[sdiy] 7-seg LED driving frequency

[Simon Brouwer]

Hi Seb,

At 00:31 25-10-2005, Seb Francis wrote:
>Hi,
>
>I'm making something that uses a triple 7-seg LED for its display.  The 3 
>digit LED has only 11 inputs (common anode per digit and common cathode 
>per segment), so you have to drive it at some kind of high frequency.
>
>I plan to use a duty cycle of 1/3 per segment, but I don't know what 
>frequency.  I was thinking a pulse width of 0.1ms per segment (overall 
>update frequency of ~3 kHz).  But this is just a number picked out of thin air.
>
>Does anyone have any experience with this kind of thing?  Are there any 
>pitfalls with using the wrong frequency?
>
>Seb

At 50 Hz refresh frequency (the frame rate of European television) you will 
not perceive annoying flicker. Beyond 70 Hz the human eye cannot perceive 
any flicker at all.

Vriendelijke groet,
Simon Brouwer.

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