Resistance Vs Impedance

[umashankar.s]

Hi all

you folks have any valid justifications with you for impedance...
i have found one..

• • Basically the impedance is depending on the thickness of the conductor. If the thickness decreases then the impedance increase. We can not reduce the thickness further after the certain limit. Since if we do then the conductor strength become weak. It can be cut at any point. So in general all the manufacture makes the conductor at constant thickness. For that constant thickness the impedance will be 90 ohms so that only we are asked to maintain 90 ohms on our PCBs to avoid impedance mismatches between on our PCBs and on the Cable.

-Bye Folks

[umashankar.s]

one more....

The arithmetic mean between 30 ohms (best power handling) and 77 ohms (lowest loss) is 53.5; the geometric mean is 48 ohms. Thus the choice of 50 ohms is a compromise between power handling capability and signal loss per unit length, for air dielectric.

[KINETIC_JOULES]

Sorry. . . please explain your question more clearly. Are you JUST wanting the difference between impedance and resistance?

"If impedance mean for the restriction of AC current, why we have to consider it for DC.?"
Please use better English. I don't mean to sound rude. I'm just having trouble following your question.

[KINETIC_JOULES]

Originally Posted by balaseven

I need answer for the folllowing questions relevant to printed circuit board technology.

What is the exact difference between resistance and impedance?

If impedance mean for the restriction of AC current, why we have to consider it for DC.?


Thanks
BS
Proficient Comrades of Boards • Index page

Impedance extends the concept of resistance to AC circuits, describing not only the relative amplitudes of the voltage and current, but also the relative phases.

[balaseven]

Hi kenetic,

R u a PCB designer?Do u have any experience with PCB technology?Then only yoy can easily understand the question.I dont want general concepts ans diffrence b/w Resistance and impedance.The answer should be related to PCB.

[The_Big_K]

easy there, balaseven. Kenetic is one of the youngest members on CE and an aspiring electrical engineer. Read her introduction here: Proud nOOb! I'm 15, and I joined this fourm to gain knowledge. Help!?

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Let the original discussion continue.

[KINETIC_JOULES]

Originally Posted by The_Big_K

easy there, balaseven. Kenetic is one of the youngest members on CE and an aspiring electrical engineer. Read her introduction here: Proud nOOb! I'm 15, and I joined this fourm to gain knowledge. Help!?

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Let the original discussion continue.

Thank you. I understand I may not know much. I'm trying. I'm still in high school for peat sake!

[balaseven]

Bigk

Thanks for the link

Tyler

me too joined here to learn something,go ahead......

bye...............

[neerajdhawan]

Hi, Impedance and resistance are same for any circuit for DC but when we talk about AC signals they may be different as impedance has to components Resistive and Reactive and we right these components to show impedance Z as Z=R+iY. R is Resistive and Y is reactive component. Impedance of a give circuit may be different for different frequencies.
Hope this replies your question partly for more details please let me know

[KINETIC_JOULES]

Originally Posted by balaseven

Bigk

Thanks for the link

Tyler

me too joined here to learn something,go ahead......

bye...............

Glad to know I'm not alone! ^_^ I'm still young. I've got time to learn everything!