BC373 Pinout, Equivalent, Application, Datasheet

The BC373 is an NPN high-voltage Darlington transistor designed for applications requiring high current gain and reliable switching performance. This article explains the construction, operation, electrical characteristics, and practical uses of the device, with a clear focus on the BC373 pinout to help designers integrate it correctly into control, driver, and amplification circuits. Key features, specifications, alternatives, and FAQs are also covered.

Introduction

The BC373 transistor is a high-voltage NPN Darlington device that combines two bipolar transistors internally to achieve very high current gain. This configuration allows the BC373 to control relatively large loads with a very small base current, making it ideal for relay drivers, solenoids, and power switching stages where simplicity and gain are important.

Pin Configuration / Pinout of BC373 Transistor

Understanding the BC373 Pinout Configuration

The BC373 is typically available in a TO-92 package. When viewed from the flat side of the package, the pin configuration is:

Correct identification of the pinout is essential to prevent damage and ensure proper operation, especially in high-gain Darlington applications.

Note: DATASHEET DOWNLOAD button is provided end of this article.

BC373 Key Features

• NPN Darlington transistor structure
• High voltage handling capability
• Very high current gain with low base drive
• Suitable for switching and driver applications
• Compact and easy-to-mount package
• Reliable performance over wide temperature range

BC373 Specifications/Characteristics

• Collector-Emitter Voltage (Vceo): 80V
• Collector-Base Voltage (Vcbo): 80V
• Emitter-Base Voltage (Vebo): 12V
• Collector Current (Ic): −1A
• Power Dissipation (PD): 625mW
• Junction Temperature (Tj): 150°C
• Storage Temperature (Tstg): −55°C to 150°C
• DC Current Gain (hFE): 10–160
• Transition Frequency (fT): 100MHz

Key Applications of BC373 Transistor

• Relay and solenoid drivers
• Motor control and switching circuits
• High-gain amplifier stages
• Power control interfaces
• Industrial and automation electronics
• Logic-level signal amplification

BC373 Equivalent / Alternatives

(Verify pin compatibility before using substitutions)

Equivalent Transistors: BC374, BC375
Alternative Devices: TIP120 (higher power), MPSA13 (lower current)

More Circuit Layouts

Working Principle of BC373

The BC373 operates as a Darlington pair, meaning the emitter of the first transistor feeds the base of the second. This results in a multiplied current gain, allowing small input signals to control larger output currents. When a small base current is applied, the transistor turns on and allows current to flow from collector to emitter, making it effective for high-gain switching and amplification tasks.

Frequently Asked Questions (FAQ)

Q1: What makes BC373 a Darlington transistor?
It internally contains two NPN transistors connected in Darlington configuration for high gain.

Q2: Can BC373 drive relays directly?
Yes, its high current gain makes it suitable for relay and solenoid driving.

Q3: What package is BC373 available in?
It is commonly supplied in a TO-92 package.

Q4: Is BC373 suitable for high-speed applications?
It supports moderate frequency applications but is mainly optimized for switching rather than high-speed RF use.

Conclusion

The BC373 is a reliable NPN high-voltage Darlington transistor that offers high current gain, good voltage handling, and simple drive requirements. Its compact size and dependable characteristics make it a practical choice for switching, driver, and control circuits in both commercial and DIY electronic projects.

Datasheet of BC373 Transistor

Click the following Button below to download the datasheet of BC373 :

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