Joined: Aug 10, 2004 Posts: 881 Location: New Delhi-India
Posted: Tue Apr 21, 2009 7:51 pm Post subject: Re: What wattage of CFL Lamp for good plant growth.
PLL stands for PHASED LOCKED LOOP
PLL here does not stand for PHASED LOCKED LOOP at all reference to the Lamps.
PHASED LOCKED LOOP are electronic Circuits that compares an input frequency and phase to a reference signal. It then generates a voltage proportional to the difference between the input and the reference. They are mostly used in digital and mixed mode (analog and digital) applications as regulators, demodulators, synchronizers and frequency multipliers and dividers.
These Circuits hence have no use in driving the PLL through a ECG(electronic control gear) or a CCG(conventional control gear).
Quoting from the Philips Website
"1980 - New phosphors, because of their superior behaviour under high radiant loads, allow miniaturization of the fluorescent lamp. Philips is the first to launch compact, narrow-tube fluorescent lamps: the SL* lamp in 1980 and the PL lamp in 1981."
Joined: Oct 04, 2008 Posts: 537 Location: Bangalore
Posted: Wed Apr 22, 2009 3:57 pm Post subject: Re: What wattage of CFL Lamp for good plant growth.
And my small bit addition to light penetration.
Sunlight is known to be between 5000 to 6000 Kelvin during normal daytime, so generally lights are made at this kelvin. For water, the higher the kelvin the better the penetration. If you have a 2 Ft tank for example and have carpet plants, you can use 8000 or 10000 Kelvin bulbs, but as you want to use them for your red plants at the back, you can use a 4000K which will appear more orangish than blueish (and will therefore have the least water penetration). I am told that the Kelvin range below 4500 really brings out the red in the plants... My red plants at the back are doing really well because of the 4000k T5 tube.
PLLs are also CFL lamps, CFL is a general terminology to represent these type of triphosphore high intensity efficients lamps.
PLL stands for PHASED LOCKED LOOP which utilises an external electronic ballast only for current frequency control. It utilises 4 pins in holder.
There are other technologies also CCFL (Cold Cathod Flurocent Lamp) , PLC (Programmed Logic Control), etc.
However it does not matter what bulbs are you using; essentially all are triphosphor flurocent lamps and can produce your desired result depending on spectrum and intensity.
A lamp will appear more bright aka more lumen if its spectrum covers a large amount of its light distribution in green range. But plants donot utilise the light frequency in green range, so lumen is important for brightness and appreance for the aquarium but not relevant to plant growth requirement. Human eyes respond more to the green spectrum, hence normal commercial bulbs aredesigned accordingly
Plants tubes like OSRAM Floura emits its light spectrum in red and blue zone with very little spread in green, so they appear very dim and pinkish. But plants can grow very well under these types of lamps. So just do not go for higher lumen ratings only
I suggest you, choose full spectrum bulbs like OSRAM 954 PLLs or Biolux FL.
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