Curve Tracer with Raspberry Pico RP2040 / RP2350

Built a compact curve tracer with the Raspberry Pi Pico, ILI9341 touchscreen, and a custom power board — supports bipolar transistors (npn/pnp), diodes, JFETs, and MOSFETs.
Here’s a preview of the curve tracer based on the RP2040. It works with an ILI9341 TFT SPI display, including touch support.
Alongside the Rapid_Development board for the Pico, it uses a constant current source built with the HC595, and a new Power Board for driving UCE.
The system runs on 12V, powered by a single 18650 Li-ion cell. The Power Board features a 12-bit ADC (MCP3204), a dual-channel DAC (MCP4822), and a power amplifier (TCA0372).
It supports measurements of standard bipolar transistors (NPN/PNP), diodes (including Zeners < 12V), JFETs, and MOSFETs.
The hardware is nearly complete — next steps are testing the software and the touchscreen interface.
The Schematic Diagram of the UCE-board:
The Schematic Diagram of the UCE-board:

A lot of positions in the menu are also changeable with 2 rotary encoders.
In the next days I will present the new Power-Board for changing Uce with Dual-Dac.
Now I have changed the current-source to 4 bit.
You can change now the base-current from 0 to 150 µA with stepwide 10 µA,
from 0 to 300 µA with stepwide 20µA
and from 0 to 750 µA with stepwide 50 µA.
Update from 29.07.2025 :
I have changed the currentsource with HC595 to a precision current-source with DAC MCP4725.
The hardware is more complex and a little bit more expensiv (I2C isolator ADUM 5201 , MCP4725) but you have more possibilities:
- precise constant-current-source from 1 µA to about 1.5 mA (4mA?) with minmal stepwide from 1 µA,
- usable as isolated constantcurrent-source with this range 5 ,
- usable as isolated constantvoltage-source from 10 mV to about 16V (R=10k)
- staircase generator for slow frequecies
- ...
Discussion (2 comments)
mausi_mick 1 week ago
Now I'll change the constant-currents-source realized with HC595 to the more flexible current-source with DAC MCP4725 because it's a lot of work to change the yet realized source code (special menu part) and the DAC-version with MSP4725 has more features.
S.I ,Elektor 1 week ago
Interesting project. Can you kindly also share the Python script for the Pico? Moreover, please share the snaps of this in action; it feels like many people will be interested in taking a look at it.
All best,
S.I
jarede2000 1 week ago