2n2222a Bipolar Junction Npn Transistor

2N2222A Bipolar Junction NPN Transistor is commonly used in general-purpose low-power amplifying/switching applications. Bipolar Junction NPN Transistor is designed for low to medium current, low power, medium voltage, and can operate at moderately high speeds. It was originally made in the TO-18 metal can as shown in the picture. We have many other NPN transistor like BD139, BC547, BC548, 2SC945 etc.
The 2N2222 is considered a very common transistor and is used as an exemplar of an NPN transistor. It is frequently used as a small-signal transistor, and it remains a small general-purpose transistor of enduring popularity.

Features of 2N2222A Bipolar Junction NPN Transistor:

1. Use in a wide variety of electronic projects, the large 600mA collector current makes this transistor ideal to use it in your electronic projects to control relays, high power LEDs, other high power transistors and ICs at the same time.
2. 2N2222A can also be used to amplify audio signals, for example, it can be used in audio preamplifier stages and also in audio amplifier stages. It can also be used as a small audio amplifier or to drive a small speaker in electronic projects.

Specifications of 2N2222A Bipolar Junction NPN Transistor:

1. Transistor Polarity: NPN
2. Collector-Emitter Voltage V(BR)CEO: 30V
3. Power Dissipation Pd: 500mW
4. DC Collector Current: 800mA
5. DC Current Gain hFE: 100
6. Transistor Case Style: TO-18
7. No. of Pins: 3
8. Collector-Emitter Voltage Vces: 400mV
9. Continuous Collector Current Ic Max: 800mA
10. Current Ic @ Vce Sat: 150mA
11. Current Ic Continuous a Max: 800mA
12. Current Ic hFE: 150mA
13. Full Power Rating Temperature: 25°C
14. Gain Bandwidth ft Min: 250MHz
15. Gain Bandwidth ft Typ: 250MHz
16. Hfe Min: 100
17. No. of Transistors: 1
18. Pin Configuration: a
19. Power Dissipation Pd: 500mW
20. Power Dissipation Ptot Max: 500mW
21. Termination Type: Through Hole
22. Voltage Vcbo: 60V

Applications:

1. Audio Preamplifiers
2. Audio Amplifier Stages
3. Switching many loads at the same time (Thanks to its 600mA output in a small TO-92 package)
4. Darlington Pairs
5. RF Circuits
6. Sensor Circuits

Package includes:

• 1 x 2N2222A Bipolar Junction NPN Transistor

• 2N2222A NPN Transistor
  2N2222A Pinout

2N2222A Pinout Configuration

Features

• Bi-Polar high current NPN Transistor
• DC Current Gain (h is 100
• Continuous Collector current (I) is 800mA
• Emitter Base Voltage (V) is 6V
• Collector Emitter Voltage (V) is 30V
• Base Current(I) is 5mA maximum
• Available in To-92 Package

Note: Complete Technical Details can be found in the 2N2222A datasheet, given at the end of this page.

Alternative

BC549, BC636, BC639, BC547, 2N2369, 2N3055, 2N3904, 2N3906, 2SC5200

2N2222A Equivalent Transistors

2N2907(PNP), 2N3904(PNP), 2N3906 (PNP), BC637, S9014, BC148, 2N4403, MPS2222, PN2222, KN2222, KTN2222

2N2222A Brief Description

2N2222A is a NPN transistor hence the collector and emitter will be left open (Reverse biased) when the base pin is held at ground and will be closed (Forward biased) when a signal is provided to base pin. 2N2222A has a gain value of 110 to 800, this value determines the amplification capacity of the transistor. The maximum amount of current that could flow through the Collector pin is 800mA, hence we cannot connect loads that consume more than 800mA using this transistor. To bias a transistor we have to supply current to base pin, this current (I) should be limited to 5mA.

When this transistor is fully biased, then it can allow a maximum of 800mA to flow across the collector and emitter. This stage is called Saturation Region and the typical voltage allowed across the Collector-Emitter (V­) or Base-Emitter (V) could be 200 and 900 mV respectively. When base current is removed the transistor becomes fully off, this stage is called as the Cut-off Region and the Base Emitter voltage could be around 660 mV.

Where to use 2N2222A

The 2N2222A transistor is very much similar to the commonly used NPN transistor BC547. But there are two important features that distinguish both. 2N2222A can allow collector current upto 800mA and also has power dissipation of 652mW which can be used to drive larger loads than compared with BC547.

So if you looking for an NPN transistor that could switch loads of higher current, then 2N2222A might the right choice for your project.

How to use 2N2222A

This transistor like all can be used either as a switch or as an amplifier. The Base-Emitter voltage of this transistor is 6V so you just have to supply this voltage across the base and emitter of the transistor to induce a base current into the transistor. This transistor will make it forward biased and thus closes the connection between collector and emitter. However one important thing to notice is the Base resistor a.k.a current limiting resistor. As the name suggests this resistor will limit the current flowing through the transistor to prevent it from damaging. The value for this resistor can be calculated using the formula

R = V / I 

To make things simple, I have shown a simplified circuit to make a transistor as switch. In actual circuit modifications might be required. I have used a base voltage of 5V and a value of 1K as current limiting resistor.

Note that the motor here draws about 500mA from the 12V power source, since the 2N2222 has collector current rating upto 800mA this circuit is possible had it been a BC547 the transistor should have been burnt.

Applications

• Can be used to switch high current (upto 800mA) loads
• It can also be used in the various switching applications.
• Speed control of Motors
• Inverter and other rectifier circuits
• Can be used in Darlington Pair.