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5-minute Clock "Battery"

A capacitor vs. flickering power
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I'm posting this here because so many people have blinking clock displays on their VCRs. Often this is because the owner can't figure out how to set the clock, but in my own case (yes, mine is blinking) it's because I got tired of resetting it every time the power went out.

What We Need, therefore, is a dinky "battery" in the VCR suitable for powering the clock-circuit for maybe 5 minutes. I recall reading about a solar-powered watch that works at night because it charges up a fairly potent capacitor in the daylight. Capacitors are better than rechargeable batteries in this regard, because they can be charged/discharged an infinite number of times with no problem. They can't store as much energy as batteries, but they are perfect for a few minutes of powering today's microcircuits.

Well, when ordinary line power is flowing, an appropriate capacitor can be charged inside the VCR. When power fails or flickers (and we all know this happens EITHER for only -- and most often -- a few seconds, OR for hours or days), then the capacitor can keep the clock powered. I wouldn't mind resetting my VCR clock after significant outages, but needing to do it for every little power flicker has got to stop!

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Obviously, this notion is perfectly applicable to other places: Clock/radios, microwave-oven clocks, etc.

Vernon, Oct 14 2004

VCR with backup battery http://www.planetom...v-fj600am_DTL.shtml
Clock backup has been further extended to 3 years, to protect clock setting. This is a great convenience in case of long power outages or when moving. [Worldgineer, Oct 14 2004]

elf promotion Clock-to-Clock_20Interface
[pertinax, Jun 27 2009]

[link]






       Genius! - Why did they not do this simple thing before?
zen_tom, Oct 14 2004
  

       I have a very old LED alarm clock (1979 vintage) that I can unplug, move to another room and plug it back in without losing the time if I move quickly enough. I suspect it's a side effect of the power supply and not a design feature.   

       I know that newer alarm clocks have them, do VCR's not have backup batteries for the clocks?
half, Oct 14 2004
  

       Nope, nor do microwaves
zen_tom, Oct 14 2004
  

       Just had a worrying thought, if you came home, and all the clocks were perfectly normal, how would you be able to tell that there had been a power-cut during the day?
zen_tom, Oct 14 2004
  

       The house clocks wouldn't match your wrist watch, and the TV Guide would be wrong.
jurist, Oct 14 2004
  

       My bedside alarm clock has a 9v battery in it to hold the time when power fails or it's unplugged.
bristolz, Oct 14 2004
  

       Backup batteries are widely known to exist (see link for one of 25k Google results for //clock backup power vcr//). However, capacitor backup is not. What's the advantage over batteries? Price? You say it's because they can be infinitely recharged, but I think batteries can be recharged enough considering how infrequently this should be needed.
Worldgineer, Oct 14 2004
  

       [Worldgineer], I greatly prefer to NEVER need to replace a battery, whenever possible.
Vernon, Oct 15 2004
  

       baked. My old Sony boombox had two battery compartments: one to put 8 Ds in for power, and one to put 4 AAs in for memory.
-----, Nov 08 2004
  

       Nice idea, but VCR is becoming obsolete.
neoearth, Dec 20 2004
  

       Several years later, VCRs are indeed mostly obsolete. It could be time to move this Idea to a different Category (any suggestions?) After all, there are still plenty of other household gadgets with blinking clocks. And I still think a capacitor is the right energy storage device to use, to deal with a short-term power outage.
Vernon, Apr 23 2012
  

       // time to move this Idea to a different Category (any suggestions?) //   

       I suggest the 'product: widely known to exist' category. Even our new rangetop oven has this feature, to say less of every digital clock in the house.
Alterother, Apr 23 2012
  

       If you don't like batteries, a little flywheel in a vacuum arrangement could supply power for a few minutes then rev up again when the mains came back on.
AusCan531, Apr 23 2012
  

       //a little flywheel in a vacuum arrangement //
Maybe even the VCR heads (or more likely, the HDD platters) themselves.
PVR with KERS.
AbsintheWithoutLeave, Apr 23 2012
  

       Let's see, what else has an internal power supply to keep the clock set... my Xbox 360, the microwave, the veterinary blood diagnostic machine downstairs, and of course the special power outage alarm with clock and LED flashlight. The aftermarket stereo I installed in Jenny's SUV has an IPS to save the custom settings when disconnected from the battery...   

       This seems to be one of those 'bakes that's such a good idea, it came true.
Alterother, Apr 23 2012
  

       >the veterinary blood diagnostic machine   

       I won't ask...
not_morrison_rm, Apr 24 2012
  

       My father is a veterinarian. The family business is a veterinary service and pet boarding kennel. My wife and I live upstairs.   

       If you like, I can come up with something more lurid.
Alterother, Apr 24 2012
  
      
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