The MMBT3904T is a popular NPN Bipolar Junction Transistor (BJT) with a maximum power dissipation of 350mW, a maximum collector-base voltage of 40V, and a maximum collector current of 200mA. It is housed in the SOT-23 surface mount package, making it suitable for use in compact electronic devices where space is limited. The MMBT3904T has a high DC current gain of 100 to 300, low noise, and fast switching speeds, making it ideal for a wide range of switching and amplification applications. Its small size, low cost, and reliability have made it a popular choice among hobbyists, students, and professionals alike