How to test LED bulb is smoothed or not?

[RF Lighting]

Wave your hand side to side in front of your face as fast as you can. You’ll see your fingers kind of jumping rather than moving constantly if the light is poorly rectified.

 

[Jackrae]

Wave your hand side to side in front of your face as fast as you can. You’ll see your fingers kind of jumping rather than moving constantly if the light is poorly rectified.

No need for a hand - just move your gaze from side to side - if there's flicker then the light will appear as a series of small white blobs. (Discovered this many years ago when driving past a series of roadside hazard lights - yellow in that case).

 

[JohnW2]

Wave your hand side to side in front of your face as fast as you can. You’ll see your fingers kind of jumping rather than moving constantly if the light is poorly rectified.

As I said, the problem for eric is that of quantification, including knowledge of the degree of flicker that is required to result in problems for his daughter.

No credible amount of smoothing will get anywhere near eliminating 50 Hz fluctuations in the light intensity - whether detected by 'ad hoc' methods you mention or more scientifically (like the sensor+'scope method I mentioned) - so the issue is not to determine whether or not flicker is present (which it always will be, if one looks hard enough), but whether it is of a magnitude to represent a problem.

Kind Regards, John

 

[Harry Bloomfield]

As I said, the problem for eric is that of quantification, including knowledge of the degree of flicker that is required to result in problems for his daughter.

No credible amount of smoothing will get anywhere near eliminating 50 Hz fluctuations in the light intensity - whether detected by 'ad hoc' methods you mention or more scientifically (like the sensor+'scope method I mentioned) - so the issue is not to determine whether or not flicker is present (which it always will be, if one looks hard enough), but whether it is of a magnitude to represent a problem.

Kind Regards, John

I have not researched it, but isn't there some persistence in the phosphor?

 

[JohnW2]

I have not researched it, but isn't there some persistence in the phosphor?

If/when there is a phosphor, then that obviously might be the case but, nevertheless, they all seem to show at least some degree of flicker (if one looks for it).

You could make the same comment in relation to fluorescent tribes, which have a much more obvious 9and necessary) phosphor but, as we know, the light output from them is very much 'pulsatile' when fed with 50 Hz.

I have certainly been known to successfully use plumb-standard LED elements in combination with photo-diodes etc for 'optical' communication over short distances at relatively high frequencies (e.g. audio).

Kind Regards, John