Re: Basic question about LEDs with USB chip

BTW a PIC will sink or source 25mA - the outputs are designed to
direct drive LEDs and 25mA is about as much current as you'll ever
need for a stock LED - I find I can get good brightness with much less
- hate LEDs so bright (as indicators rather than light source) they
make you squint.

One more question if you get around to it.
When you say 'direct drive', is it possible to not use resistors at
all to power 2 LEDs in parrallel? Thanks a lot for your help.

.

Relevant Pages

  • High brightness white LEDs damaged by custom switcher
    ... power is applied and removed. ... medium, and high brightness. ... of the LEDs were not lit. ... discuss possible scenarios, testing suggestions, and design improvements to ...
    (sci.electronics.design)
  • Re: Controlling hundreds of LEDs
    ... >4017 at different rates from a pin of the parallel port would simply ... >make the 4017 cycle through the stages faster or slower. ... Connecting LEDs ... Since the duty cycle would be constant, the brightness would remain ...
    (sci.electronics.basics)
  • Re: OT? LED Lanterns
    ... I am looking for something that I can use in the house during a power cut - say 3 hours that uses rechargeable batteries.. ... but the upside is they come on at full brightness. ... Lifetimes are similar, but manufacturing cost for high power LEDs is ridiculous. ...
    (uk.rec.walking)
  • Re: Controlling hundreds of LEDs
    ... Just note that different frequencies are ... There is no reason a single pin from your parallel port could ... Connecting LEDs ... necessarily change the brightness of each LED. ...
    (sci.electronics.basics)
  • Re: Vehicles damaged by rising bollards
    ... normal current without flashing. ... controlling brightness. ... Even those white LED torches that you buy are flashing to increase the apparent brightness (the flashing is done by the LEDs themselves). ... I hadn't heard of this use of modifying the duty cycle of LEDs to make them "brighter" - other than in optical links where the receiver had little or no persistent vision. ...
    (uk.legal)