Links to any good SMD capacitor kits?

[EBRAddict]

Anyone have a link to a good SMD 0805 or 1206 capacitor kit on eBay or Aliexpress or Bangood? I'd like to get something in X7R dialectric or better. Most of the eBay kits I saw are Y5R for values > 100pF.

I placed a $8 order on Mouser for $3 of parts last night because I needed a couple values. 

[daleykd]

The only caps I've used for SMD are the ones Tayda sells in 0805.  So, I'm interested in this, also.

[m-Kresol]

I don't think you need anything better than Y5V. The code only states that you can operate them between -30°C (Y) to 85°C (5) and that it has a maximum ±22% capacitance change with temperature. Since pedals run very low currents, the usually won't get hot. most likely they even stay at room temperature, so you don't really have to concern yourself with that factor.
One thing with ceramic caps and their specifications are that the have a way higher temperature range then plastic film or electrolytics will have. However the polarisation of the dielectric layer (the ceramic material), which gives you the permittivity and thus the capacitance is depending on many factors, one of them is temperature. The dielectric is an insulator, which means the higher the temperature, the more conducting it gets (parasitic parallel resistance) and the less of a barrier between the plates is formed, which is how the charge/energy is basically stored. I just had to read up on all of that stuff for work and it's really confusing to say the least to remember which characteristic is depending on which parameter in which way for all the different types of caps.

my point is, the tayda caps are cheap, but are totally ok for what we are doing. If you need a specific capacitance for a filter or something, just measure the caps and use the one that gets closest to your desired value.

[EBRAddict]

The only problem with small Y5V caps is they can suffer from severe voltage derating in addition to temperature derating. For some stuff it doesn't matter but for other things it does. I'd rather not have two sets of caps if one set is going to cost just a little more.

[wgc]

I have used the tayda ones without issue, but you have to buy 50 at a time, and they only offer very limited values. I agree the yv5 work just fine and imho are probably more reliable than the thru hole counterparts (based on more modern processes) though that's complete speculation on my part.

Now I just buy multiples of 10 each from mouser. Filter by value, size, manufacturers, and any other characteristic, and then sort by price. it's usually about 1.5 cents each. Once you find a brand or two that hits all your criteria it becomes a lot easier to find what you want.

[pickdropper]

The only problem with small Y5V caps is they can suffer from severe voltage derating in addition to temperature derating. For some stuff it doesn't matter but for other things it does. I'd rather not have two sets of caps if one set is going to cost just a little more.

This is exactly right.  For most practical purposes, the voltage derating is more of an issue as can the incredibly wide tolerances (some are +80/-20%).

You can get away with Y5V for some applications, but the savings just aren't worth it.  I never use them.


Sent from my iPhone using Tapatalk

[gtr2]

For lower values COGs are a good choice and more stable than XR5/XR7.

[EBRAddict]

Speaking of C0G/NP0 I found this 0805 kit which is a mix of C0G and mostly X7R

http://www.ebay.com/itm/291870111169

I know that over a few nF the C0G get expensive.

[pickdropper]

For lower values COGs are a good choice and more stable than XR5/XR7.

Yep, C0G/NP0 are the best you can get.  They don't fluctuate with voltage and temp like the others.  As you say, they are usually more appropriate for lower values as they get pricey/large for higher values.