2N3055 Transistor Pinout, Equivalent & Specs in Detail

Last updated on March 21st, 2024 at 11:02 am

First introduced in 1960 by the RCA Corporation, the 2N3055 NPN Transistor is one of the oldest transistors that is still used in many projects. 2N3055 transistor comes in TO-3 case and has maximum absolute Collector Current(continuous), Collector to Base voltage, and Power dissipation rating of 15 A, 100 V, and 115 W respectively. The maximum current gain is 120.

Note: The first 2N3055 transistor was made using the homotaxial power transistor method. In 1970, its Epitaxial base version was introduced and had better frequency properties than the former one.

What is a 2N3055 Transistor?

2N3055 is an NPN transistor commonly used in general applications like audio power amplifiers and as a series pass transistor in linear power supplies. It is one of the first multi-amp silicon power transistors designed by Herb Meisel’s engineering group in collab with RCA. MJ2955 is its complementary PNP pair with the same ratings and characteristics.

2N3055 Transistor Pinout

The pinout diagram of 2N3055 is difficult to understand as there is no visible distinction or alignment between the terminals. But you can easily identify the base terminal by looking at the distance between the terminal and the mounting hole.

To identify the pinout of the 2N3055 transistor, place it in an inverted position(leads pointing outward). Then rotate it to one of the positions shown below:

2N3055 Transistor Pinout
2N3055 Transistor Pinout(lower section is short)

a) The distance of the lower section is less than the upper one- The terminal on the right is the Base.

2N3055 Transistor Pin Diagram
2N3055 Transistor Pinout(upper section is short)

b) The distance of the upper section is less than the lower one- The terminal on the left is the Base.

The body of the transistor acts as the collector terminal.

2N3055 Specifications Table

Given below is the specifications table of the 2N3055 Transistor that lists its features.

Collector-Base Voltage(VCBO) 100 V
Collector-Emitter Voltage(VCEO)60 V
Emitter-Base Voltage(VEBO)7 V
Continuous Collector Current(IC)15 A
Continuous Base Current(IB)7 A
DC Current Gain(hFE)120(Max)
Collector Power Dissipation(PC)115 W
Storage Temperature(TSTG)-65 °C ~ 200 °C
Specifications of 2N3055 Transistor

2N3055 Epitaxial Base Version VS Homotaxial version

To begin with, the transition frequency fT of the original 2N3055 transistor is low(). The Epitaxial version has a transition frequency of 2.5 MHz.

Note: fT or Transition frequency is a measure of the input frequency stability of the transistor. Transistors can be used as amplifiers and oscillators only if applied at frequencies well below Transition frequency.

The epitaxial version has a higher cut-off frequency as well. The other ratings like max current and voltage are the same. The manufacturing cost is quite low for the TO-3 case.

2N3055 Equivalent Transistors

Transistors that are equivalent to 2N3055 are 2N6673, 2N6675, 2N5039, 2N5671, 2N5881, 2N3055A, 2N3055G, 2N3055HV, and 2N3055AG.

The last 4 transistors are different versions of 2N3055. 2N3055G is the lead-free version and 2N3055HV has higher voltage ratings.

2N3055 Complementary Transistor.

The complementary transistor of 2N3055 is the MJ2955 PNP transistor.

Where to use the 2N3055 Transistor?

This transistor is ideal for medium current and high power circuit applications. 2N3055 is used in linear power supplies as a series pass transistor. Due to its low transition frequency, it’s not practical to use it in switch mode applications. So use it only in low-frequency operations.


  • As a switching transistor in medium power applications.
  • Used in some old television models.
  • Audio power amplifiers. Typically configured in a push-pull configuration delivering up to 40 Watts into an 8 a speaker(load).
  • Sometimes used in regulator circuits
  • Series pass transistor in linear power supplies.
  • Signal Amplifiers

Datasheet of 2N3055

The 2N3055 transistor comes in TO-3 metal case packaging with two holes. These holes make it easy to attach the transistor to a heatsink. The TO-3 case is made of the metal itself and thus helps in reducing the heat.

To download the datasheet of 2N2055, click here.

Packaging of 2N3055

1. Standard TO-3 Package

2. The TIP3055 and TIP2955 are available as TO-3 P (plastic case) versions of the 2N3055 transistor. Due to the plastic casing, they have low power dissipation ratings.

3. The TIP33 plastic case.

2D Model/Dimensions of 2N3055

2N3055 Transistor Dimensions
2N3055 Transistor Dimensions
Photo of author

Ankit Negi

I am an electrical engineer by profession who loves to tinker with electronic devices and gadgets and have been doing so for over six years now. During this period, I have made many projects and helped thousands of students through my blog and YouTube videos. I am active on Linkedin.

Leave a Comment