Watch replacemnt (button) batteries?
in [Basics]
|
From: Phil Allison on 27 Jan 2010 18:44 "Charles the Anencephalic Troll" > > At the microampere level, ** But it is not a few microamps. FUCKWIT !! Go DROP DEAD YOU STINKING LIAR !
From: Charles on 27 Jan 2010 18:48 "Phil Allison" <phil_a(a)tpg.com.au> wrote in message news:7sc1eeFuk8U1(a)mid.individual.net... > "Charles the Anencephalic Troll" You have earned the first PLONK of 2010! Congratulations.
From: Phil Allison on 27 Jan 2010 18:56 "Charles the Anencephalic LYING Troll" > At the microampere level, ** But it is not a few microamps. FUCKWIT !! Go DROP DEAD YOU STINKING LIAR !
From: David L. Jones on 27 Jan 2010 23:36 Charles wrote: > "Phil Allison" <phil_a(a)tpg.com.au> wrote in message > news:7sc0fcFpp4U1(a)mid.individual.net... >> >> "Charles the Anencephalic Troll" >> "Paul E. Schoen" >>> "Phil Allison" >>>>> "terryS" >>>>> >>>>> Thanks for the info John: >>>>> That's what I was missing; the ampere hour capacity of the button >>>>> cell. Amazing something with that small a volume can be 60ma/hr. >>>>> Guess that is what the '60' in SR60W means! >>>>> And yes; if 3 years that's (60 x 10to minus 3)Ah./24 x 365 x 3 = >>>>> Of the order of 2.28 x 10to minus 6.Amps. >>>>> >>>>> >>>>> ** Shame that JF failed to say the calc gives only the AVERAGE >>>>> current drawn. >>>>> >>>>> The *peak current* draw at the moment of each "tick" is up to 100 >>>>> times higher. >>>>> >>>>> Has a big effect on the life span of the cell and what kind of cell >>>>> ESR value is tolerable. >>>> >>>> I suppose there might be a capacitor in there to handle the peaks. >>>> >>>> Paul >>> >>> Good catch Paul. >> >> >> ** There is never any such cap in a watch or battery wall clock > > At the microampere level, it does not require much of a capacitor to > smooth out (supply) current peaks. I doubt the current spikes for an analog watch would be in the microamp range. > And you will (of course not) > supply documentation that there are no such smoothing/leveling > capacitors in clocks/time pieces? Jackass. Can't say I've seen one in any watch I've opened. It would be a waste of 0.1cents (or whatever) and take up space. And no real need for it when you have a battery with 10ohms ESR or so. Dave. -- ================================================ Check out my Electronics Engineering Video Blog & Podcast: http://www.eevblog.com
From: Paul E. Schoen on 28 Jan 2010 15:13 "David L. Jones" <altzone(a)gmail.com> wrote in message news:uw88n.15679$p66.11875(a)newsfe09.iad... > Charles wrote: >> "Phil Allison" <phil_a(a)tpg.com.au> wrote in message >> news:7sc0fcFpp4U1(a)mid.individual.net... >>> >>> "Charles the Anencephalic Troll" >>> "Paul E. Schoen" >>>> "Phil Allison" >>>>>> "terryS" >>>>>> >>>>>> Thanks for the info John: >>>>>> That's what I was missing; the ampere hour capacity of the button >>>>>> cell. Amazing something with that small a volume can be 60ma/hr. >>>>>> Guess that is what the '60' in SR60W means! >>>>>> And yes; if 3 years that's (60 x 10to minus 3)Ah./24 x 365 x 3 = >>>>>> Of the order of 2.28 x 10to minus 6.Amps. >>>>>> >>>>>> >>>>>> ** Shame that JF failed to say the calc gives only the AVERAGE >>>>>> current drawn. >>>>>> >>>>>> The *peak current* draw at the moment of each "tick" is up to 100 >>>>>> times higher. >>>>>> >>>>>> Has a big effect on the life span of the cell and what kind of cell >>>>>> ESR value is tolerable. >>>>> >>>>> I suppose there might be a capacitor in there to handle the peaks. >>>>> >>>>> Paul >>>> >>>> Good catch Paul. >>> >>> >>> ** There is never any such cap in a watch or battery wall clock >> >> At the microampere level, it does not require much of a capacitor to >> smooth out (supply) current peaks. > > I doubt the current spikes for an analog watch would be in the microamp > range. > >> And you will (of course not) >> supply documentation that there are no such smoothing/leveling >> capacitors in clocks/time pieces? Jackass. > > Can't say I've seen one in any watch I've opened. > It would be a waste of 0.1cents (or whatever) and take up space. > And no real need for it when you have a battery with 10ohms ESR or so. There is a detailed explanation of the analog quartz watch movement at http://www.patentstorm.us/patents/4087957/description.html and http://www.freepatentsonline.com/4173863.html and a PDF of the patent: http://www.freepatentsonline.com/4173863.pdf Since these use CMOS logic circuits I would be surprised if there were NOT at least one small bypass capacitor across the battery power supply. Here is a web page with some ASCII schematics of watch circuits: http://www.rdrop.com/~cary/html/time.html The Bulova Accutron: http://www.elektron.demon.co.uk/accutron.html And details on how it works: http://www.elektron.demon.co.uk/works.html Note that there is a capacitor on the base of the transistor. It appears to contribute to the current pulse through the collector, which is shown to be 16 uA, with a duty cycle of maybe 10%. But this article states that a running movement draws about 7 uA. In that case a 60 mA-Hr battery would be expected to last 60,000/7 = 8571 hrs = 357 days or just about a year. Paul
First
|
Prev
|
Next
|
Last
Pages: 1 2 3 4 Prev: PCB Design services Next: Discussing audio amplifier design -- BJT, discrete |