2N3905

2N3905 is a general purpose NPN small-signal BJT. It is a type of bipolar transistor, which has been around for a long time and remains popular due to its low cost and easy availability. 2N3905 is commonly used for amplification and switching applications. It has a maximum collector current of 500mA, a maximum power dissipation of 500mW, and an operating temperature range of -55°C to 125°C.

2N3905 is a popular small-signal BJT for a variety of general purpose applications. It is most commonly used as an amplifier in radio-frequency (RF) circuits, as it can amplify electrical signals over a wide frequency range. In high-frequency applications, 2N3905 is also used as a switch. It can be used to turn on and off transistors such as MOSFETs, PNP and NPN transistors, and IGBTs. In addition, it can be used in low-frequency applications such as amplifying audio signals.

The working principle of 2N3905 consists of three terminals. The emitter terminal is the input, which supplies the current into the base terminal. The base is then amplified through the transistor and supplies the output to the collector terminal. This type of transistor works in two modes - cut-off and active. In cut-off mode, the base current is switched off, causing no current to flow through the transistor. In active mode, current is supplied to the base, which is amplified and transferred to the collector, resulting in the output current.

2N3905 is widely used in a variety of applications ranging from radio-frequency circuits to low-frequency audio amplifiers. Its low cost, high power capability and wide operating temperature range make it an ideal choice for a variety of applications. Furthermore, its easy availability and relatively low price make it an attractive option to use in hobbyist projects as well. Therefore, 2N3905 is a great option for anyone looking to build cost-effective and high-performance electronics.