[Elecraft] Re: PC boards for the K2 RIT-SPLIT LED Mod

Wayne Burdick [email protected]
Thu Oct 30 01:43:01 2003


Bill,

These LEDs may be *rated* at 10 or 20 mA, but how much they actually draw is
determined by the series current limiting resistor used. Example: if you put a 3
k resistor in series with an LED that drops 2 volts when forward biased, then
apply 5 V across them, only 1 milliamp will flow. The forward voltage drop
changes only a few tenths of a volt over its normal operating current range, so
the current drain is determined almost solely by the resistor. 

The advantage of "Super bright" LEDs is that they're much more efficient and
will actually (in most cases) look much brighter at 1 mA than standard LEDs.

73,
Wayne
N6KR



Bill Flynn AI�C wrote:
> 
> Be careful if buying "Super Bright" LEDs for the K2 Split LED Mod.  Many
> "Super Brights" draw 10 to 20 mA.  And oddly (at least in the Mouser
> catalog) not all LEDs have their mA ratings listed!  Mouser does list many
> "Low Current" LEDs that typically draw 2mA.
> 
> 73,
> 
> Bill...