Author Topic: Vishay 6400 LEDs in a serial circuit  (Read 5656 times)

Offline sausage

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on: August 10, 2009, 12:57:14 AM
Hi Guys,

This is my first post. I have started experimenting with a glove with 3 LEDs in serial with a 14.6 volt DC adapter. I have a resistor protecting the circuit. Because I got the LEDs from identical remotes, I don't know their exact specs and so use a high value resistor (I assume 20mA forward current on the LEDs).

However, I have purchased some Vishay 6400 LEDs and I read the Electronics 101 post. This led me to the serial LED calculator at: http://led.linear1.org/led.wiz

I wish to use the 14.6v adapter and three Vishay 6400 LEDs in serial:

14.6 Source voltage
1.35 diode forward voltage
100 diode forward current (mA)
3 number of LEDs in your array

But the calculator recommends a 1 Watt resistor and has marked a warning: "the wizard thinks the power dissipated in your resistors is a concern".

Could anyone recommend what resistor I should use? The 1W 120 Ohm resistor or should I wire this up in a better way?

Any help is very much appreciated.



Offline benpaddlejones

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Reply #1 on: August 10, 2009, 04:09:54 AM
sausage
The concern is the votage you are stepping down through the resistor, lets say after a few seconds of opperation wrap your fingers in bread through some sauce on and you have what we call here in OZ a sausage sandwich!

I suggest you find a lower voltage power source, something around 3-5v will be much better.

benpaddlejones :)


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Offline sausage

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Reply #2 on: August 10, 2009, 04:29:02 AM
sausage
The concern is the votage you are stepping down through the resistor, lets say after a few seconds of opperation wrap your fingers in bread through some sauce on and you have what we call here in OZ a sausage sandwich!

I suggest you find a lower voltage power source, something around 3-5v will be much better.

benpaddlejones :)

You mean a sausage sangah with dead horse? I'm over in Canberra. Nice to see an aussie doing the admin. :)

But thanks for that. I have a few other old adapters in the box. No reason I can't dig out a lower one.



Offline benpaddlejones

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Reply #3 on: August 10, 2009, 06:16:22 AM
sausage
If not take the 76th roundabout and go to Jaycar they have a cheap 3.7v one (about $19.95).

hehe

benpaddlejones :)


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