2n3904 transistor

2n3904 specifications
- It is an NPN BJT Transistor
- DC Current Gain range is 30 to 300hFE
- Collector current (IC) is 200mA
- Collector to base Voltage (VCB) is 60V
- Collector to emitter voltage (VCE) is 40v
- Emitter to base voltage (VEB) is 6V
- Transition frequency (FT) is 300MHz
2n3904 pinout

Pin Number | Pin Name | Description |
---|---|---|
Pin Number1 | Pin NameEmitter | DescriptionCurrent flows through the emitter |
Pin Number2 | Pin NameBase | DescriptionBase terminal triggers the device |
Pin Number3 | Pin Namecollector | DescriptionCurrent flows through the collector |
TO-92 package
- The package on the 2n3904 transistor in TO-92.
- It is made up of a mixture of epoxy and plastic material.
- Most of the transistors on the ‘BC’ and ‘2N’ series are been made with the TO-92 package.
- The compatibility of the TO-92 package is the main advantage of a circuit.

If you need the datasheet in pdf please click this link
2n3904 Description
- The 2n3904 transistor is known as the general-purpose transistor device and technically they are designed to have low current and low power applications.
- The maximum current gain of this transistor will start from 30 to 300hFE, this gain value will be important at amplifier applications.
- The maximum collector current at 2n3904 transistor is 200mA, which means the maximum load current allowed on this transistor.
- The power dissipation on the transistor is 625mW, this particular value indicates the power dissipation of this transistor device.
- The transition frequency on this transistor is 300MHZ, it is an important factor in transistor switching applications.
- The noise figure of the 2n3904 transistor is 5dB
- The maximum junction temperature on the 2n3904 transistor is 150°C.
2n3904 datasheet

If you need the datasheet in pdf please click this link
2n3904 transistor Equivalent
- The equivalent transistor for 2n3904 is BC549, 2n2222, 2n2369, 2n4401, KSP8098 and KTN2222a.
- Each transistor in this list is NPN transistor equivalent for 2n3904.
- The technical and physical aspects of all the transistors are the same.
2n3904 vs MPSA18 vs BC548 vs 2n3906
- The table below listed all the transistor devices similar to the 2n3904 transistor.
- In the table, we try to compare the electrical specifications of each of the transistors 2n3904 vs mpsa18, 2n3904 vs bc548, and 2n3904 vs 2n3906.
2n3904 | MPSA18 | Bc548 | 2n3906 | |
---|---|---|---|---|
Collector to base voltage (VCB) | 2n390460V | MPSA1845V | Bc54830V | 2n390640V |
Collector to emitter voltage (VCE) | 2n390440V | MPSA1845V | Bc54830V | 2n390640V |
Emitter to base voltage (VEB) | 2n39046v | MPSA186.5v | Bc5485v | 2n39065v |
Collector current (IC) | 2n3904200mA | MPSA18200mA | Bc548100mA | 2n3906200mA |
Power dissipation | 2n3904625mW | MPSA18625mW | Bc548500mW | 2n3906625mW |
Junction temperature (TJ) | 2n3904150°C | MPSA18150°C | Bc548150°C | 2n3906150°C |
Transition frequency (FT) | 2n3904300MHZ | MPSA18160MHZ | Bc548300MHZ | 2n3906250MHz |
Noise (N) | 2n39045dB | MPSA184dB | Bc54810dB | 2n39064dB |
Gain (hFE) | 2n390430 to 300hFE | MPSA18500 to 1500hFE | Bc548110 to 800hFE | 2n390630 to 300hFE |
Package | 2n3904TO-92 | MPSA18TO-92 | Bc548TO-92 | 2n3906TO-92 |
2n3904 application
- LED flasher circuit
- Relay driver circuit
- Module driver circuit
- Amplifier circuit
- Switching circuit
- Preamp circuit
- Signal amplifier
- Sensor circuit
2n3904 amplifier circuit

- The figure shows the amplifier circuit using a 2n3904 transistor.
- The circuit consists of two 2n3904 transistors and 2sc1815 transistors.
- The amplification of the audio signal is done initially by the Q1 2sc1815 transistor, then the signal reaches the input of the 2n3904 transistor.
- As we can at the circuit both the 2n3904 transistor are connected back to back, that is the output signal from the Q2 transistor will pass towards the second transistor Q3.
- Technically three-stage of amplification is done at this circuit to make an audio signal.
2n3904 as a switch

- The mini version of 2n3904 as a switch is the circuit above.
- The 2n3904 is a low-power general purpose transistor, here we can see minimum component will be used to switch the LED using the 2n3904 transistor.
- When the switch is closed the current starts to flow through the transistor base and it triggers ON and sent a signal to the LED.
- And the LED starts glowing.
- Much higher circuit arrangements will be used at switching applications of the 2n3904 transistor.
2n3904 transistor price
- The 2n3904 transistor is a low-power general purpose transistor, which had more applications at common appliances.
- The price for 2n3904 is 9rupess for 3pieces or 0.12USD dollars.