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Eco Light Bulbs

Aitch

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I had to change one of my light-bukbs yesterday, the first of the energy-saving ones to go. It was a Philips one and has been replaced with an Ozram one - one of the four free ones that everyone got in the post last year.

Anyway, one thing I have noticed is that its start-up is different from the Philips ones. They come on immediately and get brighter over a period of seconds. The Ozram comes on at full brightness, but after a delay of about a half a second. Which is a bit disconcerting.

So why the difference? Anyone know how these bulbs work?

Thanks.
 
I think some of the first energy saving bulbs I got are flourescent which seem to give a little problem with my eyes although nowhere near as bad as supermarket lights. More recently I got a couple of osram bulbs which are halogen and give much better light although not quite as efficient as the other ones. The osram bulbs I have come on instantly though so maybe they're a different type from what you have.
 
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Aitch said:
Anyway, one thing I have noticed is that its start-up is different from the Philips ones. They come on immediately and get brighter over a period of seconds. The Ozram comes on at full brightness, but after a delay of about a half a second. Which is a bit disconcerting.

So why the difference? Anyone know how these bulbs work?
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Wikipedia is your friend. It's basically a design difference in the electronic ballast: you need huge voltages (higher than wall sockets) to start a current flowing, but lower voltages to keep it flowing. The details of how these ballasts operate to perform that function can vary somewhat, leading to the performance differences you see. From your description it doesn't sound like either is actually performing incorrectly.
 
Thanks for that - I considered Wiki, but couldn't figure out what to search for!

However, the article (especially the part on Parts) appears to be Americo-centric (is taht a word?). The UK has AC mains supply, so the inverter part is not necessary and I assume the ballast circuit is different.
 
Aitch said:
The UK has AC mains supply
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So does the US (although over here, it is 60 Hz not 50 Hz). I'm not aware of any country that has "real" electricity infrastructure that provides DC to the home.
 
Aitch said:
Thanks for that - I considered Wiki, but couldn't figure out what to search for!

However, the article (especially the part on Parts) appears to be Americo-centric (is taht a word?). The UK has AC mains supply, so the inverter part is not necessary and I assume the ballast circuit is different.
Click to expand...

The US has AC mains supply too - the only difference I'm aware of is the voltage (110 for the US and 220 for UK, IIRC) [edit - I see that the frequency is different too]. That's not what the inverter is for. The inverter is applied after the AC mains is converted to DC, because it needs to operate at about 40 kHz, far higher frequency than any mains supply in the world. So the device must convert from AC to DC back to AC in order to change the frequency. So the basics of the circuitry will be the same, just altered to account for different input voltage.
 
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I write the date of installation on my flourescent bulbs, just to see if any of them will last the 5 years on the packaging.
They certainly last much longer than the equivalent incandescents, by at least a year longer. The old kind would go out in just a few months.
None have gone much more than 2 years though.
 
Terry said:
So does the US (although over here, it is 60 Hz not 50 Hz). I'm not aware of any country that has "real" electricity infrastructure that provides DC to the home.
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Of course it does, I don't know why I thought otherwise. Ah, yes I do; I've seen the QI episode that covers Edison electrocuting to elephant, in a bid to get the mains supply to be DC, once too often!

Eyeron said:
I hate these things. They actually hurt my eyes.
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The ones I have are 'warm white' which seem OK. The fact that my paper lampshades are getting old and yellow doesn't help, mind.
 
The problem with the color is not when you view them directly, as the eye is easily fooled to see 'white' when actually seing as little as two monochrome colours. The problem comes when the lamp illuminates colored objects. Colors that are not in its emitted spectrum will not be illuminated, and the color balance of an object will be changed.

Hans
 
Ziggurat said:
The US has AC mains supply too - the only difference I'm aware of is the voltage (110 for the US and 220 for UK, IIRC) [edit - I see that the frequency is different too]. That's not what the inverter is for. The inverter is applied after the AC mains is converted to DC, because it needs to operate at about 40 kHz, far higher frequency than any mains supply in the world. So the device must convert from AC to DC back to AC in order to change the frequency. So the basics of the circuitry will be the same, just altered to account for different input voltage.
Click to expand...

The current is controlled by the inductance of the ballast. At normal mains frequencies the ballast is relatively large, but by going to higher frequencies it can be reduced in size. I believe that some early compact fluorescents did work at about 40kHz, but this leads to problems with remote controls, which typically work at 38kHz. Ever find your remote didn't work so well at night?
I have examined some in the last few years and they seem to operate at higher frequencies - you can see this if you monitor the light output with an oscilloscope.
 
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