I want to make an aquarium light fixture but i don't know about the power supply.If i have ,say,30 led's that are 1w each, can i use a 12v 60w p.s. for this or do i have to use a p.s. that matches the 30w of the led's total?
who knows l.e.d.'s ,the diodes, not t.v.'s.....
- Thread starter daves66nova
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A 60 watt power supply will provide up to 60 watts continuous power demand and anything less.
The wattage of the power supply, as long as it is equal to or greater than the connected load does not matter.
What matters is the current through the led's. Too high and they will blow. You need to calculate a resistor to limit the current flow. It depends upon the specific led's current rating and the voltage supplied.
What matters is the current through the led's. Too high and they will blow. You need to calculate a resistor to limit the current flow. It depends upon the specific led's current rating and the voltage supplied.
Originally Posted By: AandPDan
The wattage of the power supply, as long as it is equal to or greater than the connected load does not matter.
What matters is the current through the led's. Too high and they will blow. You need to calculate a resistor to limit the current flow. It depends upon the specific led's current rating and the voltage supplied.
Very true - and this is why most LED applications are on a PCB with a resistor mounted for each one.
The wattage of the power supply, as long as it is equal to or greater than the connected load does not matter.
What matters is the current through the led's. Too high and they will blow. You need to calculate a resistor to limit the current flow. It depends upon the specific led's current rating and the voltage supplied.
Very true - and this is why most LED applications are on a PCB with a resistor mounted for each one.
Look up the diodes current and voltage rating. Look at the minimum voltage required for current to flow. Divide the supply voltage by the minimum voltage required for current to flow and add 1 to that and truncate . This is the number of diodes you'll connect in series and then connect to the power supply. Of course anodes are connected to cathodes and the anode side of the series diode string is connected to the positive side of the dc supply and cathode side to the negative side if the dc supply. Of course the supply must be able to maintain its terminal voltage at the current rating of the diode to function and unless these are high current diodes that wouldn't be an issue (by high current I mean greater than 100ma or so and at 30 watts that's not a problem). Typical values are 20 ma of diode current at about 0.7 volts drop across it).
here's the one i want to use,http://www.joeknowselectronics.com/?page_id=830 . the hq-5w25-c9 is the one i'm looking at.
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The forward voltage is not shown unlEss the reverse voltage is actually the forward voltage. Other diodes on the page show a forward voltage of 3 volts which if accurate the diode contains a current limiting device such as a resistor or a resistor/Zener combination. The best thing to do is to get the real specs. The specs provided are a small summary of the data sheet. If that is not available, you'll want to experiment with the diode, resistors and a pair of AA batteries in series.
I tried searching for the Part number ... Only place located was from joe knows electronics. Joe may know electronics but he didn't manufacture that diode. And it's the mfg data sheet that is needed. Of course you can always call hm.
do not waste your time on 5mm parts.thats what you linked to.few will hold up long term.
salt or freshwater?
if you are set on led's you want power leds like luxeons.
cree makes some too.
or just use a quality fluorescent made for the type of tank you will be running.my small freshwater setup has a 15w vitalite tube in it.saltwater needs lots of blue or actinic.
salt or freshwater?
if you are set on led's you want power leds like luxeons.
cree makes some too.
or just use a quality fluorescent made for the type of tank you will be running.my small freshwater setup has a 15w vitalite tube in it.saltwater needs lots of blue or actinic.
freshwater. Do you have a link on a good source for some decent ones?
In case you didn't know - LED's only operate with current flowing accross them in one direction. Use a DC power source for your LED's. You could use an AC source, but you'll only get half of the rated output for the LED's (since current is only flowing accross them half of the time).
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