The 2N3904 is basically a NPN transistor made up of silicon material. It is used for general purpose switch and amplifier. It supports the current up to 100mA when acts as switch and Its support 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 TO-92 package and used in wide range of applications. It can be used in televisions, we can use it in home appliances, can be used as small load switch, it can also be used as an amplifier.
2N3904 Pin Configuration
Detail Pins configuration of this transistor is given below
- Emitter is usually denoted by E
- Base is denoted by B.
- Collector is denoted by C.
- Bi-Polar NPN Transistor: Type
- Available Package: To-92
- Collector Emitter Voltage (Vceo): 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:
Compliment of 2n3904 Transistors:
BC557,BC556,A1015 are the best (PNP) compliment
SMD of 2N3904 Transistor
Pin descriptions of SMD is given below
2N3904 as switch:
When it is used as switch it is operated in the Saturation and Cut-Off Region. 2N3904 transistor acts as an Open Switch during Forward Bias and acts as closed switch during Reverse Bias. Biasing current should maximum of 5mA more than 5mA will damaged the Transistor so a resistor is always added in series with base pin of the transistor. Resistor value can be calculated using 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 as Amplifier:
Transistor acts as an Amplifier when operating in Active Region. 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 in 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 in televisions.
- We can also use it in home appliances circuits.
- It is also used in amplifier up to the frequency of 100MHz.