# Series and Parallel?

What is the difference between Series or Parallel if I'm hooking up a bunch of LEDs? Is one better than the other?

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guyfrom7up8 years ago
The more LEDs you can hook up in series, the more efficient your design will be. But the amount of LEDs you can hook in series depends on your power supply's voltage. For example, lets say you are lighting 21 red leds (forward voltage of 1.7v) from a 12 volt powersupply. We can light up to 7 red LEDs in series (7 LEDs x 1.7 forward voltage = 11.9 volts, which is less than the powersupply voltage). Then use a 5.6 ohm resistor in series with the 7 leds to limit current and to drop that extra 0.1 volts. Then put 3 of these sets in parrallel.

When possible, put them in series.
Zem (author)  guyfrom7up8 years ago
So if you put the 3 sets of Series in Parallel, it doesn't raise the voltage?
XOIIO8 years ago
The absolutely simplest way to say it. Parallel: LEDs with all the positive leads together, as well as the negative leads together. This i'd used in Christmas lights because if one or two lights burns out the power still goes to the good ones. Series: LEDs hooked up negative to positive to negative to positive. Not used in Christmas lights because if one bulb burns out they ann go out, and you would have to search through all of them. Hope I helped!
kelseymh8 years ago
Series means each item is connected one after another, in a chain:
`   +O-===+O-===+O-===+O-`
then you connect the battery to the dangling + and - leads at the ends.

Parallel means all the positive leads are tied together, all the negative leads are tied together, and you hook the battery up to those bundles:
`      ===+O-===   ===|==+O-==|===      ===+O-===`

"guyfrom7up" has given you information on how a series vs. parallel circuit will perform.
8 years ago