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Differential Amplifier - Differential Mode

EEM

Jun 25, 2016
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Hello, I am hoping someone could help me with part B of this problem. I am not sure of the effects the resistor would have on the differential output gain.
Also I have attached my solution to part A but I am uncertain if I derived it correctly.

Any help would be appreciated !

differentialamp.jpg
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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is there a minimum and maximum current through Rc?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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look at the circuit with that question in mind.

perhaps you could consider the minimum current through either Rc and the output voltage in that case.

As the current through Rc increases what happens to the output voltage? What effect would a low vs high value resistor have?

the answer to this question should be pretty intuitive
 

EEM

Jun 25, 2016
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To me it would make sense that the higher value the added resistor is, then the smaller the differential output gain.
I've attached a proof for my understanding of part b. Does this look OK ?

partb.jpg
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Does that mean that if the resistors were a minimum (i.e. both outputs tied to Vcc) that the gain would be at a maximum?
 

LvW

Apr 12, 2014
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EEM - why do you start with part b) of the task?
Does this mean that part a) is solved already?
If not - start with a) because this opens the way to part b).

By the way: Your result in post#5 is not OK (the right side of R3 is not grounded!)..
 
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