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Could someone please tell me what is the value of Ux? How can i calculate it?

is Ux = (U1 - U2) * R2/(R1+R2) correct?

majid khan
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    Your question doesn't really have anything to do with operational amplifiers. Were you aware of this? – Andy aka Feb 05 '24 at 16:03
  • You need to show your work so far. This isn't a homework service. – Null Feb 05 '24 at 16:22
  • For homework types of questions we expect you to show that you have made a substantial effort to solve the problem yourself. Show us all of your work and then ask a specific question. – Elliot Alderson Feb 05 '24 at 16:23
  • to solve this problem i know that i need to use the voltage divider formula, but since there are two voltage sources i am confused how should i apply the formula , i am sorry i am still in school, not a great researcher like yourself. just asked for a simple explanation, got so much backlash. thanks anyways! – majid khan Feb 05 '24 at 16:30
  • @Andyaka, you have to know what the ideal properties of the op amp inputs are to solve the problem. – Scott Seidman Feb 05 '24 at 16:31
  • @Andyaka i think the ideal properties have nothing to do with this question unless i am calculating the gain of the opamp. i only want to calculate Ux using the voltage division – majid khan Feb 05 '24 at 16:33
  • @majid khan To get you started, you might want to read this. – kaosad Feb 05 '24 at 16:36
  • Complete the circuit by drawing in the missing components (the voltage sources and ground.) This can help rather than trying to visuallize in your head. You can try several methods and compare. They should all give the same answer. But first you have to determine if the OP-amp is loading the voltage divider. – RussellH Feb 05 '24 at 17:29
  • @majidkhan look at the formula you propose and ask yourself what Ux would be if U1 and U2 were the same value then ask your self if this makes any sense? – Andy aka Feb 05 '24 at 17:46

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The opamp should be seen in such way ideal that its input current can be assumed to be zero. Hopefully you in some phase learn the cases when such assumption can be done without causing too much error nor totally blocking the functionality of the opamp. That's very important in making practical designs.

If the input current of the opamp can be seen = 0 the circuit is double input voltage divider. Solve it by using superposition. Assume at first U2 = 0V i.e. connected to the circuit ground. Calculate how much U1 generates to the opamp input. Assume it's = Ua.

Assume then U1 = 0V i.e. connected to the circuit ground. Calculate how much U2 generates to the opamp input. Assume it's = Ub.

The total input voltage is Ua+Ub. Your own formula is wrong.

The end.

oneprivate
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