Talk:Real-time clock

Computing C‑class Mid‑importance

	This article is within the scope of WikiProject Computing, a collaborative effort to improve the coverage of computers, computing, and information technology on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.ComputingWikipedia:WikiProject ComputingTemplate:WikiProject ComputingComputing articles
C	This article has been given a rating which conflicts with the project-independent quality rating in the banner shell. Please resolve this conflict if possible.
Mid	This article has been rated as Mid-importance on the project's importance scale.
	This article is supported by Computer hardware task force (assessed as Mid-importance).

Question[edit]

What kind of clock is it physically? A crystal based clock or a "CPU cycle" clock speed clock? --Procrastinating@^talk2me 13:16, 4 October 2006 (UTC)[reply]

It's a battery backed crystal based clock, generally. BruceEwing 10:38, 19 November 2006 (UTC)[reply]

Philips microcontroller[edit]

Is there any reason that we're mentioning a specific Philips microcontroller on this page? I found a hastily written statement, which I edited and linked to the product page, but it seems somewhat overly-specific and out of place. --ThinkingInBinary 14:11, 6 March 2007 (UTC)[reply]

I have no idea, someone sorta left it there. I'm going to remove it. Codeczero 02:41, 24 August 2007 (UTC)[reply]

IRQ??[edit]

I think the fact that it associated with IRQ 8 should be mentioned. CPU MeltDown 14:09, 29 May 2007 (UTC)[reply]

references[edit]

the page now has several references, they aren't great, im not super fond of using application notes (although i did use 3 different manufacturers). if you can find better references feel free to replace mine Codeczero 02:30, 24 August 2007 (UTC)[reply]

How exactly does it work?[edit]

I have a strong impression that it is battery powered, but how exactly does it still precisely retain the right time when my system is off? By off I mean unplugged, computer packed in a box while moving to a new residence. Same thing with gameboys and other devices. I haven't really tried to remove the batteries for a couple months to see if the gameboy will still preserve the correct time, but I had my gameboy on the shelf untouched for 3 years with the same batteries, and it's fine. There must be some mechanical aspect in the technology that keeps it going.

So, how does it work?--Spectatorbot13 (talk) 21:34, 22 May 2009 (UTC)[reply]

Traditionally, the real-time clock in most computer devices is maintained by a tiny lithium rechargeable battery separate from the main power source of the computer or other device. In some newer devices, this is replaced by a modern capacitor that can hold a high charge, and is recharged every time the device is switched on.

I have a minor quibble; The PCs and electric power meters I have seen tend to use a lithium primary battery, usually a CR2032 (225mA-hours). It is not rechargeable. However, the power system usually only switches to it as a last resort. Most RTCs have a current draw of less than 1 microamp, so a 225mA/Hour CR2032 will run one for something like 10% less than 225,000 hours, i.e. over 22 years. The systems with two batteries tend to make one rechargeable. For the rechargeable they use either a supercap, which never degrades, or a nicad rechargeable derated, maybe even with a software charger algorithm, to get as many cycles as possible. Ray Van De Walker (talk) 21:32, 31 August 2021 (UTC)[reply]

Certainly designs have changed over the years so there are a lot of different ways this has been and is being done. Perhaps the article should not be so specific. ~Kvng (talk) 16:42, 4 September 2021 (UTC)[reply]