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I have an LED circuit built that requires 12V @ 6A (72W) to run at approx 80% max rating of the LEDs. The circuitry works but all the power supply/adapters that I have been able to find with those specifications "pulse". The voltage is constant but the amps vary from 0-6A which makes the LEDs pulse.

I am looking for information on how to look for a power supply/adapter that has constant power output (both voltage and amps). I am in the US and plan to use the AC wall plugs at 120V 60Hz (15A breaker/wiring)

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  • \$\begingroup\$ The power supplies might be shutting down briefly due to excessive current. Can you try using just half your LED string? That should be well under the supply's rating, so it won't have to protect itself by shutting off. \$\endgroup\$ – Peter Bennett Jun 15 '15 at 23:27
  • \$\begingroup\$ I thought that might be the problem as well, so I hooked the power supply up to a volt/ammeter and it told the story of ~12V and ~0-6A. \$\endgroup\$ – Opemow Jun 17 '15 at 2:02
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Power supplies for LED's have come a long way. There are constant VOLTAGE power supplies, and constant CURRENT power supplies. LED's like constant current. What you mention is probably the "optimum voltage/current" for the LED. Since voltage and current are related to each other you can get away with more than one or the other. (For example running 24 Volts at 3amps = 72W). That being said there are now lots of power supplies that will take 115VAC and convert it to low power steady DC.. They are called "LED DRIVERS".. Ebay has tons of them.. Yes alot of manufacturers are in china but with some digging on Ebay, you can find an american supplier. Search for "CONSTANT CURRENT LED DRIVER" and find one that matches your specs.. they can be had for cheap.

6.7A 12 Volt DC Power Supply

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  • \$\begingroup\$ So do you not need to worry about a varying Voltage for LED power supplies? And why would they sell a "LED driver" that outputs varying current if that wont run an LED? (I bought a "LED Driver" meanwell product and had the same strobing result with the varying current) \$\endgroup\$ – Opemow Jun 17 '15 at 2:10
  • \$\begingroup\$ Some LED's are Constant voltage, Some are Constant Current thats why they make two different drivers. Most LED's have a Min and Max Voltage, and Mix and Max Current.. they will take what they need from a suitable PSU. All will be fine as long as you don't exceed current or voltage. Of course there are more physics in LEDs as running multiple in parallel means the PSU must compensate for the difference between LED's. So most PSU's say how many LED's you can run in parallel. The link I provided is a constant current driver \$\endgroup\$ – Tim Davis Jun 18 '15 at 19:55

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