MJ15003 Pinout Equivalent Applications Datasheet

The MJ15003 pinout is one of the most recognized references among power transistor circuits. The MJ15003 is a high-power NPN silicon transistor housed in a TO-3 metal package, capable of handling up to 20 A collector current and 250 W power dissipation.
This transistor is designed for audio power amplifiers, DC motor controllers, and high-current switching applications. Its high voltage rating of 140 V allows reliable operation in demanding power stages, making it a preferred choice for professional and industrial amplifier designs. The MJ15003 forms a complementary pair with MJ15004 (PNP) for push-pull audio outputs.

Introduction to MJ15003 NPN Transistor

The MJ15003 transistor is built to deliver superior current gain, thermal durability, and switching efficiency. It belongs to the Motorola/ON Semiconductor power transistor family, known for robust high-power linear and switching performance.

In amplifier applications, it ensures clean, low-distortion audio reproduction with remarkable headroom. For switching circuits, its high collector current rating allows it to drive heavy loads such as motors, solenoids, and power converters with ease. Its TO-3 metal can enclosure provides excellent heat conduction, enabling continuous high-power operation when mounted on a proper heatsink.

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MJ15003 NPN Transistor

Pinout of MJ15003

Understanding the MJ15003 Pinout Configuration

Proper knowledge of the MJ15003 pinout is critical before integrating it into a circuit. When viewed from the bottom (pins facing toward you, mounting holes on top), the configuration is:
Pin 1 – Base, Pin 2 – Emitter, and the metal case is Collector.

This Base–Emitter–Collector sequence ensures efficient current flow through the transistor while the metal case acts as a built-in heat path and collector terminal, simplifying thermal management and mechanical mounting.

Pin Configuration of MJ15003 Pinout

Key Features of MJ15003 Transistor

• High-power NPN transistor in a robust TO-3 metal package
• Suitable for linear, switching, and class-AB amplifier designs
• Excellent gain stability and low distortion characteristics
• Complementary to MJ15004 PNP transistor
• Superior thermal and mechanical durability
• Reliable under continuous high-current loads
• Ideal for both commercial and industrial power stages

MJ15003 Transistor Datasheet and Specifications

• Collector–Emitter Voltage (Vce): 140 V
• Collector–Base Voltage (Vcb): 140 V
• Emitter–Base Voltage (Veb): 5 V
• Collector Current (Ic): 20 A
• Power Dissipation (Pc): 250 W
• DC Current Gain (hFE): 25 – 150 (typical range)
• Transition Frequency (fT): 2 MHz
• Package Type: TO-3 (Metal Case)
• Polarity: NPN
• Pin Configuration: Base – Emitter – Collector (Case)
• Junction Temperature (Tj): 200 °C

Working Principle of MJ15003 NPN Transistor

The MJ15003 works as a current amplifier or power switch depending on biasing. When a small current is applied to the base terminal, it allows a proportionally larger current to flow between collector and emitter. In amplifier circuits, this property enables faithful signal amplification with minimal distortion.

Its high transition frequency and linear gain make it especially suited for audio power stages where clarity and stability are critical. The TO-3 package ensures effective heat dissipation, allowing the transistor to operate reliably under continuous high power and temperature stress.

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Typical Applications of MJ15003

• High-power audio amplifier output stages
• DC motor and actuator drivers
• Linear and switching voltage regulators
• Industrial control equipment
• Power inverters and converter circuits
• Push-pull complementary amplifiers with MJ15004
• RF transmitters and pulse-width modulation stages

PNP Complementary Transistor

The MJ15004 is the PNP complementary transistor to the MJ15003.
Both share identical voltage, current, and power ratings but with opposite polarities. Together they form a balanced complementary pair, ideal for class-AB and push-pull amplifier stages, ensuring smooth signal symmetry and minimized crossover distortion in high-fidelity systems.

Equivalent Transistors and Alternatives

• 2N3773
• MJ21194
• MJ15024
• 2N5686
• MJ15022 (similar high-power range)

Comparison Summary: MJ15003 vs MJ15004

When comparing MJ15003 vs MJ15004, the main distinction lies in their polarity. The MJ15003 is an NPN transistor, conducting when its base is positively biased relative to the emitter, while the MJ15004 is PNP, conducting under negative base bias.

Both have identical voltage (140 V) and power (250 W) ratings, making them perfect complements in high-power push-pull amplifier stages. Together, they deliver excellent thermal balance, consistent frequency response, and high linearity, widely used in professional audio and industrial equipment designs.

Frequently Asked Questions (FAQ)

What is the MJ15003 transistor used for?

It is used in audio amplifiers, motor control systems, and power regulators that require high current and voltage handling.

What is the package type of MJ15003?

It comes in a TO-3 metal case, designed for maximum thermal efficiency.

What is the MJ15003 pinout?

The configuration is Base – Emitter – Collector (Case) when viewed from the bottom.

What is the complementary transistor for MJ15003?

The MJ15004 PNP transistor is its complementary counterpart.

Can I use 2N3773 instead of MJ15003?

Yes, 2N3773 can often be used as a substitute in many applications due to similar ratings.

Conclusion

The MJ15003 NPN transistor is a high-performance, heavy-duty device built for power amplification and industrial switching. With its 140 V voltage capacity, 20 A collector current, and 250 W dissipation, it ensures excellent electrical stability and durability.

In combination with the MJ15004 PNP, it forms an ideal complementary pair for high-power audio amplifiers and regulated power supplies. Its TO-3 package provides superior heat management, ensuring reliable operation even under continuous heavy-load conditions.

Datasheet of MJ15003 NPN Transistor

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