Recent content by simpComp

Nevermind... I got it! Its: (-5(1-2)+3.5)/(9(2) = 0.47222 Thanks

Hello, Please view attachment! Thanks!

Hi berkeman, You talking to a very slow guy here! so I try: I went back to my algebra notes of 20 years ago and saw the example: 2 = log(base10)(100) then I tried doing the reverse: 10^2 = 100 So then I understood that its 10 to the power of (90/20)... So I did the same while following...

90/10 then the result is multiplied by 10. then 10/the result above hence: 10/((90/20)10) = 0.222? and they get 316 micro volts?

Hello, If you go to this link: http://en.wikipedia.org/wiki/Common-mode_rejection_ratio and scroll all the way down to the bottom where they show the: "Example: operational amplifiers" section... we have: I get +/-222mv ? Am I doing the math wrong?

Ahhh! The light from the sun hit my head! I see it now... thanks DrewD

Hello DrewD, totally swamped here... I will get back as soon as I have a bit of free time... Thanks

Hello Electric Red, I am totally baffled and don't even know where to start... I attempted to get vcm out of the brackets like so: vcm(1+vd/2) and vcm(1-vd/2) but then don't know where to go from there. I tried going further by dividing vcm on both sides but I have to be honest here...

"If so, you should write it out and do it yourself. " thanks

Can someone show some mathematical steps on how we go from step 1 to step 2 please. Step#1 vout = (vcm + vd/2)(Ro/Rb + Ro) (1+Rf/Ra)- (vcm - vd/2)(Rf/Ra) Step#2 vout = vcm [(Ro/Rb + Ro) (1+ Rf/Ra) -(Rf/Ra)] + vd(1/2) [(Ro/Rb + Ro) (1+ Rf/Ra) + (Rf/Ra)] thank you in advance!

yes... thanks! sc

Okay I think I got it: v1/v2 = R2/(R1 + R2) (R1 + R2) (v1/v2) = (R2/(R1+R2)) (v2) v1(R1 + R2) = R2v2 v1R1 + v1R2 = R2v2 v1R1 = R2v2 - v1R2 v1R1 = R2(v2 - v1) v1R1/(v2-v1) = R2(v2 - v1)/ (v2 - v1) R2 = v1R1/(v2-v1) Thanks!

Yes I am sorry I was missing parenthesis! v1/v2 = R2/(R1+R2) so when you say cross multiply... do you mean like this: (R1 + R2) (v1/v2) = (R2/(R1+R2)) (v2) v1(R1 + R2) = R2v2 v1R1 + v1R2 = R2v2 But now R2 is on both sides, what I really need is to isolate R2 so its on one side only...

How can R2/R1+R2 be factored out to (1/R1 + 1)R2. ? This is not true! Lets apply numbers and see... let R1 be 2 and R2 be 10: 10/(2+10) which equals to 0.83 factoring the way it is suggested we get: 10(1/(2+1)) which equals to 3.333 ? Bof ! confused?

v1/v2 = R2/(R1+R2) I don't understand how you factor R2? I gather when you say to factor R2 you mean to factor R2/R2 ? Therefore: How many times does R2/R2 go into >>>> (R2/(R1+R2)) Here below, R2/R2 goes once into R2/(R1+R2) leaving: v1/v2 = 1/(R1 + 1) R2 right?