FREE PDF FILE AVAILABLE FOR DOWNLOAD! Link at the bottom of this text!. I know the curve is the wrong way around but simply invert your X channel to fix that.
This is a very simple Curve Tracer circuit. It's simple enough to put it up on a bread-board. It can do all sorts of semi-conductors like Transistors (Si or Ge), Diodes and you'll even get traces from a PNP transistor. It measures the Collector current as a function of the Collector/Emitter Voltage at different Base currents. You can determine the number of traces on screen by changing the ratio between C4 and C5 (change value of C4). If you make a print for this and build it onto a case you could use a multi-step switch with different capacitors so you can dial in the number of traces on screen. If you invert channel one (X) then the traces will point to the right, like you normally see with curve tracers.
The Germanium transistor I demonstrated in this video was actually a PNP transistor, that's why it gave the weird curve but I didn't know that at the time :) (I'm no expert ^__^).
On my website I've written an article about this curve tracer with some test pictures and the best scope settings for viewing traces. You can read that here:
www.eddybergman.com/2017/06/si...
You can find the original article in English here:
archive.org/details/ElektorMa...
I've made a PDF file of the original article which is written in Dutch but anyway, you'll have the schematics and the PCB layout.
Here's the download link:
www.mediafire.com/file/ywoapb4...
(Should you have trouble downloading this document then write a comment below and I'll contact you and send it via email.)