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 100 mA when acting as a switch, and it supports the frequency up to 100 MHz while acting as an amplifier. 2N2222A is also an NPN transistor and is quite similar to 2N3904.
2N3904 is an NPN bipolar junction transistor designed for switching purposes at 100 mA and as an amplifier at 100 MHz frequency. It comes in the TO-92 package and is used in a wide range of applications. It can be used in televisions; we can use it in home appliances; it can be used as a small load switch; and it can also be used as an amplifier.
2N3904 Transistor Pin Configuration:
The detailed pin configuration of this transistor is given below
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- An emitter is usually denoted by E
- The base is denoted by B.
- The collector is denoted by C.
Features of 2N3904
- Bipolar 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: 625 mW
- Operating Temperature (To): -55-155°C
2N3904 Equivalent NPN Transistors:
BC548, BC547, BC636, BC639, 2N2222A, 2N2222, 2N2369, 2N3055, 2N3906, and 2SC5200 are equivalent to this transistor.
Complement of 2n3904 Transistors:
BC557, BC556, and A1015 are the best (PNP) complements.
SMD of 2N3904 Transistor
Pin descriptions of SMD are given below
2N3904 as a switch:
When it is used as a switch, it is operated in the saturation and cut-off region. The 2N3904 transistor acts as an open switch during forward bias and acts as a closed switch during reverse bias. Biasing current should be a maximum of 5 mA; more than 5 mA 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 formula.
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 be more than mA.
2N3904 Transistor as Amplifier:
The transistor acts as an amplifier when operating in the active region. The 2n3904 transistor can amplify power, voltage, and current at different configurations given below.
- Common-base amplifier
- Emitter amplifier
- Collector amplifier
The common emitter type is the popular configuration while using an amplifier; the formula for using it is given below.
DC Current Gain = Collector Current (IC) / Base Current (IB)
Applications of 2N3904:
- It is used in small load switches having low saturation voltage and high gain.
- It can also be used on television.
- We can also use it in home appliance circuits.
- It is also used in amplifiers up to the frequency of 100 MHz.
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.
3904 NPN Transistor |
3906 PNP Transistor |
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2N3904 Transistor Datasheet
The datasheet of the 2N3904 Transistor is given in detail; click