Investigating LED Bulb Power Factors

Investigating what happens to the power factor and apparent power of an LED light bulb as it is dimmed. I found that the apparent power of an LED bulb does not necessarily decrease as the bulb is dimmed. In the case of several of these bulbs, the apparent power actually increased as the bulb was dimmed. What this means is that it may be more efficient to run certain LED bulbs at full brightness rather than dimmed.

If your house has a "smart meter" that takes power factor into consideration, then these high-tech LED light bulbs won't be saving you as much as they claim on the packaging. However, if you have an old fashion electric meter, then the bulbs will be charged at their face value.

http://ledbulbreview.wordpress.com/2012/01/29/investigating-led-bulb-power-fa...

Category:

Science & Technology

Tags:

• LED Lamp Power Factor Light
• volt amps
• watts
• LED
• utilitech
• philips ambient
• eco smart
• light emitting diode
• light bulb
• dimmer

[KXKKX]

You seem to have based this entire video on a flawed assumption.

You appear to think that the dimmer itself does not have any impact on power factor.

This is a wildly flawed assumption. Check sound.westhost.com/lamps/dimme­rs.html (Not my site, but found with a quick googling.)

[oisiaa]

@KXKKX Thank you for the very informational link. That was a good read. Yes, while I didn't specify in the video, the thought did cross my mind that the dimmer itself might introduce some power factor issues into the equation. However, I don't think this invalidates anything because I am measuring the PF of a system as it would be used in practice. Any power factor I measured is the combination of the bulb with that particular dimmer.

[pvelectric]

watts divided by volts equals amps W/V=A. never heard of this "Voltamps." What's that? Why can't you just measure watts?

[oisiaa]

@pvelectric Look up "power factor" on wikipedia. It is kind of complicated.

[pvelectric]

China, ten years ago, in searching their URLs, and corresponding with a company there (buying their solar photovoltaics products), was researching LED bulbs like gangbusters. i bet you a thousand internet virtual dollars those bulbs you are "investigating" are made in China. you can be certain the Chinese have already done these tests. the utilities' Smart Meters" will dim or shut off everything at certain times, based upon usage and their programs. Texas companies do this remotely in schools.

[PeekyBooo]

You can buy 40-50watt equivalents on ebay for about $9 and they are the new high intensity LEDS, not the SMD tech, so check them.

[PeekyBooo]

tuned circuit...