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"budgie" wrote in message ... On Wed, 15 Oct 2003 02:03:05 +0000 (UTC), "Reg Edwards" wrote: Multiply top and bottom of 1/jwC by j (This does not change its value) and you get 1/jwC = minus j/wC. Back to school with your algebra. His algebra looks perfectly fine to me. But as others have pointed out, he's left the 2pi out. ------------------------------------------ Yes. I apologise for my remark about school. I gained the incorrect impression from the previous replies. The w in wC stands for omega = 2*Pi*F, the angular frequency. |
On Tue, 14 Oct 2003 19:56:43 +0100, Don Pearce, said...
On 14 Oct 2003 11:38:29 -0700, (Diego Stutzer) wrote: Hi, Well, I'm really confused. I simulate a simple serial R-C-L-Network (all in series). As far as I know the total (input-)Impedance of the network is: Z = R + jwL - j/(wC) resp. the resonance frequency (where Zin=R) is 1/sqrt(L*C). At resonance frequency, the Impedance should be real and therefore in my hummel opinion Voltage and Current schould be in phase. The funny thing is, when i build up such a network in Schematics (Cadence PSD 14.1/Orcad 9.2) and simulate it with the PSpice A/D Simulator, the current is displaced (relative to the voltage) about lambda/4 - obviously not in phase!? Can anyone tell my where I made a mistake? Or why this Problem is showing up? Thanks to anyone reading this and especially to those who post answers. D. Stutzer The impedance should be R + jwL + 1/(jwC) d _____________________________ http://www.pearce.uk.com now that were all done playing with j... Z = sqrt[R^2 + (jwL)^2 - (1/jwC)^2] = sqrt[R^2 + (jwL)^2 + (j/wC)^2] this is scary ****. mike |
On Wed, 15 Oct 2003 02:43:27 +0000 (UTC), Reg Edwards, said...
"budgie" wrote in message ... On Wed, 15 Oct 2003 02:03:05 +0000 (UTC), "Reg Edwards" wrote: Multiply top and bottom of 1/jwC by j (This does not change its value) and you get 1/jwC = minus j/wC. Back to school with your algebra. His algebra looks perfectly fine to me. But as others have pointed out, he's left the 2pi out. ------------------------------------------ Yes. I apologise for my remark about school. I gained the incorrect impression from the previous replies. The w in wC stands for omega = 2*Pi*F, the angular frequency. now that were all done playing with j... don't forget Z = sqrt{R^2 + [(wL) - (1/wC)]^2]} and Z(s) = R + Ls + 1/Cs which is just plain easier to deal with 'til you need to journey back into time domain land. no need to leave it f(t) for this deal, though. all that j stuff... that was scary ****. so easy to make a mistake. swapping w and f is another good one. only works for f/f stuff. mike |
On Wed, 15 Oct 2003 02:43:27 +0000 (UTC), Reg Edwards, said...
"budgie" wrote in message ... On Wed, 15 Oct 2003 02:03:05 +0000 (UTC), "Reg Edwards" wrote: Multiply top and bottom of 1/jwC by j (This does not change its value) and you get 1/jwC = minus j/wC. Back to school with your algebra. His algebra looks perfectly fine to me. But as others have pointed out, he's left the 2pi out. ------------------------------------------ Yes. I apologise for my remark about school. I gained the incorrect impression from the previous replies. The w in wC stands for omega = 2*Pi*F, the angular frequency. now that were all done playing with j... don't forget Z = sqrt{R^2 + [(wL) - (1/wC)]^2]} and Z(s) = R + Ls + 1/Cs which is just plain easier to deal with 'til you need to journey back into time domain land. no need to leave it f(t) for this deal, though. all that j stuff... that was scary ****. so easy to make a mistake. swapping w and f is another good one. only works for f/f stuff. mike |
On Tue, 14 Oct 2003 21:30:18 +0200, "Pawel Stobinski"
wrote: Don Pearce wrote: The impedance should be R + jwL + 1/(jwC) 1/j = j/j*j = j/-1 = -j -j/wC = 1/jwC Quite right - the unusual format fooled me. d _____________________________ http://www.pearce.uk.com |
On Tue, 14 Oct 2003 21:30:18 +0200, "Pawel Stobinski"
wrote: Don Pearce wrote: The impedance should be R + jwL + 1/(jwC) 1/j = j/j*j = j/-1 = -j -j/wC = 1/jwC Quite right - the unusual format fooled me. d _____________________________ http://www.pearce.uk.com |
On Wed, 15 Oct 2003 06:11:13 GMT, Active8
wrote: now that were all done playing with j... don't forget Z = sqrt{R^2 + [(wL) - (1/wC)]^2]} and Z(s) = R + Ls + 1/Cs which is just plain easier to deal with 'til you need to journey back into time domain land. no need to leave it f(t) for this deal, though. all that j stuff... that was scary ****. so easy to make a mistake. Especially so given the limited typography of this particular medium. I suspect few of us would have a problem if we could only view these formulae in a suitably appropriate typeface!!! -- "Windows [n.], A thirty-two bit extension and GUI shell to a sixteen bit patch to an eight bit operating system originally coded for a four bit microprocessor and produced by a two bit company." |
On Wed, 15 Oct 2003 06:11:13 GMT, Active8
wrote: now that were all done playing with j... don't forget Z = sqrt{R^2 + [(wL) - (1/wC)]^2]} and Z(s) = R + Ls + 1/Cs which is just plain easier to deal with 'til you need to journey back into time domain land. no need to leave it f(t) for this deal, though. all that j stuff... that was scary ****. so easy to make a mistake. Especially so given the limited typography of this particular medium. I suspect few of us would have a problem if we could only view these formulae in a suitably appropriate typeface!!! -- "Windows [n.], A thirty-two bit extension and GUI shell to a sixteen bit patch to an eight bit operating system originally coded for a four bit microprocessor and produced by a two bit company." |
R + jwL + 1/(jwC)
= R + jwL -j/(wC) so at resonance wL=1/(wC) ie w=1/sqrt(LC) Chris "Michael" wrote in message om... The impedance should be R + jwL + 1/(jwC) You sure?, how do the j parts cancel at resonance if they are both added?+ |
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