to mneary: THANKS A LOT
best post I get so far 
may I ask another queastion regarding LM317...?
will this work, or how do I drive multiple arrays of LEDs 20mA by current?
I want it universal, cause I want to switch the diods... cannot put a resistor in front of each string, cause if there will be 4xwhite LEDs (3.3V) or 4xred (2.1V) is a difference... but if you know a better method, please tell me...
but I wonder if the LM can drive multiple strings and if the current split 1:1
**broken link removed**
may I ask another queastion regarding LM317...?
will this work, or how do I drive multiple arrays of LEDs 20mA by current?
I want it universal, cause I want to switch the diods... cannot put a resistor in front of each string, cause if there will be 4xwhite LEDs (3.3V) or 4xred (2.1V) is a difference... but if you know a better method, please tell me...
but I wonder if the LM can drive multiple strings and if the current split 1:1
**broken link removed**
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