Capacitors vs. Batteries: Understanding the Differences in Energy Storage

In summary: When current is applied to a capacitor, initially it flows as if there is no cap, but as the capacitor charges, the current rapidly decreases and eventually stops. - AC current will alternately charge and discharge a capacitor, while DC current will only short the capacitor.
  • #1
daveed
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really, what's the difference between a capacitor and a battery? and on a circuit diagram, do capacitors have current induced to keep a current? I've only taken first year physics in high school, and we haven't covered them yet, though when i came across some problems with capacitors, neighboring resistors behaved as if the capacitors had no current-although my friend says there is current because of induction if the capacitor is fully charged?
im confused -_-

sorry if this seems dumb
 
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  • #2
A capacitor stores electric charge on conductive parallel plates. The plates are insulated from each other so there is no direct flow of current through the device. The symbol for a cap on a schematic diagram is quite accurate, though the actual device may be rolled up.

A battery stores energy in chemicals, a chemical reaction creates free electrons which are available to do work in a circuit. In most batteries the reaction only runs in one direction so when all reactants are consumed the battery is dead.

The while the chemical reaction in a battery is a key difference there is more to it. The fact that the capacitor can store energy along with the charge makes it a very useful circuit device. When DC current is switch on to a capacitor, initially current will flow as if the cap were not there, but as the charge builds up on one of the plates the current will rapidly decrease and finally stop all together, this is called "charging" the cap.

AC current on the other hand will alternately charge then discharge the cap, thus to AC a cap is nearly invisible. So in circuits a capacitor will be used to block DC and pass AC currents.

This is just a light skim of the surface of this subject, I am sure others will bring up other facets.
 
  • #3
Capacitors can store energy, as can batteries. The biggest difference you need to be concerned with is that the voltage across a capacitor necessarily decreases as current is drawn from it, while a battery can maintain its output voltage, at the same current, for a long time.

Also, as Integral said, capacitors act as shorts to AC currents, and open circuits to DC currents. Batteries act as shorts to DC currents, and, depending upon their design, may or may not also act as a short to AC currents.

- Warren
 

What is the difference between a capacitor and a battery?

A capacitor stores energy in an electric field, while a battery stores energy through chemical reactions. Capacitors are typically used for short bursts of energy, while batteries are better for sustained power.

How do capacitors and batteries work together in electronic devices?

Capacitors and batteries can work together in electronic devices to provide a steady and reliable power source. The battery supplies a constant source of energy, while the capacitor helps to regulate and stabilize the flow of electricity.

Do capacitors and batteries have a limited lifespan?

Yes, both capacitors and batteries have a limited lifespan. Capacitors can degrade over time due to factors such as temperature and voltage, while batteries can lose their ability to hold a charge after repeated use.

Can capacitors and batteries be recycled?

Yes, both capacitors and batteries can be recycled. They contain valuable materials such as metals and chemicals that can be reused to create new products. It is important to properly dispose of these components to prevent harm to the environment.

What are some common uses for capacitors and batteries?

Capacitors are commonly used in electronic devices such as radios, televisions, and computers to store and regulate energy. Batteries are used in a wide range of devices including flashlights, remote controls, and cell phones to provide a portable power source.

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