2N4400 Pinout, Equivalent, Application, Datasheet

The 2N4400 pinout follows the Emitter–Base–Collector (E–B–C) sequence and belongs to the NPN silicon transistor family designed for low to medium current applications. With a collector–emitter voltage (Vce) of 40V, collector–base voltage (Vcb) of 60V, and collector current of 600mA, the 2N4400 transistor delivers stable switching and amplification performance in audio preamplifiers, driver circuits, and signal amplifiers.
It is closely related to the 2N4401 transistor, offering similar electrical ratings but optimized for slightly different gain and frequency characteristics.

Introduction to 2N4400 NPN Transistor

The 2N4400 transistor is a general-purpose NPN silicon device housed in a TO-92 plastic package, ideal for use in low-power switching and audio signal amplification circuits. It provides excellent current gain, low leakage, and thermal stability, making it suitable for both analog and digital circuit designs.

Because of its moderate voltage and current capacity, the 2N4400 NPN transistor is widely used in oscillators, amplifiers, motor drivers, and LED control circuits. It performs effectively in both low-noise audio circuits and switching stages, ensuring consistent performance across a wide temperature range.

Datasheet Download Button is provided end of this article.

2N4400 NPN Transistor

Pinout of 2N4400

Understanding the 2N4400 Pinout Configuration

The 2N4400 pinout uses a standard Emitter–Base–Collector (E–B–C) arrangement when viewed from the flat side of the TO-92 package. This pin structure allows easy insertion into breadboards and PCBs for prototyping or circuit design.

Pin Configuration of 2N4400 Pinout

Key Features of 2N4400 Transistor

• Small-signal NPN silicon transistor for general-purpose use
• Suitable for audio amplification and switching circuits
• Low collector leakage current ensures stable operation
• High current gain for efficient signal amplification
• Compatible E–B–C pin configuration in TO-92 package
• Designed for low distortion in linear amplifier stages

2N4400 Transistor Datasheet and Specifications

• Collector–Emitter Voltage (Vce): 40V
• Collector–Base Voltage (Vcb): 60V
• Emitter–Base Voltage (Veb): 5V
• Collector Current (Ic): 600mA
• Total Power Dissipation (Pc): 625mW
• DC Current Gain (hFE): 40 to 240
• Transition Frequency (fT): 250MHz (typical)
• Package Type: TO-92
• Polarity: NPN
• Pin Sequence: Emitter–Base–Collector (E–B–C)

Working Principle of 2N4400 NPN Transistor

The 2N4400 transistor works by allowing current to flow from the collector to the emitter when a small base current is applied. As an NPN device, the base terminal must be positive relative to the emitter for conduction to occur.

This transistor amplifies input signals by using the base current to control a much larger collector current, making it ideal for signal amplification and voltage gain stages. In switching applications, the 2N4400 acts as an open or closed switch, depending on the base input signal.

More Circuit Layouts

Typical Applications of 2N4400

• Low-frequency amplifier circuits
• Audio driver stages
• Digital logic and switching circuits
• LED and relay driver applications
• Signal conditioning circuits
• Oscillator and waveform generator circuits
• Pulse and timer circuits

Equivalent Transistors and Alternatives

• 2N4401 – Similar ratings with slightly higher gain
• BC337 – Common alternative for general-purpose use
• 2N2222A – Popular NPN switching transistor
• 2N3904 – Standard small-signal NPN transistor
• S8050 – NPN transistor for medium current applications

Comparison Summary: 2N4400 vs 2N4401

The 2N4400 and 2N4401 are both NPN silicon transistors in TO-92 packages, sharing similar electrical specifications such as voltage and current ratings (Vce = 40V, Ic = 600mA).

However, the 2N4401 transistor generally offers a slightly higher DC gain (hFE) and transition frequency, which makes it more suitable for high-frequency applications and low-noise amplifier designs. On the other hand, the 2N4400 transistor is often preferred for general-purpose amplification, switching, and driver circuits where speed and gain variations are less critical.

In short, both are interchangeable in many circuits, but 2N4400 is ideal for robust general-purpose tasks, while 2N4401 is better for precision and high-frequency amplification.

Frequently Asked Questions (FAQ)

What is the maximum power dissipation of 2N4400?

The 2N4400 transistor can dissipate up to 625mW, ideal for low-power circuits.

What is the maximum collector current of 2N4400?

It supports up to 600mA, suitable for low to moderate current applications.

What is the 2N4400 pinout configuration?

The 2N4400 pinout is Emitter–Base–Collector (E–B–C) when viewed from the flat side of the TO-92 package.

Can I use 2N4401 instead of 2N4400?

Yes, both have nearly identical specifications. The 2N4401 may offer slightly higher gain and bandwidth.

What are common applications of 2N4400?

It is widely used in amplifiers, drivers, oscillators, and digital switching circuits.

Conclusion

The 2N4400 transistor is a versatile NPN silicon device designed for signal amplification and switching. With a 40V collector–emitter voltage, 600mA collector current, and 625mW power dissipation, it serves as a dependable component in audio amplifiers, driver stages, and logic control systems.

When compared to the 2N4401 transistor, the 2N4400 provides comparable performance but is generally optimized for robustness and general-purpose circuit reliability, making it a preferred choice for educational projects, experimental circuits, and low-noise designs.

Datasheet of 2N4400 NPN Transistor

Click the following Button to download the datasheet of 2N4400 Transistor :

More projects, You may like:

• Video Transmitter DIY Homemade FM Radio Transmitter
• Adjustable Power Supply DIY Battery Charger
• 12V-220V 500 Watt inverter DIY Homemade
• MPPT Solar Charge Controller DIY Homemade
• DIY LA4440 bass amplifier homemade

For more project and circuit diagrams, you can go through the Schematics in the main menu where you can find many interesting projects and circuit diagrams like audio amplifier circuits, voltage booster circuit, battery charger circuit and timer circuits etc., which are all beginner circuit projects. Feel free to check them out!

Thank you for visiting the article.