TIP120 Power Darlington Transistors

The TIP120 is an NPN Darlington power transistor designed for applications requiring high current gain and power switching capability. Its Darlington configuration provides significantly higher current gain than a conventional single transistor, allowing a relatively small base current to control a larger collector current.

The transistor is commonly used as a switching device in circuits controlled by Arduino boards, microcontrollers, sensors, and other low-power electronic systems.

Features

• NPN Darlington power transistor
• High current-gain configuration
• TO-220 package
• Three terminals: Base, Collector and Emitter
• Suitable for power switching applications
• Useful for driving suitable DC motors
• Suitable for relay and solenoid control
• Useful in Arduino and microcontroller projects
• Suitable for robotics and automation circuits
• Can be used for general-purpose transistor switching

Applications

The TIP120 can be used for:

• DC motor switching
• Relay driver circuits
• Solenoid control
• Arduino projects
• Microcontroller-controlled loads
• Robotics projects
• Automation systems
• LED and lamp switching
• Power switching circuits
• Electronic control systems
• DIY electronics and prototyping

How to Use

1. Identify the Base, Collector, and Emitter terminals from the transistor datasheet or package documentation.
2. Connect the load in the appropriate collector/emitter switching configuration.
3. Connect the base to the control circuit through a suitable resistor.
4. Connect the emitter according to the intended circuit configuration, commonly to the circuit ground for low-side switching.
5. Apply the appropriate control signal to the base.
6. Verify that the load current and transistor power dissipation remain within the device's limits.
7. Use appropriate protection components, such as a flyback diode, when switching inductive loads such as motors, relays, or solenoids.

Important Notes

• Always verify the pinout before connecting the transistor.
• A suitable base resistor should be used to limit base current when driven from a microcontroller or logic output.
• TIP120 has a relatively high voltage drop when used as a saturated switch compared with many modern MOSFETs, so heat dissipation should be considered.
• Use a suitable heatsink when the transistor dissipates significant power.
• When controlling inductive loads, use appropriate flyback protection.
• Do not exceed the transistor's maximum voltage, current, or power-dissipation ratings.
• The actual safe operating limits depend on temperature, heatsinking, circuit design, and operating conditions.

Package Includes

• 1 × TIP120 Power Darlington Transistor