Impact of Hertz on computers

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ChrisGreaves
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Impact of Hertz on computers

Post by ChrisGreaves »

How is the incoming 120vAC 60Hz power supply tied to "the clocking speed" of today's personal computers?

The local newspaper The Terrace Standard reports that a change in city power supply has caused bedside digital clocks to run faster/slower.
I get that.
A digital clock that assumes 60Hz will run faster at 60.3Hz. " ... and in this case that’s 18 seconds an hour or over the course of a day, seven minutes".
The article then goes on to say "Clock applications in computers, smartphones or other devices tied into the internet are not affected as they take their times from the internet through satellite-based calculations".
Well, yes, so it really is 7:18 a.m. as I type this.

But I wonder about what I believe is called "clocking speed", which always meant to me the time taken for one instruction-cycle in the CPU, orm one word-access from core memory. (I think the IBM 1401 was 11.5 micro-seconds; the ICL 1903A 3.5 micro-seconds)

Is the clocking speed (typically 3GHz-4GHz) delivered by some sort of crystal oscillator in the laptop, or is it a multiplied input rate, and hence dependent on the incoming rate (in this case a multiple of 60.3 Hz rather than a multiple of 60 Hz)?
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Re: Impact of Hertz on computers

Post by StuartR »

Most modern power supplies chop the incoming mains into very high frequency AC so that they can use tiny transformers to reduce the voltage. This means that the frequency of the incoming AC is not visible beyond the very early power supply components.
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Re: Impact of Hertz on computers

Post by HansV »

The subject had me think that Hertz had branched out into rent-a-computer...
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Re: Impact of Hertz on computers

Post by John Gray »

Oh, how it Hertz...
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Re: Impact of Hertz on computers

Post by Leif »

ChrisGreaves wrote:
16 Jul 2021, 09:58
How is the incoming 120vAC 60Hz power supply tied to "the clocking speed" of today's personal computers?
It shouldn't be. Modern switch-mode power supplies rectify the incoming AC to DC, and then use fast switching to convert the (DC) power. There would only be an impact if the frequency went beyond the rectifier's switching speed, but you would then probably be talking about MHz...
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Re: Impact of Hertz on computers

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HansV wrote:
16 Jul 2021, 10:10
The subject had me think that Hertz had branched out into rent-a-computer...
I visualize a flood of rent-a operations, which reminds me that I saw an image from the news this morning, a street in The Netherlands (I think) with what looked like a stranded bus and the paving stones from the sidewalks washed into the streets.
This image suggests a ripe opportunity for rent-a-vegetable-allotment downstream, but bankruptcy for those on-site.
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Re: Impact of Hertz on computers

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StuartR wrote:
16 Jul 2021, 10:03
Most modern power supplies chop the incoming mains into very high frequency AC so that they can use tiny transformers to reduce the voltage. This means that the frequency of the incoming AC is not visible beyond the very early power supply components.
Thanks Stuart.
Let's see if I understand this:-
If I had to explain it to a non-computer person, I could say that "computers (and their power supplies) have a hardware filter that takes whatever the mains current is, and convert to the computers specified requirements, voltage, amperage, frequency and so on", where it is assumed that the appropriate mains supply is used, e.g. 120vAC in North America, 240vAC in Australia.
In other (other) words, the computer smooths out and cleans up the power supply.

In my original post I supposed a magic crystal that oscillated at a specified frequency.
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Re: Impact of Hertz on computers

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Leif wrote:
16 Jul 2021, 11:08
... if the frequency went beyond the rectifier's switching speed, but you would then probably be talking about MHz...
Thanks Leif; you will have read my response to Stuart.
I think that your constraint means that the incoming power supply must be within a range of operating values, in my(computer's) case, perhaps 115-125 vAC, and so on?

Much like almost all electro-mechanical devices that operate in a range of temperatures, humidity, wind-speed and so on.

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Re: Impact of Hertz on computers

Post by Leif »

ChrisGreaves wrote:
16 Jul 2021, 12:37
I think that your constraint means that the incoming power supply must be within a range of operating values, in my(computer's) case, perhaps 115-125 vAC, and so on?
You could do worse than read what the label says by the mains input!

These days it is much cheaper for manufacturers to manufacture one PSU for all markets, and so I would expect it to state something like "90-250VAC 50-60Hz".
They then need only to supply different mains cables to match the destination country.
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Re: Impact of Hertz on computers

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(I haven't read the newspaper since I was presented with a wall of different scripts needed to run the thing. :smile:)

My impression is what Stuart & Leif mentioned.

Slightly off topic, but linked to what caused the question I think:
Perhaps I'm pushing my luck(y) envelope, or how the saying goes :grin: touching subjects related to politics, but the closing of some nuclear reactors here will have a negative impact in this regard as well. The rotational energy in large generators rotating will help balance the grid frequency (which can't be achieved with wind power or solar energy). So that rotational energy has decreased somewhat; research is going on in (several countries). That said, for a long time our hydro power was the main "regulator" for grid frequency, we had over capacity, sort of; now we are moving in the other direction at same time as just about everything is supposed to run on electricity …

They have different systems to protect the stability, and of course it depends on how long time it lasts, but the last thing would be automatic disconnection of grids. (So if anything that would be the most obvious for a computer (or something else), it would turn off, unless running on battery or UPS.)

We can take a peek at the current, eh, frequency in our national grid at their pages. Earlier today:
20210716.PNG
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Re: Impact of Hertz on computers

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Leif wrote:
16 Jul 2021, 12:45
You could do worse than read what the label says by the mains input!
Thank you, Leif. I can take a hint!
20210716_103018_HDR (Copy).jpg
For my specific PC, and I suspect all PCs in Terrace and Prince Rupert, the frequency range is 50-60Hz.
But I suspect that there is a spectrum or probability curve, such that if Newfoundland Hydro wobbles to 60.1Hz my laptop will cope with it, and also at 60.2Hz, but that as we near 60.9Hz or as much as 73Hz, the probability of the laptop functioning without failure or error drops off steeply.
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Re: Impact of Hertz on computers

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Argus wrote:
16 Jul 2021, 12:59
... The rotational energy in large generators rotating will help balance the grid frequency (which can't be achieved with wind power or solar energy)...
hello again, Argus.
Gaaaah! I had not thought of this, nor do I particularly want to.
I suppose that 50Hz (or 60Hz) comes from water turbines spinning at those frequencies (or some constant multiple thereof), but I had not thought about solar panels which tend not to rotate at all.
I further suppose that The Powers That Be have some nifty electrical circuitry that can coerce an incoming burst of electrical energy in some format to an outgoing format, much as my model railway transformer took in 240vAC and had as output 12vDC for locomotives and 15vAC for point/switch motors.

I have seen some such circuit diagrams on DCC for modern model railways, and do not want to go there (grin!)
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Re: Impact of Hertz on computers

Post by Leif »

Chris, I really don't think you need to worry about the frequency - it would take a truly momentous shift away from the norm for your PC's PSU not to work.

As far as the frequency stability is concerned, this is averaged out over the day so that people with clocks synchronised by their local mains frequency don't start going mad.

If you really want to read more, try Utility frequency - Wikipedia
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Re: Impact of Hertz on computers

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Clocks generally use 'dumb' electric motors that take what power they receive. Computers condition their power and assure constancy in its consumption other wise you get

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Re: Impact of Hertz on computers

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So my conclusion would be that I'm more worried about the stability and capacity to deliver in general, when we are moving to, eh, other sources of energy for some reasons, since that would have an effect on everything, than what small changes in grid frequency* would do to my or other people’s computers. Having a good PSU is of course important, for different reasons, load, efficiency, quality, being stable.** But my impression is that in general they are better than some decades ago.

Our highest consumption, so far, is usually in mid-winter, January February. It's the cold, in this part of the world. Here something minor happened and was returned to normal in Feb this year.
202102.PNG
* By the way, we are in sync with neighbouring countries; so that inertia talked about above includes the whole grid.

** By the way 2, I know we are talking about laptops, the same for desktops of course. Since you were looking at your adapter, and for the off topic subject efficiency of these power supplies, many know about different levels for desktop PSUs, such as Bronze, Gold etc. Some year ago I noticed the equivalent for external power supplies. It can look a bit different in the EU and North America, I think, but as we all know they usually cram in all kinds of symbols on these devices, so for example the NA variant can be found here; along the lines of what Leif sad, it makes sense for the OEMs. It can be a symbol that says "VI". They have also been looking at things such as standby consumption. So "VI" has higher efficiency and lower standby consumption compared to "V". A single mobile phone doesn't use much energy while charging, compared to, say, a desktop, but there are plenty of them as we know.
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Re: Impact of Hertz on computers

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Leif wrote:
16 Jul 2021, 13:22
Chris, I really don't think you need to worry about the frequency - it would take a truly momentous shift away from the norm for your PC's PSU not to work.
Agreed, agreed, and agreed.
I was not worried about my PC but puzzled, or curious. For nigh on 40 years my variety of PCs has operated well, avoiding problems that might have been caused by frequency shifts. Of course, tradition dictates that any PC problem nowadays can be blamed on a Microsoft Update.
As far as the frequency stability is concerned, this is averaged out over the day so that people with clocks synchronised by their local mains frequency don't start going mad.
And the clocks running fast/slow didn't worry me as much as the local paper's alarm bells, which at one point said "If you’ve been wondering why your electric clocks have been running faster this past week, wonder no more." and "Rio Tinto power runs at 60.3 hertz and our power at 60 hertz, so even that bit, .5 per cent, can make a difference and in this case that’s 18 seconds an hour or over the course of a day, seven minutes.”
This seemed to me to be unduly alarming. Terrace is bigger than Bonavista - it has a Dairy Queen - but life there is nowhere near as hectic as Toronto that rolling up seven minutes late for work would collapse the town's economy.

If you really want to read more, try Utility frequency - Wikipedia
But this pretty well quenched all motivation for me yesterday, and I have only now recovered enough to respond.

All my Physics life (i.e. the past sixty years) I have thought of electricity as a fluid, much like water. I think of voltage as water pressure (a higher storage tank) and current as the diameter of a pipe, a network of pipes through which water can be pumped/shared, and so on. These are factors on the scale of an evolved human brain; my brain (even when I was 15) was equipped to cope with this.

My brain is not equipped to deal with water that pulses 50 or 60 times a second, nor with resolving the apparent problem of making two merged wave forms of electricity synchronise when they are 180º out of phase. Or worse, an indeterminate number of degrees out of phase.
Knowing a bit about the USA from my travels makes it worse - hydro-turbines spinning in, I would guess, every state when some states operate as independent countries. Let alone Europe.

At this point I must give up trying to understand it. I was, until yesterday, someone who might have used a 60Hz digital clock and corrected it once a month, thinking that the error meant it was due for a dash of lubricating oil somewhere.
Today I really must get my rain-trough relined so that I can catch drinking water when/if the rain comes.

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Re: Impact of Hertz on computers

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Argus wrote:
17 Jul 2021, 09:47
So my conclusion would be that I'm more worried about the stability and capacity to deliver in general, when we are moving to, eh, other sources of energy for some reasons, since that would have an effect on everything, than what small changes in grid frequency* would do to my or other people’s computers.
Hi Argus.
Again, my 15-year-old brain accepted quite happily that one could (and did!) produce electricity from a solar panel, and that the solar panel "produced electricity" which was electricity, the useful fluid which, if the pressure was great enough, could heat water or drive a washing machine.
Never did I worry about a solar panel being a non-rotating device. It made electricity, and electricity was useful.
* By the way, we are in sync with neighbouring countries; so that inertia talked about above includes the whole grid.
figure-2.png
From this web page I count about 40 countries in Europe, and assuming an average of five hydro power plants per country, there are 200 hydro generators in Europe. Each with a different rate of rotation. The factors of intertia and acceleration boggle this mind. It must be done either by a nifty set of circuits, or some sort of intermediate filter. A similar but not identical device must be changing solar-generated electricity from 0Hz to 50Hz. And of course this is nothing new. The same business must have taken place with the thousands of coal-fired (hence steam-driven) generators across Europe in earlier years. Also nuclear-powered.

Thanks again
and Cheers
Chris
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Re: Impact of Hertz on computers

Post by jstevens »

It Hertz just to think about it.
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Re: Impact of Hertz on computers

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jstevens wrote:
17 Jul 2021, 14:50
It Hertz just to think about it.
Ah! John. You need some Good Vibrations
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Re: Impact of Hertz on computers

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ChrisGreaves wrote:
17 Jul 2021, 13:01
It made electricity, and electricity was useful.
ChrisGreaves wrote:
17 Jul 2021, 13:01
Each with a different rate of rotation. The factors of intertia and acceleration boggle this mind.
I like the idea of lubricating a clock; that's my level. :laugh: There's no end to the math and abstract thinking in electricity.*

* And even if someone has enough skills you can always through in strange quarks and whatnot, but I don't think they matter here ...
--
Forgot to mention: As for lubrication, it also has its levels of higher knowledge being part of the interdisciplinary science called tribology, still its rooted in ideas mostly from the 1400-1700s, so ...
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