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RSS >  4 led mount doubts
chrijj #1 14/08/2007 - 18h53

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will this be correct

Siemens SFH485P with ,Resistencia,película de óxido metálico,pirorretardante,potencia,serie ROX1S,1W,82 ohmios,5%

for 4 led mount with 12 v 1500 mham supply?

and this one?

Siemens,SFH485 Resistencia,de película metálica,alta estabilidad,uso general,0.5W,33 ohmios,1%

same 4 led mount with an 9 v supply?

i wish to do a serial mount, but where do i put the resistor? and how i connect the leds ? do i have to use just one?

sorry but this is my first time dealing with resistors...
tristan68 #2 15/08/2007 - 01h25

Electronicien en chef
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Hello Chrijj.

Your 2 setups are OK for a 4led serial assembly.

For a serial assembly , you'll just need 1 resistor for the whole kit.

About connecting , it's very simple :

you connect  :
- your battery positive lead on the resistor, first pin
- the resistor, 2nd pin to the first led anode.
- the first led cathode to the second led anode.
- the second led cathode to the third led anode.
- the third led cathode to the fourth led anode.
- the fourth led cathode to the battery negative lead.

The Led assembly wizard, available HERE provides a little schematics.

hope this helps.
chrijj #3 15/08/2007 - 01h39

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Thank you very much for your help.

I've ordered the components and when i recieve them i'll try to assemble this "circuit" and let you know if everything works well
when i posted the first message i've been trying to use your link but cant get it to work.
Now i see the scheme and the values.

Thank you again.
Edited by chrijj on 15/08/2007 at 01h41.
einsena #4 28/08/2007 - 06h01

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back in shop class if i remember correctly is that if you use serial connection then the led's would go dimmer as it being added upon
e.g the 1st LED would shine brighter then the 4th led

my question is.. why did this not happen on my assembly?
because I'm pretty sure I've connected it serially
e.g
- the 1st led is connected to the + of the 2nd led and
- the 2nd led is connected to the + of the 3th led so on and so forth

my so called assembly works btw but why is it working? : b l i n k :
Kestrel #5 28/08/2007 - 06h11

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einsena @ 28/08/2007 - 06h01 a dit:

back in shop class if i remember correctly is that if you use serial connection then the led's would go dimmer as it being added upon
e.g the 1st LED would shine brighter then the 4th led



Electricity is smarter than that, it can see there are 4 leds in series and distributes power to them equally.
einsena #6 28/08/2007 - 06h35

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hmm.. then all my past knowlage was all lies  : p i n c h :
funny thing is when i try it at logic works my assembly don't lit up : ( but anyways thanks for the answer i now know that electricity is smart : D   : D   : D   : D

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