2n3055 transistor

The 2n3055 is an NPN BJT transistor used for general purpose and high power transistor, the main specialty of this particular transistor is that it had applications at on-board circuits.

The 2n3055 transistor limited circuit applications are because of the physical and technical features shown by 2n3055, in this article we explain detailed pieces of information of the 2n3055 transistor.

We include 3055 transistor datasheet, 2n3055 transistor circuits, 2n3055 equivalent circuits, and a list of applications of 2n3055.

3055 Transistor Datasheet

3055 transistor pinout

Base (b) – Pin01

Emitter (e) – Pin02

Pin03 – Collector (TAB or Case)

The main specialty spotted at the 2n3055 transistor is that the Base (b) terminal is the first pin of the transistor and at 2n3055 we don’t have the Collector (c) terminal, but the Case or TAB is considered as the collector port.

3055 transistor pinout
3055 transistor pinout

How to connect pinout of 2n3055

2n3055 pin connection
2n3055 pin connection

The figure shows the basic connection details of the 2n3055 pinout, emitter (e) terminal will general connected to the negative supply.

The Base (b) terminal is connected across the input signal which the device needs to function as a switch.

And the body of 2n3055 is the collector (c) terminal at the circuit.

2n3055 TO3 Package

The TO3 packaging is the main specialty of the 2n3055 transistor, the outer covering of the transistor is using a metal Can, due to this transistor is capable of high power dissipation.

TO3 package is only used for power transistors, they had the advantage of high durability, and the metal can protect the device from the environment.

But the TO3 is expensive and larger sizes don’t fit at tiny circuits.

3055 Maximum voltages

  • Collector – emitter voltage = 60v DC
  • Base – emitter voltage = 7v DC
  • Collector – base voltage = 100v DC

The collector-to-emitter voltage for a transistor depends on the resistance path the external circuit provided between the base and emitter of the transistor.

The base-emitter voltage is the biasing voltage needed to connect for the 2n3055 transistor device.

And the collector to the base is 100v dc, it is the maximum voltage taken the output from the transistor 2n3055.

3055 maximum current

  • Maximum collector current = 15A
  • Maximum base current = 7A
  • Minimum to Maximum DC gain = 20 to 70 hfe

The maximum collector current is the maximum current rating of the 2n3055 transistor, and the base current here is the 7A, this will be termed as the maximum current we need to connect to the base of the 2n3055.

The DC gain of the transistor is the ratio between output and input current rating, these values must be useful at amplifier circuits.

3055 power characteristics

  • Total power dissipation = 115 w
  • Operation temperature range = -65˚C to +200˚C
  • Thermal resistance junction to case = 1.52˚C/w

The total power dissipation depends on the heatsink to which the transistor is connected and the device is designed to operate an efficient heatsink.

  • what is the ideal diode equivalent circuit

Transition frequency of 3055

The transition frequency of the 2n3055 transistor is 2.5MHz.


2n3055 transistor equivalent

The 2n3055 had many equivalent transistors such as 2n6673 and 2n6675.


2n3055 transistor working

The 2n3055 is an NPN transistor, the 2n3055 had the common working operation as like BJT transistor when a base signal of proper rating reaches the device they start working.

The only difference the device had is the covering of TAB of the transistor is acts as a collector of the transistor, but the process behind the collector working is the same as the general transistor.

The 2n3055 transistor is a power transistor, the power capacity of this transistor than other types, the reason behind the higher power specifications is the metal package of the transistor.

2n3055 transistor power supply

A concern developed to build a power supply for the transistors is main happened at amplifier circuit applications, but the power supply selected for the power transistor like 2n3055 is based on the wattage output of the amplifier circuit.

The collector-to-emitter voltage is the maximum amount of voltage capacity of the 2n3055, 1 – 60 v is the range of voltage, and 7-ampere base current.

2n3055 transistor circuits

  1. High gain transistor circuit

2n3055 High gain transistor circuit
2n3055 High gain transistor circuit

In some circuit applications, we used higher characteristics such as maximum voltage, maximum current, and maximum amplification factor, this can be done with a combination of the complementary transistor.

In this circuit a combination of NPN, high gain transistors with R1, R3, and R4 for total current amplification process.


  1. Simple voltage regulator using 3055

Simple voltage regulator using 3055
Simple voltage regulator using 3055


The circuit shows the simple voltage regulator circuit using 2n3055, the 2n3055 transistor acts as regulating component in this circuit.

The DC pulse that comes from the rectifier circuit will be initially fixed with a 12v Zener diode and pass towards the base of the 2n3055 transistor, then the 2n3055 operate to regulate the voltage at a constant level.

Advantage of 2n3055

  • It is a medium power transistor
  • It had a safe operating area
  • The 2n3055 is PB free package
  • The DC gain of this device is improved linearity
  • They had a good amplifier factor and gain factor
  • It is very easy to turn ON and turn OFF the device

Disadvantage of 2n3055

  • Expensive due to metal package
  • Larger size
  • Reverse blocking capacity is low

2n3055 applications

  • Power switching circuits
  • Amplifier circuits
  • PWM
  • Regulator circuits
  • SMPS
  • Signal amplifier
  • Power amplifier
  • UPS circuits
  • Inverter circuit


3055 transistor price

The price for the 3055 transistors per piece is around 1 to 2 dollars on the global market.

Similar Posts

One Comment

Leave a Reply

Your email address will not be published.