2N4403 Pinout, Equivalent, Application, Datasheet

The 2N4403 pinout follows the Emitter–Base–Collector (E–B–C) sequence when viewed from the flat side of the TO-92 plastic package.
The 2N4403 PNP transistor is a reliable low-power amplification and switching device, capable of handling up to –600 mA of collector current at –40 V. Designed for audio amplifier stages, signal processing, and general-purpose switching, the 2N4403 offers excellent gain stability, low noise, and fast response.

Closely related to the 2N4402, it shares identical voltage and current characteristics, making both transistors suitable for complementary or interchangeable designs in analog and digital circuits.

Introduction to 2N4403 PNP Transistor

The 2N4403 transistor is a silicon-based PNP bipolar junction transistor (BJT) designed for signal amplification and medium-current switching tasks.
It operates efficiently in audio frequency ranges, low-voltage power circuits, and driver modules. Its high current gain (hFE ≈ 100–300) ensures stable amplification, while the 625 mW power dissipation allows it to handle moderate loads.

This transistor is widely used in consumer electronics, DIY amplifier projects, and sensor interface circuits where low distortion and thermal stability are crucial.

2N4403 PNP Transistor

Pinout of 2N4403

Understanding the 2N4403 Pinout Configuration

The 2N4403 pin configuration follows a standard and easy-to-remember layout.
When facing the flat side of the transistor, the pins are arranged as Emitter–Base–Collector (E–B–C) from left to right.

Pin Configuration of 2N4403 Pinout

Key Features of 2N4403 Transistor

• General-purpose silicon PNP transistor
• Designed for low to medium current circuits
• Low noise and high DC gain for clean signal amplification
• Compact TO-92 package ideal for PCB and breadboard use
• Performs efficiently in audio preamp and driver circuits
• Compatible with NPN pairs such as 2N4401 and 2N4402

2N4403 Transistor Datasheet and Specifications

• Collector–Emitter Voltage (Vce): –40 V
• Collector–Base Voltage (Vcb): –40 V
• Emitter–Base Voltage (Veb): –5 V
• Collector Current (Ic): –600 mA
• Power Dissipation (Pc): 625 mW
• DC Current Gain (hFE): 100 – 300 (typical)
• Transition Frequency (fT): 250 MHz (typical)
• Polarity: PNP
• Package Type: TO-92
• Pin Layout: Emitter–Base–Collector (E–B–C)

Working Principle of 2N4403 PNP Transistor

The 2N4403 transistor operates when a small reverse-bias current is applied between the base and emitter, allowing a much larger current to flow from emitter to collector.
In the active region, it amplifies weak input signals; in saturation, it behaves as a closed switch.

Because of its moderate current capacity and low voltage drop, it’s often used in signal amplifiers, LED control circuits, and feedback networks. Its fast response and low leakage current make it a strong performer in linear amplification and digital control stages.

More Circuit Layouts

Typical Applications of 2N4403

• Audio amplifier pre-stages
• Relay and LED driver circuits
• Voltage and current control modules
• Signal switching and regulation systems
• Analog feedback amplifiers
• Complementary transistor pairs in dual-supply designs

Equivalent Transistors and Alternatives

• 2N4402 – Closest electrical equivalent
• 2N2907A – General-purpose PNP alternative
• BC558 / BC556 – Low-noise PNP replacements
• A733 / S8550 – For compact and low-voltage circuits
• 2SA1015 – Similar gain and current handling characteristics

Comparison Summary: 2N4403 vs 2N4402

Both 2N4403 and 2N4402 are PNP small-signal transistors featuring –40 V Vce, –40 V Vcb, and –600 mA Ic.
However, the 2N4403 generally offers higher voltage gain linearity and better saturation performance, which makes it more suitable for switching and control circuits.

In contrast, the 2N4402 provides lower noise and a slightly higher transition frequency, ideal for audio preamplifier and low-distortion amplifier designs.
Both are fully interchangeable in most low-power circuit designs.

Frequently Asked Questions (FAQ)

What is the maximum collector current of 2N4403?

It can handle up to –600 mA, suitable for medium-load switching.

Is 2N4403 interchangeable with 2N4402?

Yes. Both are PNP small-signal transistors with similar ratings; only gain and frequency slightly differ.

What is the 2N4403 pin configuration?

The 2N4403 pinout is Emitter–Base–Collector (E–B–C) when facing the flat side.

What is the package type of 2N4403?

It uses a TO-92 plastic case ideal for PCB and prototyping.

Where is 2N4403 used?

Commonly found in audio amplifiers, signal switches, and driver stages of analog circuits.

Conclusion

The 2N4403 PNP transistor is a durable, low-noise device built for signal amplification and switching in low-voltage circuits.
With its 40 V voltage rating and 600 mA current handling, it’s a dependable choice for audio, analog, and driver applications.
While 2N4402 is slightly faster in frequency response, the 2N4403 offers better switching efficiency and cleaner linearity, making it a preferred option for general-purpose PNP circuit designs.

Datasheet & Pinout of 2N4403 NPN Transistor

Click the following Button to download the datasheet of 2N4403 Transistor :

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