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TIP120 Transistor Introduction

The electronics industry is already full of equipment and components that help ease the lives of ordinary people. However, the electronics industry always has a lot of room for innovation in terms of promoting customers. When switching and amplification are needed, transistors are needed. The TIP120 is an NPN Darlington power transistor. It can switch loads up to 60V with a peak current of 8A and a continuous current of 5A. This makes it suitable for medium and high power electronics, such as controlling motors, solenoids or high power LEDs.

What is tip120 transistor

TIP120 is an NPN Darlington transistor, which is mainly used in general-purpose amplification and medium power switching applications. It consists mainly of an emitter, a base, and a collector, which are an essential part of any transistor. This is a bipolar power transistor in which both charge carriers (ie, electrons and holes) conduct, but as the NPN transistor, the main charge carriers are electrons.

The TIP120 has a Darlington pair in which two transistors are connected in this way, and the current amplified by one transistor is amplified by the other transistor. This configuration has a higher current gain than using each transistor individually. In this NPN Darlington configuration, the emitter of the first transistor is connected to the base of the second transistor so that the current can be amplified.

Transistors are electronic switches that meet the project’s power requirements. When ordinary transistors are not enough to meet the power requirements of the project, we replace them with Darlington transistors, which are the same as conventional transistors, with some exceptions, that is, they can drive larger loads. When a voltage is applied on the base side, it biases and sinks small currents, which are used to control large currents on the collector and emitter sides.

The transistor has a DC current gain of 1000 and can switch to 60V when the peak current is 8A. The device was developed using planar technology and integrated into a single-chip Darlington configuration. It has excellent high gain performance and low saturation voltage. It has a higher current gain, which means that a small amount of current from a microcontroller or sensor can be used to drive a large load. This is an NPN transistor, which carries electrons as the main carriers. Although PNP transistors have holes as the main charge carrier.

TIP120 datasheet

TIP120 Pinout &Configuration

The transistor has three terminals, as shown in the table.

Pin NumberPin NameDescription
1BaseControls the biasing of transistor, Used to turn ON or OFF the transistor
2CollectorCurrent flows in through collector, normally connected to load
3EmitterCurrent Drains out through emitter, normally connected to ground

TIP120 Features

  1. NPN Mid-Power Darlington Transistor
  2. High DC current gain (hFE), typically 1000
  3. Collector continuous current (IC) is 5A
  4. Collector-emitter voltage (VCE) is 60V
  5. Collector-base voltage (VCB) is 60V
  6. Emitter base voltage (VBE) is 5V
  7. Basic current (IB) is 120mA
  8. Peak load current is 8A
  9. Available in To-220 package

TIP120 equivalent transistor

  • The TIP120 equivalent transistors are: TIP127(PNP),2N5306、2N6532、2SD1415、2SD2495,BDT63,BDW2,KSB601,KSD560,MJF6388
  • Its Complementary PNP transistors are : TIP125,TIP126,TIP127(PNP)
  • Its family transistors are: TIP121,TIP122(NPN)
  • Its Spare NPN transistors are: BC549,BC636,2N2222ABC547,2N2219,2N44012N3904,BD139

How does a tip120 transistor work?

The TIP122 is a Darlington pair NPN transistor. It functions like a normal NPN transistor, but since it has a Darlington pair inside it has good collector current rating of about 5A and a gain of about 1000. It can also withstand about 60V across its collector- Emitter hence can be used to drive heavy loads.

TIP120 Applications

  • Can be used to switch high current (up to 5A) loads
  • Can be used as a medium power switch
  • For applications requiring high magnification
  • Motor speed control
  • Inverter and other rectifier circuits

Where to use TIP120 transistors

TIP120 transistors are known for their high current gain (hfe = 1000) and high collector current (IC = 5A), so they are often used to control high current loads or applications that require high magnification. The base-emitter low voltage of this transistor is only 5V, so it can be easily controlled by logic devices such as microcontrollers. Although care must be taken to check whether the logic device can provide up to 120mA.

So if you are looking for a transistor that can be easily controlled by a logic device to switch high power loads or amplify large currents, this transistor may be the ideal choice for your application.

TIP120 Circuit

tip120 circuit
tip120 circuit

This is the circuit that controls a 5 V motor and it draws 1 A. The TIP120 does not seem to be very efficient when controlling a 5 V motor, as it is not a conventional transistor, but a pair of transistors connected together to form a single product, which can drive a larger load.

However, obtaining high gains brings some disadvantages and limitations, which leads to higher voltage drops. Higher current designs generate more heat, which can melt the components involved in the project. For safety, you can add a heat sink to help dissipate heat and prevent the circuit from catching fire.

This transistor is a current control device, which is different from a MOSFET as a voltage control device.

That’s all for today. Hope you enjoyed this article. However, if you have doubts or have any questions about this, you can contact me in the comments section below. I’ll be happy to help you as best I can. Let us know your feedback and suggestions at any time, they allow us to provide you with high-quality work that responds to your needs and expectations, and helps you continue to give back to our products. Thank you for reading this article.


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