[SOLVED] why polarised (electrolyte) capacitors are use in power supply??

[Vraj]

why most of rectifier are having electrolyte(polarised) capacitor? what happen if there is non polarised capacitor?

i also found that if the output voltage of rectifier is so less than the capacitor voltage.but the difference is too much between them. like 9 v rectifier they use 100v capacitor,and also for diode8-O .For 500mA, they use 1n4004 rectifier diode,which also has 400v range.:roll:

 

[D.A.(Tony)Stewart]

e-caps have higher storage density and lower cost.
non-polar tend to have high V ratings and lower density, but low ESR*C time constants.

diode V ratings depend on availability of cheap silicon parts. Schottky diodes tend to cost more and have lower Vf (good) but lower Vr ratings.

 

[c_mitra]

why most of rectifier are having electrolyte(polarised) capacitor? what happen if there is non polarised capacitor?
:

Electrolytic capacitors are cheap, available in large capacities and wide range of voltages. They are widely used for filter capacitors that need large energy storage. Non-polarized capacitors are simply not available in high capacities. Electrolytic capacitors have lower specifications (they have wide variations) and greater ESR (series resistance).

 

[dick_freebird]

Due to their spiral-wound form, electrolytic caps have some
of the worst ESL (series inductance) along with not-great
ESR. But raw C*V density, they're hard to beat. Only by
tantalum, which is still basically electrolytic at the bottom
of it all (just a different foil / oxide).

 

[treez]

you can try with film capacitors also, but your volume of capacitors will be more.
Sorry, we must use the El caps, even though we hate them............but wait, do we really hate?.....i mean, reason for power supply fail is most commonly El cap, then customer wants to buy more power supply...so we make money again right?

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SOMETIMES YOU USE A PART BECAUSE YOU ALREADY HAVE IT ELSEWHERE IN THE BOM AND THERes no point in using another different part number (sorry about capitals).

 

[c_mitra]

Every component has a definite purpose; electrolytic capacitors (Al) have very high capacity and are available in a wide range of voltages. They are widely used for energy storage and power supply ripple filtering purposes. In terms of price performance they are hard to beat. They contain an electrolyte (gel/soap) and a thin film of surface oxide provides the dielectric (hence they are polarised).