BD139 Transistor Datasheet pinout

• Bipolar (BJT) Single Transistor, NPN, 80V, 1.5A, 12.5W, TO-126, Through Hole

BD139 is the medium power NPN bipolar junction transistor. The BD139 is a commonly used NPN power transistor designed for audio, switching, and amplifier applications. It has max output current load capacity across collector to emitter upto 1.5A

Specifications of BD139

• Type: NPN
• Maximum Collector-Emitter Voltage (Vceo): 80V
• Maximum Collector-Base Voltage (Vcbo): 100V
• Maximum Emitter-Base Voltage (Vebo): 5V
• Maximum Collector Current (Ic): 1.5A
• Maximum Power Dissipation (Ptot): 12.5W
• DC Current Gain (hFE): 25 to 250 (depending on the operating current)
• Package: TO-126

Collector -Emitter Voltage V_CEO

BD135: 45V

BD137: 60V

BD139: 80V

Collector Current I_C : 1.5A

Collector Peak Current I_CM : 2.0 A

Features of BD139 transistor

1. High Voltage Capability: Can handle up to 80V between the collector and emitter.
2. Moderate Current Handling: Can switch or amplify currents up to 1.5A.
3. Low Saturation Voltage: Ensures efficient operation with low power loss.
4. Thermal Stability: The package allows for better heat dissipation compared to smaller transistors.
5. High Gain: Suitable for various amplification tasks due to its high DC current gain.

Uses of the BD139 Transistor

1. Audio Amplifiers:

1. • Used in the output stages of audio power amplifiers where moderate power and good linearity are required.

2. Switching Applications:

1. • Commonly used in circuits for switching loads, such as motors, relays, and LEDs, due to its ability to handle relatively high currents and voltages.

3. Voltage Regulators:

1. • Plays a role in maintaining a stable voltage in power supply circuits, often used in conjunction with other components.

4. Driver Stages:

1. • Utilized in driving higher power transistors in larger circuits, serving as an intermediary stage to boost current capacity.

5. General-Purpose Applications:

1. • Suitable for a wide range of electronic circuits, including signal amplification, oscillators, and other medium-power applications.

Pin Configuration:

1. Collector (C): Connected to the load or the positive voltage supply in a typical circuit.
2. Base (B): The control terminal, which modulates the flow of current between the collector and emitter.
3. Emitter (E): Typically connected to the ground or the negative supply voltage.

Practical Tips for Using the BD139

• Heat Management: Use a proper heatsink if operating near the maximum power dissipation to prevent thermal damage.
• Base Resistor: Use a base resistor to limit the base current and protect the transistor from excessive current.
• Circuit Design: Check the hFE range to ensure the transistor matches the required gain for your circuit.

The BD139 is a versatile transistor widely used in electronics due to its robustness and reliable performance across a range of applications.

Complementary BD136, BD138, BD140 (PNP) are recommended with BD135, BD137, BD139

Equivalent – BD230(ECB), BD233(ECB), TIP31C(BCE) etc

Download Datasheet Pdf

• bd135_bd137_bd139 (CDIL) –Download

• bd135_bd137_bd139 (Motorola)– Download

• BD139-Datasheer (ON Semiconductor) –Download

• BD135 (Philips) –Download

bd135_bd137_bd139 datasheet (CDIL) 

BD139-Datasheer (ON Semiconductor) 

bd135_bd137_bd139 (Motorola)

BD135 -BD139 datasheet (Philips)