"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 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?+