Hi, needing a little help with this, new on here and new to high power leds, played with smaller ones before with resistors, that is all. Only some very basic knowledge of electronics so needing a little help please!
I am looking to illuminate behind the wheels on my car, when i open the doors wired to the interior light. I have wired it up with normal leds but it isnt bright enough. I have done this with 4 leds in series, one at each wheel. I have bought some 3w leds, not realising they are so easy to power! Here are the specs:
DC Forward Voltage: Min: 3.6V Max: 4.2V
DC Forward Current: 700mA
1 led per wheel arch so 4 in total
The vehicle voltage will vary from 12-14V. After reading up I see it is not good to run these with resistors with much more power! I found out about buckplugs for each led, but not keen as they aren't cheap, looking for a cheap solution.
I saw this similar thread on here...
http://forum.allaboutcircuits.com/showthread.php?t=57873
Please excuse my most likely stupid questions, happy to build the things and solder them up, just not sure what. Got the idea now of linear and switching regulators, but not exactly understanding FET and NPN transistors yet!
My questions are:
1)If i went linear, would it be better to wire 2 sets of 2 in series for a larger voltage drop meaning less heat? How hot would they get if they are only on for as long as the door is open, (not long). No idea on how quick they would heat up?
2) would this circuit let the leds fade out like the smaller powered ones with the interior lights?
3)off topic - would a 28mmx28mmx10mm heatsink be enough for these for my needs as they wont run for very long, the ones i have seen suggested for 3w are way bigger at 45x45x10mm but less easy to hide!
4)While learning on google I saw these
http://en.wikipedia.org/wiki/78xx - if i got one of the 8v ones of this and wired it in to two leds in series, would this not have the same effect? i realise this is a voltage not current regulator but would this work and be an easier fix for me? I now understand voltage and current i think, just not sure how it applies to the led .
Thanks in advance for anyones time and sorry if my knowledge is shocking, just trying to learn, thanks, allan
I am looking to illuminate behind the wheels on my car, when i open the doors wired to the interior light. I have wired it up with normal leds but it isnt bright enough. I have done this with 4 leds in series, one at each wheel. I have bought some 3w leds, not realising they are so easy to power! Here are the specs:
DC Forward Voltage: Min: 3.6V Max: 4.2V
DC Forward Current: 700mA
1 led per wheel arch so 4 in total
The vehicle voltage will vary from 12-14V. After reading up I see it is not good to run these with resistors with much more power! I found out about buckplugs for each led, but not keen as they aren't cheap, looking for a cheap solution.
I saw this similar thread on here...
http://forum.allaboutcircuits.com/showthread.php?t=57873
Please excuse my most likely stupid questions, happy to build the things and solder them up, just not sure what. Got the idea now of linear and switching regulators, but not exactly understanding FET and NPN transistors yet!
My questions are:
1)If i went linear, would it be better to wire 2 sets of 2 in series for a larger voltage drop meaning less heat? How hot would they get if they are only on for as long as the door is open, (not long). No idea on how quick they would heat up?
2) would this circuit let the leds fade out like the smaller powered ones with the interior lights?
3)off topic - would a 28mmx28mmx10mm heatsink be enough for these for my needs as they wont run for very long, the ones i have seen suggested for 3w are way bigger at 45x45x10mm but less easy to hide!
4)While learning on google I saw these
http://en.wikipedia.org/wiki/78xx - if i got one of the 8v ones of this and wired it in to two leds in series, would this not have the same effect? i realise this is a voltage not current regulator but would this work and be an easier fix for me? I now understand voltage and current i think, just not sure how it applies to the led .
Thanks in advance for anyones time and sorry if my knowledge is shocking, just trying to learn, thanks, allan
