Transistor curve tracer recommendations?

[Alex_Baker]

Hi folks!

Not too much of a newbie, but I didn't know where this would fit. I am looking for a transistor curve tracer to add to my arsenal, but while looking I found that most of the real ones are way out of my price range, old and new.

So to all of the experienced people here, what are your recommendations? Are the $40 ebay kits any good?, should I try to find a vintage one? I am not opposed to building my own curve tracer either, if there are any decent schematics out there.

[watchmaker]

you can read this thread I started:  https://www.eevblog.com/forum/beginners/my-take-on-curve-tracers-for-beginners/msg5421713/#msg5421713

There were some good posts.  I built the Thai Kit and made several revisions.  When all is said and done, it is bench toy.  It does have some utility, but it is very limited and has no protection against overloading the power transistors or the DUT.  You also need to play with ferrite beads.

The Heathkit, BK and Leader units have various tradeoffs which are discussed.  I have settled on the HK because it provides the most control of the test parameters. But it can be hard to find in good condition at a reasonable price.  But at least complete documentation is on the internet.

[Laval]

May I ask what your use case is ?

If you want to pair power transistors, then you need one that can handle a reasonable amount of current and voltage. Today, characterization of semiconductors is mostly done using a pair of SMUs (a a dual channel SMU) with software and they are very expensive. In such a case, I'm afraid the alternatives are either an oldie (which is going to be expensive too and probably require some repairs) or roll your own. There is also an "open source" DIY SMU project which might be of interest.

There is a few affordable ones, like the Peak Atlas DCA75 or some Chinese knock off but they are battery powered and can hardly source any current and have very limited voltage so they are not suited for power transistor pairing.

[mawyatt]

If your budget permits look for an old Tektronix 576 or 577. Often these aren't in working condition and one can acquire such at a reasonable price, then attempt a repair. Being the old Tek equipment, these will usually hold value, especially if you are able to get it working properly. The test/repair manuals are available and quite a few folks have these and are willing to assist in repair advice/instruction, ourselves included.

This is how we acquired an old Tek 577 that required some work to get functional.

Best

[JohanH]

There is this project, but it seems quite advanced:

https://www.eevblog.com/forum/projects/building-a-diy-curve-tracer/

[Alex_Baker]

May I ask what your use case is ?

Honestly my use case is not much more than a "bench toy" as somebody said in another thread, but I would like a device that is somewhat useful and capable. I have ways to make pretty curves if I really wanted to. A device that cannot handle power transistors is probably fine though.

There is this project, but it seems quite advanced:

https://www.eevblog.com/forum/projects/building-a-diy-curve-tracer/

I did see that project in my research, looks very nice and masterfully designed, but definitely over my head, perhaps someday.

I am thinking about copying the heath kit IT-1121, it looks like it has a decent amount of configurability, and it's old enough that it's hopefully not too complicated.

[rhb]

A Peak Atlas DCA75 will curve trace on a PC.  Slow, but much cheaper. My Tek 577 died within 5 seconds of power on because of a shorted cap. Still need to fix it.

It blew a small bridge rectifier.

Have Fun!
Reg