LED HELP.

[milkwasabadchoice]

Simple question. I bought three LED's from smallbear. The Water-Clear, High Brightness, blue ones. What currunt limiting resistor do I use with them I am using a standard 9v supply. They are not rated or marked. How do I know what resistor to use?

Thanks,
Jason

[vanhansen]

Hi Jason.  I like to use 10k on high brightness.  It may seem overkill but it keeps the brightness from being blinding and it also keeps the current draw down to well under 1mA.