We have one of these to control a nightlight. Works fine but when the light is on, the unit puts out a lot of RF noise in the FM band, which has finally driven SWMBO up the wall.
Could this be fixed by putting foil around it? Or a fine metallic mesh?
I think you would have to put the lead through a ferrite "polo" a few times otherwise the RF interference will be radiated through the mains lead. If the nightlight is a simple filament lamp then a series mains rated capacitor will dim the lamp and not waste any power (that you will pay for) or get hot. No RFI form this method.
Ah, now. Are you saying that the capacitor on its own would do it (load is an LED GU10)?
Or is that in addition to the polo and the faraday cage?
Thanks.
In article , Tim Streater writes
Start with the polos (use multiple turns through if required - 2 or 3) at both ends of the cable ie. at switch load output and just before the load (and a separate one on the supply to the switch to if reqd).
I'd be v surprised if the problem is with the photoswitch, it appears to be a relay switch for the load (less noisy) rather than a thyristor and the simple circuit will probably run off a noise free capacitive dropper. IMO, more likely to be the lamp.
For info, it's rare to have direct radiation as a problem from stuff like this, it's usually conducted out on to the cables which then act as aerials and radiate it.
I think this is the answer. I replaced it with an 11W CFL GU10 and also one of the 3.3W LED GU10s from the kitchen - no noise. I also put the nightlight into the kitchen ceiling - no noise, so I put it back on nightlight duty. No noise initially, but noise as previously after about
5 mins, so it's now replaced with the CFL again until I can get another of the 3.3W jobs.The possibly dud LED GU10 is a Greenstock 4W GU10. Oddly the body unscrews into two parts held together then just by the wires between them.
Yep - that's useful to know, thanks.
And that was a good suggestion you made - saved me taking the floor up :-)
Glad you're sorted.
It doesn't do any harm to have a few cores in stock to play with in these circumstances.
Split cores are easiest to try eg:
The 'further information' link shows a sample install on a cable.
Solid rings are cheaper but you'll need to disconnect the wiring in order to install them:
(5pk) but out of stock.
CPC are post free at the mo for in-stock orders if you fancy a low cost play, see the instructions for free delivery on-page.
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