How to Determine V- Without Knowing Resistance?

  • Thread starter Janiceleong26
  • Start date
In summary, the conversation is discussing the determination of V- for a circuit with a given V+ and Vout. The equation for gain is mentioned, but the value of V- is unknown. The conversation ends with a clarification that the question is about the gain of the whole amplifier stage, not just the op-amp.
  • #1
Janiceleong26
276
4
1. Homework Statement
image.jpg


For part ii) ,
V+ is 69mV, but how to determine V-? We don't know the resistance of X, so we can't find the p.d. across X, so how to find V-?

Homework Equations


Vout =A0(V+-V-)
 
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  • #2
Isn't the gain of this amp Vout/VR?
 
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Likes CWatters
  • #3
But Vout and VR are given.
 
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Likes CWatters
  • #4
I'm sorry, but can you please explain to me why is V-=0 in your eqn for the gain in post #2 , thanks
 
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  • #5
There is no zero in my equation in post #2
 
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  • #6
gleem said:
There is no zero in my equation in post #2
Then, how did you know that the gain is Vout/VR? Why didn't you take account of V-?
 
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  • #7
That is the general definition of gain.
 
  • #8
OK.
Vout=Ao(V+-V-), am I right?
Vout=5.8V
V+=69mV
V-= ?
 
  • #9
Why do you want V- ?
 
  • #10
gleem said:
Why do you want V- ?
So that I can use the formula, Vout=A0(V+-V-) ,and get A0
 
  • #11
The question was what is the gain of the circuit not the op-amp. that's why I commented on the simplicity of the question.
 
  • #12
Janiceleong26 said:
So that I can use the formula, Vout=A0(V+-V-) ,and get A0
So you are interested in Ao ?
Up to now I was of the opinion you were looking for the gain of the whole amplifier stage?
 
  • #13

[ Mentor note: this thread has been tidied up ]
 
  • #14
gleem said:
The question was what is the gain of the circuit not the op-amp. that's why I commented on the simplicity of the question.
LvW said:
So you are interested in Ao ?
Up to now I was of the opinion you were looking for the gain of the whole amplifier stage?
Ohhh.. I get it now
Sorry I thought they were asking for A0
Thanks so much
 

FAQ: How to Determine V- Without Knowing Resistance?

What is "V- in Part II: How to Find it?"

"V- in Part II: How to Find it?" is a scientific method used to determine the velocity of an object in motion.

Why is "V- in Part II: How to Find it?" important?

"V- in Part II: How to Find it?" is important because it allows scientists to accurately measure the speed of an object in motion, which is crucial for understanding various physical phenomena.

What equipment is needed for "V- in Part II: How to Find it?"

The equipment needed for "V- in Part II: How to Find it?" may vary depending on the specific experiment, but generally includes a stopwatch, measuring tape, and a device to track the motion of the object, such as a motion detector or video camera.

What are the steps for using "V- in Part II: How to Find it?"

The steps for using "V- in Part II: How to Find it?" typically involve setting up the equipment, recording the motion of the object, analyzing the data, and using mathematical formulas to calculate the velocity of the object.

Can "V- in Part II: How to Find it?" be used for any type of motion?

Yes, "V- in Part II: How to Find it?" can be used for any type of motion, whether it's linear, circular, or projectile motion. However, the specific equations and methods used may vary depending on the type of motion being measured.

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