2N4124 Pinout, Equivalent, Application, Datasheet

The 2N4124 pinout follows the Emitter–Base–Collector (E–B–C) configuration and is widely used in low-power amplifier and switching circuits. This NPN transistor operates with a collector-emitter voltage (Vce) of 25V, a collector-base voltage (Vcb) of 30V, and can handle a maximum collector current of 200mA with 650mW power dissipation. Due to its fast switching speed, low noise, and compact TO-92 package, the 2N4124 transistor is a preferred choice for signal processing, oscillators, and audio frequency circuits.

Introduction to 2N4124 NPN Transistor

The 2N4124 NPN transistor is a silicon-based bipolar junction transistor (BJT) designed for general-purpose low-power applications. It delivers reliable performance in small-signal amplification and switching tasks, making it a staple in both analog and digital circuits.

This transistor is encapsulated in the TO-92 plastic package and features an Emitter–Base–Collector (E–B–C) pin layout. With its moderate voltage rating and high gain stability, the 2N4124 transistor is ideal for projects that demand linear amplification and low signal distortion.

Datasheet Download Button is provided end of this article.

2N4124 NPN Transistor

Pinout of 2N4124

Understanding the 2N4124 Pinout Configuration

The 2N4124 pinout arrangement is simple, practical, and suitable for both breadboard and PCB designs. Viewed from the flat side, the pins are aligned in the order Emitter, Base, Collector (E–B–C).

Pin Configuration of 2N4124 Pinout

Key Features of 2N4124 Transistor

• Small-signal NPN transistor for general-purpose use
• Fast switching speed and low saturation voltage
• Reliable for low-noise amplification and signal gain stages
• Compact TO-92 package for easy PCB mounting
• Stable performance across temperature variations
• Complementary to 2N4126 PNP transistor

2N4124 Transistor Datasheet and Specifications

• Collector–Emitter Voltage (Vce): 25V
• Collector–Base Voltage (Vcb): 30V
• Emitter–Base Voltage (Veb): 6V
• Collector Current (Ic): 200mA
• Total Power Dissipation (Pc): 650mW
• DC Current Gain (hFE): 40 to 250
• Transition Frequency (fT): 250MHz (typical)
• Package Type: TO-92
• Polarity Type: NPN
• Pin Configuration: Emitter–Base–Collector (E–B–C)

Working Principle of 2N4124 NPN Transistor

The 2N4124 transistor works as a current-controlled device, where a small base current controls a larger collector current. When a positive voltage is applied to the base terminal, the transistor conducts current from the collector to emitter, allowing it to amplify or switch electronic signals.

In amplifier applications, it boosts weak input signals into stronger outputs, and in switching circuits, it acts as an electronic switch for controlling devices like LEDs, relays, and sensors. Because of its high transition frequency and low noise, the 2N4124 transistor is also suitable for audio and RF preamplifier circuits.

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Typical Applications of 2N4124

• Low-level audio preamplifiers
• Signal amplification in RF and IF stages
• Switching circuits in digital logic
• Oscillator and waveform generator circuits
• Pulse shaping and modulator circuits
• Analog signal conditioning

PNP Complementary Transistor

The 2N4126 PNP transistor is the complementary pair to the 2N4124 NPN transistor. Both transistors share nearly identical characteristics except for polarity. Together, they are commonly used in push-pull amplifier stages and complementary switching circuits to create balanced and efficient signal amplification.

Equivalent Transistors and Alternatives

• 2N3904 – Widely used general-purpose NPN transistor
• BC547 – Low-noise NPN transistor for amplifier circuits
• PN2222A – Higher current replacement with similar characteristics
• 2N4401 – Moderate power small-signal NPN transistor
• S9014 – Equivalent small-signal NPN type for hobby circuits

Comparison Summary: 2N4124 vs 2N4126

The 2N4124 (NPN) and 2N4126 (PNP) transistors are complementary devices designed for low-voltage and low-current applications. The 2N4124 transistor conducts when its base is biased positively, while the 2N4126 transistor conducts with a negative base bias.

Both have identical voltage and current capabilities, making them ideal for push-pull output stages in audio circuits, balanced amplifier pairs, or complementary logic circuits. While the 2N4124 sources current in circuits, the 2N4126 sinks current, providing symmetrical signal operation and improved linearity.

Frequently Asked Questions (FAQ)

What is the maximum power dissipation of 2N4124?

The total power dissipation (Pc) is 650mW, suitable for low-power circuits.

What is the maximum collector current of 2N4124?

The maximum collector current (Ic) is 200mA, suitable for small-signal applications.

What is the 2N4124 pinout configuration?

The 2N4124 pinout is Emitter–Base–Collector (E–B–C) when viewed from the flat face of the TO-92 package.

What is the complementary transistor for 2N4124?

The 2N4126 PNP transistor is the complementary device for 2N4124.

Can 2N4124 be used for amplification?

Yes, the 2N4124 transistor is used for low-level signal amplification and oscillator circuits.

Conclusion

The 2N4124 NPN transistor is a compact, reliable, and versatile device suitable for audio preamplifiers, oscillator stages, and general-purpose switching. With a Vce rating of 25V, Vcb of 30V, and 650mW power dissipation, it provides efficient performance for low-voltage analog and digital circuits.

When paired with its complementary 2N4126 PNP transistor, it forms a complete push-pull amplifier configuration, offering excellent linearity and stability for small-signal designs.

Datasheet of 2N4124 NPN Transistor

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