Ask the experts

[Waka]

I have just had a dimmer switch installed in my dinning room, the only problem is that it buzzes, the higher the light brightness the loader it is.My electrician says this is normal, I find that hard to believe.

Is he right?

 

[marcros]

i am no expert, but are the bulbs designed for dimmers? Low energy bulbs are now available for dimmers but are expensive. IME the standard low energy ones were a pain, and did buzz and flicker in our dimmer, particularly when not on full brightness. The switch then packed in, and we changed it for an on/off switch, to save buying the expensive bulbs (we didnt actually use the dimming function often anyway)

 

[steadyeddie]

We've got a small table lamp fitted with a dimmer and that buzzes too. Flippin' annoying! If I remember rightly, we used to have a wall mounted dimmer switch that buzzed so perhaps your sparky is right.

Dave

 

[cambournepete]

We had a dimmer switch which also buzzed - I think it was louder when the lights were lower, but it was several years ago.
I think it's because of the way they work - they chop the top off the electrical sine wave, IIRC.

 

[Paul Hannaby]

It's usually the laminations in the small transformer that causes the buzzing. One way round this is to varnish the transformer but if you're going to do this, remove the switch from the supply before doing it!

 

[Mike.C]

Hi Tony no it is not right, the only trouble is it seems to be hit and miss shopping. We had one that drove us around the bend and we were advised to buy a remote control one. This really did cure the problem, the only trouble was it caused another one, which was every time we pressed the remote it turned the bleeding tv on and off :roll:

Cheers

Mike

 

[bugbear]

I have just had a dimmer switch installed in my dinning room, the only problem is that it buzzes, the higher the light brightness the loader it is.My electrician says this is normal, I find that hard to believe.

Is he right?

Yeah - buzzing is normal, although expensive ones buzz a lot less than cheap ones.

BugBear

 

[Jonzjob]

Easy for the TV. Don't leave it on standby :mrgreen: :mrgreen:

 

[RogerS]

Mine doesn't buzz...but then it is quite an old one....when quality ruled the roost rather than being down to a price of naffness.

 

[Steve Maskery]

I had one in my last house. It didn't buzz at all, but it did use old-fashioned tungsten bulbs.
S

 

[Waka]

Thanks for the response guys, I did read somewhere that cheap ones were the worst, mine was £20 which I didn't think was cheap, anyway didn't like the buzzing so went back to a conventional switch, I know where I am now, its either on or off, a bit like me :lol:

 

[woodbloke]

I had one in my last house. It didn't buzz at all, but it did use old-fashioned tungsten bulbs.
S

As I understand it, dimmer switches don't work well with the new bulbs. I had dimmers in most rooms with the old bulbs without problems, but since the intro of the newer type of bulb, I've done a Waka...gone back to switches - Rob

 

[RogerS]

I had one in my last house. It didn't buzz at all, but it did use old-fashioned tungsten bulbs.
S

As I understand it, dimmer switches don't work well with the new bulbs. I had dimmers in most rooms with the old bulbs without problems, but since the intro of the newer type of bulb, I've done a Waka...gone back to switches - Rob

Should have gone back to tungsten, Rob.

 

[Digit]

I don't use a dimmer but I do use the modern low energy lamps, and anybody who tried them when they first became available, and was dissatisfied, i would say, try the newer ones. They are much better.
The only problem I have found is that the brightest ones are either bayonette or ES, sod's law, our fittings are SES!

Roy.

 

[Hudson Carpentry]

If the chop off the top of the swine wave the light wouldn't light surely? The bottom half of the swine is -230v.

The way I understand them is they give off a square wave now. The older dimmers used resisters to limit the power but the newer dimmers just alter there pulse rate in a monostable circuit. A light bulb is flashing 50,000 times in a minute, as this is far to fast for our human eyes we do not see it. The modern dimmer slows the pulse rate down so it flashes less times a minute but still faster then our eyes can compute it. the effect of a slower flashing bulb is it appears dimmer. Its apparently a safer way of doing the task.

I have remote dimmers and they buss on halogen lights. Regarding the remote feature, you can tune any button on any IR remote to do the on/off task. So fine a button thats never used on your TV/DVD remote, maybe one that only works when in Teletext and your TV on off issues are solved.

 

[Paul Hannaby]

Assuming we are talking about the usual filament / incandescent bulbs (most dimmers don't like the low energy fluorescent or LED bulbs), the bulb doesn't flash 50,000 times a minute. The supply is 50Hz so at best, the bulb would flash 6,000 times a minute (50Hz x 60 seconds x 2 for positive & negative cycles). In practice, the bulb doesn't really flash because to do so, the filament would have to go from hot to cold on each cycle to do so.

 

[devonwoody]

Our dimmer doesn't buzz, the present one is around 10 years old and we use the oldie bulbs, got a big carton of them as well. (to fit our lamp shades, replacing them would cost what we would have saved in energy charges).



However, lately we are running a table lamp with a small energy efficient bulb plus the four old lamps on a very low dim setting.

Does it actually save energy running the bulbs dimmed?

 

[Hudson Carpentry]

Assuming we are talking about the usual filament / incandescent bulbs (most dimmers don't like the low energy fluorescent or LED bulbs), the bulb doesn't flash 50,000 times a minute. The supply is 50Hz so at best, the bulb would flash 6,000 times a minute (50Hz x 60 seconds x 2 for positive & negative cycles). In practice, the bulb doesn't really flash because to do so, the filament would have to go from hot to cold on each cycle to do so.

I knew it was 50 something per minute/second hehe. A flash don't necessarily mean on off, something that cycles dimmer to brighter which is what the bulb does is still a flash!