Electronics and Communication Engineering - Electronic Devices and Circuits - Discussion

Discussion Forum : Electronic Devices and Circuits - Section 1 (Q.No. 5)
5.
A transistor has a current gain of 0.99 in the CB mode. Its current gain in the CC mode is
100
99
1.01
0.99
Answer: Option
Explanation:

Current gain = 1 + β = 100.

Discussion:
30 comments Page 1 of 3.

AJAY P ROY said:   9 years ago
In CB config: CURRENT GAIN (ALPHA, a) : Ic/Ie=.99 (given).

In CE config: CURRENT GAIN (BETA, b) : Ic/Ib.

In CC config: CURRENT GAIN (gamma, g) : Ie/Ib.

And b = a/(1 - a).

Then, g = 1 + b.

Therefore: g = 1 + (a/(1 - a)).

g =1/(1 - a) = 1/(1 - .99) = 1/.01 = 100.
(4)

Burra Dhanunjaya said:   5 years ago
However, there will be difference in application and performance of CB and CC configurations most of the people they don't consider this.

CB: To isolate output signal, impedence matching.

CC:providing high input impedence, low output impedence, high Bandwidth.
(5)

Kamran saifi said:   1 decade ago
CB is Common Base & CC is Common Collector mode. The current gain in CB mode is Ic/Ie & for CC mode it is Ic/Ib.
(1)

Nimrod said:   7 years ago
Why do we change modes from CC to CB or vice versa?

What is the practical application of changing transistor modes?

Jyoti prasad said:   6 years ago
Y-> gama B-> beta < ---> alpha

Y = B+1 = 1/1- < = 1/(1-0.99) = 100.
(1)

Hussain said:   10 years ago
Ic/ie = Alpha.

Ic/ib = beta, b = a/(1-a).

A given = 0.99.

So b = 99 = 1+99 = 100.

Kiran said:   2 years ago
Very Clearly explained and thank you for giving the use case @ Burra Dhanunjaya.
(3)

Nandan Kumar said:   1 decade ago
Please tell me about CB mode is Ic/Ie & CC mode is Ic/Ib.

Rakesh said:   1 decade ago
Sir I don't know about CB and CC please tell me briefly?

Saravana said:   7 years ago
The explanation is super, Thanks @Ajay.


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