BD139 NPN Bipolar Medium Power Transistor 80V 1.5A TO-126 Package

BD139 NPN Bipolar Medium Power Transistor 80V 1.5A TO-126 Package

The BD139 is a high-performance NPN silicon transistor designed for medium-power amplification and switching applications. It features a collector-emitter voltage of 80V and a collector current up to 1.5A, providing excellent gain stability, low saturation voltage, and reliable thermal performance.

Encased in a TO-126 package, the BD139 allows efficient heat dissipation, making it ideal for audio amplifiers, voltage regulators, motor drivers, and general-purpose power control circuits. It is commonly used in complementary configurations with the BD140 (PNP) or in push-pull amplifier stages, providing smooth and stable performance for professional, educational, and hobbyist applications.

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Features:

• Transistor Type: NPN Silicon
• Package: TO-126 (medium power with good thermal management)
• Collector-Emitter Voltage (V_CE): 80V
• Collector Current (I_C): 1.5A
• Power Dissipation (P_tot): Up to 12.5W (with proper heat sinking)
• DC Current Gain (hFE): 40–250 (typical range)
• Low Saturation Voltage: Efficient switching and amplification
• High Thermal Stability: Reliable operation in medium-power circuits
• Complementary Devices: BD140 (PNP) for push-pull amplifier designs
• Durable & Reliable: Suitable for long-term professional use

Applications:

• Audio Amplifiers: Driver and output stages in medium-power audio circuits
• Voltage Regulators: Stable regulation in medium-power systems
• Relay & Motor Drivers: Controls moderate current loads efficiently
• Signal Amplification: Low- to medium-frequency analog signal applications
• Push-Pull Amplifiers: Works with BD140 PNP for complementary amplifier stages
• Switching Circuits: For medium-current power switching applications
• Educational & Hobbyist Projects: Ideal for prototyping and experimentation

bd139-transistor-datasheet