The 2N3904 is a widely used NPN transistor that serves as a fundamental building block in electronic circuits. This general-purpose transistor is capable of handling a collector current (IC) of up to 200 mA, making it suitable for a wide range of applications. It features a maximum collector-emitter voltage (VCEO) of 40V, which determines the maximum voltage the transistor can handle between its collector and emitter when the base is open.
One of the key characteristics of the 2N3904 is its DC current gain (hFE1), which is approximately 200. This parameter is crucial for understanding how much the transistor can amplify the input signal. The transistor also has a total power dissipation (Ptot) of 625 mW, allowing it to operate within a wide range of power levels. Its maximum junction temperature (Tjmax) is 150°C, ensuring reliability under various operating conditions.
Transistor
Transistors are fundamental components in electronic circuits, acting as switches or amplifiers. They are made of semiconductor material and have three terminals: the emitter, the base, and the collector. The NPN transistor, such as the 2N3904, is a type of bipolar junction transistor (BJT) where a small current input at the base controls a larger current flowing from the collector to the emitter.
When selecting a transistor for a particular application, several parameters are important, including the collector-emitter voltage (VCEO), collector current (IC), and current gain (hFE). These parameters determine the transistor's ability to handle voltage and current levels, as well as its amplification capability. Other considerations include power dissipation, which affects the transistor's ability to manage heat, and the maximum junction temperature, which indicates the highest temperature the transistor can withstand without degradation.
The 2N3904's general-purpose nature makes it suitable for a wide variety of applications, from simple switching circuits to more complex signal amplification setups. Its reliability and performance parameters make it a popular choice among engineers for both prototyping and production.
When integrating a transistor into a design, it's also important to consider the mechanical and thermal characteristics, such as the package type and thermal resistance. These factors can influence the physical layout of the circuit and its thermal management strategy. The 2N3904, with its TO-92 package, offers a practical solution for many circuit designs, combining ease of use with effective performance.