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LED will not turn off with pot

Discussion in 'LEDs and Optoelectronics' started by wingnut, Jul 22, 2019.

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  1. wingnut

    wingnut

    242
    9
    Aug 9, 2012
    Hi all

    Can someone please tell me why the LED does not dim completely when the sweeper is fully at ground. Thanks.

    My apologies, its dimming completely now. I think the ground of the pot was not making contact.

    circuit.png
     
    Last edited: Jul 22, 2019
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    10,551
    2,350
    Nov 17, 2011
    A potentiometer is not a good way to control the brightness of a LED. A potentiometer is not designed for comparatively high currents as required for a LED. Use the potentiometer instead to control a transistor which drives the LED current.
    A modern way of controlling LED brightness is by using PWM. Much less power dissipation at the cost of higher parts count.
     
    Last edited by a moderator: Jul 29, 2019
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