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Please help! How do I lower the current strength (Amps) in a parallel circuit so I don't fry my LEDs? Answered

I have a AC/DC adapter that gives out 4.5V and 500mA, how could I lower the strength of the current so that I can connect four LEDs (4.5V, 20mA) in parallel and not fry them? Sorry if I ask the impossible, I'm a total electric beginner.
Thank you in advance!

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lemonie
lemonie

Best Answer 11 years ago

You don't "lower the strength of the current" as such, if you click here it will give you a diagram and recommended resistors (though 1 ohm isn't needed I think). You're hung up on the 500mA notice - that's the most it's designed to provide, like a car has a top-speed - you don't break it unless you actually put you foot to the floor.
If the forward voltage is 4.5, maybe do add a very-low value resistor, but you'd probably be fine without.

L

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steveastrouk
steveastrouk

11 years ago

At that rate you haven'y really got enough volts for the LEDs you have. You want to drop a volt or two in the resistors, so you need 6V plus really from the supply.

Steve

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Re-design
Re-design

11 years ago

You lower the voltage by adding resistors to bring it down.  The current will take care of itself.  The 500 mA rating on the powersupply is just the max the it is rated for.  You can find the resistor value you need by using an led calculator like this one.