|Model:||Pearl Easydim Lightbulb|
|Application:||General lighting, nightlight.|
|Bulb/Tube material:||Glass, pearl finish (internally etched)|
|Colour Temperature:||Not Stated - around 2500K at full power.|
|Peak output wavelength:||--|
|Total light output:||700Lm (Maximum, manufacturer's claim)|
|Rated lifetime:||At 75% power: 4380 Hours. At 50% power: 21900 Hours At 25% power: 32850 Hours. (manufacturer's claims)|
|Operating voltage:||230V AC|
|Operating current:||Varies (170ma - 270mA)|
|Cost (original):||£1.97 (08/10/2005, from Maplin Electronics)|
|Place of manufacture:||Within European Union|
|Date of manufacture:||Unknown - Date code L162?|
|Notes:||This is the first
one of these things I've seen in ages! We seemed to get
invaded here by millions of them around 1995, every shop in Aberdeen it
seemed was selling them - then, seemingly overnight, they vanished -
Okay, they haven't tried to take over the northeast of Scotland this time (yet), but I did spot one in Maplin, so snapped it up, as it's an interesting bit of technology I think.
Initially when you pick one of these lamps up, you'd think it is your generic 60W GLS incandescent lamp - and you'd be wrong. Well, partially. It is an incandescent lamp, yes, but one with a nifty little trick up its sleeve. This lamp has dimming hardware built into the lamp itself. It is actually quite simple to use as well.
When you initially apply power to the lamp, it starts out dim, and over the period of a second or so, it ramps up to full brightness - and will then stay there (meaning that if used in the place of a standard lamp, this will act as a soft start device - extending the lifetime of the lamp at least a little). If however you interrupt the power supply briefly (turn the power off for half a second or so) as the lamp is ramping up, it will stop at whatever level it was at when the power was turned off. It the power remains off for more than about 3/4 of a second, the lamp resets. At higher power levels, this kinda defeats the purpose of the "soft start" characteristic though!
The dimming ability of this lamp is sufficiently well implemented that it is actually useful - able to vary from the most barely visible glow, to full power, and anywhere in between. This would in theory make it perfectly suitable for applications like children's nightlights, where the ability to also have the full power of a 60W lamp on hand would be a most desirable feature. The real drawback there is that incandescent lamps - even the best halogen ones - are horrendously inefficient. This effect is exacerbated however if you dim them - as the lower the filament temperature is, the more the emission spectra shifts towards the infrared end of the spectrum. To get a barely visible glow in this lamp, it is consuming 17W - whereas a 10W nightlight will be giving out a useable amount of light! This is all down to the fact that the nightlight bulb uses a far thinner filament with a higher impedance...but that is beyond the scope of this document (for now). The good side of dimming incandescents (Halogens excepted, as if the wall temperature of these lamps drops below a certain temperature, the halogen cycle will cease to function), is that it vastly increases the life expectancy of the lamp in question. I don't know if I would believe the manufacturers claims in this case - but dimming a lamp by 25% will increase its life by a huge amount.
The dimming hardware in this lamp appears to be hidden away in the cap - and I can't see anything of it I'm afraid. The only sign that there's anything out of the ordinary at all in fact with this lamp is in the form of a metal heat shield mounded just above the stem in this lamp - presumably to prevent the heat from the filament cooking the dimmer circuit when used in a base up orientation.
|Click Thumbnails for full size images.|
This lamp added to the Virtual Display Shelf on the 9th of October 2005 at 03:28.