Reply to thread

Message

<blockquote data-quote="keep_hope_alive" data-source="post: 7464729" data-attributes="member: 576029"><a href="http://www.bcae1.com/led.htm" target="_blank">Light Emitting Diodes (LED)</a><a href="http://ledz.com/?p=zz.led.resistor.calculator" target="_blank">LED Resistor Calculator</a><a href="http://www.pcboard.ca/kits/led_notes/" target="_blank">LED Dropping Resistor Calculator</a>these links should help you.&nbsp; you need to know the forward voltage drop of each LED and the rated current.&nbsp; you can measure this with a DMM if you don&#039;t have a datasheet for them.you&#039;re simply applying ohm&#039;s law to devices in series.&nbsp; LED&#039;s have a fixed voltage drop.&nbsp; the current through all of the series devices is the same, and by sizing the resistor you are setting what the current is based on the voltage drop across the resistor.&nbsp; the voltage drop across the resistor is simply the source voltage minus the voltage drop of the LED string.blue LED&#039;s are typically around 3V drop for each, but you need to verify with your string.&nbsp; you are welcome to measure your string. you could start with a 1000ohm resistor in series, powered by a 12V supply, and measure the drop.&nbsp; then resize the resistor using ohm&#039;s law.&nbsp; you&#039;ll have one resistor per string.as for the bridge rectifier - just go buy one at Radio Shack rated for 1A.&nbsp; the AC inputs (labeled with a ~) are connected to the sub terminals.&nbsp; the DC outputs (labeled + -) go to the LED strings.i can draw a diagram later.</blockquote>

[QUOTE="keep_hope_alive, post: 7464729, member: 576029"] [URL="http://www.bcae1.com/led.htm"]Light Emitting Diodes (LED)[/URL] [URL="http://ledz.com/?p=zz.led.resistor.calculator"]LED Resistor Calculator[/URL] [URL="http://www.pcboard.ca/kits/led_notes/"]LED Dropping Resistor Calculator[/URL] these links should help you. you need to know the forward voltage drop of each LED and the rated current. you can measure this with a DMM if you don't have a datasheet for them. you're simply applying ohm's law to devices in series. LED's have a fixed voltage drop. the current through all of the series devices is the same, and by sizing the resistor you are setting what the current is based on the voltage drop across the resistor. the voltage drop across the resistor is simply the source voltage minus the voltage drop of the LED string. blue LED's are typically around 3V drop for each, but you need to verify with your string. you are welcome to measure your string. you could start with a 1000ohm resistor in series, powered by a 12V supply, and measure the drop. then resize the resistor using ohm's law. you'll have one resistor per string. as for the bridge rectifier - just go buy one at Radio Shack rated for 1A. the AC inputs (labeled with a ~) are connected to the sub terminals. the DC outputs (labeled + -) go to the LED strings. i can draw a diagram later. [/QUOTE]

Verification