Thanks to all who provided some very good links. I was looking for a
constant current IC to power some LEDs. When I use alldatasheet to search
"constant current", it found "constant current LED driver"!
Octopart also seems very useful. It gave the part name and stores that sell
it, along with the price.
It does not indicate where I can get free sample. Just kidding
The part
is only a few bucks, I'd be happy to pay for the part and get free shipping
(which cost more than the part).
BTW, isn't there an electronics parts store called "Fordham radio" or
something that I used to receive catalogs from. I can no longer find it;
just curious what happened to it.