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Feedback Comments on Electricity

by Ron Kurtus

A total of 724 comments and questions have been sent in. They are listed according to date.

You can read them to further your understanding of the subject.

List of next 10 letters




AC Transformers Does mcrowave oven convert AC to DC? USA
AC World Voltages Running US saw on UK power Ireland
DC Powering TV with a battery USA
AC World Voltages Will countries agree on same voltages? Saudi Arabia
AC World Voltages Why is voltage in Pakistan 220V and 50Hz? Pakistan
AC World Voltages What are the most common voltages in Europe? USA
AC World Voltages Using 60 Hz equipment in 50 Hz country The Netherlands
AC Transformers Permission to use figure USA
AC Question about the AC sine wave USA
AC World Voltages Why are voltages and frequencies different India

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First 10 letters

Does mcrowave oven convert AC to DC?

Topic: AC Transformers


February 19, 2014

I was told on a transformer in a home microwave that Ac voltage goes in on input side and DC current comes out on out put side . Is this true?

don - USA



A standard microwave oven transforms the 120 VAC to 4000 VAC. Then it uses a rectifier circuit to change the AC to DC, required to operate the magnetron that created the microwaves.

See The Microwave Oven — More on How AC Becomes DC for information on the topic.

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Running US saw on UK power

Topic: AC World Voltages


February 3, 2014

i have a dewalt table saw that runs off US mains power 120v and 60hz. can i run it off UK 110v 50hz transformer?

tony - Ireland



The slight difference in voltage should make no difference. However, the 50hz may result in the saw running a little slower.

I hope it works out for you.

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Powering TV with a battery

Topic: DC


February 2, 2014

Hi Ron,
Hoping you might be able to answer a few simple questions for me.
I have an AC TV set that draws 48 watts. I also have a small 12 Volt (12 amphrs) battery that I plan to hook up to an AC Inverter to power the TV.

Will this battery power the TV? and for how long (app.)?? Any thoughts greatly appreciated..

FYI - my hopes are to build and power a rifle range target system. I plan to have a camcorder and transmitter near my paper target and the TV and receiver at various ranges from 100 to 500+ yards. This system will eliminate the need to check the latest shot with a spotting scope. Thus far, I've tested at 100 yds with great success, but that was with AC power at the TV end...

Thanks for your help,

Ed - USA



It might be easier to use a battery powered TV set that already has the inverted built in. The TVs are relatively inexpensive. Battery life is about 1.5 - 2 hrs before recharging.

For your 48W TV, it probably would work but I'm not sure how long the battery would last.

Your idea of the rifle range target system sounds interesting. Best wishes in setting it up. Let me know how things turn out.

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Will countries agree on same voltages?

Topic: AC World Voltages


January 21, 2014

to begin with I would like to thank you for the helpful topic.

May I have your opinion about the future of worldwide AC voltage and frequency, do you think that all countries will go for standardizing it to the most efficient rating V/F, like 230/400V @60Hz

if yes how many years this change will take?

if you have any topic about changing to 230V single phase and 400V 3 Phase with Neutral, please share....

I am making a research about this topic, your input of course in rich my findings,,,

Thanks in advance.

Murad - Saudi Arabia



Although it would be a good idea to standardize AC voltage and frequency to the most efficient rating, as you suggest, the major problem is that so many people have electrical equipment that may not be compatible. The equipment would have to be modified or new devices purchased.

That would bring about much resistance from the people.

Likewise, power companies in all countries have a big investment in their generating equipment, and they would not be motivated to change.

If agreements would have been made years ago, when AC power was just starting out, it would have been a good move. Unfortunately, it is probably too late to make such a change, because of the huge cost involved.

Best wishes on your research on this topic. Let me know how things work out.

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Why is voltage in Pakistan 220V and 50Hz?

Topic: AC World Voltages


January 16, 2014

Why the AC voltage supply in our home has magnitude 220V and frequency 50Hz?? what is the reason??

Hamza - Pakistan



In the 1950s, European countries decided to use 220-230 volts at 50Hz as an effort to standardize. Other countries, such as Pakistan, followed suit because the electrical supplies came from Germany and Europe.

They felt that 220V was more efficient. However, 50Hz is not as efficient as 60Hz.

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What are the most common voltages in Europe?

Topic: AC World Voltages


January 9, 2014

What are the most common Transmission voltages in Europe?

Keith - USA



The List of Worldwide AC Voltages and Frequencies shows that of 200 countries, about 160 use 220-240VAC. Looking over the list, it seems that all European countries use voltages in that range.

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Using 60 Hz equipment in 50 Hz country

Topic: AC World Voltages


January 1, 2014

Hi there!

My question:
Is it possible to use equipment with the specifications 220-240V / 50 Hz (The Netherlands)
in another country (The Philippines) with 220V / 60 Hz?

Kind regards, Rob Vissers.

- The Netherlands



The voltage variation is not and issue, but the frequency can affect different devices, such as causing a clock to run faster. You can check the equipment to see if there is an adjustment for frequency. Also, there are rectifier devices that can change frequencies in a round-about way.

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Permission to use figure

Topic: AC Transformers


October 11, 2013


I am working with Dr. Mohamad Haj-Mohamadi, an ELC instructor in the North Carolina Community College system, who is developing an online ELC course to share with our 58 community colleges. Dr. Haj-Mohamadi would like to use the following image found on your Web site:

URL: [I am unable to include the URL here; it is blocked by your design.]
Figure: Simple AC transformer

If you are willing to grant permission, simply reply in an e-mail with a statement that grants permission. I will cite your Web site and list your permission within the credits for the course.

Any consideration will be greatly appreciated.

Beth Gray-Robertson
Director of Distance Learning
Halifax Community College
100 College Drive
P. O. Drawer 809
Weldon, NC 27890

Beth - USA



Yes, you have permission to use the "Simple AC Transformer" figure from the "Alternating Current (AC) Transformers" web page at

Note that I just updated the image to improve it.

Best wishes with your distance learning courses.

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Question about the AC sine wave

Topic: AC


September 3, 2013

Dear ser my ??? Are . 1st i live in mississippi usa we have 220 with 2 , 110 ac volts lin.e . I understand that the sine wave of 110 looks like lots of ssss on there sidr butconnected what or how would the 2nd line look to the 1st. Linesine wave look . Ive ordered and got the plain of the AMDAMS motor but it showe only one leg




Actually, most AC voltage waveforms are what they call 3-phase. This means they add three sine waves together that are slightly offset, such that the output is only a slight ripple, as opposed to a real sine wave. The reason is so that lights will not flicker when the voltage wave changes direction.

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Why are voltages and frequencies different

Topic: AC World Voltages


August 19, 2013

sir, whats the reason frequency and voltages are differed from country to country............i mean why frequency is in 60and50 HZ,and the voltages are in 220 and 110?
why it changes due to any environmental reason or anything else sir?

mounika - India



Nikola Tesla started AC at 240 volts and 60 Hz. 60Hz was selected, because it divided evenly into 240. However, the voltage was later reduced to 120 for safety reasons. However, many European countries decided to use 50 Hz, because it fit the metric system. Some also used 110 V, while others went to 240 V.

The reasons countries use different voltages and Hz is a combination of politics and what companies supply the equipment.

See: Background of Worldwide AC Voltages and Frequencies.

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