Tanks, impedance, the j operator and excel

[Bob]

Hi gang,
This one is directed at you math whizzes..... I have a formula for tank
circuit impedance that I am attempting to analyze/plot in MS Excel. The tank
consists of a resistor in series with the coil, a cap in parallel with the
coil resistor combination and a another resistor in parallel with the cap
and coil/resistor.
The formula consists of two quotients; One has a numerator that consists of
several terms multiplied, added, squared, etc and the denominator is
similar. The second quotient is preceded by the "j" operator. (That is the
entire quotient appears to be "j"ed rather than any single term or factor).
This quotient has a numerator and denominator similar to the first).
I assume that the first quotient is the real part of the impedance, while
the second one is the imaginary part, yielding the rectangular Z =R +/-j
form. Does this sound correct?
Assuming the math is done correctly, I believe I can use the IMABS function
on the result to get the magnitude of the impedance. Yes?
In Excel, I have entered the first quotient as ordinary numbers, i.e.
"=A1*(C2+B3)..../D4*6.28*C3......"
I'm getting numbers that seem to make sense.
The second quotient has me scratching my head a bit. I have tried using the
same process on this part, and then using "=IMABS(first quotient
results,+second quotient results)" to get the magnitude of the impedance but
I think this may be incorrect.
Any thoughts? If someone wants it, I can post my Excel file to them.....

Thanks

Bob WB0POQ

 

[Le Chaud Lapin]

Hi gang,
This one is directed at you math whizzes..... I have a formula for tank
circuit impedance that I am attempting to analyze/plot in MS Excel. The tank
consists of a resistor in series with the coil, a cap in parallel with the
coil resistor combination and a another resistor in parallel with the cap
and coil/resistor.
The formula consists of two quotients; One has a numerator that consists of
several terms multiplied, added, squared, etc and the denominator is
similar. The second quotient is preceded by the "j" operator. (That is the
entire quotient appears to be "j"ed rather than any single term or factor)..
This quotient has a numerator and denominator similar to the first).
 I assume that the first quotient is the real part of the impedance, while
the second one is the imaginary part, yielding the rectangular Z =R +/-j
form. Does this sound correct?

Yes, sounds right.

Assuming the math is done correctly, I believe I can use the IMABS function
on the result to get the magnitude of the impedance. Yes?

http://office.microsoft.com/en-us/excel/HP052091191033.aspx

It appears that, if you want to form a complex number from its real
and imaginary components, you need to synthesize the complex number
with the COMPLEX function before given that synthesized number to
IMABS.

In Excel, I have entered the first quotient as ordinary numbers, i.e.
"=A1*(C2+B3)..../D4*6.28*C3......"
I'm getting numbers that seem to make sense.
The second quotient has me scratching my head a bit. I have tried using the
same process on this part, and then using "=IMABS(first quotient
results,+second quotient results)" to get the magnitude of the impedance but
I think this may be incorrect.
Any thoughts? If someone wants it, I can post my Excel file to them.....

You probably already know that it is not necessary to use IMABS or
COMPLEX.

Just plug in omega for first quotient, omega for second quotient. You
will get two numbers, one for each quotient, X, and Y, respectively
Compute the total impedance Z from them using Pythagorean theorem.

Z = sqrt (X^2+Y^2).

Naturally, you ignore the j on second quotient.

-Le Chaud Lapin-

 

[AnimalMagic]

Hi gang,
This one is directed at you math whizzes..... I have a formula for tank
circuit impedance that I am attempting to analyze/plot in MS Excel. The tank
consists of a resistor in series with the coil, a cap in parallel with the
coil resistor combination and a another resistor in parallel with the cap
and coil/resistor.
The formula consists of two quotients; One has a numerator that consists of
several terms multiplied, added, squared, etc and the denominator is
similar. The second quotient is preceded by the "j" operator. (That is the
entire quotient appears to be "j"ed rather than any single term or factor).
This quotient has a numerator and denominator similar to the first).
I assume that the first quotient is the real part of the impedance, while
the second one is the imaginary part, yielding the rectangular Z =R +/-j
form. Does this sound correct?
Assuming the math is done correctly, I believe I can use the IMABS function
on the result to get the magnitude of the impedance. Yes?
In Excel, I have entered the first quotient as ordinary numbers, i.e.
"=A1*(C2+B3)..../D4*6.28*C3......"
I'm getting numbers that seem to make sense.
The second quotient has me scratching my head a bit. I have tried using the
same process on this part, and then using "=IMABS(first quotient
results,+second quotient results)" to get the magnitude of the impedance but
I think this may be incorrect.
Any thoughts? If someone wants it, I can post my Excel file to them.....

Thanks

Bob WB0POQ

You should post the spreadsheet workbook up in
alt.binaries.schematics.electronic

Then, we can all have a look at the real thing.

I am pretty good with excel, and this sounds pretty simple.

If you just post the entire formula for each element of your equation,
it can be worked out as well.

A diagram of the tank circuit will work as well.

 

[Bob]

You should post the spreadsheet workbook up in
alt.binaries.schematics.electronic

Then, we can all have a look at the real thing.

I am pretty good with excel, and this sounds pretty simple.

If you just post the entire formula for each element of your equation,
it can be worked out as well.

A diagram of the tank circuit will work as well.

Sigh< I fight and fight with the machine to get it to calculate, I fight
and fight with the machine to graph the stuff, I fight and I fight to find
I server with alt.binaries.schematics.eletronic, then the server tells me
the file is too large, so I remove the graphs....still too large. I'm
going back to using a slide rule....

Sorry....my frustration is showing....
Any other thoughts of where I might upload the file?

In any event, thanks for the replys.

 

[Bob]

You should post the spreadsheet workbook up in
alt.binaries.schematics.electronic

Then, we can all have a look at the real thing.

I am pretty good with excel, and this sounds pretty simple.

If you just post the entire formula for each element of your equation,
it can be worked out as well.

A diagram of the tank circuit will work as well.

Ok....here is the formula:

Z = Ry(RxRy+Rx2+w2L2) wRy2(L-CRx2-w2L2C)
---------------------------------------------------
+j --------------------------------------------------
(Rx+Ry-w2LCRy)2+(wL+wCRxRy)2 (Rx+Ry-w2LCRy)2+(wL+wCRxRy)2


Rx is the resistor in series with the coil (represents coil losses)
L is the coil
C is the capacitor in parallel with the coil/resistor network
Ry is the resistor in parallel with the capacitor coil/resistor combination
w is 2*PI*F

Sample values:
Rx = 0.2836 Ohms
L = 0.868uH
C = 335.2pF
Ry = 11 k Ohms
Fr = 9.336MHz

 

[Bob]

Just great.....the formatting is all screwed up. I give up. I just have to
keep learning over and over what a pain in the @## these %#*&$#& computers
are.

Sorry I'm really frustrated right now.

 

[Le Chaud Lapin]

Hi Bob,

You have to understand that this problem is so trivial to most people
in this group, we are having trouble figuring out what it is that you
do not understand, so it might help us to tell us what it is that you
do not understand.

You have an "equation" clump. One clump on the left, one clump on the
right. The clump on the left has bunch of R's, C's, etc. in it, and so
does clump on the left, the only difference being that the clump on
the left does not have a j attached to it like the clump on the right.

What you need to do:

1. Take the clump on the left, the one without the j. Plug in numbers
you have above into this clump on the left. When you are done, you
will get a number. Call that number X.

2. Take the clump on the right, the one with the j. Plug in the
numbers you have above, again, into this clump on the right. When you
are done, you will get another number. Call this second number Y.

Find the value of sqrt(X * X + Y * Y). This is your answer Z. Do you
have trouble computing X*X + Y*Y?

You should ignore the fact that this problem is related to electronics
or complex numbers. At this stage, it is really a "put the key in the
keyhole and turn" situation.

I think the first thing you should do is determine whether you want
to:

1. Understand what you are doing.
2. Get the answer.
3. Both.

We will be more than happy to help you with 1, 2, or 3, but you should
decide first. If the answer is 2, and 2 only, just plug in the values
you have as I described above and wait for Z to pop out.

-Le Chaud Lapin-

 

[Ben Bradley]

What is your Usenet newsgroup server? Frontiernet's servers drop
all posts over about 15k bytes (it seems "reasonable" since they don't
support binary groups, but this is undocumented by Frontiernet, and
there's at least one newsgroup FAQ that I never saw because it was
larger than that! It took a while to figure out I was missing the FAQ
posts, then a little more poking around to figure out WHY... I haven't
tested ETC yet, I'm just surprised they have a Usenet server).

Anyway, sorry, this was supposed to be about you...

Sorry....my frustration is showing....
Any other thoughts of where I might upload the file?

There are plenty of free websites such as the old geocities and
angelfire, but they've gotten a reputation of having lots of pages
full of viruses and such.

As another alternative, Excel can save a spreadsheet as a .csv
("comma separated variables") file, which is just plain ASCII, and can
be copied and pasted into a text-only post right here in this thread.
That won't show us the graphs, but you can tell us the steps you go
through to get them.

Have you tried this in LTSpice or another simulator? Do you want
the "solution" to this circuit, or are you doing this as an exercise
to learn the math? Regardless, you may want to do it in a simulator -
it'll make it more satisfying when you finally make the exact same
graph in Excel.

 

[AnimalMagic]

Sorry....my frustration is showing....
Any other thoughts of where I might upload the file?

In any event, thanks for the replys.

When posting a binary, it has to be pre-processed into a text code, and
each "message" then has to be less than 10,000 lines in size.

You cannot simply post the raw thing.

The encoder is called "uuencode" and uudecode". Another is called
yENC, but many old fogies here won't like that post.

Most news clients will transform a binary file for you on the fly.

A notice that you are using Outhouse Express... Not to be jumping on
you or anything, but you should really use a real news reader client.

Also, posting a schematic (ASCII) of the tank, and the formulas you use
would allow one to work on it.

Even a few of your cell formulae would help us to help you.

 

[AnimalMagic]

Just great.....the formatting is all screwed up. I give up. I just have to
keep learning over and over what a pain in the @## these %#*&$#& computers
are.

Sorry I'm really frustrated right now.

Naaaahhh... all one has to do is copy, then paste the line back
together in a text editor. No problem. It looks like there is only one
line that did it.

 

[AnimalMagic]

Naaaahhh... all one has to do is copy, then paste the line back
together in a text editor. No problem. It looks like there is only one
line that did it.

The only other thing I can think of is... what cell formula(s) are you
using to arrive at your conclusion?

Are you graphing a series where you bump the value of one element a bit
several times, and graph the impedance through those element value
choices?

You could graph the effect of each element.

 

[AnimalMagic]

The only other thing I can think of is... what cell formula(s) are you
using to arrive at your conclusion?

Are you graphing a series where you bump the value of one element a bit
several times, and graph the impedance through those element value
choices?

You could graph the effect of each element.

I made a post up in abse, and it is a 27kB file. Your client should be
able to grab it just fine.

 

[AnimalMagic]

Thanks

Bob WB0POQ

Dont post the formula you used in excel, with that damned "j operator".
Post the actual electronic formula you are using, parasitics and all.

Or at least give a link to a site that has the formula you mention. All
the tank circuit formulae I have found on the web do not include
parasitic elements.

Perhaps there is a good simulator model that has it.

Anyone?