Followed by a gradual development of LED lighting , more and more customers will
get the phone in front of the habit of LED lighting to take pictures, but after
an investigation determined that the presence or absence of strobe lighting is
not damage to human eyes . This approach is not entirely correct.
strobe is 100Hz, with a digital camera to take pictures of the division due to
the sampling frequency is not the same as it would render the water ripples . The
LED lighting is a DC power supply , the light source will also be announced by the
DC method ( superimposed on a DC basis , said a small shake or pulsating ) , from
a physical standpoint , it is far from glowing vacillation low shake the light
source on the degree of communication between current job. However , the input power
supply is still communication methods , it is difficult to completely avoid
communication through the LED light source ripple . So there will be LED lighting
division with a digital camera to take pictures exist shine.
determine the damage it? In fact, " human eye is sensitive to light shake on the
frequency of the low frequency scale " frequency, such as ambulances and other
warning lights is about 8-10 Hz , the most vulnerable people eye discomfort,
resulting in our vigilance. These frequencies are far below the normal operation
of the optical frequency communication scale power source , so the " foundation
does not exist normal eyes uncomfortable situation at the time when the light
source operating frequency of the civil power ." The current use of the world's
large-scale light source frequency is 50-60 Hz ( including LED displays , LED TV ) ,
so that the output ripple current LED lighting can affect the human eye 100Hz
comfortable degree of this argument even more inaccurate .
flash demand is also able to do . Roughly as follows: 1 to increase the output of
electrolytic capacitors. 2 forced choice valley-fill PFC program. 3 selected two
plans (ACtoDC, DCtoDC).
" this plan in theory be able to choose to absorb some of the electrolytic capacitor
ripple of communication , but practical experience when we notice the ripple control
within a certain scale in the future ( 10% ) , it is difficult to decline further
unless the electrolytic capacitor regardless of the cost of Cadogan , nor from the
foundation to eliminate .
mainstream kind of approach. Non- blocking scheme used Jing Feng Mingyuan perhaps
the duty cycle plan. Blocking programs can choose ChipLink perhaps IWATT ( most pre-
planned , has simply been screened ) . Circuit works as follows . Optional two large
capacitors and three diodes for power factor proofreading , because the rectifier
bridge behind a large electrolytic capacitor , the ripple will communicate absorbed
through the inductor and perhaps some of the transformer secondary current to direct