Re: Curve Tracers

On Wed, 20 Nov 2024 07:40:08 -0800, john larkin <JL@gct.com> wrote:

On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
>

Gentlemen,
>
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But they're
typically rare beasts and expensive to come by and boat anchor varieties
are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project,
using the X&Y inputs of a scope as the display. Has anyone here attempted
this? I'd be interested to know what the main challenges are likely to be.
>
-CD

>
I've considered it. It would be much more valuable if it traced
capacitances too.
>
The display should be on a computer and the data archived.
>
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
>
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that.  A good curve tracer
should measure that too.
>
Currents should go down to picoamps.
>
The fact that there aren't many curve tracers for sale suggests a
small market.

I think that the function is now done by a Fluke Data Bucket (or
equivalent) in an ATE (Automatic Test Equipment) that controls
collection of data, which is later plotted in a computer.

Joe Gwinn