Led orientation

[Daddy]

Hi
I’m new to this pedal building so as my fourth build I decided to try the Low Tide. Well everything works which came as a surprise however the led did not. I’ve checked on installation and with the long leg being the anode and supposed to go to the square marked hole, nothing. So I stripped the board out, removed the led and reversed it. Behold it now works! Am I misreading this? All documents I have read say long leg, anode, square hole. Am I wrong or was the board incorrectly marked?
Cheers

 

[Robert]

LED polarity

The LED symbol printed onto PedalPCB circuit boards is being updated, please read! Proper installation of LEDs in PedalPCB circuit boards Traditionally the Cathode of a diode is installed into the Square pad of a PCB. Symbol #1 and Symbol #2 conform to this standard. Symbol #3 is...

forum.pedalpcb.com

The round pad is the Anode.

The industry standard is square pad for the cathode of a diode. (LEDs included)

I know, some other folks do it the other way around, somewhere along the line this got reversed in the component libraries that are commonly used for stomp boxes, but if you check the default included patterns in any major PCB design software you'll see that the anode is the round pad.

For future reference, it's actually marked on the PCB itself.

A = Anode
K = Cathode

 

[Daddy]

LED polarity

The LED symbol printed onto PedalPCB circuit boards is being updated, please read! Proper installation of LEDs in PedalPCB circuit boards Traditionally the Cathode of a diode is installed into the Square pad of a PCB. Symbol #1 and Symbol #2 conform to this standard. Symbol #3 is...

forum.pedalpcb.com

The round pad is the Anode.

The industry standard is square pad for the cathode of a diode. (LEDs included)

I know, some other folks do it the other way around, somewhere along the line this got reversed in the component libraries that are commonly used for stomp boxes, but if you check the default included patterns in any major PCB design software you'll see that the anode is the round pad.

For future reference, it's actually marked on the PCB itself.

A = Anode
K = Cathode

View attachment 75842

Thanks for that Robert. I did wonder about the A and K, quite why it’s not a C can’t figure! Anyway I’m sussed from here in

 

[Robert]

Thanks for that Robert. I did wonder about the A and K, quite why it’s not a C can’t figure! Anyway I’m sussed from here in

Another old standard... According to Wikipedia:

The word was coined in 1834 from the Greek κάθοδος (kathodos), 'descent' or 'way down', by William Whewell, who had been consulted[2] by Michael Faraday over some new names needed to complete a paper on the recently discovered process of electrolysis.

Cathode - Wikipedia

en.wikipedia.org

 

[BuddytheReow]

When it comes to LEDs and their leads, big one goes in the A hole.

You're welcome.

 

[DeadAirMD]

This is all true........except I got some clear yellow LEDs from SBP, and the legs are reversed. Very confusing when I installed them the "correct way" and they didn't work.

 

[chris.knudson]

When it comes to LEDs and their leads, big one goes in the A hole.

You're welcome.

And there it is -- the most useful piece of advice I've gotten from this forum.

 

[chris.knudson]

This is all true........except I got some clear yellow LEDs from SBP, and the legs are reversed. Very confusing when I installed them the "correct way" and they didn't work.

It's pretty universal that the long lead is the positive lead -- seems odd that you would have gotten LEDs where that wasn't the case -- are you sure the board was labeled correctly?

 

[DeadAirMD]

I'll take a photo tomorrow. LED was installed on a Parasit PCB

 

[chris.knudson]

I did wonder about the A and K, quite why it’s not a C can’t figure!

It's actually because the German word for Cathode is Kathode -- hence the K.

 

[DeadAirMD]

Isn't Parasit, Swedish?

 

[chris.knudson]

Isn't Parasit, Swedish?

I actually think it's French, but what does that have to do with Cathode?

 

[KR Sound]

Horrible sketch, but you get the idea. Don’t always count on the leads being correct, especially if you trim them first.

The flat side of the LED itself is the cathode or ‘K’, and K is make of straight lines. It also goes in the square pad. The Anode side of the bulb ‘a’ is round and goes in the round pad.