Recent content by WeeChumlee

Thanks Electrician Yes, I totally see that sign change, that was an error of mine. Funny thing is that I had it right the first time but got the wrong answer so in trying to get the right answer that was a change I made. I had used an online calculator to try and get the answer, I must have...

Carrying on from this as I am getting nowhere.. ((V1-V20) / Z1) - (V20/Z4) - (V30/Z5) + ((V2+V30)/Z3) = 0 V30 = V20 - V3 ((V1-V20) / Z1) - (V20/Z4) - ((V20-V3)/Z5) + ((V2+(V20-V3))/Z3) = 0 When I put the values into get V20 and divide that by Z4 I get 8.78 - j16.59 Not the answer I got for the...

Darn: Was of course V20-V30 = 14.14+j14.14

Hi Electrician Yes indeed, that was me being lazy and not putting all parentheses in, silly of me. What I have is this: ((V1-V20) / Z1) - (V20/Z4) - (V30/Z5) + ((V2+V30)/Z3) = 0 V20-V30 = 14.14+j14-14

Hi Rob1985 I too am working on this and just can't seem to get it right. My equation is similar to yours. I have used different terminology but if I use your terminology I have: (V1-V20 / Z1) - (V20/Z4) - (V30/Z5) + ((V2+V30)/Z3) Obviously wrong as does not get the answer from mesh analysis...

Thanks for your input, I really appreciate your thoughts. Once I am quite certain what I now have is coorect I shall try the method mentioned as well. Good thing you asked me to do the math again, I don't know how I got it wrong so many times.

Oh man, I think I got it. Just did the same mistake over and over again somehow. Getting a beer, leaving it alone for a while, and coming back seem to have done it. Not got SPICE now but pretty certain I have it now. Now have I = 9.99exp-10 That's the 10 I was looking for. :-)

Calculated current was 9.998nA. (So 10nA) This though should be 1nA . with 1nA the simulation works. Somewhere is a factor 10 mistake I presume but I son,t see it.

Homework Statement The circuit of FIGURE 2 is known as a transimpedance circuit used for the measurement of very small currents. Derive the relationship between the output voltage V and the input current I; i.e. if V = kI find k in terms of R1, R2 and Rf. Homework EquationsThe Attempt at a...