Question

4. For the circuit of Fig. 6.40, calculate \(v_{out}\) if (a) R1 = R2 = 100 k\(\Omega\), RL = 100 \(\Omega\), and \(v_{in}\) = 5 V; (b) R1 = 0.1R2, RL=∞, and vin = 2 V; (c) R1 = 1 k, R2 = 0, RL = 1\(\Omega\) , and vin = 43.5 V.

Answer 1

@agent0smith
@LastDayWork
@wolfe8
Are any of you good with OP AMPS ?

Answer 2

@ganeshie8 Are you any good with circuits?

Answer 3

What formula do you think you will be using to calculate V(out)

Answer 4

could you elaborate on your question?

Answer 5

@Johnbc

Answer 6

Is there a formula that you know for solving the "V(out)" component of your circuit?

Answer 7

Not explicitly no. However the way my prof. explained it, we take advantage of the fact that there is no current going into the op amp, and that the difference between the inputs is also 0

Answer 8

ok crappy picture but

Answer 9

\(\LARGE \dfrac {0-v_{in}} {R_2}=\dfrac {v_{in} - v_{out}} {R_1}+ \dfrac {v_{out}} {R_L}\)

Answer 10

@wolfe8 help me plz.

Answer 11

Sorry buddy I'm tired and just came back to say goodnight. When I wake up I'll take a look at it again.

Answer 12

*whimpers*

Answer 13

lol jk; ok thanks.

Answer 14

@AnthonyStark any thoughts?

Answer 15

You use Kirchoff's rule though. Try googling it. I'm too sleepy to figure it out. Good luck.

Answer 16

For op amps, kirchhoff's rule is kinda useless. well to an extent.

Answer 17

it still works but is more...difficult.
I wrote/typed down what I did but it gives me the wrong answer

Answer 18

This OP Amp is connected in the Non-inverting configuration. The Amplification Factor is determined by the ratio of the feedback resistor R1 and R2, In this case 100/100 = 1.
The output voltage would then equal Vin + 1(Vin) or 5 volts plus 5 volts or 10 volts.

Answer 19

This of course is true only if the Bias voltages are of such value, that the OP Amp is not saturated by overloading.

Answer 20

@radar ok, could you dumb that down to someone who is just learning about circuits/Op amps?

I typed the equation I tried to use but this gives me an incorrect solution.
Why is that?

Answer 21

The formula that I used is from http://en.wikipedia.org/wiki/Operational_amplifier_applications

Answer 22

Look for non-inverting amplifier.

Answer 23

I will see if I can find it in some of my reference books, but that is about right for such and amplifier with that much feedback, Note that feedback is to the "inverting input" and it holds the gain back to "one"

Answer 24

Could you take a look at what I did/typed?

Answer 25

I see what you typed, how does it treat an output equal to 5 volts?

Answer 26

Does that give you an incorrect?

Answer 27

Yes, it does. I'm not sure if I need that third term.

Answer 28

And if not, why?

Answer 29

Let me check that link I gave you.