2N3055 Transistor : Pin Configuration & Its Applications

The 2N3055 is an NPN power transistor, that is used in general-purpose applications. It was launched by an American electronics company named “RCA Corporation” at the beginning of 1960 by using the hometaxial power transistor method. In the mid of 1970, it was changed to an epitaxial base and the standard used for the numbering of this transistor follows the JEDEC standard.

So finally, the 2N3055 transistor is manufactured through the epitaxial base process and mounted within a metal case that is sealed hermetically. This article discusses an overview of the 2N3055 transistor and its working with applications.

What is a 2N3055 Transistor?

The 2n3055 is an NPN transistor functions like a normal transistor that includes three terminals such as emitter, base, and collector. It is a current-controlled device where a small amount of current at the base terminal is mainly used to control a huge current at the remaining two terminals like emitter & collector.

2N3055 Transistor
2N3055 Transistor

In this type of transistor, the conduction can be carried out through the movement of both the charge carriers’ like holes and electrons. This transistor is used mainly for amplification and switching purposes in different applications. The configuration of this transistor can be done through three different configurations like a CE, CB & CC.

When this transistor is connected in CE configuration, it is not used for amplification because it includes approximately 3 MHz of transition frequency, so it allows the gain drop of forward current to 1. The maximum VCE (collector to emitter voltage) depends highly on the strength of resistance in between two terminals like base & emitter, which is provided through the exterior circuit.

Pin Configuration

The symbol and pin configuration of the 2N3055 transistor is shown below. It includes three terminals like emitter, base & collector where each terminal with its functionality is discussed below.

2N3055 Transistor Pin Configuration
2N3055 Transistor Pin Configuration
  • Pin1 (Base): It is generally used as a trigger to activate the transistor
  • Pin 2 (Emitter): This terminal is generally connected to the GND terminal
  • Pin 3 (TAB or CASE): This is a collector terminal that is directly connected to the load.

Features & Specifications

The features and specifications of the 2N3055 transistor are discussed below.

  • It is a medium power transistor
  • Transistor polarity is NPN
  • Includes three layers and three terminals
  • Available in TO-3 metal case
  • Used advanced process technology
  • Less error voltage
  • Switching speed is fast
  • It has current handling and high power capacity
  • The total dissipation of power is 115W
  • It includes an outstanding secure operating region
  • Linearity is enhanced through hfe
  • The saturation voltage from collector to emitter is low
  • Gain of DC (hFE) is equal to 70
  • The available package is Pb free
  • Voltage across collector & emitter (Max) is 60V DC
  • Operating temperature ranges from -65ºC to +200ºC
  • The current allowed by the collector (Max) is 15A DC
  • Max voltage across base & collector is 100V DC
  • Highest voltage across B (base) & E (emitter) is 7V DC
  • The maximum flow of current allowed by the base is 7A DC

Equivalent 2N3055 transistors are 2N6675, 2N6673, complimentary pair of MJ2955 whereas similar 2N3055 transistors are BUX98, MJ10023 & BDW51.

How to use 2N3055 Transistor/Circuit Diagram?

The simple voltage regulator circuit using a 2N3055 transistor is shown below. This circuit can be built with different basic electronic components like 2N3055 transistor, variable resistor-5k, 3 – LED strips which contains 4 LEDs in each strip, and a 12V battery.

Voltage Regulator Circuit with 2N3055 Transistor
Voltage Regulator Circuit with 2N3055 Transistor

Generally, a transistor working is that a voltage or current is given to one pair of terminals in the transistor then it controls the flow of current throughout the remaining pair of terminals because the output is higher as compared to input power.


This circuit is very simple to build with the necessary components. A voltage regulator in this circuit is used to change the levels of voltage. Once a stable or reliable voltage is necessary then a voltage regulator is used to produce a fixed o/p voltage. So this voltage remains stable for any modifications within input voltage otherwise conditions of load.

It works as a buffer to protect the components from damage. So, voltage regulator plays e key role in almost all electronic applications. The design of the voltage regulator circuit is; a variable resistor, the alligator clip & three LED strips need to connect toward the transistor one by one. One end of the clip is connected through the transistor whereas another end is connected through LED Strips. Once the circuit connections are done, test the entire circuit with the help of the LED strips otherwise a multimeter.

This voltage regulator circuit is used in electronic devices to provide a precise amount of voltage & avoid damage. This can also be used with the alternator in an internal combustion engine to control the output of the alternator.

Where to use 2N3055 Transistor?

The 2N3055 transistor is used as a series pass transistor within linear power supplies and also used in high power and medium-current circuits like DC to AC inverters, low-frequency power converters, audio power amplifiers. Some of the applications of the 2N3055 transistor are shown below.

  • Used in different circuits like an amplifier, power switching,
  • Used in PWM based applications
  • Used in signal amplifiers
  • Regulator based circuits
  • SMPS or switch mode power supply
  • 2N3055 transistor is mainly preferred whenever a simple switching device is necessary for loads that operate with medium power
  • This is one of the essential transistors which is easily obtainable in the market with less cost and good features.
  • This transistor is used as a detector, amplifier, switch within high and medium power-based circuits.
  • It is used to repair and design TVs and also used in the parts of cars
  • It may be used in regulated, linear power supplies, low-frequency power converters & audio amplifiers.

Thus, this is all about an overview of a 2N3055 transistor datasheet like pin configuration, features, specifications, application circuit with applications. This transistor is composed of three terminals that are used to connect an external circuit for amplification, switching purposes. This kind of transistor is used in different applications due to its good amplifying factor, so this transistor is one of the finest solutions to use in power amplifiers. Here is a question for you, what is a power transistor?

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