LED question

[Snaz]

wow sorry to be askign so many noob questions, but now its about LED's. ok here is what i come up with as far as choosing a resist to use for a red LED. 9v batt, 1.7 voltage drop and 20 milliamps = 365 ohm resist. now a friend of mine said he uses 4 LED's, 1 9V batt, and 4 1 ohm resistors(blue,blk, brwn, blk, gold) in parallel and has never burnt up a LED and the batt lasts for about 72 hrs. the LED colors are red, white, and 2 L-95's. i told him according to what i come up with he should be using less resistance. but does it really matter when dealing with such low voltage?

 

[transistor495]

Why don't you use a simple Joule Thief circuit that gives you endless hours of operation? Most of the circuits on net will be for 1.5V-3V I think. Design a Joule Thief for 9V supply and lit your LED's continuously for months.
cheers.

 

[Snaz]

hmm i had never heard of this but it seems interesting. i wonder if this has application use for other 9v stuff i use