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the capacitor

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i am monster

New Member
hey im new to this site
and very new to electronics.
im 16
i do know about little electric vechicals.
and im learing more about electrical componets

but anyway my question is what is a capacitor?
i really know what a capacitor is that it holds a charge and are measured in volts and micro farads and so when something needs power right away the capacitor will have it.... but isnt that what a battery does? so im a little confused on why eaxcly you need it and in what situations can it be useful.

any info you have
i dont know anything:(
thankyou for your time:)
 

pcbheaven.com

New Member
Yes a battery does the same, but in incredibly larger scale as the capacitor...

the capacitor also wold work as resistor in AC current, would cause 90 degrees current to voltage angle, would make filters and staff, would cut off DC currents, would do many works.

In other words, the capacitor is usually not used as a battery :D
 

ericgibbs

Well-Known Member
Most Helpful Member
hey im new to this site
and very new to electronics.
im 16
i do know about little electric vechicals.
and im learing more about electrical componets

but anyway my question is what is a capacitor?
i really know what a capacitor is that it holds a charge and are measured in volts and micro farads and so when something needs power right away the capacitor will have it.... but isnt that what a battery does? so im a little confused on why eaxcly you need it and in what situations can it be useful.

any info you have
i dont know anything:(
thankyou for your time:)
hi,:)

There is so much information on the web it would be best if you read some of these links.
Good luck with your studies.

Googled: use of capacitors
Capacitance and Uses of Capacitors
Capacitor Uses and Applications :: Electronics and Radio Today
Capacitors Tutorial, Dean Huster, Tony van Roon VA3AVR
 

Hero999

Banned
Sorry but a battery is totally different to a capacitor.

A battery converts chemical energy to electrical energy and vice versa (if it's a rechargeable battery). A capacitor stores electricity directly, as an electrostatic field.

Capacitors are much more efficient than batteries, they can also charge and discharge much faster.

Capacitors can be safely discharge to 0V and some even take just as much charge in the reverse direction. Batteries have a minimum cell voltage before they can't be recharged, they also hav e a special charging curve; the voltage and current have to be carefully controlled whilst charging a battery. Capacitors can be charge by any means providing the maximum voltage rating isn't exceeded.

Extremely large capacitors (known as super or ultra capacitors) can be used to replace batteries in certain applications. A common application is as a back-up for volatile memory.
 

i am monster

New Member
thanks for the replies

(1) so is there any projects i can make or experments i can do to see more of how a capacitor can be used?
(2) how can a curcuit benifit from having a capacitor in it?
(3)what if you dont use a capacitor? any sacarfices you make?

im thinking of maybe purchacing some kits offline or something
 

confounded

New Member
A Capacitor blocks DC

you could stick a capacitor in series with a battery and a resistor and a led, the led will light then go out as the capacitor passes the initial change in voltage then blocks the DC

A Capacitor holds charge

remove the battery, short where you had the battery and reverse the LED and it will light for a short period. (You will need a fairly large capacitor so it will probably be electrolytic and you would connect the positive terminal of this capacitor to the +ve side of you circuit)

It also has a few more complex properties
 

Hero999

Banned
Take a 1000:mu:F capacitor, connect it to a 9V battery in series with a red LED and a 470R resistor, the LED will briefly light.

Now connect the LED and resistor across the capacitor and it will briefly light.

This is the first experiment I performed with a capacitor.

Make sure you get the polarity for both the LED and the capacitor correct or else they might explode.
 

crutschow

Well-Known Member
Most Helpful Member
Capacitors are a basic circuit component, along with inductors and resistors. You add them into circuits as required to get the desired circuit function. You need to understand the function of all three to understand circuits.

A capacitor can store charge but, unlike a battery, the capacitor voltage is a linear function of the charge. Thus as you discharge a capacitor it's voltage steadily decrease as a function of the charge removed. A battery will try to maintain a steady voltage until it is nearly discharged.
 

confounded

New Member
If you really want to know about how circuits work i recommend watching the MIT lectures. The professor Avant Agarwal who teaches them is awesome and his lectures are brilliant.
I've bought the textbook they use as a course guide for these lectures and i find it usefull to understand some of the maths they use (but then im not great at maths) otherwise i think anyone can follow what he teaches.
Dont expect capacitors until about lecture 10 or something but its well worth the wait! My favourite lecture is his blues brothers impression :D

YouTube - Lec 1 | MIT 6.002 Circuits and Electronics, Spring 2007
 
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confounded

New Member
The textbook written by the professors Agarwal and Lang is ISBN-13: 978-1-55860-735-4
It cost me about £30

The book teaches about how components behave and how to analyse them in a circuit. I will write a full review for the book when i've finished it. (I think it is excellent so far)

Its not an electronics reference book though.
Everyone seems to like (and so do i) Horrowitz and Hill The art of electronics as a reference book.
 

Hero999

Banned
Everyone seems to like (and so do i) Horrowitz and Hill The art of electronics as a reference book.
I've got that one, I agree, it's a good book.

I didn't pay for it though, someone gave me a copy.:D
 
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