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Frequency of batteries

Discussion in 'Electronic Design' started by blazingbadger, Oct 3, 2007.

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  1. Our tech service guys like to joke around about customers asking this
    question. But what is the correct answer?

    They say zero because ideally the voltage should never macroscopically
    change.

    For the sake of argument I say infinity because the voltage is
    constantly microscopically changing.

    Of course you could also make an argument about discharge rates and
    the voltage changing.

    Frequency is usually defined in electrical systems using a time
    interval of one second and a complete oscillation so this might be
    suspect, but it's open to interpretation.
     
  2. It's the reciprical of how often you have to pay for sex. It can't be
    infinite, since the DC would have to been available at the Big Bang
    (sorry sex again), which is slightly longer than the availability of
    of manufactured batteries, ie 6000years


    Martin
     
  3. Charles

    Charles Guest

    Philosophical issues of this type cannot be resolved. The Fourier transform
    for zero bandwidth requires that the condition has always existed and always
    will. Sounds like God to me.
     
  4. For 'zero' change you need 'ideal' component. When you find such keep it
    for references.
    All others will have responses to changing conditions, easiest way to
    find is to introduce those changes and measure.

    Been there, done it.

    Stanislaw.
     
  5. D from BC

    D from BC Guest

    The more drain over time...the higher the frequency of battery
    changes. :p
    High frequency batteries are those cheapo dollar store zincs.
    You'll be changing those frequently :p

    ok.. Maybe that wasn't very funny.. :)

    Check out parasitic internal inductance of batteries.

    D from BC
     
  6. Phil Allison

    Phil Allison Guest

    "blazingbadger" <

    ** The "frequency" of a battery is how " frequently " you change or
    recharge it.

    Charging and discharging a battery is called " cycling ".

    The life span of a rechargeable cell is determined by the number of "cycles"
    it can accept without deterioration




    ....... Phil
     
  7. John Larkin

    John Larkin Guest

    The concept is meaningless, so don't worry about it.

    John
     

  8. Is a 'blazing badger' anything like a 'flaming ferret'?


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
  9. Benj

    Benj Guest

    Yeah, million yuks! I remember when me and my buds were smart-asses in
    High school asking the physics teacher if there was an AC battery.
    Huh, Huh, huh! (He had no idea, natch)
    Not so. A battery has a frequency distribution not a single
    frequency! The waveform of which one takes a Fourier transform would
    be a sort of step up to the battery voltage (occurs when the battery
    was manufactured) followed by a slow decay to zero as the battery
    ages. These are pretty low frequencies but not anywhere near zero.
    Yes this is true as well and often can cause problems (noise) in
    battery powered circuits. Since he voltage output of the battery comes
    from chemical effects of the atoms and larger particles making up the
    materials of the battery, the output voltage is not pure DC (or more
    exactly the pure decaying waveform we talked about above) but rather
    has relatively high frequency noise on it because of stochastic
    processes in the battery. However, the spectrum of this noise does NOT
    extend to infinity or even to high radio frequencies because a battery
    is a chemical device and chemical processes have certain speed
    limitations. This is the same effect that makes electrolytic
    capacitors poor filters at very high frequencies. The chemical actions
    simply can't follow the frequencies. So infinity is wrong as well.
    The definition of frequency is OK, but really we are talking here
    about frequency distributions or essentially a frequency density.

    So does this make sense yet?
     

  10. The correct question would have been the one
    about the impedance vs frequency

    Rene
     
  11. And that depends dramatrically on how you define "deterioration".
     
  12. D from BC

    D from BC Guest

    Perhaps it's a problem to use a 1.5V cell to power a microwave
    oscillator with no supply bypass capacitors.


    D from BC
     
  13. colin

    colin Guest

    based on 5 yr battery life, fundemental would be aproximatly
    0.00000004 hz

    Colin =^.^=
     
  14. Rich Grise

    Rich Grise Guest

    It depends on the rise-time when you switch it on. ;-)

    But seriously, "frequency" is just not applicable to batteries. They're
    "DC".

    Of course a true DC signal would have had to have started before time
    began, and stay steady until the end of time, but for practical purposes,
    it's not worth bothering with other than as an intellectual exercise.

    Hope This Helps!
    Rich
     
  15. Gibbo

    Gibbo Guest

    It's not often you make me giggle Grise but that did.
     
  16. Rich Grise

    Rich Grise Guest

    Huh? It was the Big Bang that was 6000 years ago?

    Oh, yeah, I guess that was the First Day. I don't remember which day it
    was when He plopped Earth into place, with all of the dinosaur fossils and
    evidence of plate tectonics already in place, evidently to give us all
    something to argue about 'til the end of time, which was supposed to have
    happened about 6 1/2 years ago. ;-)

    Cheers!
    Rich
     
  17. Rich Grise

    Rich Grise Guest

    Car batteries, about once every five years or so. ;-)

    Flashlight batteries, it depends on how much you use it.

    NiMH, about 1/(a few days). >:-[ (I'll never waste my money on
    NiMH again!)

    Cheers!
    Rich
     
  18. Joel Kolstad

    Joel Kolstad Guest

    What were you using them in? One area where NiMh do considerably worse than
    NiCds is in high-drain devices -- the internal resistance of NiMh is *much*
    higher than NiCds, so in high-drain devices their terminal voltages hits "end
    of battery life" much sooner. See, e.g.,
    http://www.buchmann.ca/chap9-page1.asp
     

  19. I'd guess that he had heard that lame joke for so many years that he
    couldn't even fake a grin, and didn't want to encourage the idiots.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     

  20. The correct term is EIS, short for electronic impedance spectroscopy.
    In which all frequencies are dealt with.

    Further the frequencies depend upon the Fourier spectrum of the duty cycle.

    More on my website.


    --
    Many thanks,

    Don Lancaster voice phone: (928)428-4073
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    rss: http://www.tinaja.com/whtnu.xml email:

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
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