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LED in parallel to power? Answered

I have a project and i am wondering if you can hook up a diode to the power source (hook it up in parallel to it) would you have to hook it to ground in some way??

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steveastrouk
steveastrouk

Best Answer 10 years ago

Power dissipation = current x voiltage drop. Thus 2v x 0.02 A ... or 40mW.....
HTH
Steve
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astroboy907
astroboy907

10 years ago

To All,
Here is a (simple) schematic i made of it. It is for a small dc to dc power converter (similar to mintyboost). I wanted to have an led to tell weather it was on or off. It is a 603 SMD led, with a resistor (which should be somewhere around 100 ohms) would i have to get a high wattage resistor? or because it is in parallel could it be smaller? I am also a little confused about how to wire it (see schematic)

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steveastrouk
steveastrouk

Answer 10 years ago

We need to know the supply voltage, and the LED type to comment further.

Steve

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astroboy907
astroboy907

Answer 10 years ago

is there a schematic on it? hmmm... will try reloading
The led is a 0603 SMD LED, and the resistor is also 0603. Both can be changed if necessary.

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steveastrouk
steveastrouk

Answer 10 years ago

The "Or this" diagram will work. The first is completely redundant, because you have shorted out all your circuit !

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astroboy907
astroboy907

Answer 10 years ago

k :)
Thanks! I just have 1 more question, should i get a 2.5 (or greater) wattage resistor? just in case. oh + if you were wondering i switched all my parts to non SMT :)
Also, will there be any significant power loss??

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steveastrouk
steveastrouk

Answer 10 years ago

Power dissipation = current x voiltage drop. Thus 2v x 0.02 A ... or 40mW.....

Steve

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astroboy907
astroboy907

Answer 10 years ago

can you post this as an answer?, then i will pick u as best

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AndyGadget
AndyGadget

10 years ago

If you're talking about a low voltage DC power source, it needs to have a resistor in series with the LED.  There's a calculator for the value HERE.
If it's a normal LED, enter 20mA for the current, and the forward voltage should be written on the pack they came in or in the advert you bought them from - If not, use 2V.
If you want to connect to AC or to over 12V then things are a little more complicated - Let us know the details.

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steveastrouk
steveastrouk

10 years ago

HAVE to have a resistor with it.

Steve

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Re-design
Re-design

10 years ago

Ground is just another name for NEGATIVE (usually).  So just hook that led up to the pos and the neg with any required resistor and away you go.