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Optoelectronics Question

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  • 20-02-2008 9:47pm
    #1
    Patrick07
    Closed Accounts Posts: 11 ✭


    Hi Everyone,

    Not sure if this is the correct place for this but I need help on the following Question.
    A LED is supplied with a flow of pulses at a frequency of 50Hz and this produces a visible output. If the pulse frequency is raised to 1kHz what will be the effect on the light output?

    Can anyone help with this or maybe suggest some good website for this kind of information?

    Thanks in advance.


Comments

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    #2
    Andrea B.
    Registered Users Posts: 1,926 ✭✭✭Andrea B.


    Considering voltage is above threshold, I would imagine also the same visible output as it is still off for the negative half of cycle so is on for 50% of time, irrelevant of frequency?


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    #3
    10-10-20
    Registered Users Posts: 7,159 ✭✭✭10-10-20


    Assumptions have to be made about the duty-cycle here - if it was 50% at 50Hz, and remains so at 1kHz, it will do as Andrea said.
    It's the theory behind PWM.


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    #4
    Stoner
    Registered Users Posts: 10,952 ✭✭✭✭Stoner


    agreed, it is a function of time on vs time off, however the way the question is asked I'd go with time on=time off so no change on the level of light


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    #5
    Patrick07
    Closed Accounts Posts: 11 ✭Patrick07


    Thanks for your help everyone :)


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