LED & electronics newbie project

Im brand spanking new to electronics so i have a few questions here on LEDs. If you connect say 20 LEDs in series, can you still power them with regular batteries (1.5V)? I would like to use the mains to power the LEDs. I have various adapters lying around ranging grom 5V to 12V. What changes, if any, will I have to make to the configuration and will I need extra components? I want to make lighting for a very small permanently dark room where I can use a switch to turn on the LED lights.

You won't want to hook them all up in series. At a minimum you'll need a 40V power source. You'd be better off running them in parallel or at least series-parallel. metku.net had my favorite LED resistor calculator, but they seem to be down.
uuili (author)  fungus amungus10 years ago
Thanks im checking the resistance calcs and will try and understand them. How do i connect them in parallel? Will the LEDs dim? This is the configuration i have at the moment with 20 LEDs (not tested yet). Does it look safe enough?
untitled.bmp
lemonie10 years ago
Search the internet for LED resistor calculator. There seem to be a lot of copies of the same calculator that only takes input valtage of 32V, but it would be a good start for you.