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Electronics => Electronics => Topic started by: vdemon on August 16, 2009, 04:45:28 PM

Title: CAPACITORS?
Post by: vdemon on August 16, 2009, 04:45:28 PM

I am currently building a a SAMrI sumo robot but i can't figure out if which lead is negitive the longer one or the shorter one, on the electrolytic capacitors? And the same goes for those 104 (0.1 uF) monolithic capacitors (i.e. the things that look like yellow candies on sticks) the instructions on the kit say to just put them in, so does is matter which way it goes in? ??? 

THANKS FOR ALL UR HELP  ;D

Title: Re: CAPACITORS?
Post by: Soeren on August 16, 2009, 05:10:51 PM

Hi,

Electrolytic capacitors will have the negative side marked with a "-" sign.
The negative side is the one connected to the aluminum can enclosing it and the positive side is connected through a "rubber" disc.

The 100nF (0.1µF) is a non-polarized component, so in most cases goes in either way - the rare exception is with some foil capacitors, where the pin going to the outer layer is marked, enabling it to be grounded (as shielding) in highly critical circuits handling very low signal amplitudes.

Title: Re: CAPACITORS?
Post by: Admin on August 18, 2009, 01:04:15 PM

The shorter lead is negative.

Just think:
+ has two lines
- has one line

+, positive, with more lines, added together, is longer

. . . at least thats how I always remember :P

Title: Re: CAPACITORS?
Post by: dual on August 18, 2009, 01:48:14 PM

Electrolytic Capacitor
there are two ways you can look at it. There is a side of the capacitor that is painted black and would have a (-) negative sign on it. Otherwise, the longer side is Positive, this is true for most circuit elements.

Monolithic Capacitor
there is no polarization for this kind so it does not matter which terminal goes where.