Dimmable LED GU10's

[Jamtastic3]

Hi BR,

I've got a whole load of birdies that need some dimmable LED GU10's - 5w or up and warm white ideally. I've checked the threads but this a topic where the technology is constantly changing, so I thought I'd ask if anyone has used any recently and have had great results with dimming from 0ish to 100% without that nasty snap at 20ish%.

This GU10 lamp here seems to dim really well but it's really hard to tell since the person didn't leave a big enough gap to see if the last part of the fade out was dimming out (by dial)...

 

 

Any recommendations would be very helpful.

 

Cheers!

[Brian]

I came to the conclusion a while back that looking at a lamp to judge how well it dimmed is not the way to do it. Especially with LEDs. The proper way to do it is to illuminate a surface and look at that.

[Ynot]

I came to the conclusion a while back that looking at a lamp to judge how well it dimmed is not the way to do it. Especially with LEDs. The proper way to do it is to illuminate a surface and look at that.

I'd tend to agree Brian to a point.

 

I'm assuming you mean judging the dimming curve by looking at the light it throws at an object/surface rather than looking at the actual LEDs, and as I say that's very sound advice, considering that at the lower levels you're unlikely to notice any 'steppiness' at the bottom end of the dimming range that way.

 

 

 

HOWEVER, if the LEDs are used as visual eye-candy, or are in a position where it's either obvious to punters or it can catch they eye in an obvious manner, then I'd still be concerned about the bottom end of the visual curve being visible.

[Tomo]

I thought I'd ask if anyone has used any recently and have had great results with dimming from 0ish to 100% without that nasty snap at 20ish%.

Nope, never seen a single two-wire SCR dimmed, non-tungsten luminaire that I could recommend for houselighting.

(That includes florry, LED, EL etc)

The best I've seen got down to 15% (input) at what looked around 5% (output lumens), then got flickery/shimmery.

On the way up it did far worse, snapping on at around 10% output.

 

Didn't matter because it's in an office/architectural space so they will never do a 'live' fade to or from black.

 

It's unlikely that these will ever exist either.

 

Partly because they're powered by the dimmed feed - thus below a certain amount there isn't enough power to run the electronics - and also because they are architectural and that market simply does not care about the bottom end of dimming.

 

When was the last time your office or d0mestic lighting needed dimming below 10%?

 

Technically, these really need hard power and a control signal (eg DMX) - although not all of those work well either.

 

Generally, you need to try it yourself in a dark space.

 

Ynot and Brian are absolutely right about not looking directly into the diode - as it's a point source that doesn't change colour temp, it looks much worse when shining directly into your eyes than bouncing off a surface.

[Jamtastic3]

Grrr. I thought this might be the case. I've got a considerable amount to buy so I need to get something that has the least snap to black in it. The light bounce method is a good idea though - I'll buy one of various types and test them out to see what produces the best results.

 

Cheers guys!

[J Pearce]

The led GU10s I bought for home recently have a soft switch off circuit. IF this could be dimmed, then a quick fade would have the snap off covered by this soft switch off. Obviously this then precludes a snap out.