Re: R-L-C structures on PCB

"Melanie Nasic" schrieb im Newsbeitrag news:do94fl$3kv$ snipped-for-privacy@mamenchi.zrz.TU-Berlin.DE...

Hi, > > recently I was assigned with the job to design a Printed Circuit Board (PCB) > which does a kind of analog signal formatting through on-board designed > capacitances, inductances and resistances. These components must be designed > not as discrete components (SMD, etc.) but deliberately as stray > capacitances in the form of specially layouted transmission line segments > and 3D arrangements. The material of the PCB is predefined to be FR4. > Surely I can design the circuit with tools like PSpice etc. but when it > comes to design the calculated R, L, C values on the PCB I'm out of luck > with my tools. So my question is: Is there a tool (Mentor?) which contains > both circuit simulation AND PCB layout where I can design my defined > capacitances, inductances and resistances in the form of specially routed > transmission lines? What would be the best way to perform that task, anyway? > In my opinion it must be an iterative process. Has anyone experience in this > particular application field? Any help, suggestions and examples (maybe) > would be appreciated. > > Many thanks in advance and best regards, > > Melanie

Hello Melanie,

I am sure that nobody wants to make R with the PCB-Traces. It may be Z(transmission line impedance) but never R. L and C can be stubs for example or other odd shapes along the "main" trace.

Please give a clear example(with numbers) what you have to design. All the postings so far are pure speculations about your real task. It's your turn to make the picture more clear.

Best regard, Helmut

Reply to
Helmut Sennewald
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In article , Helmut Sennewald wrote: [....]

I'm sure that isn't true.

Reply to
Ken Smith

It sounds totally impractical to me, at any rate, to try to make R from copper cladding. Anyway, I don't think the OP has thus far actually even told us the frequency of interest!

Reply to
Paul Burridge

"Ken Smith" schrieb im Newsbeitrag news:dp463q$3e2$ snipped-for-privacy@blue.rahul.net...

Hello Ken,

I am interested if there are other applications. On what application do you think except current sensing?

Best regards, Helmut

Reply to
Helmut Sennewald

What people "want" and what is "practical" are two very different things.

People do sense resistors in power supplies as PCB traces so resistors have in fact been done that way. It is a question of making something practical at the OPs frequency.

The Q of a strip line system is limited by the lossiness. It may be enough for the OPs needs.

Reply to
Ken Smith

Current sensing is the one where I know of good results from making resistances on purpose.

There have been a few cases where I wished I could make resistors inside the PCB. The one that comes to mind was the need to block 1.2..GHz with a filter. I didn't do it though. I ended up with a "U" shaped RLC circuit. The resistance of the inductor was enough for my purposes.

Reply to
Ken Smith

the evil TVC-1 chassis used a Cu trace for the filament resistor. what a POS. I shorted them on dozens of TVC-1s used as colour monitors in videogames, to crank up the filament voltage and get a bit more use out of soft tubes. most ran happily for several years afterwards.

I also read a paper a few years back on one-shot "guns" that discharged a bloody great cap into a little bit of PCB trace, and captured the resultant "bang" to fire a projectile :) The really cool part was how they used a 1N4007 as a one-time switch for (IIRC) 4kV

Cheers Terry

Reply to
Terry Given

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