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Slow Loris LED question

Started by Adamo, January 26, 2015, 08:56:07 PM

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Adamo

I don't know why I always struggle with this but how should I wire the LED for the Slow Loris 2014 build? Which leg of the LED should go into the board pad labeled LED and where does the other LED leg get attached to? Just to clarify, I do have the current limiting resistor, R11, on the board. I'm sorry about these stupid questions.

Thx
Adam


selfdestroyer

Not a stupid question at all. The anode (+) goes to the square LED pad.

Cody

Adamo

And then where do I connect the cathode leg of the led?

ggarms

Connect that leg to the closest ground you can find.

mgwhit

#4
Quote from: ggarms on January 27, 2015, 07:32:04 AM
Connect that leg to the closest ground you can find.

No, the cathode goes to a lug on the 3PDT switch (or a pad on a 3PDT wiring board) that is only grounded when the effect is switched on...a la the standard wiring diagram.  Otherwise the LED will be on all the time.

TGP39

Teach a man to fish........

Hi Adamo,
      I had the same problem regarding polarity orientation for LED's.  Matthew is correct when he says that most PCB's utilize the square hole for the positive (anode) side of the led.  The only problem is that not ALL PCB's follow this rule. So how is a builder suppose to know which rule to follow?  The answer is the schematic.  All schematics should show you the proper orientation of the Led by indicating the bar(cathode) side of the LED (just like any other diode).    Take a look at the following picture I found on the internet:




Remember this line....."Short and Fat Cathy Lives at the Bar".   This means the following rules:

A. Cathy (Cathode) is always where the bar is on the schematic.
B. Cathy (Cathode) is the shorter leg of the LED.
C. Within the epoxy case of the diode is two foil looking, jagged pieces. Those two pieces make up what is called the lead frame. All you have to remember is that the fatter piece of foil (called the anvil) aligns with the cathode. Alas, Cathy is fat also. 

Finally, on Brian's PCB and many others, they attempt to help the builder properly orient the led by showing a silkscreen image of an led. The image shows a flat side and a curved side. The flat side is where the Cathode goes. I guess you could say Cathy is flat chested as well. :)

I hope these little tips will not only get you past the Slow Loris, but all your future builds as well.

Steve.

P.S.  If you want to wire an LED so that it goes on and off when you push the bypass foot switch,  the anode (positive leg.....longer leg) goes into the led square pad on the pcb board and the cathode (remember Cathy?) has to attach to a ground terminal on the footswitch.

Edit: Matt beat me to it.
Follow me on Instagram under PharmerFx.

ggarms

#6
Quote from: mgwhit on January 27, 2015, 08:50:12 AM
Quote from: ggarms on January 27, 2015, 07:32:04 AM
Connect that leg to the closest ground you can find.

No, the cathode goes to a lug on the 3PDT switch (or a pad on a 3PDT wiring board) that is only grounded when the effect is switched on...a la the standard wiring diagram.  Otherwise the LED will be on all the time.
He's right, I assumed we were at the switch without reading further. Sorry!

Edit: Actually, I don't know what I was thinking. Stupid fast reply.

mgwhit


ggarms