PCB Instructions Call for "Yellow LED" -- What should I buy?

[seten]

Hey, I'm putting together a duophase pcb and currently ordering all the components on Mouser. I'm stuck on the two yellow LED's they call for -- not as indicator LED's, all it says is "Yellow 5mm LED". I'm looking around Mouser and all I can find (I linked one below) are ones significantly smaller than 5mm and even though theyre labelled as SMD they don't look like regular LED's and I cant think how they would be soldered onto the board.

https://www.mouser.com/ProductDetail/Wurth-Electronics/150080YS75000?qs=sGAEpiMZZMsl8UZd3ZuU6TZQtNiywqw1rqqi%252buMrrQDzxYYfHlnFeA%3d%3d

Could someone help me find what I'm lookin for and if possible link to one on Mouser?
Thanks in advance.

[patrick398]

https://www.mouser.co.uk/Optoelectronics/LED-Indication/Standard-LEDs-Through-Hole/_/N-b1jdv?Keyword=5mm+yellow+led&FS=True

[highwater]

https://www.mouser.com/ProductDetail/Lite-On/LTL-307YE?qs=sGAEpiMZZMtmwHDZQCdlqYmodwJszB5WBdoa50cQHAU%3d

12 cents each, the cheapest I see.

[seten]

Thanks guys! So whats the reason for using different particular colors when using them in the signal flow instead of as an indicator?

[bluebunny]

Different colour LEDs have a different forward voltage (when they start to conduct).  I'm not familiar with the circuit you mention, so I can't speculate how this feature is used in your case.  But in an overdrive, for instance, they would change the clipping characteristics (e.g. tube screamer uses common signal diodes, like 1N4148; the Clay Jones boutique variant uses red LEDs).  If you can post a schematic, we can tell you more about what your yellow LEDs are doing.

[diffeq]

Thanks guys! So whats the reason for using different particular colors when using them in the signal flow instead of as an indicator?

One reason would be different forward voltage, for example in a clipping circuit. Would yieild a different 'cutoff' voltage and output level.

[PRR]

On paper, photo-resistors work better with certain colors of light.

Complicated by different LED colors being more/less efficient, more/less turn-on voltage, and different blends of photo resistor stuff.

And by all new LEDs being much more efficient (brighter) than 1980s stuff.

The "5mm" is mostly about mounting. 5mm used to be THE most common size. However in this build there's no mounting.

If you have Red or Green, or 3mm, try them. Even 1mm SMD might work, if you can get the micro-legs connected to old-style leg-pads.

[Sooner Boomer]

This might help clarify things...

http://lednique.com/wp/wp-content/uploads/2016/09/IV-curves-all-colours.png

[Sooner Boomer]

Additionally, there are several pedals that offer switchability between different colors of LEDs in the feedback loop.  The differences in clipping/distortion can be quite noticeable.

[seten]

Thanks guys! Here's the schematic/parts list. It's a mutron phaser ii clone, sorry I should've mentioned that.
https://www.pedalpcb.com/docs/DuoPhase.pdf

I have a couple more questions. It calls for 12 LDR's. Are those optocouplers? If so, i still need help finding ones to buy because searching for LDR optocoupler on mouser didn't give me anything that looks anything like the optocouplers I used in the last pedal kit I built.

Also, is there any reason these DPDT switches wouldnt work for guitar pedals? https://www.amazon.com/gp/product/B013DZB6CO/ref=ox_sc_act_title_1?smid=A1ONFA8JYPSCVJ&psc=1

[idy]

The LEDs work together with the LDRs to make optocouplers. An oscillator makes a voltage wiggle up and down. This lights up the LEDs. They are standing in the middle of a little circle of LDRs. These change resistance and make the phase stages sweep.

This is a very complicated circuit and you are asking very basic questions, the answers are kind of missing the level of your confusion. For example SMD means surface mount: no legs to go through holes in your pcb, designed for robot assembly, may be used by skilled humans with the right tools and a magnifying glass.

You will need to determine light and dark resistance for the LDRs. The PCB doc does not specify. You can ask others who have done this exact circuit, and also search the forum for others who have gone before. Many of these types of phaser/filter ciruits want dark resistance over 1M and light resistance in the order of Ks (1000s of ohms.) I have used Tayda generic LDRs in similar circuits, but always tested them first to pick "teams" of LDRs that behave consistently among themselves.

Best advice: Read through the forum threads on similar phasers. You will find suggestions for LDR values. And learn a ton.

[PRR]

> It calls for 12 LDR's. Are those optocouplers? If so, i still need help finding ones

Photo Resistors. A blend of Lead, Cadmium, or/and Selenium on a 2-leg wafer.

These were VERY common 1959 through 1990. You could buy bags of assorted cheap photoresistors, or tightly specced hermetic seal units for air/space work. They were in every oil-furnace and most streetlights. They became a low-profit commodity. Then someone said "Lead is bad!!" (So is Cadmium.) True, though the amount is tiny and few people snacked on foto-Rs, it (and vulture capitalism) was one more reason to quit the business. I don't think any are made in the EU or USA/Can, and not by the more reputable Chinese factories. Anybody can mix the stuff in a pig-shed, so there are several sources, of variable quality. (The burner and light applications don't need tight specs.)

Oddly Mouser does have ONE CdS Photoresistor, item number "Adafruit 161". And it has a fantastic user-guide. It is extremely hard to tell by the specs if it will work in your application: resistances and timings are measured at all different light levels between products. At a buck it is cheap enough to try. But for a circuit that needs a dozen working all together, it seems risky.

[seten]

The LEDs work together with the LDRs to make optocouplers. An oscillator makes a voltage wiggle up and down. This lights up the LEDs. They are standing in the middle of a little circle of LDRs. These change resistance and make the phase stages sweep.

This is a very complicated circuit and you are asking very basic questions, the answers are kind of missing the level of your confusion. For example SMD means surface mount: no legs to go through holes in your pcb, designed for robot assembly, may be used by skilled humans with the right tools and a magnifying glass.

You will need to determine light and dark resistance for the LDRs. The PCB doc does not specify. You can ask others who have done this exact circuit, and also search the forum for others who have gone before. Many of these types of phaser/filter ciruits want dark resistance over 1M and light resistance in the order of Ks (1000s of ohms.) I have used Tayda generic LDRs in similar circuits, but always tested them first to pick "teams" of LDRs that behave consistently among themselves.

Best advice: Read through the forum threads on similar phasers. You will find suggestions for LDR values. And learn a ton.

I will do that. Didn't realize just how lost I was so I'm looking for through hole, not SMD correct?

I decided to make a new topic since at this point its quite different from the original subject

[idy]

You could go to Tayda, splurge on baggies of their various cheapies, and then sort.
You could go to Small Bear and just buy 12 that are more "sorted."

"Auditioning" will be hard in this circuit, i.e. putting in sockets and then trying  out various candidates. But not necessary if you can find something that others have gotten good results with.

And crude testing, i.e. putting an ohm meter to the LDR then sticking it in the dark and measuring, then shining light on it and measuring, is not that hard and maybe good enough.