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Like the title says i want to control around 30volts of current (multiple LEDs that will be running all at once, added up to about 30volts.) i want to use a micro-controller to control it so i can add some effect to it, the controller will control 4 LED strips which take about 4.5V ea. and a 12V light strip. any help or ideas to control this project would be great

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    \$\begingroup\$ Just letting you know, current is measured in Amperes, not Volts. Please describe your planned circuit, perhaps we can help you design it a different way. 30V supply for LEDs sounds odd to me. If you are putting like 15 LEDs in series, that might not be the best way to do it. \$\endgroup\$ – dext0rb Apr 4 '12 at 3:20
  • \$\begingroup\$ Ask a question and walk out. Don't ever return to read the answers. \$\endgroup\$ – Federico Russo Jul 9 '12 at 16:12
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Most micro-controller boards will give you a 0 (LOW) or 5V (HIGH). 5V will turn on the gate of an N channel MOSFET. Even low cost MOSFETS should allow 50-60 Volts from the drain to the source.

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IRF520PBF at a common US distributor is 96 cents.

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My favourite way of doing things like this is with the good old ULN2803. It's such a simple chip to use, and you can use it to switch high voltage and current, and even inductive loads.

It's available in DIL and SOIC packages.

Using a 2803 to light LEDs.

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    \$\begingroup\$ Note that the 2803 is dimensioned for 5V inputs, 3.3V may not give you enough drive current. \$\endgroup\$ – stevenvh Apr 4 '12 at 8:33
  • \$\begingroup\$ Oh, where did he mention 3.3v? \$\endgroup\$ – Rocketmagnet Apr 4 '12 at 8:45
  • \$\begingroup\$ Nowhere, but he doesn't mention 5V either. Just a general remark, might be useful. Don't take it personal. \$\endgroup\$ – stevenvh Apr 4 '12 at 8:47
  • \$\begingroup\$ Oh right. No, sorry, I wasn't taking is personally, I thought I probably had missed something as I often do. \$\endgroup\$ – Rocketmagnet Apr 4 '12 at 9:00
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    \$\begingroup\$ Just checked the datasheet. Looks like 3.3v would be OK. \$\endgroup\$ – Rocketmagnet Apr 4 '12 at 9:01
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I've done a project similar to this, I made a network-controlled power board. I used a couple of relays to switch circuits on/off.

If you do go with relays, be sure to have a power diode placed in reverse so that when you close the relay the electromagnetic bubble doesn't fry your Arduino.

If the Arduino doesn't have enough current to switch the relay on, use a saturated NPN to boost the signal. This site has some good information on what I think your wanting.

EDIT: As PetPaulsen mentions below, you could also just use transistors

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    \$\begingroup\$ For most relays you cannot switch them directly by the microcontroller (also listed under disadvantages in the link you provided). You have to use a transistor anyway to drive the relay. In this case its easier, cheaper and less space costly to switch the LED's with the transistor. \$\endgroup\$ – PetPaulsen Apr 4 '12 at 5:53
  • \$\begingroup\$ I agree, a transistor solution would be best. \$\endgroup\$ – 478Analyst Apr 4 '12 at 14:03

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