Ceramic Capacitor Question - Page 1
Forum section: electronics / beginners

author: SteveGB
author_rank: Contributor
timestamp: February 25, 2023, 08:04:49 pm
content: Trying to build up a few components for electronics projects (Arduino, future DIY projects and playing around with spare lithium batteries/LEDs)So far have bought a selection of capacitors ; electrolytics, and more recently ceramic caps. Ceramics are 50v 10pF to 100nF in a selection box.I'm looking to extend the ceramic range to 0.1uF to 10uF. Firstly, is this range a good choice/potentially useful? Secondly, I notice there are both light brown 50v versions and then 1KV blue versions. Its not clear if there's any particular reason not to go for the higher voltage selection. Is there any reason I should not?Any thoughts from those with greater experience?

author: SteveGB
author_rank: Contributor
timestamp: February 26, 2023, 04:03:13 pm
content: Wonder if anyone can offer advice?

author: Nominal Animal
author_rank: Super Contributor
timestamp: February 26, 2023, 05:40:42 pm
content: Quote from: SteveGB on February 25, 2023, 08:04:49 pmThis is the range I use for my supply bypass needs (ie. between VCC and GND close to a chip) in my own projects. Lots of 0.1µF = 100nF and 1µF bypass caps. Small for close range, large for when supply is further away. (I used to do the cargo-cult "both" when I didn't know better.)1, 4.7, 6.8, and 10 µF are also commonly used with some of the switchmode circuits I've used (straight off datasheets, and TI Webench).I can imagine needing some of the lower range (that you already have) like 10nF in button debouncing circuits, but I prefer to do that in software, so I rarely if ever need any of the ones you already have.(I do need very specific 8/10/12/18 pF (C0G?) caps to use with 24 MHz crystals; 24 MHz because I prefer my projects to have USB 2.0 connectivity.)I'm a pure hobbyist though, connecting sensors and my own MCU projects to Linux SBCs, typically; not an EE.

author: JohanH
author_rank: Frequent Contributor
timestamp: February 26, 2023, 06:36:40 pm
content: You don't need the 1 kV capacitors except for special high voltage stuff. If you stick to Arduino and low voltage, 50 V is fine.

author: mariush
author_rank: Super Contributor
timestamp: February 26, 2023, 06:44:33 pm
content: I would suggest buying some surface mount ceramic capacitors in the 10nF , 100nF (0.1uF) , 470nF (0.47), 1uF , 2.2uF, 10uF and maybe a few 22uF 10v/16v rated onesLook for category X7R or X5R for 1uF or higher, if available look for C0G or NP0 (better than X7R and X5R) for under 1uFFor voltage rating, you want it to be much higher than the voltage you're gonna have ... for example, if you think you're gonna use a 10uF with an arduino or microcontroller running on 5v, you'd want the ceramic capacitor to be rated for at least 25v.For decoupling (0.01uF, 0.1uF) lower ratings like 10v or 16v would be fine, especially if you go for smaller capacitor sizes like 0603.For sizes, 0603 are probably very common, 0402 should be even more common and cheaper but they're small and hard to use by a beginner.0805 is almost as wide as 0.1" spacing, so you can easily solder a couple wires to the ends and make a through hole capacitor out of it. They're also quite easy to solder.0603 capacitors can often be soldered in footprints for 0805 capacitors.ex :0.1uF 50v 0805 get 50 for less than 2$ -https://www.digikey.com/en/products/detail/kyocera-avx/08055C104KAT2A/5635050603 is cheaper, get 100 for 1.2$ or 500 for 4.3$ -https://www.digikey.com/en/products/detail/samsung-electro-mechanics/CL10B104KB8NNNC/38866581uF 50v 0805 less than 4$ for 50https://www.digikey.com/en/products/detail/taiyo-yuden/UMK212B7105KG-T/26489870603 is

author: TimFox
author_rank: Super Contributor
timestamp: February 26, 2023, 07:01:49 pm
content: C0G/NP0 capacitors are far better for ESR, dielectric absorption, temperature co-efficient, and voltage co-efficient, which are all important for signal purposes.When you get to power-supply applications, X7R and X5R are a decent compromise for higher capacitance applications, where you are not passing a signal through the device.You will find, however, that C0G SMT capacitors get larger than most people want, somewhere above 100 nF.Leaded "MLCC" (multi-layer ceramic capacitors) are usually a SMT ("chip") capacitor with leads soldered to the pads and encased in plastic, so they have the same properties as the SMT devices (except for longer leads).Old-fashioned "disc ceramic" capacitors are a single layer of dielectric with electrodes on each side, and are available in higher voltages but lower capacitance than MLCCs.Except for C0G/NP0, you must check the data sheet to find out how much capacitance you really have with voltage applied to the unit: all the other ceramics have a substantial negative voltage co-efficient of capacitance.

author: Vovk_Z
author_rank: Super Contributor
timestamp: February 26, 2023, 07:15:31 pm
content: Quote from: SteveGB on February 25, 2023, 08:04:49 pmBlue throughole 1kV ceramic caps are made of Y5V ceramics, so I won't use them until there is a strong need to use exactly this type.

author: shapirus
author_rank: Super Contributor
timestamp: February 26, 2023, 07:25:12 pm
content: Quote from: mariush on February 26, 2023, 06:44:33 pmThis is a good idea, even if you use only breadboards for soldering: SMT caps (0805 and bigger -- I haven't tried anything smaller yet) are easy to fit and solder there, they are good at saving board space and, in case of bypass capacitors, can be placed closer to the IC pins than THT caps.Same goes for SMT resistors.

author: Siwastaja
author_rank: Super Contributor
timestamp: February 26, 2023, 07:32:26 pm
content: You don't need many different values for power bypassing. E.g., you don't need 10nF cap here, 100nF there and 1uF somewhere else (especially not in parallel, ignore that advice). You can just always use 1uF, even if datasheet circuit shows 100nF (in 99% of cases, that is). You can also parallel capacitors. Need 2.2uF? Just parallel two 1uF parts.For example, you could just stock 1uF 0603 16V, 4.7uF 0805 16V and 1uF 1210 100V and solve 99% of your power bypassing needs with these parts.Some 6.8pF, 12pF, 18pF, 22pF come handy with different types of crystals; can also double as signal filtering. Add some 220pF and 1nF for more options in filtering.If you plan on building some analog filter stuff, then you are going to need many C0G/NP0 type capacitors with many values. But you can just order these when working on a project. When you order the opamps and stuff, anyway. Just make it a habit that if your simulations/example circuits shows you need a 50pF capacitor, why not buy a few sizes around this value, like 22, 33, 47, 68, 100 pF. These cost some cents each, after all.Generally, just work on projects and always order a few excess parts, you start building a stock of components that have "evolutionary" process of choice (after all, you have used them once - chances are high you need them again), usually better than what you get if you try to sit down and guess what you need.

author: SteveGB
author_rank: Contributor
timestamp: February 26, 2023, 07:42:11 pm
content: All sounds like good advice - many thanks all!

author: shapirus
author_rank: Super Contributor
timestamp: February 26, 2023, 07:55:08 pm
content: Quote from: Siwastaja on February 26, 2023, 07:32:26 pmThis is one of the most valuable advices given here

author: SteveGB
author_rank: Contributor
timestamp: February 28, 2023, 11:53:14 am
content: Appreciate the advice and explanation Tim

author: SteveGB
author_rank: Contributor
timestamp: February 28, 2023, 11:56:11 am
content: Just as a matter of understanding, is there any reason that a 1Kv ceramic cap couldn't be used in place of a say 16 or 25v cap? Would there be the same effective performance? Would they present greater ESR? Would there be a greater danger from shock? etc

author: Siwastaja
author_rank: Super Contributor
timestamp: February 28, 2023, 12:04:05 pm
content: No particular reason. ESR is fine. It's going to be in physically larger package, which means larger ESL (inductance - you can't get them as close to power pins), though, but if it's still just some 1206 package that's not catastrophic increase (except for maybe the most demanding ICs).But if you have ICs with a lot of pins (and possibly many power pins), using smaller packages makes your life so much easier. And wiring large parts far away from the chip can actually cause power quality issues. That's why I'd suggest 0402 package size for IC power bypassing, or if you have real trouble working with it (which does not go away by practicing a few times), then maybe 0603.But you need 1-2kV MLCCs so rarely (the only thing that comes to mind is Ethernet) that I would not bother buying them in advance.

author: fourfathom
author_rank: Super Contributor
timestamp: February 28, 2023, 04:25:55 pm
content: Another nice thing about surface-mount capacitors is that they're so damn cheap. Look at LCSC prices, for example: a 0603 package 0.1uF 10% 50V X7R capacitor (YAEGO) costs $1.90 for a thousand of them. Or get a reel of 4000 for $6.40 -- that ought to last you for a while! Or get 50 of the 100pF 2% C0G 100V 0603 caps (YAEGO) for 66 cents. Resistors are even cheaper.Shipping costs are not trivial, but when I was building up my own hobby-inventory I combined a good number of caps and resistors into one order and even with shipping it was a great way to stock up. I try to keep a good range on hand, usually values from the 20% series (2% or 5% tolerance). I do a lot of RF work, so I need values in the pF range, but for regular coupling and bypass applications you might get by with needing only a few capacitor values.For hand-breadboarding 0805 size parts are easier to work with, but 0603 are still fairly manageable. I also carry a very few 1206 and 1210 resistors, for their higher power dissipation.

author: Nominal Animal
author_rank: Super Contributor
timestamp: February 28, 2023, 06:12:13 pm
content: Quote from: Siwastaja on February 28, 2023, 12:04:05 pmI haven't needed any of those, because all my Ethernet projects use MagJacks with both the magnetics and the 1-2kV 1000pF=1nF cap built-in within the connector housing itself. Things like the Teensy Ethernet Kit do seem to include an additional 100nF X7R 50V one, though.I don't think it makes sense to really try to minimize the BOM cost before you're making lots of 50 of more, and have a company to do B2B purchases for the components.I do occasionally lust after those nice 0805 and 0603 SMD capacitor (C0G, NP0, X7R) and resistor "books", but it is not because I actually need the values: it is just because"it would besonice to have them if I ever need a specific one". Tool hoarder mentality, not real need!There is a lot even in simple hobbyist-level two-sided SMD board design (inthe kind of projects I've 'designed'– i.e. copied from datasheets and application notes, then trying to design a board following the guidelines shown in them) that could be made much better with advice from experienced board designers.For example, if you have a say digital isolator that benefits from two 100nF (C0G/NP0/X7R) supply bypass caps, one on each side of the isolation barrier, with signals in the 0-24 Mbit/s or Mbaud range, say, on a two-layer board: What is the actual difference between placing the caps on the same side of the board, vs. on the opposite side of the board compared to the IC? I will be soldering these by hand (so 0805, or 0603 at minimum), so I can make the conductor length to the silicon shorter if I put them on the opposite side of the board from the IC.I for one highly respect the help all the experienced members here are willing to give us hobbyists!

author: Vovk_Z
author_rank: Super Contributor
timestamp: February 28, 2023, 09:12:53 pm
content: Quote from: SteveGB on February 28, 2023, 11:56:11 amConsider price and temperature properties (Y5V, X7R. etc).