DX  » Community » Reviews » KD-QP-9W-NBG E27 9W COB 1100lm Warm White Light LED Bulb (110~220V)
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  • Overall Rating: 4
  • Price: 3
  • Quality: 2
  • Ease Of Use: 5
  • Usefulness: 5
Great light output, bad driver circuit – KD-QP-9W-NBG E27 9W COB 1100lm Warm White Light LED Bulb (110~220V) Reviews

posted by andremurari on 06/19/2013 Certified Owner

Involvement:Expert (understands the inner workings) - Ownership:1 day to 1 week

As light point of view it looks almost perfect. * Real 9W, real 1100 lumens - very bright!! * Made of one COB LED emitter (the better one - not a lot of smd, or high intensity output LED) * Low power lost as heat * Better E27 lm/w LED bulb sku at dx.com
As eletric point of view it have one horrible driver circuit. *Poor power factor (around 0.33) (0-1 scale) (see specs review pic) *Doesn´t have any filter. Causes a lot of harmonic distortion which dirts your power network. (see FFT review pic)
*You can easily substitute a 18W compact fluorescent (PL) or a 100W incandescent light bulb by this lamp (economizing 9WH or 91WH) . The Illuminance it´s pretty similar. *The light doesn´t look to have green light component as others reviews mentioned. *The circuit could be optimized to have a great power factor and low THD.
If you intend to use several of these lamps I suggest you to use at least an third order LC filter to not cause EMI into your AC network. This kind of bad switching power supply can even cause abnornal nobreak trigger.


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