BC547 is a Bipolar Junction Transistor (NPN) type, used in a variety of applications such as small signal amplification, switching, and current control.
Part number: BC547
Functions: 45V, 100mA, NPN Epitaxial Silicon Transistor
Package information: TO-92 Pin Type
Manufacturer: ON Semiconductor, Fairchild
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Description
BC547 is a general-purpose NPN bipolar junction transistor housed in a TO-92 (SOT54) package, designed for low-power switching and amplification applications. It features low collector current capability up to 100mA and voltage ratings suitable for signal-level circuits. This transistor is widely used in audio amplification, signal processing, and general switching applications.
Features
- NPN general-purpose transistor
- Maximum collector current up to 100mA
- Collector-emitter voltage up to 45V
- Low noise and good gain characteristics
- Compact TO-92 plastic package
- Complementary PNP types available (BC556, BC557)
Pinout
Absolute Maximum Ratings (Tc = 25 °C)
| Parameter | Symbol | Value | Unit |
| Collector-Base Voltage | VCBO | 50 | V |
| Collector-Emitter Voltage | VCEO | 45 | V |
| Emitter-Base Voltage | VEBO | 6 | V |
| Collector Current (DC) | IC | 100 | mA |
| Peak Collector Current | ICM | 200 | mA |
| Total Power Dissipation | Ptot | 500 | mW |
| Junction Temperature | Tj | 150 | °C |
| Storage Temperature | Tstg | -65 to +150 | °C |
Design Notes
- Ensure base current is properly limited using a resistor to avoid excessive IB
- Operate within safe operating area (SOA) to prevent thermal runaway
- Consider gain variation (hFE) across different batches for analog design
- Use appropriate biasing for linear amplification applications
- Thermal dissipation should be managed for continuous high-current operation
Typical Circuit Usage
- Low-power signal amplification stages
- Switching loads such as LEDs, relays, and small motors
- Audio pre-amplifier circuits
- Digital logic interfacing and level shifting
How to Choose This Part
- Select for low-current (<100mA) switching or amplification needs
- Ensure voltage ratings exceed circuit operating conditions
- Check gain (hFE) classification if precise amplification is required
- Suitable for through-hole prototyping and general-purpose designs
- Consider complementary PNP (BC557) for push-pull configurations
Applications
- General-purpose switching circuits
- Signal amplification
- Audio electronics
- Consumer electronics
- Educational and prototyping circuits
Alternative / Equivalent Products
- 2N3904 NPN transistor
- PN2222A NPN transistor
- BC548 NPN transistor
- 2SC1815 NPN transistor
Other data sheets within the file : BC546, BC548
BC547 Datasheet PDF
