I can’t find the answer to my question on Google so maybe you guys can help?
I am trying to source a substitution part for the following component as there is no way that I am paying $62 for one resistor:
https://www.mouser.com/ProductDetail/667-ERJ-3GEYJ335V
I found this one, but the series code is different. Virtually everything else matches. The one in the link above is: ERJ-xGE
The component I found to replace it is this, but the series code is: ERJ-U
https://www.mouser.com/ProductDetail/Panasonic/ERJ-U03J335V?qs=sGAEpiMZZMu61qfTUdNhGyeJ7bfa48HNpMdff9naw2Q%3D
How important is it that the series codes match? Will this replacement one that I have found work?
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What’s the circuit? Resistors are resistors, and their main property is the nominal resistance. All other things depend on where the resistor is used:
- Tolerance (how important is the exact resistance value in the given circuit?).
- Footprint (if you have an existing PCB).
- Power rating (if exposed to enough voltage, and the resistance is low enough, it needs to be able to handle the current going through it)
- Temperature coefficient (if used in temperature-sensitive precision circuits, where the resistance value must change in the same way as other component values elsewhere in the circuit)
- Voltage rating (if using in high-voltage circuits)
- Packaging (if you’re using a machine to populate your PCBs)
For most cases, the first and maybe the second additional property is all that matters.
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It’s the Mutated Rings PCB. I only have kiCad files but can’t open them to get the schematic.
EDIT: found the files online
EDIT: It’s R50
Located here where I placed the green arrow.
https://modularaddict.com/mutated-rings-pcb
[I put on my moderator hat and removed the other pages; interested parties can get them from the source – @fredrik]
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Yeah, I just dug up the schematics here and it’s a pull up for the brightness FM CV input (aka V/OCT) to keep it centered if nothing’s plugged in. Absolutely no special requirements at all; anything from a few hundred ks upwards should work there afaict (or lower than that, even, since it’s disconnected if anything’s plugged in) Nah, the more off you are the more you need to compensate with the manual controls, so might as well use a 3.3M (see below). But any 3.3M will work.
(ok going too low may put unnecessary load on the voltage reference maybe)
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I love how you can just look at that and it makes sense to you. It’s like a super power 
Thank you!
Can I ask one other question? On the BOM for the Mutated Plaits PCB , Mouser has a capacitor listed as “Not recommended for New Designs” Should I find a replacement or since this PCB was created a couple of years ago is it fine? It was this one here:
81-GRM185C1H200JA01J
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Nah, that’s fine, unless perhaps if you plan to build more than 6,200 of them The “not recommended” usually just means that the manufacturer has a newer model, not that there’s anything wrong with the old one.
For this one, the nominal value and the C0G/NP0 dielectric type are what matters; that code means it’s a “class 1” ceramic capacitor that’s very stable also if the temperature changes (cf the “Temperature coefficient” I mentioned earlier). If the BOM explicitly specifies a C0G/NP0, it usually does so for a reason, so better use the right type.
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Okay. Thanks. There’s a few things that are listed as “obsolete” but don’t offer a replacement recommendation. I’m doing a search and filtering down each item until I can’t get any further and then just choosing the cheapest from those. I assume that’s the only way to really do it. I do always make sure the type is exactly the same, voltage, temp, size, etc…
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The quantity discount structure is… interesting.
If you won’t pay $62 for one, how about $70 for 10,000?
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Why even list that as an option!?!?!!?
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I know! I saw that too…haha. I like how 100 is $4,474 and 10k is $70. Completely bass-akwards.
It’s actually the normal connection for the FM_CV (frequency modulation control voltage?) which the circuit seems to want to default near 1.65V (half the 3.3V supply voltage).
So I would recommend sticking with a 1% 3.3M resistor to avoid offsetting the frequency.
But any 1% 3.3M resistor will do, no need for a $65 one.
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That has to be an error, given the $70 for 10000, $37.79 for 5000 and $44.74 for 100 sounds about right.
Don’t know how they got to the $61.54 unit price though.
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Oops, looked at the label at the connector, not the output 
. And the reference is −10 V, not 1.0 V. There’s a manual knob also on this input afaict, so you can still compensate for the wrong value, but otoh it’s not like there’s a shortage of 3.3M resistors (it’s an E6 value after all)…
(the expensive one was ±5% btw)
I have a general question about SMD resistors for you guys. For through hole I was able to buy a bunch of metal film 1/4w resistors of varying resistances so that I have stock as it’s cheaper to buy more than 5 most of the time. @fredrik explained that tolerance and the footprint are the things to pay attention to, for the most part. That being said, could I get away with buying a bunch of 1/10W resistors of varying resistances in 0603 or 0402 sizes? Or is that a waste of money and should I just buy only the quantity on the BOMs since the resistors may vary and be more unique to certain designs?
It’s up to you, but a pragmatic approach is to round up when you order things (if not else because you’ll drop or misplace things ), and round up more for common components. Or you can go crazy completionist and stock up, and many years down the line your kids will find your stash and be amazed over how weird components looked back in 2020.
Here’s a couple of articles on this topic:
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It’s funny because I actually read those articles before I placed my first Tayda order in January…haha.
I’ll just stick to my rounding up to the nearest 10th philosophy when it comes to resistors.
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very good read . I have been wondering [ to lazy to actually write down numbers and figure it out ] about buying the big resistor mutli packs . I have picked up a couple and it has been nice to have for that odd value that some designs call out for , but there will be a lot of values i never use [ well maybe some day i will try design lol ] the same with ceramic caps . but it doesn’t take long to see which values you do use a lot of and for those it may not be a money thing but a convenience to have them at hand in bulk .
one thing that has influenced my bulk buys is that I build a lot of MFOS stuff and Ray used a lot of the same components on different modules , most likely so he was able to use what he had on hand .
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I bought a bag of two hundred 100k resistors once, and since starting to build modules I’ve been chewing through it — another 9 yesterday. Can’t remember what I paid but I’m sure it was one of my better minor buying decisions.
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When I buy them locally, I get 100 for $5. I started out with a couple of assortments and now I just buy whichever values I run out of. Sounds like Sam is doing the same, except he buys 1000 at a time 
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