Overview
The BD139 is a medium power NPN bipolar junction transistor (BJT) produced by STMicroelectronics. It is designed for use in audio amplifiers and drivers, particularly in complementary or quasi-complementary circuits. The transistor is housed in a TO-126 plastic package, which is non-conductive and helps in reducing noise in the circuit. The BD139 is known for its high collector current and low price, making it suitable for both commercial and educational electronic projects.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Transistor Type | NPN | |
| Max Collector Current (IC) | 1.5 | A |
| Max Collector-Emitter Voltage (VCE) | 80 | V |
| Max Collector-Base Voltage (VCB) | 80 | V |
| Max Emitter-Base Voltage (VEBO) | 5 | V |
| Max Collector Dissipation (Pc) | 12.5 | W |
| Max Transition Frequency (fT) | 190 | MHz |
| DC Current Gain (hFE) | 25 - 250 | |
| Storage Temperature | -65 to 150 | °C |
| Operating Junction Temperature | -55 to 150 | °C |
| Package Type | TO-126 |
Key Features
- High Collector Current: The BD139 can handle a maximum collector current of 1.5 A, making it suitable for driving high-current components such as high-power LEDs, relays, and motors.
- High Voltage Ratings: It has high collector-emitter and collector-base voltage ratings of 80 V, allowing it to operate in circuits with low to medium voltage levels.
- Low Saturation Voltage: The transistor has a low collector-emitter saturation voltage of 0.5 V, which is beneficial for efficient operation in digital electronics.
- Wide Gain Range: The DC current gain (hFE) ranges from 25 to 250, providing flexibility in amplification and switching applications.
- Non-Conductive Package: The TO-126 plastic package is non-conductive, reducing the risk of noise interference in the circuit.
Applications
- Audio Amplifiers: The BD139 is specifically designed for use in audio amplifiers and drivers, particularly in complementary or quasi-complementary circuits.
- Switching and Amplification: It is used in switching and amplification applications, including driving high-current loads such as LEDs, relays, and motors.
- Push-Pull Amplifier Circuits: Often used in pairs with the PNP transistor BD140 to create push-pull amplifier circuits.
- Educational and Commercial Projects: Its low price and high performance make it a popular choice for both educational and commercial electronic projects.
Q & A
- What is the maximum collector current of the BD139 transistor?
The maximum collector current of the BD139 transistor is 1.5 A.
- What is the maximum collector-emitter voltage rating of the BD139 transistor?
The maximum collector-emitter voltage rating of the BD139 transistor is 80 V.
- What is the package type of the BD139 transistor?
The BD139 transistor is housed in a TO-126 plastic package.
- What is the range of the DC current gain (hFE) for the BD139 transistor?
The DC current gain (hFE) of the BD139 transistor ranges from 25 to 250.
- What are the typical applications of the BD139 transistor?
The BD139 transistor is typically used in audio amplifiers, switching and amplification applications, and push-pull amplifier circuits.
- What is the maximum operating junction temperature for the BD139 transistor?
The maximum operating junction temperature for the BD139 transistor is 150°C.
- How does the BD139 transistor differ from its PNP counterpart, the BD140?
The BD139 is an NPN transistor, while the BD140 is a PNP transistor. They differ in polarity and are used for switching and amplification of positive and negative voltages, respectively.
- What is the maximum collector dissipation of the BD139 transistor?
The maximum collector dissipation of the BD139 transistor is 12.5 W.
- What is the transition frequency (fT) of the BD139 transistor?
The transition frequency (fT) of the BD139 transistor is 190 MHz.
- Why is the BD139 transistor preferred in audio amplifier circuits?
The BD139 transistor is preferred in audio amplifier circuits due to its high collector current, high voltage ratings, and low saturation voltage, making it efficient for audio amplification.
- How should the BD139 transistor be handled to ensure its safety?
To ensure the safety of the BD139 transistor, avoid operating it from voltages higher than 80 V, limit the load current to 1.5 A, use an appropriate heat sink, and avoid exposing it to temperatures below -55 °C or above +150 °C.
