Light intensity question.

Apocalyptical

Active Member
If i turn down the dial on my QB, lets say fifty percent, is the decrease if ppfd reading linear, following the fifty percent decrease?
 

anexgrower

Well-Known Member
probably not but I'm guessing within 10%, use the light meter app "korona" readings to be closer to reality light levels
 

Apocalyptical

Active Member
probably not but I'm guessing within 10%, use the light meter app "korona" readings to be closer to reality light levels
Im trying to figure out the mathematical form of the function behind it without having to use machines, but i guess id need the specs behind everything being used. Either way, i was still wondering whether it was linear/logarithmic/exponential or something along those lines XD
 

anexgrower

Well-Known Member
Im trying to figure out the mathematical form of the function behind it without having to use machines, but i guess id need the specs behind everything being used. Either way, i was still wondering whether it was linear/logarithmic/exponential or something along those lines XD
Right, we don't really know how those dimmers are engineered, but guessing they were aiming for half as much light power at 50% setting, and this may be controlled by PWM which is actually a pretty accurate and linear way to control power.
 

Apocalyptical

Active Member
Right, we don't really know how those dimmers are engineered, but guessing they were aiming for half as much light power at 50% setting, and this may be controlled by PWM which is actually a pretty accurate and linear way to control power.
I'm good with numbers, but dont really know anything when it comes to engineering/electrical application. Guess ill do some reading. Thank you!
 

LEDTonic - Max

Active Member
One of the easiest ways to find out is to buy a power meter (Kill A Watt).
If you're wondering about efficacy gain from dimming, generally, dimming the lamp to 50% power consumption will result in a couple percent more light per watt.

Example (made up numbers):
If it produces 1000 PPFD at a certain spot at 100% power, dimming it to 50% power consumption, it measures 525 PPFD in the same spot.
 

Apocalyptical

Active Member
One of the easiest ways to find out is to buy a power meter (Kill A Watt).
If you're wondering about efficacy gain from dimming, generally, dimming the lamp to 50% power consumption will result in a couple percent more light per watt.

Example (made up numbers):
If it produces 1000 PPFD at a certain spot at 100% power, dimming it to 50% power consumption, it measures 525 PPFD in the same spot.
Ok so its fairly linearly minus a tiny percentage range. Thank you.
 

insomnia65

Well-Known Member
if you are good at numbers as you sound like numbers matter (as they should) a kilowatt is a good start as is korona, there's calculations also in this site and links, Shane on MiGrow also does some stuff on youtube.
 

anexgrower

Well-Known Member
Thanks for mentioning our app! :) Just wanted to let you know that the app is now called Photone:
Good to know, I don't blame you for changing the name.
BTW there's a video that shows how very accurate the app is:
 

Autofire

Well-Known Member
Thanks for mentioning our app! :) Just wanted to let you know that the app is now called Photone:
would the accuracy of the app depend on how good the phones light sensor is?
 
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