On Thu, Mar 8, 2018, at 9:16 PM, Barry Roberts wrote: > It's not Linux-related, but I'm curious what other nerds think. I was > listening to KUER on the way home from work tonight, and they were > talking about this: > https://www.theverge.com/2018/3/8/17095440/europe-clocks-running-slow-electricity-frequency-kosovo-serbia > > I don't know if I've ever owned a clock that would act like that. > Maybe some really old clock with an AC motor. But they talk about the > clock on a microwave, and show a digital clock on a stove. Those all > have crystal oscillators that run on DC and I'm pretty sure would not > be affected at all by a .1% change in the AC frequency (that number > was from the radio --.1% or 344 seconds in about 6 months, I think). > > Am I crazy? Are there really a bunch of clocks in Europe that > actually depend on the 50hz alternating current frequency for > timekeeping? The whole thing sounds like some non-technical reporter > grossly misunderstanding electronics to me.
the grid has to maintain its frequency anyways so why not also use it for a clocksource. i'm not an expert in low level digital components, i wouldn't be surprised if a circuit could be built to generate a clock signal using components that could be built into an integrated circuit. that would eliminate the need for another component. also, as rafferty pointed out, it is likely to be more accurate than a crystal oscillator. a quick google search yielded [1] talking about this specifically related to clocks. [2] also has a description of an experience using a coffee pot built for one grid being used in the other and the effect that it had. i also don't think its coincidence that the frame rates for analog video standards in countries using 50Hz utility is 25Hz and countries where the utility is 60Hz have a frame rate approximately 30Hz. i don't think it was a direct decision or that the devices use the frequency this way but plays a part. [3] has some info about this. this doesn't seem crazy to me. mike [1] https://en.wikipedia.org/wiki/Utility_frequency#Time_error_correction_(TEC) [2] https://electronics.stackexchange.com/questions/71769/why-would-a-modern-digital-clock-rely-on-mains-frequency [3] https://en.wikipedia.org/wiki/NTSC#Lines_and_refresh_rate /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
