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Steve G., Electrical Engineer
Category: Electrical
Satisfied Customers: 17976
Experience:  Spent 20 years as an Electrical Engineer, designing electrical plans and specifications.
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# I have a technical question which has provoked debate at our

I have a technical question which has provoked debate at our work breaks. It concerns the lumen output of a 100w watt incadescent light bulb operating in the 120v north american market, with an approximate output of around 1600 lumens, v the 100w equivalent operating in the 230v market with an approximate 1300 lumens. (these figures are courtesy of google!) Can you please explain the difference for me, as it appears to contravene OHMS LAW.

Hello there and welcome to Just Answer. My name is XXXXX XXXXX I will be assisting you today. I am an engineer with over 30 years of electrical and electronic training, repair and installation experience. I will try and answer your question accurately and precisely so that we can get you on your way.

I'm not sure why it contravenes ohms law. The resistances in each bulb are different.

Please let me know so that we can continue.

Regards

Steve

Customer: replied 3 years ago.

I understand that the resistances are different,and I was out of line to question ohms law, but my question is why is the output different, being that both bulbs use the same energy (100w). only the volts and amps are a different mix because of the necessary change in resistance.

Are the bulbs the same brand and type? Manufacturers are going to write whatever they want on the packaging. If company A makes a 1300 lumen lamp you can bet that that company B is going to make one with 1400 lumens.

Please let me know so that we can continue.

Regards

Steve

Customer: replied 3 years ago.

when we googled 100w incadescent light bulb lumens, those were the approximate figures that was quoted for the two voltages, the 120v being generally about 300 lumens above the 230v. Maybe you can check on google yourself to see what I mean. Also is the american Volage exactly half european voltage? Our voltage is set at 233v

American household voltage is nominally 120V. It can be 110V or 115V or 120V.

Here is a whole page of 60W 120V lamps. You can see that the lumen variation between lamps is significant. http://www.1000bulbs.com/category/60-watt-standard-shape-light-bulbs/

Lumen output depends on several factors including the lamp coating. Here in the US, 220V incandescent light bulbs are usually considered industrial or commercial so the color temp may be different to a 'cool white' lamp one would use in the home.

I'll be here if you need further help with this issue. Please let me know.

Regards
Steve
Customer: replied 3 years ago.

So, to clarify and bring this debate to a conclusion. are you saying that the available voltage has no material effect on the lumen output? Am I also to understand that it is the coating on the bulb, the type of manufacture, and the particular design, bearing in mind that 100w is a target, not a bullseye, and that manufacturers can be 'creative' in their lumen output? I would appreciate your clarification on these questions, so that this discussion can be 'put to bed' once and for all! I appreciate your patience in this matter, and will mark you accordingly! I have more meaty questions coming up soon!

Yes to all of the above. Voltage has no effect on lumen output.

I'll be here if you need further help with this issue. Please let me know.

Regards
Steve