2N3904 vs. 2N2222 Transistor Comparison: Understanding the Differences

Published:February 19, 2024

Dr. James Anderson is a distinguished figure in electrical engineering, specialising in electronic components. Dr. Anderson has dedicated his career to pushing the boundaries of electronic component technology. With over 20 years of experience in academia and industry, he has earned a reputation as a leading expert.

2N3904 and 2N2222 are among the most popular NPN bipolar junction transistors in the electronics market. They are also quite similar in appearance. However, some may wonder why 2N3904 is more popular than 2N2222. If you're unsure about which one to use or which is superior, it would be wise to understand their differences before making a decision. In this article, we'll compare and contrast these two transistors. Additionally, we'll discuss whether they can be used interchangeably, when to use each type, and what factors to consider before using them.

 

Overview of 2N3904

 

The 2N3904 is a three-terminal NPN BJT (Bipolar Junction Transistor) constructed with silicon material and housed in a TO-92 package. In this transistor, electrons are the majority of charge carriers, carrying negative charges. Its state can be altered by a small voltage at the base terminal, typically around 0.7V, transitioning it from reverse bias to forward bias for conduction.

Commonly utilized in general-purpose switching or low-power amplification applications, the 2N3904 is tailored for medium voltage and low-power applications, operating at moderately high speeds.

This NPN transistor is highly popular and finds extensive use as an amplifier and simple electronic switch, capable of handling 200 mA of power and operating at frequencies up to 100 MHz when used as an amplifier.

 

Overview of 2N2222

 

The 2N2222 is a widely used NPN bipolar junction transistor suitable for both switching and amplification of analog signals. Enclosed in a TO-18 package, this transistor can be made of silicon or germanium, saturated with either positively or negatively charged material through a process called doping. Its structure consists of a positively charged region sandwiched between two negatively charged regions, hence termed an NPN transistor.

Notable among its advantages compared to similar transistors is its ability to handle high currents, typically capable of switching an 800mA load current, a substantial rating for its size. In amplification applications, it accepts an analog signal at the collector while another signal is applied at its base, often representing a voice signal with an analog frequency of around 4kHz.

The 2N2222 is commonly used in VHF (Very High Frequency) amplifiers and switching applications. With three terminals—Base, Emitter, and Collector—it operates like a standard NPN transistor. This transistor offers a constant DC collector current of 800mA, making it suitable for low to medium-current applications. Operating with a 10ns delay time, 225ms storage time, 60ms fall time, and 25ms rise time, it achieves a high transition frequency of 250MHz. It comes in a TO-92 package.

 

2N3904 vs. 2N2222: Pinout

 

2N3904 Pinout

 

Pin No. Pin Name Description
1 Emitter Current Drains out through emitter
2 Base Controls the biasing of transistor
3 Collector Current flows in through collector

 

2N2222 Pinout

 

Pin No. Pin Name Description
1 Base Controls the biasing of transistor
2 Collector Current flows in through collector
3 Emitter Current Drains out through emitter

 

2N3904 vs. 2N2222: Package

 

2N3904 Package

 

The 2N3904 transistor is housed in a TO-92 package, which features an external covering made of plastic and epoxy of appropriate dimensions. One of the main advantages of the TO-92 package is its compatibility and lower cost. However, this package is not suitable for high-temperature environments.

 

2N2222 Package

 

The 2N2222 transistor is housed in a TO-18 package, featuring an external covering made of metal.

The TO-18 package offers several advantages for the 2N2222, including its ability to handle higher current values and withstand high temperatures. Essentially, the TO-18 package functions as a heat sink for the transistor.

 

 

The 2N2222 comes in a TO-18 metal package, whereas the 2N3904 is housed in a TO-92 plastic package.

The primary difference due to the package variation lies in the power handling or current (Ic) capability.

Power Dissipation, Pd = V x I = Vce(sat) x Ic

The TO-18 package has a Pd of 1.8 W at 25°C (Tc), while the TO-92 package has a Pd of 1.5 W at 25°C (Tc).

The 2N2222 is engineered to manage larger currents up to 1000mA. However, the TO-18 packaging incurs significantly higher production costs compared to the TO-92 plastic casing, affecting its competitiveness and popularity.

To address this, the PN2222 was introduced with the TO-92 packaging and a specification of 600-800mA, depending on the vendor.

As emphasized earlier, current handling is largely dictated by the package. While the 2N3904 is rated for 200mA Ic, theoretically, it should be capable of handling at least 600mA Ic.

 

2N3904 vs. 2N2222: Features

  • The affordability of both the 2N2222 and 2N3904 transistors contributes to their widespread availability and versatile use across various devices.
  • The 2N2222 is renowned for its high-speed operation, while the 2N3904 is favored for its modern high-speed circuitry.
  • Among its counterparts, the 2N2222 stands out for its exceptional ability to handle high currents.
  • With a collector current of 200mA, the 2N3904 is suitable for a range of applications. In comparison, the 2N2222 boasts a collector current close to 1 ampere, making it adept at managing high loads similar to the 2N3904.
  • The collector current dissipation characteristics of both the 2N2222 and 2N3904 demonstrate their capabilities as amplifiers.

 

2N3904 vs. 2N2222: Specifications

 

  2N3904 2N2222
Type of  Transistor Bipolar Junction Transistor (BJT) Bipolar Junction Transistor (BJT)
Type of BJT NPN NPN
The maximum current that the transistor can handle from the emitter to the collector (called collector current, Ic) 200mA 1A
The maximum voltage that the collector of the transistor can handle (called the collector-emitter voltage, V CEO )  40V 40V
Voltage and Current It can handle up to 40V of collector-emitter voltage, and can handle up to 200mA of collector current.  It can handle up to 60V of collector-emitter voltage, and can handle up to 500mA of collector current.
Power Dissipation up to 625mW of power up to 800mW of power
Gain between 100 and 300 between 150 and 500

 

2N3904 vs. 2N2222: Maximum Ratings

 

  2N3904 2N2222
Collector – Base Voltage 60V 75V
Collector Current (continuous) 200mA 600mA

 

2N3904 vs. 2N2222: Equivalents

 

2N3904 Equivalents

The following transistors are equivalent to the 2N3904: BC548, BC547, BC636, BC639, 2N2222A, 2N2222, 2N2369, 2N3055, 2N3906, and 2SC5200.

 

2N2222 Equivalents

2N3904, BC547, BC548, and 2N3906 are transistors that can be used as alternatives to 2N2222.

 

2N3904 vs. 2N2222: Complementary PNP

 

2N3904 Complementary PNP

The 2N3904 NPN transistor requires a PNP complementary transistor.

The 2N3906 is the most commonly used PNP transistor with the 2N3904.

 

2N2222 Complementary PNP

The 2N2222 transistor is an NPN type device that requires a complementary PNP transistor in some circuits.

In applications such as siren circuits, amplifier circuits, and flash circuits, a combination of NPN-PNP transistors is necessary. For the 2N2222 NPN transistor, the 2N2907 PNP transistor is commonly used.

 

2N3904 vs. 2N2222: Applications

 

2N3904 Applications

  • Module driving circuits
  • LED driving
  • Relay driving
  • Amplifier circuits
  • Amplifier modules
  • Television applications
  • Home appliances
  • Used as a simple switch to control heavy loads due to its low saturation voltage and high gain
  • Fast switching applications such as pulse width modulation (PWM) due to its fast switching speed

 

2N2222 Applications

  • Amplifier circuits
  • Complementary transistor amplifier circuits
  • Used as a switch
  • Pulse width modulation (PWM)
  • Embedded systems
  • Automation systems
  • Inverter circuits
  • Rectifier circuits
  • Speed control systems
  • High current circuits
  • Audio preamplifiers
  • Sensor circuits
  • Used to switch several loads simultaneously
  • RF circuits
  • Darlington pairs
  • Motor drive circuits like VFD or variable frequency drives
  • Used as an amplifier to amplify voltage, current & power
  • Darlington pair transistors are used for attaining the maximum current from the emitter terminal to the collector.

 

2N3904 vs. 2N2222: Datasheet

 

2N3904 Datasheet

2N2222 Datasheet

 

2N3904 vs. 2N2222: What are the Similarities?

One similarity between the 2N3904 and the 2N2222 transistors is their maximum voltage rating. Both transistors can handle up to 40V across the collector-to-emitter terminals, making them suitable for similar voltage requirements in electronic circuits.

 

The Difference Between 2N3904 and 2N2222: Comparison Table

 

  2N3904 2N2222
Pinout in a straight line in an inverted triangle pattern
Collector to emitter voltage (VCE) 40 30
Emitter to base voltage (VEB) 6v 5v
Collector current (IC) 200mA 800mA
Power dissipation 625mw 500mw
Junction temperature (TJ) 150°C 200°C
Transition frequency (FT) 300MHZ 250MHZ
Noise (N) 10db 4db
Package TO-92 TO-18
Cost cheaper more expensive

 

 

 

Can We Use 2N3904 Instead of 2N2222

 

When considering the substitution of a 2N2222 with a 2N3904, several key factors must be taken into account. Comparing the specifications and characteristics of both transistors, we note that their collector-to-emitter voltage ratings are identical. Additionally, both transistors share the same total device dissipation of 625mW, and their transition frequency (fT) is also consistent at 300MHz. However, a significant disparity arises in the collector current ratings of the two transistors. Specifically, the collector current rating of the 2N3904 is 200mA, whereas that of the 2N2222 is 600mA.

The viability of using a 2N3904 as a replacement for 2N2222 hinges on the specific circuit in question. In scenarios involving amplification or RF circuits, substituting a 2N3904 for a 2N2222 is typically permissible. However, when dealing with switch circuits, additional considerations become paramount.

Given the 2N3904's 200mA collector current limitation and the recommended practice of operating transistors at least 20% below their absolute maximum ratings, it is crucial to evaluate the load being driven by the 2N2222 in the circuit. By adhering to this rule, only 160mA remains available for use. Therefore, it is imperative to ascertain the type of load being driven by the 2N2222 and determine its maximum current requirement. This can be achieved by referencing the datasheet of the load component, consulting the supplier for specifications, or employing an ammeter to measure the current. Alternatively, selecting an equivalent transistor with a collector current rating of 600mA or higher is another viable approach. Such alternative transistors can typically be found on the 2N2222 datasheet.

 

Can We Use 2N2222 Instead of 2N3904

The 2N2222 can serve as a substitute for the 2N3904 in most applications, including amplification, RF, or switching. This is due to its nearly identical or superior characteristics compared to the 2N3904.

 

Conclusion

The 2N3904 and the 2N2222 are similar in their voltage handling capabilities, both capable of handling up to 40V across the collector-to-emitter terminals.

However, the 2N2222 can manage a higher operating collector current. This current, which flows from the emitter to the collector terminal, powers the load. While a 2N3904 can withstand currents of up to 200mA (milliamperes), a 2N2222 can handle up to 1A (ampere), which is five times more.

The choice between the two depends on the required current. For currents below 200mA, either transistor will suffice. If the requirement is between 200mA and 1A, the 2N2222 is the better choice. In most cases, the 2N3904 is adequate, but if more than 200mA is needed, the 2N2222 should be used.

 

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FAQ

  • Is a 2N2222 the same as a 2N3904?

    Both the 2N3904 and the 2N2222 can handle the same amount of voltage across their collector-to-emitter terminals.

  • What is the maximum voltage for 2N3904?

    40V.

  • What is the advantage of 2N3904?

    2N3904 can bear lower current, lower power, and medium voltages.

  • Why is 2N2222 so popular?

    The 2N2222 transistor is suitable for applications requiring low to medium current, as it provides a constant DC collector current of 800mA.

  • Which is better BC547 or 2N2222?

    The 2N2222 transistor has a higher power rating compared to the BC547.

  • Can I use C945 instead of 2N2222?

    The C945 is a general-purpose small signal NPN transistor, similar to the 2N2222. The main difference lies in their maximum continuous current ratings: the C945 is rated at 150mA, while the 2N2222 can handle 500mA. However, if you're operating at a few mA, such as below 100 mA, the difference between them is negligible.

  • What is the difference between 2n3904 and 2n3906?

    Both transistors are bipolar, with the 2n3904 being an NPN and the 2n3906 being a PNP. Consequently, they exhibit different schematic symbols and functions in terms of polarity.

  • What is the difference between 2n2907 and 2n2222?

    The 2N2907 is the PNP complement of the 2N2222 NPN transistor, both housed in a TO-18 package.

  • What is the difference between 2n4401 and 2n2222?

    The 2N4401 has a collector current limit of 500mA and a power dissipation of 652mW, making it suitable for medium loads compared to the 2N2222.

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