Tip 120 as power transistor

A transistor is a semiconductor which is a fundamental component in almost all electronic devices. Transistors have many uses including switching, voltage or current regulation and amplification. Transistor controls a large electric output signal with changes to a small input signal. Since a large amount of current can be controlled by a small amount of current, a transistor acts as an amplifier. Transistor also acts as switch which can open and close many times per second.

The TIP120 also known as Darlington transistor. It was designed as a medium power switching transistor and can be used to switch a motor on and off. This type of transistor can use a small current to switch and amplify a much larger current to the motor or other load such as buzzer. The controlling pin on the transistor or base is sensitive to too much current, so the circuit required a 1k Ω or 2.2kΩ resistor coming from the output pin into TIP120. This transistor coupled with a motor power supply and will allow the circuit to run a DC motor and empower the circuit to activate many other devices. Therefore, for this project i used a TIP120 because it can pass more current especially if i add a heat sink on the transistor and handle larger load.