BD137 NPN Transistor Pinout Datasheet

Introduction

The BD137 transistor is a medium-power NPN bipolar junction transistor (BJT) designed for audio amplification, signal processing, and switching applications. It can handle a collector current up to 1.5A and has a collector-emitter voltage rating of 60V, making it suitable for driving moderate loads such as relays, lamps, and small motors. With its ability to deliver good linear performance and withstand relatively high power, the BD137 is widely used in audio amplifier output stages, voltage regulators, and driver circuits.

Encased in the TO-126 package, the BD137 offers excellent thermal performance and reliability. The transistor’s DC current gain (hFE) ranges between 40 and 250, depending on the variant and operating conditions, making it versatile for both switching and amplification purposes. Its transition frequency of 190 MHz also makes it well-suited for high-frequency applications beyond standard low-frequency switching.

BD137 NPN Transistor

Due to its strong electrical characteristics, cost-effectiveness, and availability, the BD137 is a popular choice among hobbyists, students, and engineers. It is often paired with its PNP complementary transistor in push-pull amplifier designs, providing efficient performance in audio and signal processing systems. Whether in consumer electronics or educational projects, the BD137 is valued for its robust power handling and versatility.

BD137 Pinout

BD137 Transistor Key Features

• Medium-power NPN transistor designed for audio and switching applications.
• Suitable for driving relays, motors, and lamps.
• High transition frequency (190 MHz) for wideband use.
• Rugged TO-126 package with good heat dissipation.
• Reliable for amplifier and driver stages.
• Popular choice for both DIY and professional circuits.

Specifications/Characteristics of BD137 NPN Transistor

• Maximum Collector-Base Voltage (Vcb): 80V
• Maximum Collector-Emitter Voltage (Vce): 60V
• Maximum Emitter-Base Voltage (Veb): 5V
• Maximum Collector Current (Ic): 1.5A
• Total Power Dissipation (Ptot): 12.5W
• DC Current Gain (hFE): 40 – 250
• Transition Frequency (ft): 190 MHz (typical)
• Junction Temperature Range: -55°C to +150°C
• Package: TO-126

BD137 Pin Configuration

More Circuit Layouts

Key Applications of BD137 NPN Transistor

• Audio power amplification.
• Driver stages for relays, motors, and lamps.
• Switching circuits up to 1.5A.
• Voltage regulation and power supply circuits.
• Push-pull amplifier designs.
• General-purpose medium-power electronic projects.

PNP Complimentary Transistor

BD138 (PNP) is the complementary transistor to BD137.

Equivalent Transistors of BD137

• BD135 (lower voltage NPN transistor, 45V).
• BD139 (higher voltage NPN transistor, 80V).
• 2N3019 (NPN medium-power transistor).
• MJE340 (NPN transistor for high-voltage applications).
• TIP31 (NPN power transistor alternative).

(Pin configuration of some transistors mentioned here may different from BD137).

Datasheet of BD137 NPN Transistor

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