# Convert American bought digital clocks to use in 50Hz main supply

#### electro_yas

Joined Dec 20, 2010
15
First you will need to change the voltage by a step down transformer.

This method can be used for the American digital clocks where main supply frequency is used as the clock pulse. Normally these digital clocks use LM8560 or SC8560 ,and these ICs have an option to select 50Hz or 60Hz. But America's main AC is 60Hz therefore this pin is not connected to any . Just look at the datasheets of these ICs and connect the relevant pin to the correct point.

#### Wendy

Joined Mar 24, 2008
22,328
Sure, it could be done, but your trying to convert a $20 (or much less) clock with a$30 (or more) project.

The simplest way is an inverter. Just build a precision time base in the oscillator section. With just a little more circuitry it can be a nifty battery backup.

Or find where the 60 hertz in used by the clock and modify that circuit. While you're about it disable the battery backup oscillator to use yours too. Thinking about it this is the simplest, but a lot skill required.

I suspect it would be much cheaper to buy one in the country of origin.

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#### electro_yas

Joined Dec 20, 2010
15
Yes , you are correct it will take some money to buy a transformer to step down the voltage to the appropriate level but to change the frequency option you will need just one wire because many clock ICs have both the options.

I thought of making an inverter before and it was not worth it unless I have many American bought digital clocks. But it will be a good idea for other electronic gadgets even thought it will be impossible to maintain exactly 60Hz.

#### Wendy

Joined Mar 24, 2008
22,328
Actually it isn't that hard. Phase locked loops can use a simple reference and generate a completely new frequency. You could also convert 50Hz to 10Hz, then multiply it X6. There are many ways to generate a stable frequency from another. Are you really interested in a frequency conversion?

#### electro_yas

Joined Dec 20, 2010
15
I think for that you will need to first convert main supply into dc and again convert it into ac by a transformer like an inverter circuit. It can be done but expensive , is there any method which can be done with less cost and high energy efficient ?

#### blueroomelectronics

Joined Jul 22, 2007
1,757

#### thatoneguy

Joined Feb 19, 2009
6,359
There isn't an efficient(95%+) way to convert 50Hz to 60Hz. You could try a motor/generator combination for items other than a clock that aren't available in 50Hz, but those are rather cumbersome.

If you have the datasheet for the IC inside your clock, you can change the setting if the timebase is derived from the power line. Battery operated "Atomic Clocks" that set themselves by WWVB (US) are becoming very popular here, so line frequency is irrelevant. I believe there are a few stations in the EU that transmit a time standard as well, though I'm not familiar with how common the radio-set clocks are there.

Many new portable generators are now actually converting to DC then using an inverter to produce the output. This allows for higher fuel efficiency than running at the constant required RPM.

The reason I mention this is the use of DC->60Hz Inverters is very widespread now, and many off the shelf items are available. It is only a matter of converting the 50Hz to DC.

#### electro_yas

Joined Dec 20, 2010
15
"Battery operated "Atomic Clocks" that set themselves by WWVB"

How to construct a basic clock with that method.

#### thatoneguy

Joined Feb 19, 2009
6,359
"Battery operated "Atomic Clocks" that set themselves by WWVB"

How to construct a basic clock with that method.
What location are you in? WWVB is a low power 60kHz signal, which covers only most of the US. During the day, there is too much noise in that band, so the radio/atomic clocks set themselves between midnight and 6am, sometimes more than one time if the signal is available.

I don't have the information for Europe, Switzerland had one running at 40kHz, but I do not know of it's current status.

Ready made modules for the US are available, and the cost for a complete clock with time/temp/calendar is under \$20 here.