I borrowed this general curve tracing circuit from
stoneslice’s prototype and video.
Rather than rely on an AC power supply, this uses a simple DC-powered oscillator to drive a test signal across the device under test.
It features a DPDT switch to toggle and compare two devices under test.
Although uncalibrated so not particularly good for accurate measurements, it generates nice plots
for resistors, capacitors, and diodes.
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
