wiring LED's

[DaveW]

Hey, 400 of my posts were nonsense anyway.

Xmastree, you have quite a few resistors there, but you can manage with a single resistor in series unless i've forgotten something important.

Just for a sort of footnote.

Oh, a CBB, i have too much respect to get offended by anything you could say. Anyway, you make every post count

-Dave

[Aero]

I'm not sure if that would work though, becase while each series is geting teh same voltage, each LED in the series is getting progressivly less so they would just be dimmer in order wouldn't they?

[DaveW]

No, circuit's don't work like that. Voltage is potential difference; it's not like fuel that gets used up at each stage. It's more like rain falling into different sized buckets.

I know it's a crap analogy, but hey. I'm tired, it's the best i can come up with, and water analogies in electronics are more common than STDs in the Red light district.

-Dave

[Aero]

No, circuit's don't work like that. Voltage is potential difference; it's not like fuel that gets used up at each stage. It's more like rain falling into different sized buckets.

I know it's a crap analogy, but hey. I'm tired, it's the best i can come up with, and water analogies in electronics are more common than STDs in the Red light district.

-Dave

hmmm....well I'm pretty sure I understand how the work, I must be saying something wrong. (electricity was the only test I got an "A" on in Physics this year so I must understand something somewhere). bah, my brains too fried to thinka bout this right now, ACT tomarrow so sleep now.

[crazybillybob]

What daves trying to say is that you can limit the current in an entire branch with 1 resistor (this only works if all the LEDS are the same kind and color)


So here's a little drawing to help

................Res
+---------^^^--------|<-----gnd
..........................|----|<----Gnd



OK Ignore the ....... It's just so everything stay where I drew it!

Hope that helps.

Crazybillybob

[CanaBalistic]

I had it at the diagram but the more you guys talk the more i get confused.

[Omega]

I had it at the diagram but the more you guys talk the more i get confused.

Diagrams > Geeks rambling on

[xmastree]

I know it's a crap analogy, but hey. I'm tired, it's the best i can come up with, and water analogies in electronics are more common than STDs in the Red light district.

Damn, what a time for me to lose my conenction... I've been chomping at the bit waiting to answer this.

Think of an LED forward voltage as an overflow in water terms. The voltage can never get higher than the level of the overflow. Try to raise it and it just flows faster. Feed it through a small pipe (resistor) and you have flow control.

I've prepared a simple explanation, but I've put it in its own thread, here.

[xmastree]

I'm not sure if that would work though, becase while each series is geting teh same voltage, each LED in the series is getting progressivly less so they would just be dimmer in order wouldn't they?

No, the voltage across each would be the same.
If you measure from each one to ground, yes, each will be less. But if you measure across each LED they'll be the same.

As for only one resistor and LEDs directly in parallel. Not a god idea. If manufacturing tolerances cause one LED's voltage to be lower than the other, that one will take the lion's share of the current.

[DaveW]

Bah, who gives a crap anymore. Now i'm going to have to breadboard the simplest LED circuits, all because of this thread. Thanks a lot guys!

-Dave (who is only kidding )