On Sun, 3 Feb 2002, Spehro Pefhany wrote:

> At 10:27 PM 2/3/02 -0600, you wrote:
>
> >As in a rapid transition from light emitting diodes to noise emitting
> >diodes...  8-)
>
> If they are run at 3mA average current and 1/8 duty cycle, if the CPU
> latches up they will see 24mA. Not fatal at normal Ta. Another reason
> not to push the duty cycle too low. Even 50mA won't likely be
> instantly fatal for most types.

In the case of my circuit, the CPU latching up would cause the LEDs to see
someting closer to 500mA, whatever a saturated 2N2222A will pass.  That's
why the watchdog.  8-)

Under normal conditions they see a maximum of 1/16 (6.25%) duty cycle.  At
full brightness it's somewhere near 31mA.  It works well, they only get
very slightly warm when run at full brightness.

Dale

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