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10w 9v led proper circuit

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Member level 3
Oct 5, 2012
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Salam to all

I have purchased an led of 10w 9v and i want to connect it to 220ac as in circuit but facing some problem please see the attachment!!!!!!!!!!!!!!!!!!


  • 10w led jpg.JPG
    10w led jpg.JPG
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I'm not sure what kind of led it is, usually leds need a constant current mechanism rather than a constant voltage one unless your led has already some kind of current limiter.

As a 10w led I would expect it to get very hot so what you describe may be perfectly normal, such high power leds should be attached to a metal surface that works as a cooler to dissipate the heat.

These are power components, and as such will generate heat. If you do not provide sufficient heatsink then it will get very hot.

your LED rated for 10W will have to dissipate 10w. Have you put it on a heatsink ? It should also have a small current limiting resistor in series.

your 7809 will need to dissipate upto 5w, maybe even upto 8w depending of the type of transformer & rectifier you are using. The standard TO-220 package is capable of only ~1w without heatsink.

Recommendation - use proper heatsinks/ cooling system. Post your circuit & component specifications if you have any further doubts.

I'm not sure where the + and - contacts are (I see the indicators but not sure where the contacts are) but this should be attached to a heatsink for sure and a quite big one.

where did you get the 9v specification for this LED ?

As such, I think you will probably need more than 9v to power this. You could possibly use a 12v supply with a series resistor - maybe a 0.5 ohm/ 2 watt.
However if you have the detailed specs for your led, then please post, otherwise difficult to see from a pic what this component does.

This thread is really old but still to clarify things,its a Chinese high power warm white led,(p=10w,forward voltage=9-11v,forward current=900mA).I m not dt good with electronics but usually it is connected with a 22ohm/5w resistor and then directly to a 12v DC power supply.and it needs at least an inch by inch heatsink.usually a combination of these is used as floodlights.and the brightness,oh,ul see after images for at least a minute.

Not 22 ohms. Refer to ohm's law. And if you are using few feet of sub-standard wire to power it. you don't need any.

i made a circuit for my led lamp. pub. in Elektor Electronics 9/2003 A simple switched regulator with 70 % efficiency. change R6 and L1 wire size for more current.

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