Q1- Capaitors are open for dc frequency why.? Q2-Capacitors are short for AC analysis is generally short. why..? Q3-For what frequencies, we open capacitors even when we are doing ac- analysis.Why we do so ? Q4-Do frequency range effects the role of capacitor?
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D His orals for his Masters Thesis are next week. If he passes, he has an offer to be the Chief Engineer at a startup... their business plan is to hire cash strapped engineers over 50, chain them to their workstations and treat them like mushrooms, and use their ideas to take over the world.
Just think of a capacitor as a battery.. If you have any idea what's so ever happens to a battery when being charged and discharged, the currents it produces! It should open your eyes. If you can't see beyond this, you need to go back to the very basics... If anything, that sounds like a home work question and its funny it should be posted on a Sunday. Day before returning back to school I might add.
May not be in your case, just an observation I made.
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"I\'d rather have a bottle in front of me than a frontal lobotomy"
http://webpages.charter.net/jamie_5
A1 - they have infinite reactance at 0 Hz (ignoring leakage) 1/(2 x pi x f x C) A2 - they approach a very low reactance at some high frequency (see above equation) A3 - you treat them as opens for dc analysis or at very low frequencies A4 - yes (see above equation)
Seem like badly worded questions! Or somebody has paraphrased them badly.
Looks like homework or an assignment!
Now thinking back to when I was about 14 or so, 60+ years ago; before I even studied electronics and was just dabbling/experimenting!
Also DC is not a frequency; unless you want to consider it is zero frequency!
Q1: Hence since the reactance/impedance Xc of a pure capacitor, C, at zero hertz (F = 0), or any other frequency F is given by Xc = 1/(2pi x F x C); for anyone who can read that's in all, the books!
If F = zero the circuit through the capacitor is infinitely high, you end up with one over zero, because F = zero, in other words Xc is infinitely high and the capacitor, at that frequency only, is effectively an 'open'.
Q2: Question not true. Xc as above is dependent on frequency F. So again the formula Xc =1/(2pi x F x C). It is quite possible to design values of F and C that will cause Xc to be very small or very large!
Two examples: a) Xc = 1/(2pi x 1 x 1^6) That is one hertz per second and a capacitor of one microfarad. Xc will = about 160,000, ohms. b) Xc = 1/(2pi x 1,000,000 x 1000^6) That is one megahertz per second and a capacitor of 10 microfarads) Xc will = about 0.016 ohms! Big differences depending on the sizes/values of C and F
Q3: depends in practice on what we are doing/measuring!
Q4: Read and understand the Xc formula, what happens as F increases or decreases? What happens as C increses or decreases? Perhaps note that they mathematically sort of the same! As either one gets larger, Xc the reactance/impedance, of the capacitior is lower?
There was nothing worth while in the post that would make any difference. It really was another classic Jamie post... Post crap and then argue about it.
" Typical useless post. If you had an ounce of capability you would make some attempt to learn where you might be wrong, or post a technically competent justification. But, since you don't, all you can do is post more crap. You're as useless as your posts."
You are showing yourself to be technically incompetent boob. Don't you even care?
Do you always sit for hours and paint a picture of some one that you absolutely know nothing of?
You seem to have an obsession with me. May I suggest, you might be in dire need of help? Not that i'm not flatter with all the attention you're giving me. If gives me a nice cozy feeling of being wanted! :)
Please go play in traffic else where. You're way out of your league if you think for one moment that your comments have any value what so ever.
It just makes you look like some one with a problem that should be kept in the privacy between you and your doctor.
Now go beat your head against the wall for a while..
-- "I'd rather have a bottle in front of me than a frontal lobotomy"
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