The BF458 is an NPN high-voltage transistor designed for high-voltage amplification and switching applications. This article explains the BF458 pinout, key features, electrical specifications, working principle, applications, and suitable equivalents in a clear, consistent format.
Introduction
The BF458 is a high-voltage NPN bipolar junction transistor commonly used in video amplifiers, power supply circuits, and high-voltage signal stages. With its ability to handle high collector-emitter voltages and moderate power dissipation, the BF458 is well suited for demanding analog and switching applications.
Pin Configuration / Pinout of BF458 Transistor
Understanding the BF458 Pinout Configuration
The BF458 is available in a TO-126 package with an E-C-B pin configuration when viewed from the front:
| Pin# | Pin Name |
|---|---|
| 1 | Emitter |
| 2 | Collector |
| 3 | Base |
Correct identification of the BF458 pinout is essential for safe operation and accurate circuit design.
Note: DATASHEET DOWNLOAD button is provided end of this article.
BF458 Key Features
- NPN high-voltage bipolar transistor
- Designed for high-voltage amplification
- Moderate power dissipation capability
- Stable performance at medium frequencies
- Suitable for video and power applications
- Robust TO-126 package for better heat handling
BF458 Specifications/Characteristics
- Collector-Emitter Voltage (Vceo): 250V
- Collector-Base Voltage (Vcbo): 250V
- Emitter-Base Voltage (Vebo): 5V
- Collector Current (Ic): 100mA
- Peak Collector Current (Icm): 300mA
- Total Power Dissipation (Ptot): 6W
- Junction Temperature (Tj): 150°C
- Storage Temperature (Tstg): −65°C to 150°C
- DC Current Gain (hFE): 26
- Transition Frequency (fT): 90MHz
Key Applications of BF458 Transistor
- Video amplifier stages
- High-voltage audio amplifiers
- Power supply regulation circuits
- Switching circuits requiring high voltage handling
- Industrial and consumer electronics
BF458 Equivalent / Alternatives
(Verify pin compatibility before using substitutions)
Equivalent Transistors: BF459
Alternative Transistors: BF457, MJE340
More Circuit Layouts
Working Principle of BF458
The BF458 operates by controlling a high-voltage collector current using a small base current. When the base-emitter junction is forward biased, carriers flow from the emitter to the collector, enabling amplification or switching. Its high breakdown voltage allows it to function reliably in circuits exposed to elevated voltages.
Frequently Asked Questions (FAQ)
Q1: What type of transistor is BF458?
BF458 is an NPN high-voltage bipolar junction transistor.
Q2: What is the maximum voltage rating of BF458?
It supports up to 250V collector-emitter voltage.
Q3: What is the BF458 pin configuration?
The BF458 uses an E-C-B pinout in a TO-126 package.
Q4: Is BF458 suitable for video applications?
Yes, its high voltage rating and 90MHz transition frequency make it suitable for video amplifier circuits.
Conclusion
The BF458 NPN high-voltage transistor is a reliable component for applications requiring high voltage tolerance, moderate power handling, and stable amplification. Its robust TO-126 package and dependable electrical characteristics make it a strong choice for video, power, and industrial electronic designs.
Datasheet of BF458 Transistor
Click the following Button below to download the datasheet of BF458 :
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