Digital clock 50 60 cycle issue

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hameeds01

Joined: 23 Aug 2005
Posts: 308
Helped: 15
Location: NUST Islamabad

02 Nov 2009 7:02 Digital clock 50 60 cycle issue

I have a digital Clock which requires 110v, 60Hz but in my country we have 220v, 50Hz. Now for this purpose I am using stepdown transformer & I am feeding 110v, 50 Hz to my clock, now the problem with my Digital clock is that it runs slow, u can say - 35 sec per 24 hours

betwixt

Joined: 04 Jul 2009
Posts: 388
Helped: 64
Location: Wales, UK

05 Nov 2009 10:46 Re: Digital clock 50 60 cycle issue

Most digital clocks use the mains cycles as the reference clock. They divide by either 50 or 60 to provide the seconds count. It sounds like you are dividing by 60 when you should be dividing by 50 so you lose about 10 seconds every minute.

Manufacturers of digital clock ICs usually make them compatible with both frequencies so you may find a pin tied high or low that you can reverse to change the count ratio. Otherwise, you need to find the pin that monitors the mains frequency and provide a 60Hz signal of your own to replace the one from the mains.

Brian.

ark5230

Joined: 29 Jun 2009
Posts: 188
Helped: 15
Location: India

08 Nov 2009 19:20 Digital clock 50 60 cycle issue

Loss of 35 seconds in 24 hours should be attributed to something else. Had it been due to frequency of AC mains, the time lost should be of the order of 4 hours a day.