series or parallel...what is difference?

I have read here of people wiring two or more LEDs in series and also parallel.What is the difference between the two and what are the advantages of each method.I do not know the difference but I did manage to wire two LEDs together to use one power source.I put the neg. lead of one to the pos lead of the other.Pushed these out of the way and then used the two remaining leads to attatch to the battery.Both LEDs worked but it did not appear much brighter than one LED.Is this in series?By using the method I used are Both LEDs receiving less power than if I used only one?

you wired them in series.

That way you need twice as much voltage to push the same current through them.

How would you wire them in parallel?...Is this why two LEDs are dimmer than one because they are receiving less volts than one single LED?

for a parallel connection you would use separate wires to feed the leds.

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AilSnail said:
you wired them in series.

That way you need twice as much voltage to push the same current through them.


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This is quite true, although there's a serious advantage in that each electron in that current gets two chances to make a photon for us, the total light is twice what a single LED would give at that current. If your supply allows, this is 'a good thing', at least WRT efficiency.

Doug Owen

Using LED's as the example. You wired yours in series by connecting positive to negative and then taking the remaining positive and negative leads to the battery. When you wire in series the voltage is split between all the devices in the series and the amperage stays the same.

To wire them in parallel you would hook both positves to the postive on the battery and both negatives to the negative on the battery. When wired in parrallel voltage remains the same across each device and amperage is split.

When batteries are wired in series the voltage increases and the amperage stays the same. When wired in parallel voltage stays the same and amperage (or current) increases.

Mutech

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Robocop said:
How would you wire them in parallel?...Is this why two LEDs are dimmer than one because they are receiving less volts than one single LED?

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In parallel, you hook the positive leads of all the LEDs together. And the negatives. The block is then wired as a single LED would be. In this case the current will divide between the LEDs, but not necessarily evenly.

In the case you did, the total current was no doubt lower for two LEDs in series. What was your battery? The rest of the circuit?

Doug Owen

The battery supply was a 12 volt 21/23 battery in a small solitaire mod direct drive.If I have understood correctly I have read that LEDs are more of an amp device rather than volts.Is this correct?When I first became interested in LEDs I thought that the more volts supplied the brighter the light.I have since learned that it is the mah that are more important to an LED.(is this correct)If this is true when wired in parallel the amperage is split between the number of LEDs so would this not be a bad thing as far as brightness?(due to lower amps)

Yes, you are absolutely correct to think of LEDs in terms of current, rather than voltage. Truth be known, most folks that define them in terms of voltage don't really know what is going on anyway, so I guess it doesn't really matter.

Current (flow of electrons) is what makes light. For a given current, the LED will have a voltage associated to it, the forward voltage, Vf. While it's true that supplying that voltage will force that current through the LED *under those exact conditions*, this is a dangerous oversimplification.

Circuits, in general, need something to relate current to voltage. Usually this is resistance, following Ohm's Law. For LED circuits like the simple ones we use, we need to subtract the Vf at the current we're using from the battery voltage before making this calculation. We also need to include all the resistances (including the connections, ones inside the LEDs and battery). In your case, the battery you're using has a very large internal resistance. This limited current and kept things from killing LEDs. FWIW, I suspected that was what you were doning, it's the only common battery that would do this. Consider yourself lucky.

Doug Owen