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LED Series circuit problem

Asherz

Asherz

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Well I'm not sure where to post this but this is the only place i know that could help me with this kind of thing :)

Basically i am trying to make a circuit with 5 LED's in to light up a board, running from a 9V power supply.

The LED's are blue and at the moment I have got 3 LED's working with one 200ohm resistor in a series circuit of the 9V battery, but when I connect a fourth non of them light up, I have tried different LED's for the fourth one and non work so it's not a bad diode or anything.

I'm really stumped, I've tried adding another resistor but still nothing


any help someone could give me I would really apreciate.

thanks

-Ash
 





FireMyLaser

FireMyLaser

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Each LED has a voltage drop of around 3.3V so that's why it wont work with more than three in series with 9V.

Instead connect each LED to it's own 330 ohm resistor and then connect them all in parallel to the 9V.

Or make two groups of two LEDs in series plus a 120 ohm resistor and connect those groups in parallel together with one (fifth ) LED with it's 330 ohm resistor to the 9V.


Sorry if it sounds complicated, I can make a schematic tomorrow.
 
Asherz

Asherz

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cheers guys, I think that maybe, I might just have two seperate circuits one with 3 leds in and the other with 2 in each with one resistor 200ohm's... because Im not great at soldering and I cant be botherd to re-do it lol.

Do you think this is ok? as each battery pack has a switch anyway.

I hope that will work, I guess another option would be is to get another 9V battery pack and hook it up and add another few resistors?

cheesr
 
Asherz

Asherz

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I've just had an idea, If I keep the 5 LED's in a series circuit, then when the resistors come of the positive wire on the battery pack, but 3-4 resistors in parrel which will increase the current and there for power all 5?

will this work ok :)
 
FireMyLaser

FireMyLaser

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No, what did I just say? You can't connect more that 3 LEDs in series because it exceeds 9V. In fact three is to many, the battery will soon sag so they wont light. Pretty rude of you to ignore my previous post.

Option 1
5led1.jpg

5x 330 ohm.

Option 2
5led2.jpg

2x 120 ohm and 1x 330 ohm.

I suggest option 2 because it draws less current from the battery.
 
Asherz

Asherz

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hey firemylaser, im really sorry if I came across as being rude, I didn't mean to.

Thanks very much for taking the time to draw a diagram of the circuit, I used the option two circuit and got it all up and running on the back of the board. Thanks very much its really apreciated.

I did modify it slightly, as I ran the three resistors onto a circuit board, and then joined four LED's onto two resistors and just the one resistor on the 5th one.

Thanks again for the help it's really apreciated, more than you know :)

-Ash
 
Asherz

Asherz

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firemylaser, can I ask is that a real video in your avatar? Or is it edited?

It's bluddie cool if it's real :) Pretty good job of editing if it was changed aswell.
 
Asherz

Asherz

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Hey, heres a quick schematic (AKA shitty drawing) of what I got together,

circuitie3.jpg


I hope you like it :p looks better in real life lol.. cant believe i call my self a graphic designer lol

cheers again for your help.
 
Asherz

Asherz

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I know the resistors isn't a great choice, but I found it worked out quite well, as the single LED is inside the model, so it lights up most of it well. which is handy :)

But I didn't get much choice on the resistors as when I bought them I didn't really know what I was doing and the guy in the shop planned on linking each LED with 1 200OHM resistor, but in my setup its inpracticle.. So this worked out ok.
 
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