Capacitors & Inductor

[cool.man]

why an inductor is a dc bypass

Hi,
I have seen some articles related to capacitors and inductor but i still confused in
1.what is the difference b/w polar and non-polar capacitors and where we use them.
2.if capacitors block DC then why we use capacitors in power supplies (i-e at input and output of 7805 or others).
3.what actually an inductor does means what is the function of an inductor.

I think capacitor is a voltage based device and inductor is a cuerrent based device.
Plz clear my mind if anyone knows
Thankx

 

[xulfee]

wikipedia ac inductance

in power supplies capacitor just smooth out ur output comming from rectifier,inductor stores K.E where capacitors P.E,ur concept is rite that inductor is current base device where other is voltage based.

 

[GrandAlf]

capacitor inductor dc

Polarised caps have to be used the right way round
Non Polarised can be either way
Capacitors are used for passing AC. They will however pass DC while they are charging, until full. In power supplies they are used to store energy, to smooth out fluctuations in supply.
Inductors pass DC and block AC. Must be the right inductance to suit the frequency used.

Suggest you Google or Wikipedia for more info.

 

[Fahmy]

function of capacitors & inductors

1-polar caps must be connected such that it is positive terminal receives higher potential than the negative one. It can be damaged if connected in a reverse way. The reason that we need polar caps is that the capacitance of polar caps is usually much higher than non-polar caps.

2- The capacitor is connected in parallel to the supply and not in serious. So it just rectify the voltage and filter out noise.

 

[laktronics]

156-pe capacitor

Hi,
Further to what is stated above, polar capacitors use polarity sensitive dielectric like electrolytes. They are used since they have an advantage of high capacitance to physical volume ratio comapred to non polar capacitors. But polar capacitors have got more parasitic inductance and therefore at high frequency applications requiring small capacitor values nonpolar capacitors are used.

Capacitors block DC and pass AC. So they are used in SHUNT in power supplies to bypass AC components and noise. Inductors are complementary devices to capacitors and they pass DC, but blocks AC. So they are used in SERIES in power supplies to block AC componenets and noise from appearing at the output.

Regards,
Laktronics

 

[lsimeon]

why capacitor blocks dc

Hi,

2.if capacitors block DC then why we use capacitors in power supplies (i-e at input and output of 7805 or others).

Thankx

the primary function of these capacitors are to prevent the fluctuations to reach the IC regulator, it is actually used as a protection to the IC and commonly with reverse diode across the ICs terminals...

 

[Naveed85]

use of inductors pass dc

we use the capacitor as a filter in power supply you have to see power supply schematic diagram it is use in parallel to bridge it passes ac therefore it is use to remove the ac factor after rectifydc moves toward the load and feed into bridge negative point.
inductor is an electrical component. in ac it legs the current by 90 degrees
voltage lead the current by 90 degrees

 

[Kral]

7805 power supply design with inductor filter

sushi4664,
The voltage across an inductor is proportional to the rate of change of current.
.
The current through a capacitor is proportional to the rate of change of voltage.
.
The impedance (reactance) of a capacitor is inversely proportional to frequency.
.
The impedance (reactance) of an inductor is directly proportional to frequency.
Regards,
Kral

 

[lsimeon]

difference b/w polar and nonpolar capacitor

naveed85 - yes of course the capacitors are used for filtering purposes especially in power supplies, thats why we have a filter stage after the rectifier stage when designing a power supply - but that was very basic and assumed that everyone here already knows that thing... if you will read again the question of hayee(question 2) the capacitor that she is telling there is not the filter capacitors in the filter stage, it is a form of a snubber circuit...