V Phase

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You might perceive a 25Hz flicker but you're still getting 50Hz albeit with an odd-ball waveform.

[Dave Plowman (News)]

A fast acting 'bulb' would flicker at 100 Hz since it 'works' on both the positive and negative halves of the cycle. But filament bulbs don't cool quickly enough to show this. Nor have I seen any flicker when using a diode to extend bulb life. Although this might depend on the type of bulb it's used with. I've only used it on spots lighting a 'feature'.

[Tabby]

e:

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But a) a lot less suppliers of them b) odds are you wont have one in the bits box(es)

NT

[dennis]

It also increases the current flowing on one half of the cycle by a lot (if you only had half the power the lamp probably wouldn't glow much). I wonder what that does to the meter?

[Graham.]

When I was a kid I made a light-beam telephone link between me and the guy who lived opposite. It used MES torch bulbs and ORP12 photo-cells. The bulbs were run normally from DC with a little modulation from the secondary of the speaker transformer of an amp. The speech was intelligible so it must have been good for a few kHz. There was a slight visual flicker but not one that the casual observer would notice.

The Xmas tree lights with the series diode, I only perceive the flickering when I move my head or eyes and perhaps when they are in extreme peripheral vision (a well documented and researched effect)

Maybe I am particularly sensitive to this, let me ask a question here,

Does everybody notice the flicker from strobed LED vehicle tail lights, and LED traffic lights?

Again it's only when rapid eye movment makes the lights into a string of dots across my retinas but I am surprised not to hear more complaints about it.

[Bob Minchin]

No, I don't notice that effect only the much quicker on to off time than a filament lamp.

Bob

[Dave Liquorice]

Yes I see flicker from LED vehicle lights and it annoys me. Can't say I've noticed it with LED traffic llights but the instant on or off switching isn't pleasant and they are far too bright. I really detested LED cats eyes. They flicker really badly in your peripheral vision and I found this is very distracting when you have a whole line of them flickering away all the time as you drive past 'em. Fortunately they don't appear to be very robust and the stretch of road about a mile long that had them now only has a dozen still working. B-)

[David Paste]

I do. I would imagine many people do.

It's to do with the way the light-sensing cells in the eyes are wired up. The peripheral cells are wired up as many sensor cells to one information-carrying nerve, whilst the detailed vision in the middle of the retina (that's the coating of the back of the interior of the eye which senses light photons - a biological CCD or CMOS if you like) has more or less one sensor cell per info-carrying nerve. That is why you can't read from your peripheral vision, it is a part of your vision which has evolved to be sensitive to movement, or changes in state of light but is low resolution, whilst the middle bit is high resolution to allow you to study the thing you are looking at properly. Very useful in evolutionary terms!

[Andy Burns]

Yes, but not all the time; usually notice it more when they're travelling *across* my field of view, rather than when I'm following a car that's braking.

I don't tend to notice those flickering, just notice that they *are* LED by the instant switch from colour to colour.

[Andy Burns]

The odd thing about those it when they show up in your rear view mirrors, when there's no oncoming traffic.

[Chris J Dixon]

I was not at all happy about the way they were talking up the "green" aspects of the work they were doing.

Initially, they mentioned 4 Solar PV panels saving £500 per year. In the end they fitted 6, 1.05 kWp, and the claimed return had dropped to £400.

rainwater recovery system was a massively expensive installation, but I got the impression that is was "feel good". There was no mention of the family being on a water meter.

Insulation was mentioned a lot, but I didn't spot anything other than roof lagging. Did they do anything to the walls?

With the existing extension, wouldn't the loft have required planning permission? I have had a search around and can't find anything relevant.

Is it just me, or did the finished building look completely out of place from the rear?

Did Charlie's dim bulbs get by without being spotted?

Chris

[sm_jamieson]

How much would the installation have cost ? Is that saving reasonable ? How many years to pay for itself ?

He said they were putting in celotex in addition to the tri-iso type foil in the roof. Never mind the foil is useless in the first place !

Probably - they may have already had it. The dormer was fairly small.

It was weird with the huge appendage half way down the garden. Also, did you notice at the end, the garden seemed a very strange shape? Not sure if they had borrowed part of next door, or a funny camera angle.

Simon.