Question
Download Solution PDFA change in the value of the emitter resistance RE in a differential amplifier
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFDifferential amplifier is shown below:
Differential voltage Gain (Ad) is given by:
Ad = -gmRc
And the Common-mode gain (Acm) is given by:
\({A_{cm}} = \frac{{ - {R_c}}}{{2{R_E}}}\)
We can observe that with an increase in RE, Acm decreases.
Note:
\(CMRR = \left| {\frac{{{A_d}}}{{{A_{cm}}}}} \right|\)
\(CMRR = \frac{{{g_m}{R_c}}}{{\frac{{{R_c}}}{{2{R_E}}}}}\)
\( = 2{g_m}{R_E}\)
We can observe that with an increase in RE, Acm decreases, and CMRR increases.
Last updated on Jul 2, 2025
-> ESE Mains 2025 exam date has been released. As per the schedule, UPSC IES Mains exam 2025 will be conducted on August 10.
-> UPSC ESE result 2025 has been released. Candidates can download the ESE prelims result PDF from here.
-> UPSC ESE admit card 2025 for the prelims exam has been released.
-> The UPSC IES Prelims 2025 will be held on 8th June 2025.
-> The selection process includes a Prelims and a Mains Examination, followed by a Personality Test/Interview.
-> Candidates should attempt the UPSC IES mock tests to increase their efficiency. The UPSC IES previous year papers can be downloaded here.