Curve tracer/ component tester sugestion's

[large_ghostman]

Hi, in a couple of thread's over the last month or so, the subject of curve tracers and component testers, has come up.
A while back i did an octopus circuit, and it was ok, it work's fine (not used it much)but is pretty basic, since talking about these kinds of thing's I am now wanting to make a much much better one, mainly from salvaged junk.
So if you wouldn't mind, I would like some suggestions of what i can add to my "multi tester/curve tracer". I realize this is a long term project, I will do it in parts. I am in no rush, so this is planning stage, if it takes a year then fine, i wont be working on it full time.
If i tell you what i have and my idea's of what i can do with them, i would be grateful for suggestion's. Main purpose of project is to build something useful with salvaged stuff (i can buy odd little bits, but it's a junk bin project), and to learn.
I will also fully document it and post as i go, i will video this one as well, There are some techniques i would really like to try out, and this project would give me the chance.

So here goes

I have a old HP LA 16500 B, I am using most the boards in another (16500c). It has a touch screen and oscilloscope card in it. (the idea would be to pull bit's from some of this stuff, and put the bits in one or two cases, so it's like a single instrument)
NOT FINISHED WILL EDIT REST OF POST LATER

 

[4pyros]

I think I would go with a box to hook up to a scope, that way if your CRT display fails you can still use the curve tracer on another or any scope.

 

[cowboybob]

This is exactly what Billy Mayo needs.

If and when he ever figures out how to operate a scope...

 

[4pyros]

The 1st thing I would consider is a varible voltage curve tracer.

 

[4pyros]

This is exactly what Billy Mayo needs.

If and when he ever figures out how to operate a scope...

You keep him out of this thread!

 

[4pyros]

This is neat;

 

[cowboybob]

You keep him out of this thread!

Oops. My bad...

 

[MikeMl]

Here is my Poor Man's curve tracer. Useful for testing diodes, LEDs, transistor junctions.

**broken link removed**

Note, I updated this. The Variac is optional.

 

[dr pepper]

I have a commercial black box tracer made by hameg, the only thing it has that the above circuit doesnt is a power led.
The above circuit is all you need to repair stuff.
A mate of mine had a 5" crt telly modded as a curve tracer, thats going back 20 years.
You could build something to display transistor curves with a microcontroller if you really want.
Depends whether you want to repair stuff or do some fancy measurements.

 

[MikeMl]

.... It is more customary to look at I plotted along the vertical axis and V plotted along the horizontal axis when looking at the IV curve of say a diode...

We are more used to thinking about Current vs Voltage...

PS, I modified the schematic in the posting, above.

 

[Jaguarjoe]

My Dad and I made this PMCT about 55 years ago. Worked great with a 6.3V filament xfmr. Prolly still would work great if I could find it!

 

[ronsimpson]

I need more options.
R1=(switch + 100, 1k, 10k)
Transformer = 40V + 6.3V plus a high/low switch.
....A transformer with a center tap will give you two settings.

A $BIG$ curve tracer has many different current settings and voltage settings.

 

[large_ghostman]

Of course this is ME, so it will have to log data to matlab, that data will have to print out transistor datasheet type graphs. Its not really a curve tracer/components tester, Its a chance to be creative and learn alot in a way that gives maximum fun!
LG
Merry Christmas Everybody.

 

[4pyros]

Merry Christmas to you and our family.

 

[dr pepper]

I' think I've referenced this before, this guy has done what you say only with logic, there isnt a complete schematic but there is drawings of his current source and wave generator, usefull for your project.
The basic version also linked on that page is hwat we have been talking about.

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

Merry crimbo.
Bah humbug, I'm at work-again.

P.S. Did you get any great pressies LG, despite me being as enthusiastic in electronics as you my parents rarely bought be anything electronicy for crimbo.

 

[large_ghostman]

I mainly asked for electronics books, alot are out of print, I had 32 books in the end all electronics related.
I also got some money!
Why are you working!

 

[large_ghostman]

Yes you have given me that link before I am going to use alot of it in mine. there is a schematic
you can download it here
https://www.changpuak.ch/electronics/curve_tracer/CurveTracerV2_Schematics.pdf
It was one the links, that got me thinking about doing one

 

[4pyros]

Lots of reading, when I was your age My dad had me in a book of the month club with lots of electronics books. I so looked forward to the new book every month.

I am now trying to put new brake pads on my van in 20 degree cold.

Stay in and read, stay warm.

 

[dr pepper]

My parents didn't buy me many books or any electronic mags, consider yourself lucky.
I always seem to get the short straw when it comes to crimbo holiday working and end up doing it, that said I get extra readies and the time off next year when its warm.
4 pyro's today I crawled about under a pump station outside for nearly an hour, yes I know how you feel, cold, and the really annoying thing is the issue turned out to be a 'breaker inside the main building!
Very very quiet today, I rarely see absolutely no one about and nearly nothing running.

 

[large_ghostman]

Alot of what i want in the tester will be analogue. I will sit a scope on the top of the box,or to the side of the case depending! I have found the old psu, from a 16500c LA. It is very large and beefy, not sure of all the different power rails but there are alot, so it should do for all the power requirements. When i get a chance I will upload a pic of the beast, small problem it dosnt work tho. Not sure whats wrong, but i get a feeling it is something very simple, maybe the large power resistor. I will have a look tomorrow.
The one thing i do want is to be able to have my own text on the scope screen, tough one but should be doable, I also want a LED tester/pro-filer, so i can accurately work out fV etc.
Also have added a servo tester to my list, this will also be analogue, probably based around 555 or 556 timer. I have alot of servo's, small ones. These are mainly for my railway layout, i have around 70 more to fit (Chinese ones i got very cheap in bulk).
Going to go for a clear acrylic case (will make it on cnc mill). Full list of parts we can use later