justwantin
New Member
I'm looking for some advice if possible
I have been working on the attached circuit for use in decorative lanterns. The 1 watt LED's provide white light while a cluster of 5mm yellow LED's in the middle simulate the flickering of an oil lamp. I thought my circuit was OK and have been trying out various LED configurations using a benchtop PS for a week or so. I now have my LED configuration looking good through the ricepaper and thought before I solder it all up on a PCB I'd try it out using a 12V 1A power plug. The online LED wizards I used to work out my arrays figured I'd be drawing 700mA for the one watt LEDs and 200mA for the 5mm LEDs but actually I measured 350-60 mA and 2-5 mA respectively> I did not expect the 5mm's to draw so little flickering randomly
The short of it is that while I had no heat problems on either LM317 working off the bench top PS at 12.5V I have a serious heat problem on the top LM317 ( 7V ) when hooked up to the 12V, 1A power plug. I did not push it too far after 80C but changed to a larger heatsink for no joy.
When I hooked up my multimeter in line between the power plug and the circuit my overheating problem went away. This leads me to believe my problem is solvable without using an excessivly large heatsink but it's beyond my level of knowledge at present.
I hope my hasty schematic is clear enough, I'm fairly new to all of this.
I have been working on the attached circuit for use in decorative lanterns. The 1 watt LED's provide white light while a cluster of 5mm yellow LED's in the middle simulate the flickering of an oil lamp. I thought my circuit was OK and have been trying out various LED configurations using a benchtop PS for a week or so. I now have my LED configuration looking good through the ricepaper and thought before I solder it all up on a PCB I'd try it out using a 12V 1A power plug. The online LED wizards I used to work out my arrays figured I'd be drawing 700mA for the one watt LEDs and 200mA for the 5mm LEDs but actually I measured 350-60 mA and 2-5 mA respectively> I did not expect the 5mm's to draw so little flickering randomly
The short of it is that while I had no heat problems on either LM317 working off the bench top PS at 12.5V I have a serious heat problem on the top LM317 ( 7V ) when hooked up to the 12V, 1A power plug. I did not push it too far after 80C but changed to a larger heatsink for no joy.
When I hooked up my multimeter in line between the power plug and the circuit my overheating problem went away. This leads me to believe my problem is solvable without using an excessivly large heatsink but it's beyond my level of knowledge at present.
I hope my hasty schematic is clear enough, I'm fairly new to all of this.