BC547 NPN General Purpose Transistor

Overview

The BC547 is a widely used NPN bipolar junction transistor (BJT) designed for general-purpose amplification and switching applications. This component is part of the BC54x family of transistors and is characterized by its low noise, high current gain, and moderate power dissipation capabilities. The BC547 is available in multiple package options, including TO-92, TO-18, and TO-5, making it versatile for various circuit designs.

With its robust performance and reliability, the BC547 is commonly employed in consumer electronics, industrial control systems, and educational projects. Its electrical characteristics make it suitable for both analog and digital circuits, including signal amplification, oscillator circuits, and low-power switching applications.

Features

• NPN Bipolar Junction Transistor (BJT): Suitable for amplification and switching.
• High Current Gain (h_FE): Typically ranges from 110 to 800, ensuring efficient signal amplification.
• Low Noise Operation: Ideal for audio and RF applications.
• Moderate Power Dissipation: Maximum power dissipation of 625 mW (TO-92 package).
• Multiple Package Options: Available in TO-92 (standard), TO-18, and TO-5 packages.
• Wide Operating Temperature Range: -65°C to +150°C, suitable for various environments.
• Lead-Free and RoHS Compliant: Environmentally friendly manufacturing.

Applications

The BC547 transistor is used in a broad range of electronic circuits due to its versatility and reliability. Common applications include:

• Signal Amplification: Used in audio preamplifiers, RF stages, and sensor interfaces.
• Switching Circuits: Functions as a switch in relay drivers, LED drivers, and logic circuits.
• Oscillators and Waveform Generators: Employed in RC oscillators, multivibrators, and clock circuits.
• Educational and Hobbyist Projects: Frequently used in breadboard experiments and DIY electronics.
• Consumer Electronics: Found in radios, televisions, and small appliances.
• Industrial Control Systems: Used for low-power control and automation tasks.

Electrical Characteristics

The following table summarizes the key electrical specifications of the BC547 transistor under typical operating conditions (unless otherwise specified):

Absolute Maximum Ratings

• Collector-Base Voltage (V_CB): 50 V
• Collector-Emitter Voltage (V_CE): 45 V
• Emitter-Base Voltage (V_EB): 6 V
• Collector Current (I_C): 100 mA (continuous)
• Total Power Dissipation (P_tot): 625 mW (TO-92 package)
• Operating Junction Temperature (T_j): -65°C to +150°C
• Storage Temperature (T_stg): -65°C to +150°C

Typical Electrical Characteristics (T_A = 25°C)

• DC Current Gain (h_FE): 110 to 800 (at I_C = 2 mA, V_CE = 5 V)
• Collector-Emitter Saturation Voltage (V_CE(sat)): 0.25 V (max) at I_C = 10 mA, I_B = 1 mA
• Base-Emitter Saturation Voltage (V_BE(sat)): 0.9 V (max) at I_C = 10 mA, I_B = 1 mA
• Transition Frequency (f_T): 300 MHz (typical)
• Noise Figure (NF): 5 dB (typical at 1 kHz, I_C = 100 µA, V_CE = 5 V)

Package Information

The BC547 is available in multiple package styles, each suited for different assembly and application requirements. Below are the key package details:

TO-92 Package (Standard)

• Package Type: Plastic, through-hole mounting.
• Lead Configuration: Straight leads (no lead clip option available).
• Dimensions: Approx. 4.7 mm (L) x 3.7 mm (W) x 4.2 mm (H).
• Packing Quantity: 2,000 units per box (bulk option available).

TO-18 Package (Optional)

• Package Type: Metal can, through-hole mounting.
• Lead Configuration: No lead clip (standard).
• Dimensions: Approx. 5.3 mm (diameter) x 4.7 mm (height).
• Packing Quantity: 2,000 units per box.

TO-5 Package (Optional)

• Package Type: Metal can, through-hole mounting.
• Lead Configuration: No lead clip (standard).
• Dimensions: Approx. 8.6 mm (diameter) x 5.3 mm (height).
• Packing Quantity: 1,500 units per box.

Bulk Packing Information

For high-volume production, the BC547 is available in bulk packaging options, including reels and ammo boxes:

• Reel Packing: 2,000 units per reel (EOL codes: D26Z, D27Z, D74Z, D75Z).
• Ammo Packing: 2,000 units per ammo box (EOL codes: D26Z, D27Z, D74Z, D75Z).
• Intermediate Box Dimensions: 375 mm x 267 mm x 375 mm (FSCINT label).
• Maximum Quantity per Intermediate Box: 10,000 units.

Conclusion

The BC547 NPN transistor is a versatile and reliable component for general-purpose amplification and switching applications. Its high current gain, low noise characteristics, and multiple packaging options make it a popular choice among engineers, hobbyists, and manufacturers. Whether used in consumer electronics, industrial systems, or educational projects, the BC547 delivers consistent performance and ease of integration.