The BC547 and 2N2222 transistors are both widely used NPN bipolar junction transistors (BJTs) but have different specifications and characteristics. Here's a breakdown of their differences:
BC547: The BC547 is an NPN transistor with the following specifications:
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Maximum Collector Current (IC): The BC547 typically has a maximum collector current rating of 100 mA (milliamperes). This rating indicates the maximum current allowed to flow through the transistor's collector terminal without causing damage.
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Maximum Collector-Emitter Voltage (VCEO): The BC547 generally has a maximum collector-emitter voltage rating of 45 volts. It signifies the maximum voltage that can be applied across the collector-emitter junction without risking failure.
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Current Gain (hFE or β): The current gain of the BC547 transistor typically ranges from 110 to 800. This parameter represents the amplification capability of the transistor, showing the ratio of the collector current (IC) to the base current (IB).
2N2222: The 2N2222 is also an NPN transistor commonly used in various applications. Here are its specifications:
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Maximum Collector Current (IC): The 2N2222 has a significantly higher maximum collector current rating compared to the BC547. It typically has a rating of 800 mA (milliamperes), allowing it to handle greater current levels.
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Maximum Collector-Emitter Voltage (VCEO): The 2N2222 generally has a maximum collector-emitter voltage rating of 40 volts, which is slightly lower than the BC547's rating of 45 volts.
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Current Gain (hFE or β): The current gain of the 2N2222 transistor typically falls within the range of 100 to 300, which is generally lower than the BC547's range of 110 to 800.
Ratings & Characteristics Comparison:
| Ratings & Characteristics | BC547 | 2N2222 |
|---|---|---|
| Collector-Emitter Voltage (Vceo) | 50V | 40V |
| Collector Current (Ic) | 100mA | 600mA |
| Total Device Dissipation (PD) | 500mW | 625mW |
| DC Current Gain (hFE) | 110 To 800 | 30 To 300 |
| Frequency (fT) | 300 MHz | 250 MHz |
Differences:
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Maximum Collector Current: The 2N2222 has a significantly higher maximum collector current rating (800 mA) compared to the BC547 (100 mA). This makes the 2N2222 more suitable for applications requiring a higher current-handling capability.
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Current Gain: The BC547 generally has a wider range of current gain (110 to 800) compared to the 2N2222 (100 to 300). This means that the BC547 might exhibit higher amplification capabilities in some applications, depending on the desired gain range.
Similarities:
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Maximum Collector-Emitter Voltage: Both the BC547 and 2N2222 transistors have similar maximum collector-emitter voltage ratings. The BC547 has a rating of 45 volts, while the 2N2222 has a rating of 40 volts. This means that they can handle similar voltage levels across the collector-emitter junction.
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NPN Transistor Type: Both the BC547 and 2N2222 are NPN transistors, indicating they have three layers with a negatively-doped layer sandwiched between two positively-doped layers. This similarity allows them to function as NPN BJTs.
When selecting a transistor for a specific application, it is important to consider the required maximum collector current, maximum collector-emitter voltage, and current gain. Additionally, consult the datasheets provided by the manufacturer for detailed specifications and information to ensure the proper selection of the transistor for your specific circuit needs.
