Casio EV-680 led mod

Post by **gannon** » Wed Feb 09, 2005 5:39 pm

Guest26 wrote:
2 dosnt wiring resistors in paralell half the resistance?
No the resistance stays the same thorugh out a parrell circuit but the current is halfed though in a parrell circuit.

actually, no the resistance doesn't stay the same. the equation is Rt=1/((1/R1)+(1/R2)+etc...)

Guest · Post by **Guest** » Thu Feb 10, 2005 8:06 pm

Guest26 wrote:
Quote:
2 dosnt wiring resistors in paralell half the resistance?

No the resistance stays the same thorugh out a parrell circuit but the current is halfed though in a parrell circuit.

actually, no the resistance doesn't stay the same. the equation is Rt=1/((1/R1)+(1/R2)+etc...)

Your right. I fogot thereistance of each load is equal to the resistance of the electrical source.

goodie · Post by **goodie** » Sat Feb 19, 2005 8:16 pm

After reading the pocket tv chapter in Ben's book, I successfully removed the tuner and inverter. I also connected the LEDs to the regulator, rather than to the batteries directly. But it still looks the same. The LEDs I was using are the same ones that it recommended in the book. The picture is not only dark, but it also seems to have a weird grayish tint to it (kinda like when you look at a LCD from the wrong angle). Any ideas?

goodie · Post by **goodie** » Tue Apr 19, 2005 4:37 pm

Okay, I've been thinking about this. Since it seems to work good for everyone else, I must have simply done something to mess up the LED's. Since the batteries don't output a constant voltage, could it be possible that hooking the LED's directly to the batteries instead of going through a regulator could have damaged them, so that they wouldn't shine as brightly?

nos_slived · Post by **nos_slived** » Tue Apr 19, 2005 5:45 pm

If the LEDs weren't rated for the current of your battery, then you definatly damaged them. An LED may not burn out immediatly, but it will lose brightness.

Post by **Gamelver** » Tue Apr 19, 2005 5:54 pm

um, I think when you said current, you meant voltage

....'cause the LEDs will only consume the current they need....

nos_slived · Post by **nos_slived** » Tue Apr 19, 2005 6:05 pm

Oh, sorry. I haven't slept in a few days, and I am having some problems thinking right now. Not to mention that a certain member angerred me with a certain post a few minutes ago.

Post by **Gamelver** » Tue Apr 19, 2005 6:08 pm

hmmm.....perhaps, geeoh

?.......

Post by **bicostp** » Tue Apr 19, 2005 6:26 pm

I concur. He was trying my patience.

goodie · Post by **goodie** » Tue Apr 19, 2005 8:44 pm

I had it set up just like in Ben's book. Except the power was coming directly from 4 NiMH's instead of the TV's 5v regulator. But the voltage would be only 4.8 volts, so I don't know...

nos_slived · Post by **nos_slived** » Tue Apr 19, 2005 10:02 pm

Your LEDs may have been labelled wrong. It is odd for LEDs to lose brightness if you have them setup according to their specs.

goodie · Post by **goodie** » Tue Apr 19, 2005 10:16 pm

It was the exact same LED's that Ben uses. At least they were supposed to be... Perhaps I could order some more. If those are not bright, then I don't know what I'll do.

goodie · Post by **goodie** » Thu Apr 21, 2005 4:24 pm

While looking at eBay, I found a bunch of white LEDs. They are 3mm, so I think they would fit. Also, there are ones rated at 5,000-10,000mcd. The digikey ones are only 1,000mcd. I think these might make it brighter. By the way, does anyone know what mcd an average pocket tv's flouresent backlight is?

goodie · Post by **goodie** » Sat Apr 23, 2005 8:02 pm

BTW, how bright (in mcd) can I make it without it being dangerous to my eyes? I want to be sure I don't get ones that are too bright.

soundwave · Post by **soundwave** » Sat Apr 23, 2005 8:07 pm

I don't know, but this place has 14-16,000mcd LEDs, is that too bright?