Adapter for 5 mm led

[oupulino]

Hi I bought 5 mm led they are rated for 12 V now I like to connect 12 of them,I have 1 Adapter 12V DC 1000mA if I connect this adapter to 12 led it does nothing then I connect to 3 led it works great,then I have second adapter 12V 500mA this one can run 6 led not so bright I don't understand what I have to do to run 12 led ,what kind adapter I need

[eli@fijireefrock.com]

i have done this a while back
here is a starting informative site about led arrays and sequences.
should be easy to follow.:smile:
http://led.linear1.org/led.wiz

[oupulino]

I have no idea about resistors the are same on each led I don know which one I ask the seller about this info we see what happen

[eli@fijireefrock.com]

ok this is how i remenber it.
your 5mm led are probably the basic ones.
white or blue led 5mm forward voltage should be no more than 3.3v and 20 mA for forward current.

Solution


each 120 ohm resistor dissipates 48 mW
the color code for 120 is brown red brown
1/4W resistors are fine for your application
together, all resistors dissipate 192 mW
together, the diodes dissipate 792 mW
total power dissipated by the array is 984 mW
the array draws current of 80 mA from the source.
the 12v 500mA power source you have is plenty for your array.
fill in the gap in the site i originally posted and you get a drawing graph of you array.