2N7002 by Vishay Intertechnology is a N-CHANNEL FET with 60V DS Breakdown Voltage, 0.115A Drain Current, and 7.5 ohm On Resistance. Ideal for SWITCHING applications due to its SINGLE configuration with BUILT-IN DIODE. Operates in ENHANCEMENT MODE, suitable for surface mount with GULL WING terminals.
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.
ULN2803A by Texas Instruments is a peripheral driver with 8 functions. It has a max supply voltage of 3V and can operate in temperatures ranging from -40 to 85°C. This IC is commonly used as a buffer or inverter based peripheral driver for various applications.