LEDs

[Steve]

In general, are LED lights dimmable using normal bog standard dimmers? My mate has got a fancy modern wall light (25 white LEDs)on a 2G dimmer and i was just wondering if this was safe / ok.

I'm going to buy her a new dimmer anyway, because the other half of it has completely packed in, and the side that is working has to be wrenched right round 360 degrees before anything happens.

 

[plugwash]

you'd have to ask the makers of the led light units. it all depends on how the power supply is designed.

 

[breezer]

its not the leds you have to worry about, its the transformer / rectifier

not all transformers can be "dimmed"

 

[ban-all-sheds]

How do you know there's a transformer involved?

 

[Big_Spark]

How do you know there's a transformer involved?

Because LEDS do not work at Mains voltage..generally they are fed via Tx's rated at up to around 18V (No load) and have a constant current output which will be matched to the quantity of LED's connected to it..So a Tx for a unit with 25 LED's would likely cause damage to the LED's if connected to a unit with say 10 LED's as the voltage and Constant current output would be higher..

These Tx's a easily damaged and generally not dimmable. If they have no load attached they give no output and this often fools people into thinking the Tx is knackered when it is not..a costly error quite often.

 

[plugwash]

technically that doesn't nessacerally mean a transformer is involved though, could be a transformerless smpsu especilly if the leds and thier power cuircuitry are in the same unit.

if you had sufficiant leds you could even wire them in series add a resistor for current control and run the lot directly off the mains.

 

[Big_Spark]

technically that doesn't nessacerally mean a transformer is involved though, could be a transformerless smpsu especilly if the leds and thier power cuircuitry are in the same unit.

if you had sufficiant leds you could even wire them in series add a resistor for current control and run the lot directly off the mains.

You could indeed, but then they would not meet British Standards....