2N2221A-Transistor by ON Semiconductor – NPN General Purpose Amplifier, TO-18 Package

2N2221A-Transistor Overview

The 2N2221A transistor is a widely used NPN bipolar junction transistor designed for general-purpose amplification and switching applications. It features a robust structure that supports medium power handling and fast switching speeds, making it suitable for a broad range of electronic circuits. With a maximum collector current of 800mA and a collector-emitter voltage rating of 40V, this transistor balances performance with reliability. Its versatility and availability from leading suppliers such as IC Manufacturer make it an essential component in industrial, automotive, and consumer electronics projects.

2N2221A-Transistor Key Features

• High Collector Current: Supports up to 800mA, enabling the transistor to drive moderate loads efficiently.
• Moderate Voltage Rating: Collector-Emitter voltage of 40V allows compatibility with a wide range of circuit voltages.
• Fast Switching Speed: Suitable for switching applications requiring rapid on/off cycles, improving overall system responsiveness.
• High Gain: Provides a DC current gain (hFE) typically between 100 and 300, ensuring effective amplification in signal processing circuits.

2N2221A-Transistor Technical Specifications

2N2221A-Transistor Advantages vs Typical Alternatives

This transistor offers a superior balance of current handling and voltage rating compared to many generic NPN transistors. Its reliable gain and fast switching capabilities make it preferable for both amplification and switching tasks, outperforming alternatives with lower frequency response or reduced current capacity. Additionally, its standardized TO-18 package ensures easy integration into existing designs while maintaining thermal stability and durability.

Typical Applications

• Switching circuits: Ideal for driving relays, LEDs, and other moderate loads in control systems due to its high collector current rating and fast switching.
• Signal amplification: Utilized in low-noise audio and RF amplifiers where stable gain and frequency response are essential.
• Oscillator circuits: Functions effectively in oscillator designs requiring moderate frequency operation up to 250 MHz.
• General-purpose electronic prototypes: Commonly used in experimental boards and educational kits for its versatility and availability.

2N2221A-Transistor Brand Info

The 2N2221A transistor is a standardized component produced by multiple semiconductor manufacturers, including top-tier IC suppliers. It is recognized for consistent quality, long-term availability, and compliance with industry standards. This transistor is often featured in product portfolios targeting engineers and sourcing specialists seeking a dependable and well-documented bipolar transistor solution for industrial and consumer electronics.

FAQ

What is the maximum collector current this transistor can handle?

The maximum collector current for this transistor is 800mA. This rating allows it to manage moderate load currents in switching and amplification applications without compromising device reliability.

Can this transistor be used in high-frequency circuits?

Yes, with a transition frequency (fT) of approximately 250 MHz, it is suitable for many high-frequency applications including RF amplifiers and oscillators, offering good performance at these frequencies.

What package type does this transistor come in?

This device is typically provided in a TO-18 metal can package, which offers enhanced thermal dissipation and mechanical stability, making it reliable in demanding environments.

Is the 2N2221A suitable for power amplification?

While it can handle collector currents up to 800mA and power dissipation up to 500mW, it is generally best suited for low to moderate power amplification rather than high-power stages, ensuring efficient performance in most general applications.

What are the voltage limits for safe operation?

The transistor has a collector-emitter voltage rating of 40V and a collector-base voltage rating of 75V. Staying within these limits ensures device longevity and prevents breakdown during normal operation.