[ILUG-BOM] Blackle - Black Google -- saves energy.

Rony gnulinuxist at gmail.com
Wed Oct 8 20:43:52 IST 2008

jtd wrote:
> On Wednesday 08 Oct 2008 13:24, Rony wrote:
>> The sites are about LCD-CRT comparisons. What I want to know is the
>> difference in power consumption between a CRT running a white image
>> and the same running a black image. IMHO, there is no noticeable
>> difference as the EHT power is generated all the time and the
>> control and signal processing circuits are running all the time.
>> The small differences in the cathode voltage and subsequent control
>> of the beam current does not make any power saving. The only
>> advantage may be to the eye as it reduces glare.
> Most of the power is consumed by the deflection circuits and the 
> filament. Not the cathode which emits electrons. The brightness is 
> determined by the acceleration grid (afair).
Filaments are generally consuming 5W-6W each. In the old B/W sets, a few 
turns of wire across the EHT core would be used for powering the 
filament. The grid voltage sets the ambient level of brightness but the 
signal is given to the cathode and is inversely proportional to the 
white level. So a low signal level means more emission for white and 
high level ( including H & V blanking ) means low emission for black. 
Its been many years so I could be missing something.

> With an LCD the backlight consumes substantial power and keeping a 
> black image on screen makes no difference to the power consumption.
True! Is plasma better in power consumption?

HP appears to have developed a special laptop that consumes very low 
power and it has developed a new screen that is extremely low on power.



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