The 2N3904 is basically an NPN transistor made up of silicon material. It is used for a general-purpose switch and amplifier. It supports the current up to 100mA when acts as a switch and It supports the frequency up to 100MHz while acting as an amplifier. 2N2222A is also an NPN transistor and is quite similar to 2N3904.

2N3904 is NPN Bipolar Junction Transistor designed for switching purposes at 100mA and as an amplifier at 100MHz frequency. It comes in the TO-92 package and used in a wide range of applications. It can be used in televisions, we can use it in home appliances, can be used as a small load switch, it can also be used as an amplifier.

2N3904 Transistor Pin Configuration:

Detail Pins configuration of this transistor is given below

    • An emitter is usually denoted by E
    • The base is denoted by B.
    • The collector is denoted by C.

2N3904 Transistor pinout

Features of 2N3904

  • Bi-Polar NPN Transistor: Type
  • Available Package: To-92
  • Collector-Emitter Voltage: 40v
  • Continuous Collector current (IC): 200mA
  • Base- Emitter Voltage (VBEO): 6V
  • Collector-Base Voltage (VCBO): 60V
  • Power Dissipation: 625mW
  • Operating Temperature(To): -55-155C

2N3904 Equivalent NPN Transistors:

BC548BC547 BC636, BC639, 2N2222A, 2N2222, 2N2369, 2N3055, 2n3906, 2SC5200 are equivalent of this transistor.

Compliment of 2n3904 Transistors:

BC557,BC556,A1015 are the best (PNP) compliment

SMD of 2N3904 Transistor

Pin descriptions of SMD are given below

2N3904-Transistor-SMS alternate

2N3904 as a switch:

When it is used as a switch it is operated in the Saturation and Cut-Off Region. 2N3904 transistor acts as an Open Switch during forwarding Bias and acts as a closed switch during Reverse Bias. Biasing current should maximum of 5mA more than 5mA will damage the Transistor so a resistor is always added in series with the base pin of the transistor. Resistor value can be calculated using the below formulae.

RB  = VBE / IB

The value of VBE should be 5V and the Base current (IB depends on the Collector current. The value of IB should not more than mA.

2N3904 Transistor as Amplifier:

The transistor acts as an Amplifier when operating in Active Region. 2n3904 transistor can amplify power, voltage, and current at different configurations given below.

2N3904 transistor as amplifier

The Common emitter type is the popular configuration while using an amplifier the formula of using is given below.

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

Applications of 2N3904:

  • It is used in small load switch having low saturation voltage and high gain.
  • It can also be used on television.
  • We can also use it in home appliances circuits.
  • It is also used in amplifier up to the frequency of 100MHz.

2N3904 vs 2N3906:

The basic difference between 2N3904 and 2N3906 is the only type of transistor. Transistor 3904 is an NPN transistor while 3906 is a PNP transistor as shown below in the figure.

2N3904 VS 2N3906

3904 NPN Transistor

3906 PNP Transistor

  • Type: Bi-Polar NPN Transistor
  • Collector Base Voltage (VCB) is 40V
  • Type: Bi-Polar NPN Transistor
  • Collector-Base Voltage (VCB) is 60V

2N3904 Transistor Datasheet

The datasheet of the 2N3904 Transistor is given in detail click

Related Posts