BC547 Transistor: Datasheet, Pinout and Equivalent

BC547 Transistor Description

The BC547 is a commonly used NPN bipolar junction transistor (BJT) that belongs to the BC54x series of transistors. It's designed for general-purpose switching and amplification applications. Here's a description of the BC547 transistor:

• Type: NPN BJT (Bipolar Junction Transistor)
• Polarity: NPN (Negative-Positive-Negative)
• Package Type: TO-92 (through-hole)
• Maximum Collector Current (Ic): 100 mA
• Maximum Collector-Emitter Voltage (Vceo): 45 V
• Maximum Collector-Base Voltage (Vcbo): 50 V
• DC Current Gain (hFE): Typically ranges from 110 to 800
• Transition Frequency (ft): Approximately 100 MHz
• Low-Frequency Noise Figure: 4 dB

BC547 Transistor Pinout

• Pin 1 (Collector): Marked as 'C', this pin serves as the terminal for current flow into the collector.
• Pin 2 (Base): Controls transistor biasing.
• Pin 3 (Emitter): Current exits through the emitter terminal.

BC547 Transistor Features

• NPN Configuration: Suitable for applications where collector is more positive than emitter.
• Small Signal Amplification: Designed for amplifying weak signals.
• Low Collector Current: Ideal for low-current applications (up to 100 mA).
• Low Voltage Operation: Works within low collector-emitter voltage range (up to 45 V).
• Broad Gain Range: DC current gain (hFE) ranges from 110 to 800.
• High Transition Frequency: Transition frequency (ft) around 100 MHz.
• TO-92 Package: Convenient for handling and mounting.
• General-Purpose Use: Versatile for switching, amplification, and more.
• Low Noise Figure: Noise figure of 4 dB, suitable for noise-sensitive applications.
• Common Collector-Base Voltage: Max collector-base voltage (Vcbo) of 50 V.
• Reliable and Widely Used: Proven reliability in various electronic designs.

BC547 Application

Amplification: Amplify weak signals in circuits like audio amplifiers and sensor interfaces.

Switching: Control current flow in low-power devices and digital logic circuits.

Oscillators: Generate clock signals and periodic waveforms.

Voltage Regulation: Stabilize and control output voltages.

Signal Processing: Condition signals for better performance.

Audio Circuits: Power sound amplifiers and equalizers.

LED Drivers: Drive LEDs in basic lighting setups.

Voltage Followers: Isolate and match input-output voltages.

Logic Gates: Form part of basic digital logic operations.

Education: Illustrate transistor characteristics in electronics teaching.

BC547 Application circuit

Below is the circuit diagram for the ON/OFF touch switch utilizing the BC547 transistor. The circuit becomes operational upon power supply activation. When power is applied, the relay switches to the "off" mode. As a result, the base terminal of transistor Q3 remains at a high level due to the R7 resistor, maintaining the transistor in a cut-off state.

BC547 Transistor Equivalent

2N3904

BC547 Transistor Datasheet

Download BC547 transistor datasheet here>>

2n5551 vs 2n2222a vs bc547

2N5551:

Type: NPN Bipolar Junction Transistor

Applications: General-purpose amplification and switching

Power Handling: Moderate

Frequency Range: Moderate

Commonly Used For: Signal amplification, switching applications

2N2222A:

Type: NPN Bipolar Junction Transistor

Applications: General-purpose switching and amplification

Power Handling: Low to Moderate

Frequency Range: Moderate

Commonly Used For: Switching applications, small signal amplification

BC547:

Type: NPN Bipolar Junction Transistor

Applications: General-purpose amplification and switching

Power Handling: Low

Frequency Range: Moderate

Commonly Used For: Signal amplification, switching applications, basic digital logic

Comparison:

The 2N5551, 2N2222A, and BC547 are all NPN transistors commonly used for general-purpose applications. They share similar features and can be used interchangeably in many cases. However, the choice between them depends on specific circuit requirements, power handling, and frequency considerations. If higher power handling is needed, the 2N5551 or 2N2222A might be more suitable. For basic applications and low-power scenarios, the BC547 is a cost-effective option.

BC547 Advantages and Disadvantages

Advantages of BC547 Transistor:


Versatility: The BC547 is versatile and can be used in a wide range of general-purpose applications.

Cost-Effective: It's an economical choice for basic electronics projects.

Availability: Widely available and commonly stocked by suppliers.

Ease of Use: Simple to integrate into circuits due to its through-hole TO-92 package.

Low Noise: Relatively low noise figure, suitable for low-noise applications.

Amplification: Offers small-signal amplification for various sensor and signal processing circuits.

Disadvantages of BC547 Transistor:



Limited Power Handling: Not suitable for high-power applications due to its low power handling capability.

Limited Frequency Range: Moderate transition frequency limits its use in higher-frequency applications.

Low Voltage Rating: Limited maximum collector-emitter voltage (Vceo) compared to some other transistors.

Non-SMT Package: The through-hole TO-92 package might not be suitable for surface-mount technology (SMT) designs.

Temperature Sensitivity: Performance might vary with temperature changes, requiring careful consideration in temperature-sensitive applications.

FAQS about BC547

Q: What is the maximum collector current (IC) of the BC547?

A: The maximum collector current (IC) of the BC547 is typically around 100 mA.



Q: What is the maximum collector-emitter voltage (VCEO) of the BC547?

A: The maximum collector-emitter voltage (VCEO) of the BC547 is typically around 45 V.



Q: Can the BC547 be used for high-power applications?

A: No, the BC547 is not designed for high-power applications due to its limited current and voltage ratings.



Q: Is the BC547 suitable for audio amplifier circuits?

A: The BC547 can be used in low-power audio amplifier circuits, but it might not be suitable for high-power audio applications.