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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




DC Speed of electron flow through in DC current Pakistan
DC Circuits On/Off switch for 110 Volt DC USA
AC World Voltages AC frequency date in Japan incorrect Australia
AC World Voltages Buying device on eBay from Italy Australia
DC Fundamental units Pakistan
AC Transformers Risks in using a transformer South Africa
Electric Charge Why don't electrons repel each other in orbit? Pakistan
AC World Voltages Going to Australia on vacation USA
Ohm's Law Ohm's law and DC generator India
AC World Voltages Increase voltage from 100v to 240v Kenya

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First 10 letters

Speed of electron flow through in DC current

Topic: DC


November 22, 2014

in which speed electron flow through in Dc current

amjad - Pakistan



The speed of an electron in a DC circuit is also called the electron drift velocity. Electricity passing through a copper wire of radius 1 mm, carrying a steady current of 10 amps, has a drift velocity of only about 0.024 cm/sec.

It surprises many scientists how slow they travel in a wire. However, the effect of that movement causes the electricity to travel close to the speed of light, because of the movement of the electromagnetic field.

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On/Off switch for 110 Volt DC

Topic: DC Circuits


November 13, 2014

Is there an on/off switch for 110DC as shown in your diagram. Or can I use a standard 15a or 20a light switch?

Bob - USA



It depends on the amperage of the circuit. The list of 110V DC Power Supplies shows a range of amps from 4.5A to 40A.

If the current is less than 20A, you can use such a light switch.

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AC frequency date in Japan incorrect

Topic: AC World Voltages


October 30, 2014

On your "Electricity - AC World Voltages" page it states that the 50Hz/60Hz split in the Japanese power system happened after WWII.

Wikipedia states it happened about 50 years before that.

Eastern Japan (including Tokyo, Kawasaki, Sapporo, Yokohama,
and Sendai) runs at 50 Hz; Western Japan (including Okinawa,
Osaka, Kyoto, Kobe, Nagoya, Hiroshima) runs at 60 Hz.
This originates from the first purchases of generators
from AEG for Tokyo in 1895 and from General Electric for
Osaka in 1896.[3][4]

Tom - Australia



Thanks for pointing that out to me. I noticed that the resource I used that stated the split in frequencies happened after WWII no longer exists.

I'll make the correction.

Thanks again for the information and sorry for the inconvenience.

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Buying device on eBay from Italy

Topic: AC World Voltages


October 28, 2014

I am considering buying a MiniDisc combo deck on Ebay,from Italy. Their current is 230 volts at 50hz.In Australia we have 240 volts at 50hz.Will the unit function properly in Australia,on 240 volts? Dennis Moore.

Dennis - Australia



There is about a 10% variation in the designated voltages, so the difference between 240 VAC and 230 VAC should not be a factor. However, you do need to make sure the Italian outlet plugs will fit in your Australian outlets.

See Electricity in Italy for pictures of their outlet plugs. You would probably need some sort of adapter to fit your outlets.

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Fundamental units

Topic: DC


October 22, 2014

my question is please can you tell me what is the fundamental unit of direct current and fundamental unit of alternating current?

amina - Pakistan



There are three fundamental units for AC and DC electricity. Current is measured an amperes (also called amps), voltage is measured in volts, and resistance is measured in ohms.

These fundamental units are related by the equation: V = IR.

AC electricity has another factor: frequency.

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Risks in using a transformer

Topic: AC Transformers


October 15, 2014

1. what are the risks/problems of using DC and AC Transformers?
2. what does the two transformers used for? (DC and AC Transformers)

Tonia - South Africa



If you use the a transformer indented for lower voltages with a high voltage input, it could overheat or blow out.

Transformers are used to change the voltage to make it more usable.

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Why don't electrons repel each other in orbit?

Topic: Electric Charge


October 10, 2014

electrons are charged negatively charged particles as like charges repel each other then how electones are moving in an orbital why they dont repel eachother.

Moon - Pakistan



Electrons in the orbits or shells of an atom are separated, so to an extent they do repel each other. But a bigger question is why the negatively charged electrons do not fall into the positively charged nucleus.

The reason for both situations is that in very close distances--like with an atom--the Quantum Theory takes effect and properties at greater distances do not hold.

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Going to Australia on vacation

Topic: AC World Voltages


September 21, 2014

HI I am going to Australia on vacation and I want to get an electrical outlet converter that uses 240 volt AC 50 hertz system. Do you know where I can find that and want is this called?

Corey - USA



You can see some good information from Australia: Power and Appliances.

Another good site is Aust. Electrical Converters that includes a link to Amazon for one that costs about $25.

It is also good to check with your travel agent, if you are using one.

Have a good time on your trip.

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Ohm's law and DC generator

Topic: Ohm's Law


September 11, 2014

ohms law is applicable for generator and how

upendra - India



The output current from a DC generator is I = V/R(i), where R is the internal resistance of the generator.

The current in the DC circuit is I = V/R, where V is the output of the generator and R is the resistance of the circuit.

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Increase voltage from 100v to 240v

Topic: AC World Voltages


August 31, 2014

I have ajapanes generator of 100v. Can i use it in Kenya where the voltage us 240v and how can the voltage be increased from 100v-240.

philip - Kenya



The 100 volt AC is too low to power devices requiring 240v. You would have to use a 100 to 240 VAC voltage converter or AC transformer.

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