This Q & A is one of thousands posted in our Technical Expertise area, and answered on a daily basis by our Voltimum Experts.
Question: A customer of mine replaced a 12V MR16 lamp that failed with an MR16 LED lamp and found that it flickered continuously, so she asked me to fix the problem.
From previous discussions with manufactures at trade shows, I presumed it was because the 20W / 60W transformer being used for the halogen bulb was 'unhappy' being asked to only supply 5W, so I went off in search of a replacement LED driver.
I discovered that there are two types of 12V LED drivers for use with MR16 lamps. One is constant current and must only be used for constant current LEDs wired in series. The other is constant voltage and must only be used with constant voltage LEDs wired in parallel.
None of the LED lamps I looked at gave any indication of being constant voltage or constant current. The only conclusion I could come to was that the constant current variety is for dimmable LEDs and constant voltage is non-dimmable.
So why is this happening?
Incidentally, my answer was to replace it all with a 230V GU10 LED!
Answer: I'm afraid the answer is - depends on the bulb in question!
For example, Philips MR16 LEDs are intended to directly retrofit. They run on a 12V AC supply, as you would get from a halogen transformer, and they have technology that fools most transformers into seeing them as a larger load than they are, bypassing any minimum loading requirements.
Other manufacturers take a different approach.
To see many more Q & A in Voltimum UK's Experts Area, please click on the link. Experts from leading organisations provide online answers to your technical questions on a broad range of subjects. Our searchable database of existing Q & As now contains over 3,500 entries; you can browse through them here.
