OpAmp Circuit Analysis Example 1-FE/EIT Review

[@CarlosGuerraT]

Question about Electrical-Electronics 1/8 : Vc=Vout=AVin=-2microVolts, ¿why do you say Vc is a positive signal?

[@user-fj5yt1ls1o]

Thanks for the lesson. I just wanna ask about Vo, at Qb its -iR which is good. but in the Qc, you said Vc = Vo = +iR .. I read the comments below, but I didn't get it tho. Could I have an explanation for that ?

[@siddharthsrivastava6499]

Hi!, I wanted to clarify if electrical machines is a part of the EIT syllabi for FE in electrical and computer sc. ? The reason I as is because the latest syllabus mentions it, but the NCEES reference manual does not have any formula reference sheet for this topic. Need help clarifying this, thanks.

[@chenxiaomaoify]

I think your solutions about a and b parts are correct. But for c part, Vc=Vo=-If*R. I think you missed the negative sign.

[@jonathanhill3932]

Ms. Raiya forgot the negative voltage for Vc. Other than that GREAT VIDEO! Hehe I should of prepared for this test two years ago but meh going to smash it out before the end of the year! Thanks for all your great content!

[@kaziabir1]

teacher's pet lol

[@ryantheroux8531]

Vo is negative because of the voltage gain therefore Il is negative. Current would be flowing from node b to node c.

[@markwelbourn3653]

Good video, thanks!

[@svanahbeauty4977]

Why is Vo not just i(L) * R(L)? rather than i(F) * R(F)?

[@douglasehlers3591]

Dear Miss Energy, First thank you for the op amp lessons. I am taking the FE in 3 weeks and the Kaplan book I bought is awful. So your lessons really help! I think where people are confused is where I{L} is pointed down. Since the V{out} is negative and V{B} is zero, the voltage would flow from higher voltage to lower voltage; in the opposite direction of I{L}. If you get time, please help me understand how I{L} can be positive (part c of answer) and be pointed in the direction that it is shown; down. Thank you.

[@237Lecamer]

Thanks for this video, it really helps. From question b) Vout= -Rf If, from question c) it is now Vc=Vout= Rf If, why did you omit the negative sign?

[@RaiyaAcademy]

For question b): Look at the answer I gave Gokhan above. For question c, we are also following the direction of the current coming out of point C. Hope that helps.

[@InverseAgonist]

The sign of the current coming out of point C is given by the voltage drop from C to ground; since the voltage at C is negative, the current coming out of point C is negative. Or, more simply, a node of negative voltage will sink current from ground.

[@pballplaya76]

I am not sure you did this problem correctly. B) Gain = Vo/Vi; Vo=Vab(Rl/(Rf+Rl); Vab=If*(Rf+Rl) Gain = 4 C) Iout = 0 and therefor Il = If

[@RaiyaAcademy]

What voltage is Vab though? I'm not sure what you mean by Vab given that Va=Vb=0. (If x Rf) is the voltage difference between Vout and Va but Va is already zero.

[@kedisiolankus4766]

i dont understand that why V_out .= - ( i_f x R_f) ???

[@RaiyaAcademy]

Think of it as a potential difference between point A and point C. It's the voltage across the resistor R_f following the direction of the current . Therefore, we have: V (at point A) - V (at point C) = I_f x R_f. V (at point A)= 0 V(at point C)= Vout Vout = -I_f x R_f Hope that helps.

[@robelfesshaye424]

Gain A= Ri/Rf=0.5

[@MultiUnknownXYZ]

Gain A = Vo/Vi = -Rf/Ri = -2, since no current going through op-amp.

[@ThairWHadid]

Gain = Iout / Iin ......so it should = 0.5

[@InverseAgonist]

Voltage gain

[@anthonyababat9008]

Per Professional Code of Ethics...It's not a good idea to express opinions if we're not an expert on the subject matter or not 100% sure on a certain subject discussed in the public. But thanks for trying..your other videos are good though!