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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: 


   
20250716120636_image.png

 
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
 - ...