novice: why do electrolytic capacitors...

[mike]

Why do electrolytic capacitors have to be connected the correct way around? Why
does a circuit not work correctly if an electrolytic capacitor is reversed? Is
it like a battery - only sinks rather than sources a charge?

 

[Kryten]

"mike" <mike@noname.nothere> wrote in message
newsl8g01dgtsr1uad4b94kc8svsai4qmndcs@4ax.com...

Why do electrolytic capacitors have to be connected the correct way
around? Why
does a circuit not work correctly if an electrolytic capacitor is
reversed? Is
it like a battery - only sinks rather than sources a charge?

Initially, current builds a very thin insulating layer on one electrode
(just like anodisation of aluminium). Reversing the polarity reverses the
process and so destroys the layer.

 

[keith]

On Tue, 08 Feb 2005 02:24:51 +0000, mike wrote:

Why do electrolytic capacitors have to be connected the correct way around? Why
does a circuit not work correctly if an electrolytic capacitor is reversed? Is
it like a battery - only sinks rather than sources a charge?

They make more noise one way than the other.

--
Keith

 

[Pooh Bear]

mike wrote:

Why do electrolytic capacitors have to be connected the correct way around? Why
does a circuit not work correctly if an electrolytic capacitor is reversed? Is
it like a battery - only sinks rather than sources a charge?

To answer this - I rather like the Japanese name for an electrolytic cap. They call
it a 'chemicon' - i.e a chemical capacitor ( condensor ) .

It relies on electro-chemical processes to work correctly.

As such, it effectively has an anode and cathode. This is why it has to be used the
right way round.

If you want more info - google is your friend !


Graham

 

[Paul Burke]

mike wrote:

Why do electrolytic capacitors have to be connected the correct way around? Why
does a circuit not work correctly if an electrolytic capacitor is reversed? Is
it like a battery - only sinks rather than sources a charge?

I saw a guy test a power supply once, 20A at 50V unregulated, and the
bloke building it had put all 4 filter capacitors in the wrong way
round. Like a wedding!

Paul Burke

 

[Anders F]

"Paul Burke" <paul@scazon.com> wrote in message
news:36rb6jF54iei8U1@individual.net...

mike wrote:
Why do electrolytic capacitors have to be connected the correct way
around? Why
does a circuit not work correctly if an electrolytic capacitor is
reversed? Is
it like a battery - only sinks rather than sources a charge?


I saw a guy test a power supply once, 20A at 50V unregulated, and the
bloke building it had put all 4 filter capacitors in the wrong way
round. Like a wedding!

But probably a bit more messy... ;-)
Btw. there's a "basic" group where all the "novice:" posings might be better
off....

/Anders

> Paul Burke

 

[Tim Wescott]

mike wrote:

Why do electrolytic capacitors have to be connected the correct way around? Why
does a circuit not work correctly if an electrolytic capacitor is reversed? Is
it like a battery - only sinks rather than sources a charge?

Search on "borax" and "rectifier" for the full story. You can think of

an electrolytic capacitor as a really crappy diode that happens to have
a lot of junction capacitance.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Rob Gaddi]

mike wrote:

Why do electrolytic capacitors have to be connected the correct way around? Why
does a circuit not work correctly if an electrolytic capacitor is reversed? Is
it like a battery - only sinks rather than sources a charge?

Basically, yes. When reversed it acts as a very effictive current sink,

but only for a fairly short time.

 

[Michael A. Terrell]

Paul Burke wrote:

mike wrote:
Why do electrolytic capacitors have to be connected the correct way around? Why
does a circuit not work correctly if an electrolytic capacitor is reversed? Is
it like a battery - only sinks rather than sources a charge?


I saw a guy test a power supply once, 20A at 50V unregulated, and the
bloke building it had put all 4 filter capacitors in the wrong way
round. Like a wedding!

Paul Burke

This is where you need to bring a supply up with a variac that has an
AC current meter to monitor the current. The test procedures I wrote
for linear power supplies with a bank of "Computer grade" capacitors
explained the reason, and the danger of not doing it right.

--
Beware of those who suffer from delusions of adequacy!

Michael A. Terrell
Central Florida