The TIP120 is a Darlington transistor. Essentially, it is just two bipolar junction transistors (like the PN2222 above) connected together in one package.

Just be careful to take note of the pin order.

  • Max Voltage: 60V
  • Max Current (peak): 8A
  • Max Current (constant): 6A
  • Please note that these can get really hot if you are trying to switch a lot of current. You might need a heat sink.
  • Look into MOSFET transistors if you need to drive lots of current, they are more efficient and don’t heat up so much.

Control Motor Speed With Arduino and Transistor

For a small motor you could use either of the transistors (PN2222 or TIP120). The TIP120 is just going to be able to handle more current.