BSS138LT3G by Onsemi is a N-CHANNEL FET with a min DS breakdown voltage of 50V. It is used for switching applications and has a max drain current of 0.2A and max drain-source on resistance of 3.5 ohm.
ULN2803ADW by Texas Instruments is a peripheral driver with 8 functions, open-collector output characteristics, and built-in transient protections. It operates b/w -40 to 85 °C and has a max supply voltage of 3 V. Ideal for applications requiring buffer or inverter-based peripheral drivers with sink current flow direction.
STM32H743IIT6 by STMicroelectronics is a 32-bit microcontroller with integrated cache and a max supply voltage of 3.6V. It is commonly used in industrial applications due to its wide temperature range (-40°C to 85°C) and various connectivity options (CAN, I2C, UART, USB).