# Digital light meter



## JohnR (Apr 12, 2010)

UMMM pulling your leg? 
A light meter measures the exitance of light from the fixture, and this can vary depending on lamp wattage, and lightshade or lens. Also color, and the time-life of the lamp can change how much output there is.


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## 480sparky (Sep 20, 2007)




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## Edrick (Jun 6, 2010)

Wasnt this topic already posted


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## desertbucks (Feb 19, 2011)

I thought it was bogus when I heard about it as well, wanted to see if I was missing something!


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## The_Modifier (Oct 24, 2009)

A lux meter, photographers sometimes use them, one of the local tv camera guys I know has one.

http://www.valuetesters.com/Light-Meter.php 




Edrick said:


> Wasnt this topic already posted


 I think you mean this post HERE


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## tkb (Jan 21, 2009)

I keep that meter in the truck right next to the lamp bender. :whistling2:


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## Edrick (Jun 6, 2010)

The Light meter we use in film / photography wont help in any way to figure out if it's T8 or T12. It'll tell him if he's shooting on Kodak Tungesten 500 Speed what F Stop he needs to set his aperture at however to obtain a certain look.


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## Ima Hack (Aug 31, 2009)

I don't think anything like that exists.

This is what I have, it does about everything, but it dosen't tell me lamp type.

http://www.extech.com/instruments/product.asp?catid=10&prodid=64


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## desertbucks (Feb 19, 2011)

They do make it, I finally found it. Advance makes a D1 or sensor switch that is hand held and determines if a light fixtures is magnetic or electric by the push of a button. If it is a green light it is electronic and if it is red it is magnetic ballast. Works great for lighting audits!


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## backstay (Feb 3, 2011)

http://www.atlantalightbulbs.com/library/sensor_switch/D-1.pdf


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## BBQ (Nov 16, 2010)

Pretty sure the frequency of lamp pulsing can be measured and used to determine a mag ballast from an electronic.


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## 76nemo (Aug 13, 2008)

BBQ said:


> Pretty sure the frequency of lamp pulsing can be measured and used to determine a mag ballast from an electronic.


 
Really?.........wow. I never knew something of that sort existed. I don't get into lighting design or installs, but when I read the first post here, I immediately thought..."BS".

I'd like to get my hands on one or see it's schematics.


I am sorry to come across as simple again, but is this type of meter necessary to a film crew, and film crew only????????

You worked stage Bob, is this how you are aware of such a meter????

mxslick??????


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## BBQ (Nov 16, 2010)

http://www.advance.philips.com/content.aspx?id=17


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## 76nemo (Aug 13, 2008)

BBQ said:


> http://www.advance.philips.com/content.aspx?id=17


 

No kidding. Man I like public forums!!!!!!


Thanks Bob:thumbsup:


That's a whole new ballpark to me:001_huh:


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## Greenblinker (Aug 4, 2008)

I have one of the above mentioned "ballast checkers". Worked great on a retro job for a bunch of schools. Any T12 was to be changed or converted to electronic T8. It was a good proofer for us as we worked and the supers on the final walk through. You can hold the button down and keep it pointed up as you walk down a hall and it will change colors accordingly as you walk past the fixtures. 

Sent from my EVO SHIFT using Electrician Talk


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## Ima Hack (Aug 31, 2009)

desertbucks said:


> They do make it, I finally found it. Advance makes a D1 or sensor switch that is hand held and determines if a light fixtures is magnetic or electric by the push of a button. If it is a green light it is electronic and if it is red it is magnetic ballast. Works great for lighting audits!


Well I'll be damned,  What does one cost?


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## Electric_Light (Apr 6, 2010)

desertbucks said:


> I was told that there is a hand held meter of some kind that can determine if a light is T8 or T12 by walking under the light, anyone know what this is?


Turn it off and observe as the switch is flipped back on. If it comes on instantly, its most likely T8(majority of installs are instant start). If it comes on dim and "grows" to full output, its most likely T12 on magnetic rapid start, the most widely installed system prior in the US prior to T8 instant start. 

Missed spots are very easy to find. It's faster if you get someone to throw the switch on your count. They're like drivers who aren't paying attention and starts moving two seconds after the light turns green. They'll stick out like a sore thumb. Please PM me if you know of a faster way.l

If there's a distinct delay, then BAM!, full output, its probably programmed rapid start T8(not very common).

Another way is to take a pencil or something, swing it back and forth between your fingers. If you can see a rainbow effect or "multiple images" of pencils, then you've got magnetic. You'll have to just get a hand of object/background contrast. You'll learn how it works in a few minutes once you try it out under known magnetic ballast and known electronic ballast. This effect is diminished on three phase system with luminaires on multiple phases, so I recommend the first method.


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## Dennis Alwon (May 9, 2009)

Ima Hack said:


> Well I'll be damned,  What does one cost?


$50 bucks here but philips is $100


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## MDShunk (Jan 7, 2007)

desertbucks said:


> I was told that there is a hand held meter of some kind that can determine if a light is T8 or T12 by walking under the light, anyone know what this is?


Call Miss Cleo:


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