about capacitors

[jasto]

can a capacitor generate charge/current that can light a bulb and for how long?
can they be used as batteries?

 

[Grossel]

Generally, a capacitor can get a lamp to light, but probably just for a split second.

Capacitors is NOT batteries.

A capacitor is designed to charge and discharge a million millions and further millions of times without tearig and wearing, opposed to batteries that will loose capacity when the nmber of charge/discharges increases.

 

[crutschow]

A large supercapacitor may be able to light a small LED for a short period of time, but still not near as long as a battery of the same physical size.

 

[ADWSystems]

The discharge time to 66% is t=RC and using V=IR (R=V/I) then also t=C*V/I.

Lighting a lower current LED from a or bunch of super caps maybe possible. Where are you headed with this?

 

[wuchy143]

C = I * dv/dt

Looking at the equation you can gain some insight into how a cap works. As you CHANGE the voltage(dv/dt)(+ or - relative to it's current voltage) you can get current to move out of the capacitor to feed a load etc.(pulsing an LED for example)

The capacitor does not generate charge itself. You must apply a voltage to it so the electrons all flow from the + side of the plate to the - side of the plate. Once the electrons are done traveling to the - side the capacitor is said to be charged and now when discharged could supply power to whatever you need.

Also, I remember reading about nano technology and capacitors. You may want to do some research on the two topics because I'm almost positive that they make caps that are a huuugggee capacitance but still very small. I want to say they are up to 5F which they use in very low power electronics(a watch). Anyone know more about the topic??

 

[DerStrom8]

Capacitors act, in a sense, like tiny rechargeable batteries. They store the energy with which they are charged, and then they discharge it. The difference is, as many people here have already mentioned, that it discharges rather quickly, so using it to power a light bulb the way you want it to is not really possible.
Der Strom

 

[wuchy143]

I was mistaken about the nanatech batteries. From a quick google search they are not being produced yet. They are being worked on at MIT. So in the future we may be able to have caps as a battery.

**broken link removed**

 

[Gobbledok]

Check out **broken link removed**

A 55 Farad capacitor. Not quite small enough for a watch or anything but that is a huge capacity.