[Boatanchors] Request for info.

[CEMILTON at aol.com]

In a message dated 7/28/2006 11:37:01 AM Eastern Standard Time,  
n5cm at rtconline.com writes:

Also,  can someone tell me the type LED I could use and
the value of dropping  resistor necessary? Where available?
I have already queried the Yaesu List  but no response.



GA Ken,
 
Radio Shack usually carries a variety of LED's.....................Red,  Blue 
(near white), Green and even some "white" ones.  Not all that pricey  and you 
can buy one at a time versus ordering just one and paying shipping for  100.
 
Figuring out the series resistor is pretty easy.  Establish your  source 
voltage, e.g., 13.8vdc from the rig itself.  The ratshack LED  package will show 
you both operating voltage and current.  Subtract the LED  voltage (nominally, 
2.1v) from the source voltage (13.8vdc).  Divide the  result by the LED 
current (20ma, 40ma, etc. depending on which LED you  bought).  Remember, 20ma is 
.02a (use this value) or whatever current your  LED is.  The resultant answer 
will be the value of resistor needed.   Use the nearest standard value resistor. 
 Err on the high side and use a  1/2 watt size.
 
This is just basic ohms law for a d.c. series circuit where voltage drops  
are being calculated.
 
There are some very bright (3,000 to 5,000 mcd) Red LED's that make a  pretty 
meter light.  If you're into red and not color blind.
 
Hope this helps.
 
73 de W4MIL
Chuck