Power ratings on Dell LCD monitors

[farmgrown]

When you look at almost any LCD monitor (e.g. Dell G2410), the tech spec for voltage says 100-240VAC/50/60 Hz (2A maximum), but then they cite typically 25-50W for typical operational power consumption. Does anyone know under what conditions the 2A maximum occurs? I've tried tunneling through tech support, sales support, etc at Dell and so far can't find intelligent life.

 

[smah]

That depends on what you mean by 'conditions'. Highest current draw will occur at lowest voltage & highest power.
I=P/V --> so 50W/100V=2A. In traditional CRT monitors, the color white consumes the most power (Watts) and black consumes the least. I suspect the same is true with LCD's but I don't know that for sure. More questionable is how they define 'typical operational' conditions.

 

[farmgrown]

Dear smah,
Thanks for taking the time and your reply.

You might want to double-check your arithmetic:
I=P/V=50W/100V = 0.5A rather than 2A which is still a factor of 4X. Also in the case of the Dell G2410, the operating power is listed @ 25W which is 1/4A by same logic.
I do know that LCD displays can consume more power at low temperatures (like near freezing) and also when driven to maximum brightness in high temperatures.
Thanks,
farmgrown

 

[smah]

woops, very bad math

 

[Johnthephoneguy]

I would think your initial startup would be the highest power consumption.

JohnThePhoneGuy

"If I can't fix it, it's not broke!

 

[BadBigBen]

Have a Read, especially the comparison chart on the following table:

Monitor power consumption basics

http://reviews.cnet.com/green-tech/monitor-power-efficiency/

Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[JimInKS]

This won't give you the initial inrush current you typically get when a device is turned on, but it is great for steady state power consumption measurements.

http://www.cyberguys.com/product-details/?productid=5382

 

[farmgrown]

Johnthephoneguy is right that the greatest consumpion is at startup typically called the inrush current. But the inrush current for these monitors is typically 20-30+ A (yes, not a typo) which usually lasts for only a very brief period like a half-cycle, 8ish milleseconds or so. But it's still a different number from the 2A number, so it's still some other condition.

The read BadBigBen referred to was a good read on the different aspects power consumption is modulated (.e.g by brightness level, etc). However, the range of consumption is still within the operating range (typically less than 100W) which still doesn't tell me what the 2A (or 230Watts+)
condition is.

To JimInKS: not having an inrush capability is OK since I don't believe that is the 2A spec. This is a nice unit that could record consumption but I'm still clueless as to what conditions to cause 2A condition.

Thanks to all for their efforts to puzzle it out. I am also continuting to see what Dell can come up with. finally have someone agreed to go look at it.