Go Down

Topic: The capcitor (Read 990 times) previous topic - next topic

Leonidas

What does it do?

i understand that it stores energy and discharges it when filled completely, but why would you use it? what does it do for you in a circuit? what simple uses does it have?

biocow

Capacitors also take time to fill up and discharge. This can act like a cushion in your circuit.

A circuit without a cap is like slamming on the gas pedal of a drag racer. 0 - 100mph in a few seconds.

Add a Cap and resistor and it's like slowly stepping on the gas of a Cadilac. You'll get to 100mph eventually, it'll just take 15 or 20 seconds.

And just the opposite. No cap = slamming into a brick wall. With a cap = slowing from 100 to 0 over 30 seconds.

I'm sure others will have better examples and similes.
10 PRINT CHR$(7)
20 GOTO 10

MarkT

The deep answer is that capacitors have state.

More practically capacitors allow filtering, store values as charge or voltage, decouple, couple, store energy, integrate a current...  There's so much they are used for its amazing!

Have a look in the learning section for circuits with capacitors - the commonest use is decoupling in a microcontroller, but in analog circuits everything uses capacitors.
[ I won't respond to messages, use the forum please ]

Grumpy_Mike

A capacitor is a frequency dependent resistor for AC.

Therefore it can be used to short out high frequencies and let low ones through if you put it across a signal, or the other way round if you put it in line with the signal.
Quote
the commonest use is decoupling


True if you want to read about that then see:-
http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html

westfw

Capacitors do calculus!

Seriously.  This same question was asked about a month ago:

http://arduino.cc/forum/index.php/topic,52838.0.html


Leonidas

wow, thanks you guys... i guess i have to study up alot more than i thought! =)

Grumpy_Mike

Just another point:-

Quote
i understand that it stores energy and discharges it when filled completely,


No that's not how it works. It will only discharge when is is placed across a load or sees a voltage lower that it has charged to.
If it worked like you thought it would be an oscillator all by itself.

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy