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                        Tech. question?

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                        2 replies
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                        Anonymous
                        • Member since
                          November 2005
                        Tech. question?
                        Posted by Anonymous on Tuesday, January 11, 2005 8:54 PM
                        I need to know what size resistor I need to drop a 9v-batt.down to a max. of a 4.5v led without frying it.Ohmns' law was a long time ago for me!Thanks.
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                        Anonymous
                        • Member since
                          November 2005
                        Posted by Anonymous on Thursday, January 13, 2005 8:26 AM
                        Assuming a current of 20mA you need a 225 ohm resistor. A current of 30 mA and you need a 150 ohm.

                        Personally, I stay away from 9V batteries. They have the lowest current capacity of common batteries. I suggest AA's or AAA's.

                        Scottie
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                        Anonymous
                        • Member since
                          November 2005
                        Posted by Anonymous on Thursday, January 13, 2005 11:04 AM
                        Thanks,Scottie this helps alot.
                        Report Abuse
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