Machine-translated by Google. Questions are authored in English.
Top

Discussion

A transistor has \( \beta = 100 \) and \( f_{T} = 300 \ \mathrm{MHz} \). Its beta cut-off frequency is

  • A.300 MHz
  • B.30 MHz
  • C.30 kHz
  • D.3 MHz

Answer: D

Dividing the transition frequency by the low-frequency gain:

\[ \begin{aligned} f_{\beta} &= \frac{300 \ \mathrm{MHz}}{100} \\ &= 3 \ \mathrm{MHz} \end{aligned} \]

giving 3 MHz, beyond which the current gain starts to fall. The other options misplace a decade. The reciprocal relation between gain and bandwidth is what the transition frequency encodes, and it means a stage run at lower gain automatically has more bandwidth available.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.