2N2222 Transistor

The 2N2222 is a widely used NPN bipolar junction transistor (BJT). It is designed for low-power to medium-power applications, making it suitable for a variety of switching and amplification tasks. It is especially known for its robust performance and versatility in electronic circuits.

General Information

Type: NPN Bipolar Junction Transistor
Application: General-purpose, switching, and amplification
Packaging: TO-18 (metal can) and TO-92 (plastic)

Key Features

Medium power-handling capacity
High-speed switching
Versatile and robust design
Widely used in analog and digital circuits

Specifications

Parameter	Symbol	Value
Maximum Collector-Emitter Voltage	V_CEO	40 V
Maximum Collector-Base Voltage	V_CBO	75 V
Maximum Emitter-Base Voltage	V_EBO	6 V
Maximum Collector Current	I_C	800 mA
Power Dissipation	P_tot	500 mW (TO-92), 800 mW (TO-18)
Transition Frequency	f_T	250 MHz
DC Current Gain (h_FE)	h_FE	100–300

Pin Configuration

The 2N2222 transistor has three pins, which are arranged as follows:

Pin 1: Emitter
Pin 2: Base
Pin 3: Collector

Applications

The 2N2222 transistor is used in a wide range of circuits, including:

Signal amplification
Medium-power switching
Oscillator circuits
Motor drivers
Relay drivers
RF circuits

Circuit Example

Simple Relay Driver Circuit A 2N2222 can be used to drive a relay:

Connect the emitter to the ground.
Connect the collector to one terminal of the relay coil.
The other terminal of the relay coil is connected to a DC power supply.
Add a flyback diode across the relay coil for protection.
Apply a base current through a resistor to switch the relay on.

Advantages

Medium-power capability
High switching speed
Versatile and widely available
Rugged and reliable

Limitations

Limited to medium-power applications
Not suitable for very high-current or very high-voltage circuits

Common Alternatives

Other similar transistors include:

2N2907 (PNP counterpart)
2N3904
BC547

2N2222 Transistor

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