Electronics and Communication Engineering - Analog Electronics - Discussion
Discussion Forum : Analog Electronics - Section 1 (Q.No. 12)
12.
In figure, VEB = 0.6 V, β = 99. Then VC and IC are
Answer: Option
Explanation:
VC = 20 - 1.98 x 10-3 x 5.4 x 103 
9.3 V.
Discussion:
11 comments Page 1 of 2.
Sandeep said:
1 decade ago
Why 400/9 is taken?
Arif said:
1 decade ago
Use these formulas:
Ib = (Vcc-Vbe)/(Rb+BRc).
Ic = BIb.
Vc = Vcc-IcRc.
Ib = (Vcc-Vbe)/(Rb+BRc).
Ic = BIb.
Vc = Vcc-IcRc.
Sivaiah said:
9 years ago
In question, they mention it as Veb but it is Vbe.
Chenelyn Cedron said:
9 years ago
@Sandeep It's 400/99, just a typo error.
In fact, if you are bookish enough and you hate approximations, your first equation might look like this:
Vcc = V{5.4k} + V{400k} + V{be}.
Vcc = ((B)(Ib) + 1)(5.4k)(Ic)/B + (400k)(Ic)/B + V{be}.
Substituting the given gives:
20 = (99 + 1)(5.4k)(Ic)/(99) + (400k)(Ic)/(99) + 0.6.
This would give you an Ic of 2.043 mA.
Then since Vce = Vc = Vcc - IcRc,
Vc = 20 - (2.043mA)(5.4k) = 8.97 V. Pretty close to letter A.
In fact, if you are bookish enough and you hate approximations, your first equation might look like this:
Vcc = V{5.4k} + V{400k} + V{be}.
Vcc = ((B)(Ib) + 1)(5.4k)(Ic)/B + (400k)(Ic)/B + V{be}.
Substituting the given gives:
20 = (99 + 1)(5.4k)(Ic)/(99) + (400k)(Ic)/(99) + 0.6.
This would give you an Ic of 2.043 mA.
Then since Vce = Vc = Vcc - IcRc,
Vc = 20 - (2.043mA)(5.4k) = 8.97 V. Pretty close to letter A.
Neeraj said:
8 years ago
Operating Vbe should be 0.7.
Prutha said:
8 years ago
I am Not clear with the solution. Please explain.
Aman said:
7 years ago
Apply kvl from 20-Ic * 5.4-Ib * 400-0.6 = 0.
You will get Ib=. 02ma.then Ic=BIb=1.98ma.
Now you can easily find Vc.
You will get Ib=. 02ma.then Ic=BIb=1.98ma.
Now you can easily find Vc.
Karthik said:
7 years ago
What is 400/9?
Vasanthakumara D said:
6 years ago
This question 400/9 how come 9?
Rajani said:
6 years ago
It should be 400/99 not 400/9.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers