So is it normal for a dimmer to buzz a little?
Dimmable Lighting Buzzing
- Thread starter ort67
- Start date
So is it normal for a dimmer to buzz a little?
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As I said, it is quite common, particularly when the dimmer is 'turned right down'. Does your dimmer still buzz (as much, or at all) when you turn it up to full brightness.
Kind Regards, John
Poor form though. Unless you're doing something like overloading the dimmer, a good quality unit shouldn't humm. Transformers on the other hand, you need to mix/n/match with some care to avoid buzzing at some level. As for LEDs, especially low voltage ones, you're just asking for trouble of some sort and if it is only buzzing you can think yourself quite lucky.
I can't disagree with that but, at least in my experience, many of them do, particularly at high levels of dimming (very dim light).
Kind Regards, John
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Dimmer is humming at all levels of dim, increases a little when the dim is higher, might return this one and try another one.
What do you mean by asking for trouble with LEDs? What could be used instead?
No semi-conductor device should ever make any noise while operating. Buzzing sounds invariable come from the coils in the units when the windings are loose enough to vibrate. A "fix" is to brush two part resin into and around the windings to lock them in place. It doesn't always work as some resins will strip the insulation from the wire in the windings.
Other than the quality of the light using LEDs should not be a cause of trouble be they low voltage ( 230 volts ) or EXTRA low voltage ( 12 volt typically ).
The problems are created when ELV ( 12 volt ) lamps are fed with from electronic transformers. The LED lamp consists of the LED element(s) and a driver module which controls the amount of current flowing through the LED element. Both the electronic transformer and the driver use switch mode controls to regulator their outputs. ( some lamps use a resistor to control the current ).
The "12 volts DC eff " is seldom smooth DC hence the "eff" . At the extreme it is a series of varing voltage pulses greater than 12 volts that average out to be 12 volts.
For a filament lamp this pulsing output is acceptable as the thermal inertia of the filament smooths out the pulsing energy.
For a LED driver designed to work with a 12 volt DC input the pulsing energy from an electronic transformer will cause the driver to operate in an unstable mode and thus the driver is un-able to properly control the current it feeds to the LED element.
Other than the quality of the light using LEDs should not be a cause of trouble be they low voltage ( 230 volts ) or EXTRA low voltage ( 12 volt typically ).
The problems are created when ELV ( 12 volt ) lamps are fed with from electronic transformers. The LED lamp consists of the LED element(s) and a driver module which controls the amount of current flowing through the LED element. Both the electronic transformer and the driver use switch mode controls to regulator their outputs. ( some lamps use a resistor to control the current ).
The "12 volts DC eff " is seldom smooth DC hence the "eff" . At the extreme it is a series of varing voltage pulses greater than 12 volts that average out to be 12 volts.
For a filament lamp this pulsing output is acceptable as the thermal inertia of the filament smooths out the pulsing energy.
For a LED driver designed to work with a 12 volt DC input the pulsing energy from an electronic transformer will cause the driver to operate in an unstable mode and thus the driver is un-able to properly control the current it feeds to the LED element.
Thanks for explaining, but why is that a problem? What does it do? It can't control the current feed, what does that mean?
It means the current through the LED element varies erratically instead of being constant. Since the brightness of the light is directly related to the current through the LED then the LED will flicker as teh current fluctuates. There may be pulses of current that exceed the maximum current the LED element can carry and these pulses will shorten the life of the LED element.
Yes, the biggest trouble is with 12V LEDs. Unless you get the compatibility between dimmer, driver, and lamp exactly right then it may flicker, not dim smoothly, not dim at all, or not even light.
Mains voltage lamps are less trouble, but you can still have problems depending on the type of dimmer. The traditional leading edge dimmers have quite tight load requirements and one sized for traditional lamps probably won't work with LEDs. Trailing edge dimmers are often touted as the solution but are not necessarily better than a properly sized leading edge dimmer. Digital dimmers are the real answer, but that means a complete replacement with specialist lamps.
Mains voltage lamps are less trouble, but you can still have problems depending on the type of dimmer. The traditional leading edge dimmers have quite tight load requirements and one sized for traditional lamps probably won't work with LEDs. Trailing edge dimmers are often touted as the solution but are not necessarily better than a properly sized leading edge dimmer. Digital dimmers are the real answer, but that means a complete replacement with specialist lamps.
If it weren't for the power consumption issue, it would be nice to turn the clocks back a few decades - lighting used to be so straightforward
Kind Regards, John
If it weren't for the power consumption issue, it would be nice to turn the clocks back a few decades - lighting used to be so straightforward
Kind Regards, John
I've often imagined how dumb we're going to feel when tidal or fusion or something else makes electricity so cheap and green that we'll be glad to heat our homes with lots of 100W filaments in glass globes, far more eco-friendly than those gas-guzzling boilers
You jest to some extent, but .... !!I've often imagined how dumb we're going to feel when tidal or fusion or something else makes electricity so cheap and green that we'll be glad to heat our homes with lots of 100W filaments in glass globes, far more eco-friendly than those gas-guzzling boilers
Maybe not in our lifetimes (certainly not mine) we are inevitably going to run out of all fossil fuels eventually, so will probably then be largely dependent upon electricity (although possible, I would guess, maybe wrongly, that very-large-scale manufacture of synthetic liquid and gaseous fuels is never going to be realistic) - hopefully, as you say, generated in some very eco-friendly way. The problem then, of course, will presumably be that the present electricity distribution network would be woefully inadequate - and it could take a very long time, and an awful lot of money, to address that.
Kind Regards, John
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