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2N3904 Transistor: Datasheet, Equivalent, Pinout [Video]

Author: Iggy Date: 7 Apr 2021  942

2n3904 pinout

2N3904 is a Transistor. This blog covers 2N3904 Transistor pinout, datasheet, equivalent, circuit and other information on how to use and where to use this device.

Playing with Transistors: NPN 2N3904 Transistor Experiment


2N3904 CAD Model

2N3904 Pinout

2N3904 Circuit

2N3904 Applications

2N3904 Features

2N3904 Advantage

2N3904 Working

2N3904 Package

2N3904 Parameters

2N3904 Manufacturer

2N3904 Documents

2N3904 Environmental and Export Classifications

2N3904 Equivalents

2N3904 Product Compliance

2N3904 Popularity by Region

2N3904 as Amplifier

2N3904 as Switch

Where and How to use 2N3904

How to Safely Long Run 2N3904 in a Circuit

Component Datasheet


Ordering & Quantity

2N3904 CAD Model

2n3904 symbol

2N3904 Symbol

2n3904 footprint

2N3904 Footprint

2N3904 Pinout

2N3904 Genernal Purpose NPN Transistor Pinout

Pin Number

Pin Name




Current Drains out through emitter



Controls the biasing of transistor



Current flows in through collector

2N3904 Circuit

  • Delay and Rise Time Equivalent Test Circuit

2N3904 Circuit: Delay and Rise Time Equivalent Test Circuit

  • Storage and Fall Time Equivalent Test Circuit

2N3904 Circuit: Storage and Fall Time Equivalent Test Circuit

2N3904 Applications

  • Sensor Circuits
  • Audio Preamplifiers
  • Audio Amplifier Stages
  • Darlington Pairs

2N3904 Features

  • Bi-Polar NPN Transistor
  • DC Current Gain (hFE) is 300 maximum
  • Continuous Collector current (IC) is 200mA
  • Base- Emitter Voltage (VBE) is 6V
  • Collector-Emitter Voltage (VCE) is 40V
  • Collector-Base Voltage (VCB) is 60V
  • Available in To-92 Package

2N3904 Advantage

2N3904 Genernal Purpose NPN Transistor

2N3904 Transistor

2N3904 is a widely used general purpose transistor. It is mostly used by electronic students and hobbyists in their projects, but it is also used in commercial electronic products. It can be used in wide variety of electronic applications for switching and amplification purposes. The maximum collector current of the transistor is 200mA therefore user can drive loads under 200mA in their electronic applications, Moreover 2N3904 also work good as an amplifier, the total device dissipation is 625 milliwatt due to which it can also be used for audio and RF signal amplification purposes.

2N3904 Working

  • 2N3904 has 3 layers in it i.e. single P doped layer embedded between two N doped layers.
  • These 3 layers are different from each other in terms of size and concentration of doping.
  • The centred layer is very small in size and is low concentrated as compared to the other two N doped layers.
  • Collector layer is bigger in size than the other two layers and thus highly doped.
  • A small current on the P doped layer transforms into a higher current on other two terminals.

2N3904 Package


2N3904 Genernal Purpose NPN Transistor Package

  • 2N3904 Straight Lead

2N3904 Package Straight Lead

  • 2N3904 Bent Lead

2N3904 Package Bent Lead

2N3904 Parameters


Discrete Semiconductor Products Transistors - Bipolar (BJT) - Single


ON Semiconductor





Part Status


Transistor Type


Vce Saturation (Max) @ Ib, Ic

300mV @ 5mA, 50mA

Current - Collector Cutoff (Max)


DC Current Gain (hFE) (Min) @ Ic, Vce

100 @ 10mA, 1V

Frequency – Transition


Operating Temperature

-55°C ~ 150°C (TJ)

Mounting Type

Through Hole

Package / Case

TO-226-3, TO-92-3 (TO-226AA)

Current - Collector (Ic) (Max)


Voltage - Collector Emitter Breakdown (Max)


Power – Max



ON Semiconductor

Product Category

Bipolar Transistors – BJT

Mounting Style

Through Hole

Package / Case


Transistor Polarity




Collector- Emitter Voltage VCEO Max

40 V

Collector- Base Voltage VCBO

60 V

Emitter- Base Voltage VEBO

6 V

Collector-Emitter Saturation Voltage

0.3 V

Maximum DC Collector Current

0.2 A

Pd - Power Dissipation

625 Mw

Gain Bandwidth Product fT

270 MHz

Minimum Operating Temperature

- 65 C

Maximum Operating Temperature

+ 150 C


5.33 mm


5.2 mm




4.19 mm


ON Semiconductor

Continuous Collector Current

0.2 A

DC Collector/Base Gain hfe Min


Product Type

BJTs - Bipolar Transistors


TransistorsBJTs - Bipolar Transistors

2N3904 Manufacturer

ON Semiconductor (Nasdaq: ON) is driving energy efficient innovations, empowering customers to reduce global energy use. The company offers a comprehensive portfolio of energy efficient power and signal management, logic, discrete and custom solutions to help design engineers solve their unique design challenges in automotive, communications, computing, consumer, industrial, LED lighting, medical, military/aerospace and power supply applications. ON Semiconductor operates a responsive, reliable, world-class supply chain and quality program, and a network of manufacturing facilities, sales offices and design centers in key markets throughout North America, Europe, and the Asia Pacific regions.

2N3904 Documents

General Announcement - 2D Barcoding (PDF)

Process change notification (PDF)

Process change notification (PDF)

2N3904 Environmental and Export Classifications



RoHS Status

RoHS non-compliant

2N3904 Equivalents

2N2222, S8050, 2N4401, BC537, SS9013 (Pin configuration of some transistors may different from 2N3904 therefore check pin configuration before replacing in a circuit)

2N3904 Product Compliance











2N3904 Popularity by Region

2N3904 Popularity by Region

2N3904 as Amplifier

A Transistors acts as an Amplifier when operating in Active Region. It can amplify power, voltage and current at different configurations.

Some of the configurations used in amplifier circuits are

1. Common emitter amplifier

2. Common collector amplifier

3. Common base amplifier

Of the above types common emitter type is the popular and mostly used configuration. When uses as an Amplifier the DC current gain of the Transistor can be calculated by using the below formulae

DC Current Gain = Collector Current (IC) / Base Current (IB)

2N3904 as Switch

When a transistor is used as a switch it is operated in the Saturation and Cut-Off Region as explained above. As discussed a transistor will act as an Open switch during Forward Bias and as a closed switch during Reverse Bias, this biasing can be achieved by supplying the required amount of current to the base pin. As mentioned the biasing current should maximum of 5mA. Anything more than 5mA will kill the Transistor; hence a resistor is always added in series with base pin. The value of this resistor (RB) can be calculated using below formulae.


Where, the value of VBE should be 5V for 2N3904 and the Base current (IB depends on the Collector current (IC). The value of IB should not exceed mA.

Where and How to use 2N3904

2N3904 Genernal Purpose NPN Transistor

2N3904 Transistor

2N3904 can be used in any electronic applications which fall under its electrical characteristics, let suppose if you want to switch a load in an electronic application that requires current under 200mA then this transistor will work quite well and you can drive variety of loads with this transistor for example relays, high power transistors, LEDs, a portion of an electronic circuit etc. When using as an amplifier it can be used in audio amplification stages, as an amplifier to drive small speakers, as an audio preamplifier and it can also be used in amplification stages of RF applications.

How to Safely Long Run 2N3904 in a Circuit

To get good and long term performance from this transistor it is suggested to not drive loads more than 100mA, always use a suitable base resistor, do not provide collector-emitter voltage more than 40V and always operate or store in temperatures above -55 centigrade and below +150 centigrade.

Component Datasheet

2N3904 Datasheet


  • What is a 2N3904 Transistor?

The 2N3904 is a common NPN bipolar junction transistor used for general-purpose low-power amplifying or switching applications. It is designed for low current and power, medium voltage, and can operate at moderately high speeds.

  • How Does a 2N3904 Transistor Work?

2N3904 is a NPN transistor hence the collector and emitter will be left open (Reverse biased) when the base pin is held at ground and will be closed (Forward biased) when a signal is provided to base pin. 2N3904 has a gain value of 300; this value determines the amplification capacity of the transistor.

  • What is PNP NPN?

PNP sensors produce a positive output to your industrial controls input, while NPN sensors produce a negative signal during an “on” state. ... NPN, or “sinking” output sensors, work in the opposite way, sinking ground voltage to an input when it's on.

  • Whats is A Transistor?

A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit.

  • What is the Gain of a Transistor?

The current gain for the common-base configuration is defined as the change in collector current divided by the change in emitter current when the base-to-collector voltage is constant. Typical common-base current gain in a well-designed bipolar transistor is very close to unity.

Ordering & Quality

Photo Mfr. Part # Company Description Package PDF Qty Pricing
2N3904BU 2N3904BU Company:ON Semiconductor Remark:TRANS NPN 40V 0.2A TO-92 Package:TO-226-3, TO-92-3 (TO-226AA)
In Stock:75103
1+: $0.20000
10+: $0.16200
25+: $0.13600
100+: $0.06640
500+: $0.05542
1000+: $0.03851
2000+: $0.03579
4800+: $0.03095
9000+: $0.02567

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