# BJT voltage gain

Discussion in 'Homework Help' started by hamza324, Jul 10, 2011.

1. ### hamza324 Thread Starter Member

Jul 10, 2011
33
1
hi ....

I was reading through my book and could understand the difference between "terminal voltage gain" and "overall voltage gain"
BJT single stage amplifiers

Last edited: Jul 10, 2011
2. ### Jony130 AAC Fanatic!

Feb 17, 2009
3,993
1,116
Can you show as the diagram or the text from that book.
General speaking when we treat the amplifier alone the the voltage gain is equal
Av = Vout/Vin

But if we consider the influence of the source resistance and input resistance of our amplifier we get the overall gain.

Overall gain = Vout/Vs = Vin/Vs * Vout/Vin = 0.5 * 100 = 50V/V

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Jul 10, 2011
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4. ### lazukan New Member

Mar 29, 2011
5
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terminal voltage gain refers to V (collector ) / V ( base)= Beta
Overall voltage gain refers V ( out) / V( in)
It is the matter of the fact that at which terminal or branch you take the measurements

Correct me if i am wrong

Lazukan

5. ### RLC New Member

Jul 20, 2011
13
0
Terminal gain refers to β gain (Hfe) which we can directly measure on
Multi-meter.
While overall voltage gain refers to, taking gain with taking source Impedance and Load impedance into consideration

6. ### Adjuster Well-Known Member

Dec 26, 2010
2,147
300
β is a measure of current gain: it is not directly related to voltage gain, although due to its effect on input impedance it does make a contribution to overall voltage gain.

Last edited: Jul 21, 2011
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7. ### RLC New Member

Jul 20, 2011
13
0
yeah ur right i realized my mistake
Thank u