The P2N2222A is a well-known general-purpose NPN transistor. This article will discuss the P2N2222A transistor in detail, including its specifications, features, working circuits, applications, safe operation and more.

Catalog

P2N2222A Transistor Basic

The P2N2222A from onsemi is a general-purpose NPN silicon transistor. It is designed for low-power amplification and switching applications. It is an enhanced version of the classic 2N2222 , offering reliable performance, fast switching speed, and stable operation in everyday electronic circuits.

This transistor is commonly used in signal amplification, LED driving, relay control, and microcontroller interfacing. Packaged in a TO-92 through-hole form, the P2N2222A is easy to install and suitable for compact designs.

If you are interested in purchasing the P2N2222A, feel free to contact us for pricing and availability.

P2N2222A Transistor CAD Models

P2N2222A Transistor Pinout Details

Alternatives & Equivalent Model

• 2N2222A

• 2N2222

• MPS2222A

• KSP2222A

• 2N4401

• BC337

•BC547

• S8050

P2N2222A Transistor Specifications

Electrical Characteristics

P2N2222A Transistor Features

General-Purpose NPN Transistor

The P2N2222A is a general-purpose NPN bipolar junction transistor designed for everyday electronic applications. It is suitable for both switching and signal amplification, making it a flexible component for a wide range of low-power circuits, from learning projects to commercial electronics.

High Collector Current Capability

With a maximum collector current of up to 600 mA, the P2N2222A can handle moderate loads compared to many small-signal transistors. This allows it to drive relays, LEDs, small motors, and other loads that require higher current than basic signal transistors.

Fast Switching Performance

The transistor offers a high transition frequency of around 300 MHz, enabling fast switching operation. This makes it effective in digital circuits, pulse applications, and logic-level switching where quick response times are important.

Stable DC Current Gain (hFE)

The P2N2222A provides a minimum DC current gain of 100, ensuring predictable amplification. This stability helps designers achieve consistent performance in amplifier stages without excessive signal distortion.

Low Saturation Voltage

Its low collector-emitter saturation voltage improves efficiency during switching. When fully turned on, the transistor wastes less power as heat, which is beneficial in battery-powered and energy-efficient designs.

Wide Operating Temperature Range

Designed to operate from −55°C to +150°C, the P2N2222A performs reliably in harsh environments. This wide temperature tolerance makes it suitable for industrial, automotive, and outdoor electronic applications.

TO-92 Through-Hole Package

The TO-92 package makes the P2N2222A easy to handle, solder, and replace. It is ideal for prototyping, breadboarding, and traditional PCB designs where through-hole components are preferred.

P2N2222A Transistor Working in Circuit

P2N2222A as a Constant Current Dummy Load

In the first circuit, the P2N2222A works as part of a constant current dummy load used to draw a fixed current from a power supply for testing. When switch S1 is turned on, a control voltage is applied through R1 to the base of the P2N2222A. This base current allows the transistor to conduct and drive the second power transistor, which actually handles the high load current. The P2N2222A acts as a control device, regulating how much current flows through the load resistor. By setting the base current properly, the circuit maintains a stable load current even if the supply voltage changes slightly.

P2N2222A as a Small-Signal Amplifier

In the second diagram, the P2N2222A is configured as a common-emitter amplifier for small AC signals. The input signal is coupled to the base through a capacitor, while resistors around the transistor provide proper biasing so it operates in its active region. When a small input voltage is applied, it causes a small change in base current, which results in a much larger change in collector current. This produces an amplified voltage at the output. The emitter resistor improves stability, while the bypass capacitor increases AC gain, making this circuit suitable for audio or low-frequency signal amplification.

P2N2222A as a Multistage Amplifier Driver

In the third circuit, multiple P2N2222A transistors are connected in stages to increase overall signal strength. The first transistor amplifies the initial signal, and its output is passed through coupling capacitors to the next stage. Each P2N2222A boosts the signal further while maintaining isolation between stages. The capacitors help block DC while allowing AC signals to pass, ensuring stable operation. In this setup, the P2N2222A functions as a reliable general-purpose amplifier transistor, commonly used in low-power audio, signal conditioning, and hobby electronics projects.