2N4401 Pinout, Equivalent, Application, Datasheet

The 2N4401 pinout follows the Emitter–Base–Collector (E–B–C) sequence and belongs to the family of NPN silicon transistors designed for low-to-medium current switching and signal amplification.
With a collector–emitter voltage (Vce) of 40 V, a collector–base voltage (Vcb) of 60 V, and a collector current of 600 mA, the 2N4401 transistor is widely used in amplifiers, LED drivers, digital logic circuits, and audio preamplifier stages.
It is the close performance variant of the 2N4400 transistor, offering slightly higher gain and faster switching.

Introduction to 2N4401 NPN Transistor

The 2N4401 is a small-signal NPN transistor in a TO-92 plastic package known for its reliability and strong electrical performance. It can handle up to 600 mA collector current with excellent frequency response and low noise characteristics, making it suitable for audio, instrumentation, and digital control systems.

Because of its high DC current gain and moderate power dissipation (625 mW), the 2N4401 NPN transistor delivers stable amplification and smooth saturation switching in both analog and digital circuits.

Datasheet Download Button is provided end of this article.

2N4401 NPN Transistor

Pinout of 2N4401

Understanding the 2N4401 Pinout Configuration

The 2N4401 pin configuration follows the standard Emitter–Base–Collector (E–B–C) sequence when viewed from the flat side of the TO-92 package. This arrangement ensures compatibility with most PCB and breadboard layouts for easy prototyping.

Pin Configuration of 2N4401 Pinout

Key Features of 2N4401 Transistor

• General-purpose NPN silicon transistor
• Suitable for signal amplification and switching circuits
• Offers high gain and fast switching speed
• Low collector leakage for stable operation
• Compact TO-92 plastic package with E–B–C pin sequence
• Compatible replacement for several small-signal NPN types

2N4401 Transistor Datasheet and Specifications

• Collector–Emitter Voltage (Vce): 40 V
• Collector–Base Voltage (Vcb): 60 V
• Emitter–Base Voltage (Veb): 5 V
• Collector Current (Ic): 600 mA
• Total Power Dissipation (Pc): 625 mW
• DC Current Gain (hFE): 70 to 300
• Transition Frequency (fT): 250 MHz (typical)
• Package Type: TO-92
• Polarity: NPN
• Pin Sequence: Emitter–Base–Collector (E–B–C)

Working Principle of 2N4401 NPN Transistor

The 2N4401 transistor operates as a current-controlled device, where a small current at the base terminal controls a much larger current between the collector and emitter.
In active mode, it amplifies input signals, while in saturation mode, it functions as a switch for controlling LEDs, relays, and logic signals.
Its high transition frequency and gain stability make it a reliable component for audio, oscillator, and driver applications.

More Circuit Layouts

Typical Applications of 2N4401

• Audio amplifier and pre-driver circuits
• LED and relay drivers
• Digital logic interface circuits
• Signal amplifier in low-noise designs
• Oscillator and timing circuits
• Switching and control modules
• Pulse and wave-shaping circuits

Equivalent Transistors and Alternatives

• 2N4400 – Same voltage/current, slightly lower gain
• BC337 – General-purpose NPN alternative
• 2N2222A – Standard NPN switching transistor
• 2N3904 – Small-signal low-current version
• S8050 – Medium current NPN transistor

Comparison Summary: 2N4401 vs 2N4400

The 2N4401 and 2N4400 transistors are electrically similar NPN devices, both rated at 40 V Vce, 60 V Vcb, and 600 mA Ic, packaged in the TO-92 case with the same E–B–C pinout.

However, the 2N4401 transistor is optimized for higher gain and faster switching response, making it slightly more efficient in audio pre-amplification and digital switching applications.
The 2N4400 transistor, in contrast, is often preferred for general-purpose circuits requiring rugged reliability.

In summary, while both are interchangeable, 2N4401 is better suited for precision and speed-sensitive circuits, and 2N4400 is ideal for standard amplifier and driver applications.

Frequently Asked Questions (FAQ)

What is the maximum power dissipation of 2N4401?

It can safely dissipate up to 625 mW under standard operating conditions.

What is the maximum collector current of 2N4401?

The transistor can handle up to 600 mA, suitable for moderate current switching.

What is the 2N4401 pinout configuration?

The 2N4401 pinout is Emitter–Base–Collector (E–B–C) when viewed from the flat side.

Can I replace 2N4401 with 2N4400?

Yes. Both have similar voltage and current ratings; however, the 2N4401 provides slightly higher gain and bandwidth.

What are common applications of 2N4401?

The 2N4401 transistor is used in amplifiers, oscillators, switching, and signal driver circuits.

Conclusion

The 2N4401 NPN transistor is a reliable, high-gain, low-noise device ideal for both analog amplification and digital switching.
With its 40 V voltage rating, 600 mA collector capacity, and 625 mW power dissipation, it serves as one of the most versatile TO-92 package components available.
When compared to 2N4400, it provides slightly improved gain and frequency response, making it a top choice for audio pre-drivers, signal amplifiers, and precision control circuits.

Datasheet of 2N4401 NPN Transistor

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