noob question: How do I stop multiple LEDs from dimming

Other Hardware General Electronics
1

Hey everyone,

I am new to and learning electronic stuff and loving messing with my arduino.

I am sure there is a way to connect multiple LEDs that are on at the same time and not have them get more and more dim as you add another LED.

How do I do that?

Thanks in advance

2

Each LED needs it own current limiting resistor... or what you see... happens.

3

Remember each Arduino pin can only provide 40mA - or about 2 LED's worth at 20mA per LED.

If you need more LEDs than that controlled from one pin, you will need to use a transistor to drive the LEDs.

Do some research, paste us a schematic diagram of what you think you want to make, and we will tell you if it will work.

4

There are two ways to wire LED's together:

  1. If you put the LED's in parallel you need a current limiting resistor for each one.
  2. If you put the LED's in series you have to add up their voltage drops before calculating the single current limiting resistor.

If you put more than 2 or 3 LED's in series you will need more then 5V to drive them.

5

Here is a good guide to using transistors to switch LEDs.
http://www.sqlskills.com/blogs/paulselec/post/Arduino-figuring-out-transistors-and-associated-resistors.aspx