LED lamps, source and value

Thanks very much. This may be an option for me to look at.

Reply to
Scott
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Nothing noticeable, holding a portable radio close to most of the bulbs on DAB or FM.

Reply to
RJH

Some people are more suseptable to certain things than others from UV for sunburn to epileptic fits, soem are colour blind some see colours in sound. Soem peolpe use SAD lighting.

yes siun rises (I see them in photos) and sunsets have quite differnt lighting.

But useful if yuo want to find out why something happens. It doesn;t have to be cruel unless you want quick results. ;-)

Reply to
whisky-dave

As I don't possess a DAB radio, that will be a tad difficult.

I could always try driving the car - which does have a DAB radio fitted - through the bedroom wall, I suppose ...

Reply to
Terry Casey

The 12v ones tend to be powered by a toroidal transformer expecting to drive a lot more current into the original quartz halogen lamp fittings.

Halogen lamps require a substantial current and run mad hot so the fittings are designed to insulate the ceiling from the very hot lamp.

This is almost a perfect storm for an LED bulb PSU. No way to convect away hot air and a PSU that is over voltage due to an out of spec load. They should be able to cope with the higher voltage within reason but they cannot cope with having a running temperature much above 95C without significantly shortening their lifetime.

Reply to
Martin Brown

I am. I assumed you had more knowledge of linear supplies than you do.

Linear supplies don't normally produce rfi, though it is possible, seldom, for them to. But as I pointed out, no-one uses them for efficiency reasons.

CR PSU LEDs have way less RFI than SMPSU types.

NT

Reply to
tabbypurr

In decently designed lighting the bare lamps are not directly visible.

NT

Reply to
tabbypurr

That is the position with mine. I was told (rightly or wrongly) that there is no minimum load for a toroidal transformer. You seem to be suggesting that the voltage can increase, but I thought these lamps could cope with up to 24 volts anyway.

In my case the lamps are on a track so I don't think they are particularly thermally insulated. There is plenty of air surrounding.

Does this cause RF interference or simply a problem with lifespan?

Think I'll go back to halogen lamps and make energy savings in some other way (or maybe plant a tree as carbon offset). .

Reply to
Scott

Unfortunately you have used a phrase here that also has a distinct engineering meaning namely a previous power supply technology that used to work by having a big chunk of iron transformer rectifying it and then having a voltage regulator that dissipated the excess unwanted voltage as heat to leave a nice smooth output at high current.

Switched mode PSU is the exact antithesis of linear PSU. Being highly efficient at turning low current high voltage into high current low voltage with a minimum of weight and heat.

In addition because LED devices are current driven the PSU used with them is by a regulated current source rather than a voltage.

I find a mixture of LED and LED spotlamps in classic spotlamp fixtures works OK. The design allows enough airflow to allow them to stay cool.

Reply to
Martin Brown

The transformer is quite happy with the load it is just that it outputs somewhat more than its nominal voltage when it is so weakly loaded since it is designed to deliver a fairly high current output at 12v.

It is the ones built into the ceiling fittings that fail very often.

Cooks the capacitors. I have yet to see significant RF interference off any that I have bought even somewhat dodgy Chinese ones. I have largely given up on DAB radio though - internet streaming works a lot better.

Reply to
Martin Brown

Any cover over the light source is going to reduce the light it produces.

It's quite common to have exposed fluorescent tubes in places where it is simply working light.

Once you decide that what the fitting looks like - and the quality of the light it produces - LEDs are often not the best answer. Yet.

Reply to
Dave Plowman (News)

Most people know no different. Concealed fluorescents can make genuinely good lighting.

They have advantages for kitchen use, under cupboard in particular. Watch the light quality, it's very variable and sometimes not the CCT claimed.

NT

Reply to
tabbypurr

Indeed. But aren't so efficient. Everyone seems to want LEDs because they cost less to run. If that isn't the most important thing, they aren't the only choice.

This is the problem. Although simply using any old fluorescent tube isn't going to give the best light quality either.

Reply to
Dave Plowman (News)

Florries are what they claim. LEDs often aren't.

NT

Reply to
tabbypurr

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Reply to
sullyjlsk

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