http://en.wikipedia.org/wiki/Curve_tracer
http://en.wikipedia.org/wiki/Current%E2%80%93voltage_characteristic
Schematic:
.-----------------------------------------------------------------.
| Arduino |
| pin_x_in=A2 |
| |
| pin_amp_out=A1 | |
| pin_pwm=D9 | pin_x_out=A3 |
| | | |pin_rail=D10|
'-----------------------------------------------------------------'
| 100k MC33201 | Vin| Vout| |
| ___ |\ | | | |
'-|___|--o--------|+\ | ___ | .---. | |
| | >--o----|___|--o--| X |--o-----'
--- -|-/ | | '---' |
100n --- | |/ | R=120 --- ---
| | | --- 100n --- 100n
| | | |
GND '-------' GND GND
Vamp