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All appliances in house go out in power outage but not the digital clocks?

BowlOfRed said:
As you still have the digital clocks around, you can test this. Clocks tend to have very low power draw, so the power supply can keep them updated for a while after unplugging.

My first digital clock I had (was around 1980) could last around 8 seconds or so of being unplugged without losing the time. I could relocate it from room to room by hurrying it from one outlet to the next.

Take your clocks, and unplug them for one second and see if the time remains. Then try two seconds if that works.

Now do the same for the other devices. You'll probably find that they turn off much more rapidly and can't be without power for as long.
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I just tried it, my hypothesis was right. The other two clocks go out in what seems almost instant, but which I can tell is several milliseconds, I timed it at around 0.21 and 0.18. The other seems to go out with the other appliances, maybe a split second later
 
DebunkThisPls said:
Thank you Dave. If you don't mind, do you have any explanation for the comment another user listed? They talk about having a similar experience except their clock lasted much longer and even after being unplugged
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Some digital clocks have backup batteries. This would likely be a "button cell" type battery. Since digital clocks are generally plugged in all the time, and the clock draws power only if the clock is unplugged or the power is out, they can last for years.
 
Dave Rogers said:
Unplugging it has the same effect as the power outage. The power supply is the part of the clock that converts the higher voltage AC from the mains to the low voltage DC that the electronics of the clock needs.

Dave
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Of Course, I'm an idiot, I apologize
 
Jack by the hedge said:
Deadpan humour. The delayed moment of realising that what we are reading is nonsense is what makes it funny.

The ridiculousness of taking so much effort is another aspect of why it's funny.
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Ill trust your opinion, I'm not very familiar with this forum nor the people in it, so I'll assume you're right.
 
OP, learning about electricity is a lot of fun, too. Just to kick you off: there are two main kinds you will run across, AC (alternating current) and DC (direct current). You know that band AC/DC? That's where they get their name. AC is the power lines outside and the outlets and lights in your house; DC is mostly battery stuff like your laptop and cel phone. There's a whole wild history about the two battling for use on the modern power grid.

Ever wonder why a light bulb doesn't burst from all the power that is reaching it? That's called resistance, where the huge amounts of available power are dialed down for low use.

Then you can learn amperage, wattage, voltage, current, Ohms law and all kinds of stuff. Start a-googling. You won't regret it. Lots of posters here can lend a hand if you get stuck.
 
Jack by the hedge said:
Deadpan humour. The delayed moment of realising that what we are reading is nonsense is what makes it funny.

The ridiculousness of taking so much effort is another aspect of why it's funny.
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Thermal said:
OP, learning about electricity is a lot of fun, too. Just to kick you off: there are two main kinds you will run across, AC (alternating current) and DC (direct current). You know that band AC/DC? That's where they get their name. AC is the power lines outside and the outlets and lights in your house; DC is mostly battery stuff like your laptop and cel phone. There's a whole wild history about the two battling for use on the modern power grid.

Ever wonder why a light bulb doesn't burst from all the power that is reaching it? That's called resistance, where the huge amounts of available power are dialed down for low use.

Then you can learn amperage, wattage, voltage, current, Ohms law and all kinds of stuff. Start a-googling. You won't regret it. Lots of posters here can lend a hand if you get stuck.
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I definitely will, thanks. One question though. All the other times we've had a flicker or really quick power outage like the original story, the clock has gone out, at least the very sensitive one. Is there any reason it didn't go out last time? Maybe just coincidence or a slightly fast outage that may not cut it off?
 
DebunkThisPls said:
I definitely will, thanks. One question though. All the other times we've had a flicker or really quick power outage like the original story, the clock has gone out, at least the very sensitive one. Is there any reason it didn't go out last time? Maybe just coincidence or a slightly fast outage that may not cut it off?
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Very broadly: capacitors are not all identical. Some will hold more power longer, depending on what they were designed to handle. Some appliances have a built-in battery backup, which means they can tell when they lost primary power and revert to a small DC storage battery built in. I've seen this on appliances that have programmable features that you wouldn't want to have to reset every time some drunk plows into a power pole outside

Eta: again, very broadly: you know how your laptop can run off a cord, and keep going when you unplug it? Kind of the same thing.
 
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Yes I get this comparison, but i was more so talking about the one specific clock. I understand the others have higher power supplies, but this one clock would always go out until this latest one
 
DebunkThisPls said:
Yes I get this comparison, but i was more so talking about the one specific clock. I understand the others have higher power supplies, but this one clock would always go out until this latest one
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Hard to say without knowing more about that specific device, how old it is, etc. Might just be that there was a fraction of a second difference that made it react differently. As any device ages, it deteriorates and might behave a little differently than it has in the past, kind of like an incandescent light bulb that works fine but one day burns brighter and later burns out
 
DebunkThisPls said:
I definitely will, thanks. One question though. All the other times we've had a flicker or really quick power outage like the original story, the clock has gone out, at least the very sensitive one. Is there any reason it didn't go out last time? Maybe just coincidence or a slightly fast outage that may not cut it off?
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The difference in time that will allow the clock to stay set versus turning off could be very small. A fraction of a second longer of an outage and the clock may have to be reset.

And since you aren't tracking the power into the clock with any sort of sophisticated instrument, it is hard for you to know which outage was worse for the clock on that sort of scale.

I am terrible at electrical circuits. Barely passed the one class I had to take. Nonetheless, it is fascinating even if you can just grasp the basics of how this stuff works. And how small changes in a circuit, or even in other appliances on the same circuit, can impact the power a device receives.
 
Our radio alarm clock has a backup battery inside it, as I remembered while resetting from DST to ET. The battery needed changing, too.
 
The cap is charging/discharging to smooth out the ripple in the rectified AC. Now suppose you had a way of shutting off the AC at any point. If you shut it off when the AC is crossing 0v vs shutting it off at the peak (around 120Vac in the US), how would that affect how long the cap might supply power to the circuit? I wouldn't think it would matter much, but I've never looked into this aspect of a AC/DC converter. If i did the math right, 60Hz is about 16.6ms.
 
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