Doug, Perhaps we should all by additional units just for experimenting. A bit of fun, don't you think?
73, Bill K9YEQ -----Original Message----- From: Dave Van Wallaghen [mailto:[email protected]] Sent: Saturday, February 21, 2009 8:53 AM To: Bill Johnson Cc: 'Doug Joyce'; 'Jack Smith'; [email protected]; 'Ken Kopp' Subject: Re: [Elecraft] Leds for W1 Good Morning Bill, There has been a lot of back and forth on this, so let me share the direction I'm going to take on this. I ordered red, yellow and green LED's made by Luxen that all have very similar specs. My guess is that they will be significantly less bright than the existing red LED's and that we would have to play with a resistor pack value that would provide the happy medium of brightness and current draw (and not stressing the LM78L05 as Jack has pointed out). Doug has already experimented a little with this and found 470 ohms gave him the brightness he desired. At this point, I'm not sure what the current draw would be or if that is feasible with the LM78L05. I believe that I might be able to come up with the right combination of LED's and resistor packs to obtain a decent level of brightness with uniformity between the LED's without compromising the design with an exorbitant current draw. As I said yesterday, I will take current measurements before I start and make comparisons during the experimentation, hopefully arriving at a state that provides the happy medium discussed above. I should have most of the parts in here sometime early next week. My desire is to have the least impact possible on the W1 design and minimize the impact on the builder as well. And hopefully we can provide this solution to new as well as existing units. Then again, I may be all wet here ;-) I guess the worst case is that I have to buy another W1 from Elecraft ;-) 73, Dave W8FGU Bill Johnson wrote: > It seems we need to find a set of colored LED's that give similar output as > the reds.... With the research done so far, doesn't look at that likely. I > wonder if there are other resources. I wonder if a resistor pack of a > slightly higher value than 470 might be a better compromise and change the > value of the SWR reds so they won't draw more than the others. This would > help reduce power draw. > > > 73, > > Bill > K9YEQ > K2 #35; KX1 #35; K3 #1744; mini mods > > > -----Original Message----- > From: Doug Joyce [mailto:[email protected]] > Sent: Friday, February 20, 2009 9:40 PM > To: Bill Johnson; 'Dave Van Wallaghen'; 'Jack Smith' > Cc: [email protected]; 'Ken Kopp' > Subject: Re: [Elecraft] Leds for W1 > > Bill: I've done some further testing and believe it's going to take > increasing the current to approx 6 to 7 ma to get the new coloured LEDs to > be bright enough. That would involve reducing the 2.2 Ks to approx 470 ohms > and finding a source for a suitable resistor pack. At this higher current > the red LEDs are still brighter than the other colours and there is no easy > way to separately control the current to individual colours. > > There are also a number of other things to check such as the ability of the > U3 regulator to handle the increased current. Battery life will also be > reduced and perhaps this "coloured version" needs to be run from a wall > wart. > > 73 > > Doug, VE3MV > > ----- Original Message ----- > > > The Professional version does not have this message > > > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
