Show Us Your Curve Tracer

[Calvin]

Hi,

Having waited for years, I ordered my locky_z on ebay as soon as he offered the latest batch last year.
Unfortunately does it not work as I hoped for 
It mostly draws just weird fuzzy lines on the display.
So I just put it aside since I had no time to dig into the issue deeper.
I heard though that another user had similar problems and got a replacement.
Unfortunately is locky_z  hard to contact and doesn´t respond very well (starting from not giving a rating on ebay to not responding on mails).
My old Tech 576 is a much more trustworthy guy in comparison. 

regards
Calvin

[Johnny10]

What about the B&K Model 501A ?

My first Curve Tracer.
Now where did I put it?

Remember also that all of the Tektronix and B&K models came with terrific manuals,

[rsjsouza]

I am glad you liked the content, Electro Fan.

The kit is really good as the schematics and the microcontroller code are freely available. Also, one additional aspect is the ability to create your own scripts for testing, as well as save the data in tabular text form for post processing. I haven't done that yet, but it is quite promising.

I am having a blast with it.

[rsjsouza]

Having waited for years, I ordered my locky_z on ebay as soon as he offered the latest batch last year.
Unfortunately does it not work as I hoped for 
It mostly draws just weird fuzzy lines on the display.

Calvin, I don't know what extent of testing you did but, depending on the set conditions, the DUT will only show really squiggly lines as it is not properly biased. I did that at the beginning and was really miffed at the results.

For example, the software by default sets the base resistor to 1M, which is quite high for most of the general purpose bipolar transistors. Also, if the collector resistor is too high, the Ic will be too low and therefore potentially cause the transistor to be simply in cutoff.

At any rate, I am sad to hear that you had a bad experience. His user's guide has a very thorough debug section, though. Yes, not an ideal solution but still some hope. Good luck!

[Messtechniker]

My semi-finished  semiconductor curve tracer. Completed and verified D/A converter and USB link. Output stages need to be built one day.
More on this here:
https://www.dl4jal.de/kls/kls.html

[FrancisM]

Here's my own one, designed for small signal transistors. I got the idea from an old Elektor article.
It can show output characteristics and transconductance curve of jfets or mosfets.

The sweep is an adjustable triangular wave of +-14V max, the current limit can be set to 25mA or 250mA. Done with a TL074.
The base (gate) is voltage driven by a pic18F1320 and a double buffered dac MCP4822. I select the base resistor with jumpers.
Having a single bipolar supply, the current is monitored across a 0.1 Ohm shunt in the emitter (source). It's then amplified 100x by an AD797 to the Y output. I can change triangular's wave frequency to get rid of the looping effect with highly capacitive transistors.

The result is not that bad on newer DSOs, no flickering at all with the right setup, but still not such a nice trace as with my TEK 2465B.
Things may probably change in the next coming years with affordable high definition scopes.

The first screenshot is from an NPN ZTX851, little transistor with big die. It behaves nicely at low Vce. I don't like the colour but can't change it.
The second one is the transconductance curve from an N chanel PF5102. It was first in the fridge, then on the setup and heated with an air gun. With persistence, one can see the sweet spot of it's zero tempco.

I also own a USB Locky_Z one. I got it many years ago at the first run for cheap. It's fully made of used parts and was first released for the chinese market. But it still works.

Francis

[Martin Hodge]

A Tek 575 connected to an Eico 667 tube tester through a custom curve tracer circuit.
Curves are from a 6AU6 pentode.

[graybeard]

A Tek 575 connected to an Eico 667 tube tester through a custom curve tracer circuit.
Curves are from a 6AU6 pentode.

I have been considering how to adapt tubes to my 575.  Thank you for this example!

[Jay_Diddy_B]

Hi group,

I have a few. I have a Huntron 2000 for troubleshooting.

Tektronix 576 for looking at transistors and diodes.

Tektronix 571

My best curve tracer is an HP 4155B Semiconductor Parameter Analyzer:




This picture is Id and GM versus Vgs for 2N7002 MOSFET.

The vertical scale (Id) is logarithmic and goes from 1fA (1E-15) to 100mA (1E-1) 14 decades 

Regards,
Jay_Diddy_B

[Electro Fan]

Hi group,

I have a few. I have a Huntron 2000 for troubleshooting.

Tektronix 576 for looking at transistors and diodes.

Tektronix 571

My best curve tracer is an HP 4155B Semiconductor Parameter Analyzer:

(Attachment Link)


This picture is Id and GM versus Vgs for 2N7002 MOSFET.

The vertical scale (Id) is logarithmic and goes from 1fA (1E-15) to 100mA (1E-1) 14 decades 

Regards,
Jay_Diddy_B

14 decades to a femtoamp?!  Very neat!

[jh15]

Where is pic?
I'll show you mine (Tek  575 with pussy on top enjoying the heat, , if you show yours. (Might just show 2 photos offset by eyelength for 3d.)

[sorenkir]

This one is quite an oscure model (Br 01 from Leybold-Heraeus, made in Germany):



Front panel is mislabeled : read Uc instead of Ub on the right!
I think I will have to do a lot of reverse engineering to get it back to work, as it died the other day...



Michel.

[Calambres]

I made one based upon the infamous "Thai Kit" (https://www.ebay.com/itm/141138017533).
Already talked about it some time ago in this very forum.



This kit is also heavily based upon an ELEKTOR magazine article (Dic. 1989). I made a small modification to the kit to let it switch between 8 and 4 curves and subsequently the total µA/mA. This is a photo of the guts while I was still prototyping it:




It needs a good ole CRO (preferred) with XY mode to show the curves.



The most interesting feature of my build is that it can compare (match) up to 6 transistors/FETs at the same time at the flip of a rotary switch. Here you can see it in action testing some transistors, first with four small transistors (2SC1815) and one power transistor:



The second is showing the details of four small transistor (2SC1815) curves:

[Ground_Loop]

This is my vintage Heathkit. It has served me well. The one thing I would change about it is the single ended sweep to bipolar. It does sweep positive and negative, but not continuously. You need change the control settings to sweep the opposite direction. I gave some thought to modifying it, but gave up after realizing I would need to hack on the enclosure to accomplish it.

[Electro Fan]

This is my vintage Heathkit. It has served me well. The one thing I would change about it is the single ended sweep to bipolar. It does sweep positive and negative, but not continuously. You need change the control settings to sweep the opposite direction. I gave some thought to modifying it, but gave up after realizing I would need to hack on the enclosure to accomplish it.

(Attachment Link)

(Attachment Link)

That's a nice combination of curve tracer and oscilloscope.  Definitely good idea to retain their vintage dignity.   

[Electro Fan]

I made one based upon the infamous "Thai Kit" (https://www.ebay.com/itm/141138017533).
Already talked about it some time ago in this very forum.



This kit is also heavily based upon an ELEKTOR magazine article (Dic. 1989). I made a small modification to the kit to let it switch between 8 and 4 curves and subsequently the total µA/mA. This is a photo of the guts while I was still prototyping it:




It needs a good ole CRO (preferred) with XY mode to show the curves.



The most interesting feature of my build is that it can compare (match) up to 6 transistors/FETs at the same time at the flip of a rotary switch. Here you can see it in action testing some transistors, first with four small transistors (2SC1815) and one power transistor:



The second is showing the details of four small transistor (2SC1815) curves:

Really nice post and congrats on your curve tracer.  I was going to ask how you did this:
"The most interesting feature of my build is that it can compare (match) up to 6 transistors/FETs at the same time at the flip of a rotary switch" but then I saw your link which explains your approach as you steadily worked it all out.  Your posts in that the thread and the whole thread had a lot of good info so I edited one of the posts at the front of this thread to make it easy to find the thread.

[Calambres]

If someone is interested, I have a pdf of the original ELEKTOR article the Thai kit is based upon. Not that it is very diffiult to find but if someone wants it without much hassle, drop me a note.

[edavid]

This is my vintage Heathkit. It has served me well. The one thing I would change about it is the single ended sweep to bipolar. It does sweep positive and negative, but not continuously. You need change the control settings to sweep the opposite direction. I gave some thought to modifying it, but gave up after realizing I would need to hack on the enclosure to accomplish it.

(Attachment Link)

(Attachment Link)

That's a nice combination of curve tracer and oscilloscope.  Definitely good idea to retain their vintage dignity.   

I disagree - I would never connect a curve tracer to an MCP scope like the Tek 2467B 

[Electro Fan]

This is my vintage Heathkit. It has served me well. The one thing I would change about it is the single ended sweep to bipolar. It does sweep positive and negative, but not continuously. You need change the control settings to sweep the opposite direction. I gave some thought to modifying it, but gave up after realizing I would need to hack on the enclosure to accomplish it.

(Attachment Link)

(Attachment Link)

That's a nice combination of curve tracer and oscilloscope.  Definitely good idea to retain their vintage dignity.   

I disagree - I would never connect a curve tracer to an MCP scope like the Tek 2467B 

Your concern is using up the useful life on the MCP or something else?  (I'm guessing Ground_Loop doesn't trace curves all day every day, and his MCP likely has it's timeout feature operating.)

[Ground_Loop]

I also have 7 scopes on my bench and a 555 in the corner.   On the rare occasion that I use the curve tracer I usually go to the 67 because i have a preset for the curve tracer.  And the timeout works just fine.

[edavid]

I disagree - I would never connect a curve tracer to an MCP scope like the Tek 2467B 

Your concern is using up the useful life on the MCP or something else?  (I'm guessing Ground_Loop doesn't trace curves all day every day, and his MCP likely has it's timeout feature operating.)

The timeout is a convenience, but it won't protect the CRT from burns if you make a determined effort.

(MCP = microchannel plate image intensifier)

[Martin Hodge]

A Tek 575 connected to an Eico 667 tube tester through a custom curve tracer circuit.
Curves are from a 6AU6 pentode.

I have been considering how to adapt tubes to my 575.  Thank you for this example!

The circuit is designed by Dennis Tillman. Attempting to attach PDF... nope, too big.
Instead search for "An Inexpensive Vacuum Tube Curve Tracer Adapter for All Tektronix Semiconductor Curve Tracers"

[Martin Hodge]

Here's the 575 testing the tunnel diode in the trigger of the 'b' timebase of a Tek 535A.

Vertical: 0.5 mA/div
Horiz: 50 mV/div

[Electro Fan]

Here's the 575 testing the tunnel diode in the trigger of the 'b' timebase of a Tek 535A.

Vertical: 0.5 mA/div
Horiz: 50 mV/div

Vintage Tektronix, tunnel diode, beautiful photography... doesn’t get much better.

Super Cool! 

[TERRA Operative]

I built one of the Thai Kits tracers, it works well.

https://youtu.be/uU_KjH-jJnA

I also have a Tek 577-177 that I have to repair one day (blown tants etc) and a 4145A that I have to track down a bunch of triax cables to connect it to the test fixture (and do the SD card floppy drive swap and maybe a colour LCD swap too if I feel like spending money).