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Capacitors

Discussion in 'Car Audio / Security / Electronic Accessories' started by Prowler, Oct 28, 2003.

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  1. Citizen_Insane

    Citizen_Insane Senior Member

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    I learned that last year in AP Physics (in HS)!
     
  2. SIRH22

    SIRH22 Member

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    Mad props to CRX-YEM. :worthy:
     
  3. Jim Truett

    Jim Truett Senior Member

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    The quiescent current draw of that capacitor would be when it was fully charged, caused by the ESR (equivalent series resistance) of the capacitor. That term does not apply to a charging or discharging state.

    Also a capacitor labeled 103k would be a .01uf 10% tolerance.

    The capacitor, if manufactured properly, will have a vent. If it is installed backwards in a circuit at or below it's rated voltage it will not explode, but the boiling electrolyte will come spraying out of the vent.

    Resistor color chart

    Capacitors
     
  4. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    :werd:

    That was high school for me, along with freshman physics... and that was over 10 years ago (HS physics). I still remember that stuff, you should too!
     
  5. bcman

    bcman Senior Member

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    in that diagram, the cap is in parallel, not series. typo?
     
  6. liquid00meth

    liquid00meth Senior Member

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    yea, its actually parallel, the ground wire is out of series.

    good catch.
     
  7. 98civicsedan

    98civicsedan Member

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    Just remember that after you charge the capacitor, DO NOT TOUCH BOTH LEADS AT ONCE. If you do, someone will be waking you up later and the cap will be oozing liquid out of both ends.
     
  8. cheese9988

    cheese9988 Senior Member VIP

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    Caps do some nasty stuff when they are hooked up backwards, on large caps there is usually a small plastic button for safety, if that pops out your in for trouble.
     
  9. bigballer

    bigballer Junior Member

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    I remember reading somewhere on the web from a guy who is an car audio expert that capacitor is really a waste of money. He suggests that your money is better spent at buying a new higher amperage alternator. Upon consideration, I'm thinking about getting rid of my 1 farad cap on my system which pumps about 400 watts RMS. I haven't notice any different after I install the cap. My system is not louder. No problem with the blinking headlights when the bass hits before or after.

    Just my 2 cents.
     
  10. CRX-YEM

    CRX-YEM Super Moderator Moderator VIP

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    A capacitor will not make you system any louder. that's not why it's used.
    A capacitor hooked up in parallel with the battery is kinda like a water storage tower.

    Your battry can only charge up to some specify limit, and can only have a draw of some maximum current. w/ the capacitor in parallel the capacitor also charges up to the same potential as the battery. When a larger amount of current is draw and the voltage of the battery drops when a deep bass note is being amplified the capacitor is there as a sort of reserve, allowing the system to instantaneously gain full potential.
    In the long run it gets rid of the ripple in the DC line making it cleaner. The only major differnce that can be visual seen is if you had headlights that dimmedwon't as much. audibly you really won't be able to tell. The only time you could tell is if your system was drawing so much power that the cars charging sytem can't keep up. and your amp would actually cut out (no sound ) until the pwer is restored.

    So if you say you didn't have a problem in the first place then you didn't need a capacitor. your vehicles charging system was capable of powering the system you have.
     
  11. liquid00meth

    liquid00meth Senior Member

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    capacitors are definitley not a waste of money. The battery in your car is not meant to drain extremely quickly, and doing so only wears them out faster. A capacitor can absorb those quick spikes in power consumption, so the battery doesn't see much of a difference.
     
  12. cheese9988

    cheese9988 Senior Member VIP

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    :withstupid: Caps are not a waste of money, even with a good alternator and batt sometimes the lights will still dim. Caps are used in everything from small power supplies to industrial applications for the same type of thing.
     
  13. $k@m Art1$t

    $k@m Art1$t Junior Member

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    Capacitors do help a lot if you can't afford a new alternator. I got a 1.5 farad cap off eBay and it has stopped my dimming headlights and made my subs hit harder while the engine is running. This is with an Audiobahn 800 watt amp, so I'm sure if you have a 1200+ watt amp you would need more caps to see a difference. I come home from college every semester now and re-install my system. I used to use a light bulb to charge the cap until I lost it, now I just hook up the power directly to the cap, and it charges within seconds once I connect the battery. I haven't had any problems with melting wire or anything like that, I'm assuming that 4 gauge wire can handle those high currents.
     
  14. acourt

    acourt Junior Member

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    im not that up on the tech side of car audio but i do know that some high end amps such as jl audio's have plenty of capacitance built in to them thus they run full power even when the voltage drops.i deduct that you reduce your chance of needing a high output alternator caps or extra batteries with these type amps,
     
  15. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Not correct. The JL amps supply constant power because they have power regulation circuits that condition the input power so that the amplifier always has a stable voltage to work with. They're not loaded up with capacitors.
     
  16. davets

    davets Member

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    I am one to belive that a cap is nothing but bad news to your cars electrical charging system. All the things said before are true, it does help dimish the power spikes when your at a stop light, or like situations. With out a resistor to limit the amount of current drawn then it will essentially be depleted after a long red light and will be getting charged, and uncharged, to feed the amp at the same time. Thus causing a larger drain on your electrical system. Of course this is just my opinion as to why I will never have a cap in my system.

    What I would/ have done in my cars is:
    1. Get a new/better battery. Optima red or yellow tops are usually preferred, depending on your desired result
    2. Upgrade 'The Big 3'. This includes increasing the size of the wiring A. between the battery(+) and the alternator(+) B. between the battery(-) to the body or frame and C. the chassis to the engine block
    3. Do all of the above with the larger then stock wiring.

    More on upgrading the big three can be found here.

    have fun
     
  17. cheese9988

    cheese9988 Senior Member VIP

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    Holy bring an old thread back. But an alternator is the best upgrade because it supplys the entire car with power. It is what charges the battery, charges the cap and the rest of the electrical system when the car is running.
     
  18. davets

    davets Member

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    hey, its a sticky who cares :p
     
  19. regal1975

    regal1975 Junior Member

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    Caps are very beneficial in daily driven systems... they help smooth out voltage just as they do in any other electrical system...

    the only case when they hurt is in the case of a competition system.. where you are playing test tones, which do not give the cap sufficient time to recharge.. and this makes them simply another drain as most mics now wont register anywhere nearly as fast as that capacitor will discharge...


    <------ iasca, dbdrag, slap competitor since 2001..
     
  20. Toxis

    Toxis Junior Member

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    caps are not a bad idea but typically, I dont' recommend them. No one here has really named their #1 benefit. Sure they stabilize voltage to a point, they help give extra power in short bursts when needed but they really help more so with ground loops and other feedback errors. For everyone saying they give x amount of watts... BS! They don't make power, they store power. In extreme competition (as stated above) they're more hurting than helpful because they try to recharge and end up pulling power away from the amps instead of giving more power to them. But in daily driving cars, they work for a small storage bin but I still believe a second battery will be 20 times better. Get a quality SVC or Optima battery and you'll get fast enough response that you'll be happy to listen to your 50 cent albums... with the occasional bass cd's.

    I just realized how old this thread is but my point still stands. :D
     
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