Output voltage of differential amplifier

  • Thread starter pforpashya
  • Start date
  • #1
12
0

Homework Statement



Find output voltage of differential amplifier having differential gain of 100 and common mode gain 0.1 if input voltages are v1=2+0.55sinwt and v2=0.5-0.005sinwt

Homework Equations





The Attempt at a Solution



well, from sedra smith book i found the formula for output book

v0= Ad(v1-v2)+Acm(v1+v2)/2

if i have to subtract two AC signals with dc offsets i get v1-v2= 1.5+0.55sinwt am i correct?

so can right it as 2.11sinwt
again for Acm i have to take average of two signals which will be 1.25+0.272sinwt

i have to divide it by 2 hence it becomes 1.522sinwt

the final ans i am getting is 211.15sinwt am i correct?
 

Answers and Replies

  • #2
rude man
Homework Helper
Insights Author
Gold Member
7,856
792

Homework Statement



Find output voltage of differential amplifier having differential gain of 100 and common mode gain 0.1 if input voltages are v1=2+0.55sinwt and v2=0.5-0.005sinwt

Homework Equations





The Attempt at a Solution



well, from sedra smith book i found the formula for output book

v0= Ad(v1-v2)+Acm(v1+v2)/2

if i have to subtract two AC signals with dc offsets i get v1-v2= 1.5+0.55sinwt am i correct?
Your sin term is off by about 1%.
so can right it as 2.11sinwt
????

again for Acm i have to take average of two signals which will be 1.25+0.272sinwt

i have to divide it by 2 hence it becomes 1.522sinwt
????
You don't divide the average by 2 again! And what happened to the dc term?

the final ans i am getting is 211.15sinwt am i correct?[/QUOTE]

Don't think so.
Your starting formula is correct but then you seem to be floundering with the math.
 

Related Threads on Output voltage of differential amplifier

Replies
49
Views
2K
  • Last Post
Replies
2
Views
4K
Replies
0
Views
1K
Replies
3
Views
1K
Replies
4
Views
3K
Replies
7
Views
2K
  • Last Post
Replies
13
Views
5K
  • Last Post
Replies
2
Views
936
  • Last Post
Replies
1
Views
5K
Top