-pro.html

Video



The unit offers long term semiconductor analysis capability and works 'stand-alone' and connected to a PC. Firmware and Software is updated on the web site and may be upgraded by the user.

Aurora

[Smith]

Yes the peak does a verry good job, is quite small, fast, can test a lot of components, and has lots of options. It costs quite  a lot more, but I do think its worth it.

[HighVoltage]

Yes the peak does a verry good job, is quite small, fast, can test a lot of components, and has lots of options. It costs quite  a lot more, but I do think its worth it.

Totally agree,
For simple curve tracing, the PEAK is doing a great job and is very easy to use.

[all_repair]

http://www.diyaudio.com/forums/vendors-bazaar/205733-intelligent-curve-tracer-3-0-release-11.html

[SteveyG]

I concur with the DCA75 suggestion, review here:

Noppe

Consider this one ...
http://www.syscompdesign.com/CTR-101_ep_60-1.html

Best regards,
gazelle

Lol, that's a whole order of magnitude beyond apples vs. oranges.

LMAO, comparing apples with tart tatin.

[MadTux]

If you want a curve tracer, best get old Tektronix 575/576/577. These have enough power to even test power transistors to death. HP 4145/4155 is also nice if you can find it cheaply. 7CT1N is nice for small tranistors, if you already have 7k mainframe. Tek 370/371 if you have lots of money. Tek 571 is also sometimes found quite cheaply if lucky, goes up to 1A IIRC.

What would be really cool if someone would develope a modular USB curve trace controller to be conncted to GPIB capable DVMs that has several high resolution DAC channels to control PSUs with analog remote input.

Idea is to use DAC channels for remote control of cheap HP power supplies (E36xx series and HP 626X/627X series) Beefy 626X/627X in constant voltage mode to supply transistor CE. Small HP E36xx for base supply in constant current mode. Put some shunts on collector supply and use a cheap HP345x DVM to measure CE current (voltage over shunt).

Controller board  sets base current on E36xx via DAC channel and sweeps CE voltage in small steps on 626X/627X PSU on second DAC channel while measuring CE current over GBIB connected DVM.

Improvement would be to use 3 GPIB multimeters to measure CE current and make precise regulation (e.g. PID controller on controller board) of base current and CE voltage.

That way you could get highly accurate transistor curves with nearly unlimited power in digital format, so no need to photograph the CRT to compare transistors. Also all parts are really cheap on ebay, in contrast to highly expensive Keithley 2400 sourcemeters.

Parts are also modular, nearly everybody has a PSU with analog remote input and some GPIB capable multimeter. So everything that is needed is a controller board for a few 10s of dollars with 2x 16bit DACs, a few HPIB connecors and isolated USB connector.

[dadler]

I recommend the peak as well, but be warned that the voltages and currents are limited, due to it being driven by 5v USB and an internal AA cell. It boost converts this to 12v which is the max (depending on the mode. For example, it cannot identify zeners with >11v breakdown voltage).

[casinada]

There is another Curve tracer on ebay that can handle +/- 36V 2.5A
http://www.ebay.com/itm/locky-zs-curve-tracer-finished-PCB-/111587792253?pt=LH_DefaultDomain_0&hash=item19fb26957d
You have to add power supply and Heatsink to finish it. He has a Yahoo Group but It hasn't been active for a while.

[radioFlash]

There is another Curve tracer on ebay that can handle +/- 36V 2.5A
http://www.ebay.com/itm/locky-zs-curve-tracer-finished-PCB-/111587792253?pt=LH_DefaultDomain_0&hash=item19fb26957d
You have to add power supply and Heatsink to finish it. He has a Yahoo Group but It hasn't been active for a while.

The person who developed it is goes by "locky z" and he has a discussion of it on DIYAudio with a schematic.

http://www.diyaudio.com/forums/vendors-bazaar/205733-intelligent-curve-tracer-3-0-release.html

[all_repair]

There is another Curve tracer on ebay that can handle +/- 36V 2.5A
http://www.ebay.com/itm/locky-zs-curve-tracer-finished-PCB-/111587792253?pt=LH_DefaultDomain_0&hash=item19fb26957d
You have to add power supply and Heatsink to finish it. He has a Yahoo Group but It hasn't been active for a while.

Or get through an agent or direct from Taobao, there is a complete set with a solid alumimum case.
http://item.taobao.com/item.htm?spm=a1z10.1-c.w4023-1727506432.4.TcAODj&id=9100380344

For those who already bought the PCB assembly from ebay:
http://item.taobao.com/item.htm?spm=a1z10.1-c.w4004-1727506435.5.TcAODj&id=40132519890

Got it for a while, under-utilized for me.  I normally just do a rough match or characterisation through DY294. 

[Rupunzell]

There are MANY semiconductor manufactures to this day that are still using the Tektronix 576 as their standard curve tracer. The data and information a properly calibrated 576 can deliver is invaluable for design and overall evaluation of semiconductors, vacuum tubes, resistors, capacitors, inductors and more. Most anything that tell's it's story with a V-I curve can be tested with the 576, up to 1500 volts, 20 Amps pulses and 200 Amps with the 176 fixture. It can measure down to nano amps. step generator in current voltage, inverted, DC bias offset on the steps and a lot more.

There is a independent test gear repair company in Silly Valley that offers flat rate repair for Tek 576 and even same day turn around.
http://www.equiptek.info

One can tap in to the internals of the Tek 576 and route the X-Y signals to a DSO or similar digitizer and get the 576 data into digital format.

The Tektronix 576 was designed in the early-mid 1960's and has retained it's usefulness and market value to this day.

The later Tektronix-Sony 370 series cost more but offers a better interface for data. Functionally, the difference between the 576 with it's options and the 370 series is not much.

The Tek 576 is BIG heavy (about 70 pounds) and very serviceable. Not a hobby toy. No proper analog design lab is complete without one.



Berince

If you want a curve tracer, best get old Tektronix 575/576/577. These have enough power to even test power transistors to death. HP 4145/4155 is also nice if you can find it cheaply. 7CT1N is nice for small tranistors, if you already have 7k mainframe. Tek 370/371 if you have lots of money. Tek 571 is also sometimes found quite cheaply if lucky, goes up to 1A IIRC.

What would be really cool if someone would develope a modular USB curve trace controller to be conncted to GPIB capable DVMs that has several high resolution DAC channels to control PSUs with analog remote input.

Idea is to use DAC channels for remote control of cheap HP power supplies (E36xx series and HP 626X/627X series) Beefy 626X/627X in constant voltage mode to supply transistor CE. Small HP E36xx for base supply in constant current mode. Put some shunts on collector supply and use a cheap HP345x DVM to measure CE current (voltage over shunt).

Controller board  sets base current on E36xx via DAC channel and sweeps CE voltage in small steps on 626X/627X PSU on second DAC channel while measuring CE current over GBIB connected DVM.

Improvement would be to use 3 GPIB multimeters to measure CE current and make precise regulation (e.g. PID controller on controller board) of base current and CE voltage.

That way you could get highly accurate transistor curves with nearly unlimited power in digital format, so no need to photograph the CRT to compare transistors. Also all parts are really cheap on ebay, in contrast to highly expensive Keithley 2400 sourcemeters.

Parts are also modular, nearly everybody has a PSU with analog remote input and some GPIB capable multimeter. So everything that is needed is a controller board for a few 10s of dollars with 2x 16bit DACs, a few HPIB connecors and isolated USB connector.

[Wirehead]

I bought the built earlier version from Thailand as it was so cheap. Works fine and is an interpretation of an Elektor design. Cr*p it is not.

I concur. Recently ordered the kit + the dual supply and it works a treat!
I've put the kit in a small enclosure (a repurposed serial port switcher). Has a 4-way (9 pin...) switch. Great for matching transistors!

Sure it's no Tek curve tracer, but I don't need anything like that. I like restoring amplifiers etc,.. and it's great to verify if *insert obsolete part* actually still works, or to match input diff pairs!

 

[Fraser]

Nice work.

It is certainly adequate for less demanding tasks, and in my experience works well. It is a bargain at the asking price.

Nice re-purposing of the enclosure. 
Fraser

[EEVblog]

Noppe
Consider this one ...
http://www.syscompdesign.com/CTR-101_ep_60-1.html

I like the look of that, I might have to get one...

[Skimask]

Noppe

Consider this one ...
http://www.syscompdesign.com/CTR-101_ep_60-1.html

Best regards,
gazelle

Hmmm....and I'm building a handheld version of that right now....like right this moment, solder is hitting the heater, bits are flowing back and forth...

[GreyWoolfe]

I am going to ask a stupid question here.  I just got one of the curve tracer kits that Fraser and wirehead got.  My kit didn't include the PCB mounted RCA jacks and the RCA to BNC adapters.  I just got a couple of bulkhead mount BNC jacks.  My plan is to put this in an enclosure with my octopus circuit tester. 

Here is the stupid question.  What is the best thing to use to connect the BNC connectors to the board?  Would plain wire work or is there something better? I even have a broken Chinese scope probe that I can salvage the wire from.  I just used short pieces of wire with the octopus and that works fine.

If the RCA jack is the best way to go, does this look correct?  http://www.ebay.com/itm/1Pcs-PCB-Mount-2-RCA-Female-Stereo-Aux-Audio-Video-Jack-AV-Socket-Connector-/400979088030?hash=item5d5c37529e:g:ViMAAOSwd0BV0OpG

[CustomEngineerer]

I am going to ask a stupid question here.  I just got one of the curve tracer kits that Fraser and wirehead got.  My kit didn't include the PCB mounted RCA jacks and the RCA to BNC adapters.  I just got a couple of bulkhead mount BNC jacks.  My plan is to put this in an enclosure with my octopus circuit tester. 

Here is the stupid question.  What is the best thing to use to connect the BNC connectors to the board?  Would plain wire work or is there something better? I even have a broken Chinese scope probe that I can salvage the wire from.  I just used short pieces of wire with the octopus and that works fine.

If the RCA jack is the best way to go, does this look correct?  http://www.ebay.com/itm/1Pcs-PCB-Mount-2-RCA-Female-Stereo-Aux-Audio-Video-Jack-AV-Socket-Connector-/400979088030?hash=item5d5c37529e:g:ViMAAOSwd0BV0OpG

Mine came the same way. I ended up just soldering the little hollow pins that came with it in each of the spots for the probe connections, then just clip my probes on to them. Seems to work ok, but was really confused with how the hell the BNC's were supposed to mount. I had managed to find a few of the pics of a fully assembled kit with the RCA connectors but didn't have anything like that until a couple of days ago when I found a similar double RCA jack on an old donated piece of stereo equipment. Haven't had a chance to mount it yet though.

[GreyWoolfe]

I am going to ask a stupid question here.  I just got one of the curve tracer kits that Fraser and wirehead got.  My kit didn't include the PCB mounted RCA jacks and the RCA to BNC adapters.  I just got a couple of bulkhead mount BNC jacks.  My plan is to put this in an enclosure with my octopus circuit tester. 

Here is the stupid question.  What is the best thing to use to connect the BNC connectors to the board?  Would plain wire work or is there something better? I even have a broken Chinese scope probe that I can salvage the wire from.  I just used short pieces of wire with the octopus and that works fine.

If the RCA jack is the best way to go, does this look correct?  http://www.ebay.com/itm/1Pcs-PCB-Mount-2-RCA-Female-Stereo-Aux-Audio-Video-Jack-AV-Socket-Connector-/400979088030?hash=item5d5c37529e:g:ViMAAOSwd0BV0OpG

Mine came the same way. I ended up just soldering the little hollow pins that came with it in each of the spots for the probe connections, then just clip my probes on to them. Seems to work ok, but was really confused with how the hell the BNC's were supposed to mount. I had managed to find a few of the pics of a fully assembled kit with the RCA connectors but didn't have anything like that until a couple of days ago when I found a similar double RCA jack on an old donated piece of stereo equipment. Haven't had a chance to mount it yet though.

That's funny, I was the same way with the connectors.  I put them in the big holes and looked.  OK, this isn't going to solder and they are touching.  Also, where do the shields connect?  That's when I remembered that there was thread and saw the RCA connectors.  Using the pins was a good idea, but as I stated, I am going to put this in a project box so I will be using bulkhead BNCs.

[Wirehead]

I am going to ask a stupid question here.  I just got one of the curve tracer kits that Fraser and wirehead got.  My kit didn't include the PCB mounted RCA jacks and the RCA to BNC adapters.  I just got a couple of bulkhead mount BNC jacks.  My plan is to put this in an enclosure with my octopus circuit tester. 

Here is the stupid question.  What is the best thing to use to connect the BNC connectors to the board?  Would plain wire work or is there something better? I even have a broken Chinese scope probe that I can salvage the wire from.  I just used short pieces of wire with the octopus and that works fine.

If the RCA jack is the best way to go, does this look correct?  http://www.ebay.com/itm/1Pcs-PCB-Mount-2-RCA-Female-Stereo-Aux-Audio-Video-Jack-AV-Socket-Connector-/400979088030?hash=item5d5c37529e:g:ViMAAOSwd0BV0OpG

Use the BNC connectors. Much better than RCA. Use twisted wires and keep these as short as possible. Connect to the scope via short Coaxial BNC <> BNC cable.

I've got mine in a repurposed enclosure as seen above. Due to the added wire length to the device-under-test (because of the switch), I've added a 1nF capacitor between the emitter and the collector. It gives sharper traces with less noise, whilst not interfering with the measurement. 

[GreyWoolfe]

I am going to ask a stupid question here.  I just got one of the curve tracer kits that Fraser and wirehead got.  My kit didn't include the PCB mounted RCA jacks and the RCA to BNC adapters.  I just got a couple of bulkhead mount BNC jacks.  My plan is to put this in an enclosure with my octopus circuit tester. 

Here is the stupid question.  What is the best thing to use to connect the BNC connectors to the board?  Would plain wire work or is there something better? I even have a broken Chinese scope probe that I can salvage the wire from.  I just used short pieces of wire with the octopus and that works fine.

If the RCA jack is the best way to go, does this look correct?  http://www.ebay.com/itm/1Pcs-PCB-Mount-2-RCA-Female-Stereo-Aux-Audio-Video-Jack-AV-Socket-Connector-/400979088030?hash=item5d5c37529e:g:ViMAAOSwd0BV0OpG

Use the BNC connectors. Much better than RCA. Use twisted wires and keep these as short as possible. Connect to the scope via short Coaxial BNC <> BNC cable.

I've got mine in a repurposed enclosure as seen above. Due to the added wire length to the device-under-test (because of the switch), I've added a 1nF capacitor between the emitter and the collector. It gives sharper traces with less noise, whilst not interfering with the measurement. 

I will make a short pair of BNC cables like I did for the octopus.  The box will sit right on top of the Tek 2235 that I am using for the octopus.  I am sure that I have a 1 nF cap to add.  Thanks for the tip on using twisted wires and I will keep them as short as possible.

[McBryce]

I have one of these PCBs (assembled) that was part of a box of random PCBs I picked up at an auction. I don't need it, so if anyone (especially in Germany due to postal costs) is interested in having it let me know (send PM).

McBryce.

[DBoulanger]

Hi,

Although there is no post in that topic since a little while, I figured that it wouldn't any harm to add one.

I recently acquired this kit in a flea market where the person was selling electronic parts and boards, mainly for parts.  Some of the boards were intact, some of them had a rough journey !  For a box of may 30 boards or so, I ended up paying $20, which wasn't bad a all.

Anyhow, despite my efforts to understand what may be wrong, the calculated gain with the scope trace is always higher than the ones I obtain with my DCA55 for instance.  I have a transistor tester, a DMM and the DCA55 that give me similar values, within a margin of 20 or so, but the curve tracer is close to 100 more,

For instance, I tried with 3 2N2222 and the figures were roughly the same, in the 230-250 range using my "regular" testers.  The curve tracer gave me values in the 350 range.  I can understand that the current used to evaluate the gain isn't the same, but having values so different from each other, make me wonder if I missed something.

By the way, I found some RCA jacks that fits perfectly on the board, footprint wise.  I bought them on eBay, "Audio Video AV 2 RCA Female Jack Socket Chassis PCB Mount Connectors 5 Pcs", item #321695325968.  The ones that were suggested earlier in this thread, didn't have the same footprint.

Bye for now.

[suenrod]

I am considering the same. The price sure is right if it can be used for transistor matching.

[suenrod]

Any performance issues to report? Has Dave and crew ever done a comparison on these VS a real curve tracer?

Would this be a suitable curve tracer for matching RF power transistors? I'm not worried about measuring gain accurately. More of a subjective go/no-go comparison between transistors until I find a set that matches.
I would love to see how they fair up to a REAL curve tracer.

hint hint Dave

[steverino]

If you're a follower of Paul Carlson's youtube channel, Mr. Carlson's Lab, he mentioned he's going to be sharing a curve tracer device he designed and built.  I think he's going to initially release it to Patreon subscribers.  Stay tuned...

[DBoulanger]

Indeed, this will be something interesting to follow.

As far as the gain precision is concerned, you're pretty much right, this might not be the most important thing.  Being able to measure it, within a reasonable error margin, is however interesting since it makes the learning process a bit easier as you can evaluate results with formulas and then apply the theory.

When the results are way off, determining what is right and what is wrong might not be too obvious for the beginners.

If only the overall aspect/look of a given traces set is what you're looking for, to compare transistors for instance, then this curve trace might do the job for you.

I don't have power transistors so I can't really tell you how well this trace would perform while testing these.

Nevertheless, even if this is an old subject, it's always interesting.

[rstofer]

So, I was wondering if the Digilent Analog Discovery could be coerced into doing curve tracing...

Yup!
https://ez.analog.com/community/university-program/blog/2013/12/07/analog-discovery-bjt-curve-tracer-program

I haven't tried it yet but the description and posted image make it pretty clear that it will work.

[Anks]

HI looking for a bit of help. I bought one of these kits a while ago and I've lost the schematic and build guide that was sent with it. If anyone could please send me a link to the correct schematic for the ebay kit that would be a great help.

Thanks Kris

[DBoulanger]

Hi Kris,

The documentation, along with the schematics, are available on the Thaikits.com website.

The link is http://www.thaikits.com/index.php/download.html?download=15:ch-012-user-paper-and-schematic

The password to extract the schematic from the zip file is "jojo2520", which is in fact the eBay's seller name.

Hope that helps.

[Lbud4]

I have one of locky z's curve tracers -- posted on the first page. I have had mine for several years and it works great. 

http://www.ebay.com/itm/locky-z-039-s-Intelligent-curve-tracer-PCB-New-/112168145773

His software is fairly comprehensive and is fairly bug free.

[Bryan]

I bought the built earlier version from Thailand as it was so cheap. Works fine and is an interpretation of an Elektor design. Cr*p it is not. I bought this newer ready built revision but have yet to play with it.

You do get what you pay for, but cheap does not always mean no good. The unit comes with a schematic so can be easily modified to meet individual needs. Its basic but it works.

The built version is here:

http://www.ebay.com/itm/Power-Transistor-Curve-Tracer-adapter-XY-Oscilloscopes-NPN-PNP-Vce-10V/140547987228?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D29384%26meid%3D8f4b0b82c46a48f98457355e541117ce%26pid%3D100005%26rk%3D2%26rkt%3D5%26mehot%3Dag%26sd%3D141138017533&rt=nc

There is a utube review on it. Also available in kit form. A few gotchas the reviewer found though.

https://youtu.be/7exRUNCQ-hI

[McBryce]

Wow, could he have made it any bigger or uglier?

McBryce.

[rodpp]

Wow, could he have made it any bigger or uglier?

McBryce.

kkk ugly, for sure. But not  that  big:

[McBryce]

That Sony has to be that big. It's full of CRT and electronics and I'm pretty sure there's not much spare space inside. The other above could fit in a box 1/4 the size.

Btw: I have one of those Thai Curve Tracer PCBs (80% built) knocking about that I never intend using. If anyone is interested in buying it for their own experiments send me a PM.

McBryce.

[Anks]

Hi Kris,

The documentation, along with the schematics, are available on the Thaikits.com website.

The link is http://www.thaikits.com/index.php/download.html?download=15:ch-012-user-paper-and-schematic

The password to extract the schematic from the zip file is "jojo2520", which is in fact the eBay's seller name.

Hope that helps.

Thanks DBoulanger

[torch]

I bought one of these last year. Just got around to putting the main circuit board together last night. It works exactly as advertised. It gives a very nice, crisp, clear trace when used with my analog Tek 475. Not so much with my Rigo DS1052E, but that's the fault of the Rigol -- it has a terrible display in XY mode. Also, the scope needs to be bandwidth limited to 20MHz as the signal is kind of noisy.

The hfe calculation is 9% high when comparing measurements of a 2N2222 with the results provided by my Karl-Heinz type transistor checker when taken at the extreme end of the ramp. I found similar results with a small PNP transistor, making a total sample count of 2. 

I left the 2N2222 in there for a couple of hours with no heating. It was drawing 39mA from the +leg of the power supply and 17mA from the -leg.

I also tried it with one CXL154 (an NPN power transistor) in the high power mode. It worked fine with that too, with the +leg drawing 59mA and the -leg remaining at 17mA.  Slightly warm after 1 hour. That one measured 33 on the Karl-Heinz, 35 on the curve tracer, but the package claims an HFE of 100 (AC vs DC?).

I tried a big ol' IGBT and got a capacitor-like lissajous pattern that slowly rolled from left to right.

I have yet to assemble the power supply board and put it all in a nice case with switches and BNC connectors, but I think it will be a nice piece of kit when it's all done, when used within it's limitations.

[Calambres]

Sorry to restart an old topic but I'm getting this kit and I'd like to know if it can be used with FETs too.

[IulianP]

I was wondering... on the ch-012 from Thailand, what are those two big yellow things on top of the board?

[McBryce]

Relays.

McBryce.

[Calambres]

I have built one of these kits and it works fairly well but I'm having a problem I cannot address.
I can get quite clean curves out of this but only if I plug the transistor in its own board socket:






So far, so good, but I have added an outboard 3P4T switch and a ZIF (Zero Insertion Force) socket in the project box to allow four transistor matching easily, very much like Wirehead's project in this same thread, plus a couple of banana socket trios to test external power transistors:



The problem I'm facing is that this setup requires some cabling:



and once I take some wires out of the supplied testing socket, the curves in the scope distort big time:



I have tried using coaxial cables from the 4-pin socket to another 4-pin socket just to see if this could improve things but the distorsion is even worse:




It is courious that if I firmly grab the coaxial loom with my hand, the distorsion disappears completely:




I assume there are some stray capacitances in the external wiring but I have no idea what to do to solve this problem.

Any ideas?

[Calambres]

C'mon... anyone?

I'm stuck! 

[Bud]

The thing is oscillating. Try putting a few EMI supression ferrites over the cable bunch. A few of them.

Try to use twisted wire pairs for each of the lines. Connect one wire from each pair to ground on the board side. Leave these ground wires unconnected on the remote socket side or connect them together, see if one or the other way works better.

Edit: BTW the original article posted at the beginning of this topic says connection length should not exceed 10cm, they knew long wires will create problems.

Edit: the twisted wire should have a few twists per inch, not just loose twist like in network cables. You can use a drill to make a length of twisted wire.

Also what else you can try is putting small EMI chokes right on the legs of the transistor being tested.

[Calambres]

Thanks for your answer.

With EMI suppression ferrites you mean ferrite beads, right?

I know the 10cm warning in the original ELEKTOR article but this is not compatible with what I'm trying to do. I'll follow your suggestions and report them back here once done.

Thanks again.

[Bud]

Yes ferrite chokes, ou can use snap-on split chokes or regular ones since you can run your wires through the core.

[Calambres]

The thing is oscillating. Try putting a few EMI supression ferrites over the cable bunch. A few of them.

Positively yes: it's oscillating a lot!
I've got no ferrite beads in my parts bin but have tried your other suggestions:

Try to use twisted wire pairs for each of the lines. Connect one wire from each pair to ground on the board side. Leave these ground wires unconnected on the remote socket side or connect them together, see if one or the other way works better.
Edit: the twisted wire should have a few twists per inch, not just loose twist like in network cables. You can use a drill to make a length of twisted wire.

Nope!  No difference at all. No matter how I use twisted pairs grounded on one side or both, that thing is still oscillating.

Also what else you can try is putting small EMI chokes right on the legs of the transistor being tested.

That is a good idea but it's not practical. I pretend to use this kit to compare and match up to 4 trannies/FETs at a time from a batch and that would be a PITA.

Edit: BTW the original article posted at the beginning of this topic says connection length should not exceed 10cm, they knew long wires will create problems.

That is the key, obviously. I have reoganized things inside the box and have rewired and shortened the leads drastically and have had partial success. At least two of the four slots in the ZIF socket are now free from oscillations. Have not tested the banana connectors yet. They are intended to test bigger power transistors that wouldn't fit in the ZIF socket but I am afraid that the necessary additional leads may make things go wrong. As soon as I try it all, I'll let you know.

Thanks again for your suggestions.

[KD0CAC John]

My approach & understanding of this subject - your bad signals / distortion is from what I'm into - ham radio , is called common mode current - and impedance mismatch that creates CMC , that is a 3rd signal path on the outside of the shield of the coax .
Also my approach with issues like this - is to solve / eliminate the cause of the issue , rather than coverup or react to he issue .
It could also not be CMC , is could be bad coax , or the BNC connector not correctly installed .
I may look for one of these kits , besides building one of Mr. Carlsons units . 

[Calambres]

...could be bad coax , or the BNC connector not correctly installed...

I had to stop working on this project but kept thinking about it and that is exactly the same conclusion I ended up with. More on next week.

[L_Euler]

Get one of these off eBay.  The used TeK tracers are all really expensive for ones that work.

https://www.ebay.com/itm/Vintage-HEATHKIT-IT-3121-SEMICONDUCTOR-CURVE-TRACER-TESTED-WORKING-WITH-LEADS/223323953921?epid=1500692003&hash=item33ff251b01:g:okoAAOSwg-tcO5St:rk:1:pf:1

[Calambres]

Back to the bench. Partial success 

I've discarded a problem with the BNCs or coaxial cables. After much tinkering with the switch and ZIF cabling I have succeeded in making all 4 test slots to work fine but no way I can extend the first two ZIF slots to the banana sockets for the power trannies. No matter how I route the cables, the oscillations come back. Besides I'm having problems with the other cabling, i.e.: the wires from the board to the PNP/NPN external switch also make it to oscillate a lot. The "Small/Power" cabling do not seem to affect the circuit stability at all.

I'm forced to discard the current box, which I had lying 'round in my shop, and use a smaller one.

[Edit: typo]

[TERRA Operative]

So my turn to build one of these things.
I got it almost finished and ready to close the lid, but I seem to have one small problem.
Mine seems to trace really slowly, like one line per second or so. (Actually looking at it now, it traces the whole graph in 2 seconds or so).
I'll have to take another look tonight (I fired it up for the first time at 3am in the morning, so no time to troubleshoot yet), so can anyone suggest where I should start looking?
In all probability, I have a resistor with a wrong value installed or something silly, but if someone can tell me a likely place to poke first, that would be appreciated.


EDIT: Well, I tested all the diodes and resistors, they all seem ok and in the right spots. I'll have to check the capacitors next, then I guess go buy a new CD4024 and TL074 to see if one of those is busted somehow.

[beanflying]

Not trying to intrude on the Thai Kit which looks fairly good. Just an assortment of links people might find useful on home brew Oscilloscope based curve tracers.

So far I have a 100V + Transformer and some of the power supply bits in a box for a build of something along these lines http://www.paulvdiyblogs.net/2017/12/building-curve-tracer.html

Nice simple and basic https://github.com/tardate/LittleArduinoProjects/tree/master/Electronics101/GeneralCurveTracer

Garden variety Octopus Curve Tracer I found because I have just brought the same Scope (Non C version) the circuit comes from http://levysounddesign.blogspot.com/2016/04/octopus-tester-component-curve-tracer.html

 

[Calambres]

Still working on it. Had to remake all the wiring. Not yet a complete success. More on this later...

[TERRA Operative]

Well, I found my problem... 100nF is not interchangeable with 1nF... haha. 
Turns out I had two capacitors swapped around... durrrr.

That'll teach me to construct things after midnight (no it won't  ).

I also found that using shielded wire for the connections from the PCB to the front panel would distort the waveform on the scope if I had the shields grounded.
Leaving the shields completely disconnected results in a clean trace, so that's how they'll stay.

Once I have the enclosure finished, I'll post some pics (and a link to the youtube video I'm making).

[Calambres]

I also found that using shielded wire for the connections from the PCB to the front panel would distort the waveform on the scope if I had the shields grounded. Leaving the shields completely disconnected results in a clean trace, so that's how they'll stay.

I already found what you say about grounded shielded wires but didn't try to leave the shields unconnected. Thanks for the tip! 

[Calambres]

Finally sorted it out. Everything showed right when I added ferrite beads in the Base/Gate wires, as close as possible to the transistors.
Changed the 3P4T for a 3P7T for yet more versatility.






Works like a charm! 

[TERRA Operative]

Here's my attempt at an enclosure... It turned out ok, and works well which is a plus.
Too bad the available enclosures weren't just a few centimeters larger so I could have a little more elbow room inside to route wires more neatly..

[Calambres]

Nice one! 

I forgot to mention something:

If you see my project, two posts back, you'll notice that there are three switches instead of the two indicated by the kit itself. I have implemented a third switch for 4 / 8 curves as per the second page in the original ELEKTOR article linked early in this thread. This also limits the amount of current the DUT is going to manage, just in case... I had to cut the track going to pin 9 of 4024 and install a couple of wires to a SPST:
- Closed: 8 Curves
- Open: 4 curves

See the cited article for more details.

[TERRA Operative]

Ah cool. I'll check it out.

[TERRA Operative]

Uploaded a vid on building my curve tracer.

https://youtu.be/uU_KjH-jJnA

[Calambres]

Nice!

[Calambres]

A couple of small, quick and crappy youtubes showing my Curve Tracer in action:

https://youtu.be/ZDL0xF_rmE4

https://youtu.be/207ZFMRFako

[TERRA Operative]

Nice, characterizing up to 4 transistors at once is pretty sweet.

I thought about making an A/B adapter for mine, but I got a Tek 577-177 for cheap to restore, so all my effort is probably going to go into that now...

[Calambres]

Quoting myself 

Finally sorted it out. Everything showed right when I added ferrite beads in the Base/Gate wires, as close as possible to the transistors.

Not really!... the graph was still somewhat fuzzy if you look closely. I had to put ferrite beads in ALL the C-B-E wiring and switching inside the box. Now the trace is much clear. I can even use my old Tek TDS-320 crappy XY mode with a bit of success. Still much better in my old trusty analog HAMEG HM 203-6. Now the traces are crisp and clear.

[beanflying]

Just adding these here for interest. I got a pair in to look at and they seem to be as claimed a ceramic body as they are heavy for size. One of them has an issue with a malformed contact on one position that I am not sure is correctable. Overall based on first impressions looks good but QC isn't. I will do some testing with repeated insertions on the damaged one and see how the plating is holding up.

Just an 'option' but maybe Zif sockets are better  eBay auction: #254121206657

[TERRA Operative]

I've been looking at these myself, I'm thinking of grabbing a couple to use in a custom jig for my Tek 277-177.
Just another project in the pile of projects.

[innkeeper]

I've got a range of curve tracers and testers ... an octopus curve tracer, and it-3132, thaikits curve tracer (jojo2520), tek 576

Here are my thoughts....

Octopus V/I  tracer - cool device look it up - very cheap to build and works good but has lotta limitations but good on the cheap, I think thaikits might sell one, but an easy diy project.

Low voltage low current tracers - ie eBay kits /  peak  etc ... limited voltage and current makes it useful for some applications but are very limited in the voltage and current ranges they can test. might be the solution for you but know the limits...many hook to scope XY


older Commercial / KIT XY scope units - units like BK precision, leader, heathkit, that hook up to scopes. these typically have wider voltage and current rages but, are time-consuming to set up to get accurate readings. Very functional and a cheap alternative to a full blown tracer, though, you can damage the units or the device under test more easily than on a dedicated unit by setting it up wrong. great for the serious hobbyist.

Professional stand alone tracers - in this i include the older Tektronix 575,576,577,370,371, and its more modern counterparts made by Keithly and the like. typical advantages here are high voltages, high currents, and more limits and safety features over the scope XY counterparts., as well as ease of use, and speed of use.  defiantly the way to go if you're using it professionally for matching components, or characterizing production components, qa testing and so on.

there are exceptions to the above, so basically i am saying that you should know the voltage and current limits of what you are looking at and be aware of what safety features it has or doesn't have.

[705jas]

Hi All

I just ordered one of these Curve Tracer kits on ebay

https://www.ebay.com.au/itm/Transistor-Curve-Tracer-adapter-Oscilloscopes-Plus-Power-supply-UnAssembled-Kit/291531434190?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

and it says I need a +15/-15 1amp transformer.  New to all this so any suggestions on what and where to get one appreciated. 

Thanks.

[McBryce]

I used one of these: https://www.ebay.com/itm/Dual-Voltage-Regulator-Module-15V-Positive-Negative-PCB-With-7815-7915-/173121178263
together with a 220V transformer with 18V-0V-18V output (borrowed out of some printer I think).

Edit: Just noticed, if you bought the one you linked to, then the regulator board and parts are included, you just need a transformer like I described above.


McBryce.

[srtate1]

This thread has been asleep for a long time, but I just built one of these Thai kit curve tracers.  The main board and power supply board were pre-assembled.  It is mounted in a metal case with short shielded cabling from board to panel mounted BNC connectors. The traces don't look right to me -- they have longer curves to peak current than I am used to seeing.   I have tried short test leads to the transistors with no change to the curves.  Does this look right to you?  If not any ideas about how to get that shoulder more distinct?

[TimFox]

Is that because you have both vertical inputs on AC coupling?

[srtate1]

I caught that earlier and moved it to DC coupling.  No change.