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When to use what type of capacitor? — Parallax Forums

When to use what type of capacitor?

XNORXNOR Posts: 74
edited 2006-08-04 21:26 in General Discussion
Greetings!

I am confused about all the different types of capacitors out there confused.gif
(Mylar, Polyester, Ceramic, Monolithic Multilayer, Electrolytic,
Tantalum, Epoxy Dipped, Metallized, Silver Mica).

When does one use which type? What are the differences?

Thanks for any insight! smile.gif

Comments

  • RDL2004RDL2004 Posts: 2,554
    edited 2006-08-04 15:16
    http://www.uoguelph.ca/~antoon/gadgets/caps/caps.html
  • XNORXNOR Posts: 74
    edited 2006-08-04 21:26
    RDL2004 said...
    http://www.uoguelph.ca/~antoon/gadgets/caps/caps.html

    Thank you! smile.gif
    That's a very informative webpage!
  • rame12rame12 Posts: 3
    Really a Great article about Capacitors, thanks
    But I think SMD capacitors (comes in Stripes) are missing, from the list (in which I am interested)
    I just found a less lengthier version of this (including SMD), if some dont want to get into theoretical detail.
    Types of Capacitors
    Now these two articles are enough to get the decent knowledge about Capacitors.
    Share your knowledge. It’s a way to achieve immortality.
  • evanhevanh Posts: 15,917
    edited 2016-02-16 11:12
    Surface mounts are still from the same list of types, just in a different package. Most common rectangular SMD are either ceramic or tantalum. SMD tantalums are plastic packaged with easy to read label and pad at each end, while ceramics are bare with solder blob encasing each end and often entirely unlabelled because they are so small.

    There is also SMD aluminium electrolytics as well but they look almost identical to their through-hole counterpart, just with pads at the bottom rather than legs.
  • Peter JakackiPeter Jakacki Posts: 10,193
    First post spammer I suspect replying to a 10 year post......... never ceases to amaze me.
  • evanhevanh Posts: 15,917
    edited 2016-02-16 11:42
    Lol. He got me!

    EDIT: Actually, Rame was probably just googling the subject and dredged it up. Or maybe he's trying to direct traffic to his link ...
  • rame12rame12 Posts: 3
    Thanks evanh, for the info. Sir, can you tell me how to solder a SMD ceramic capacitor, into board? I have searched but there are examples for soldering SMD electrolyte cap, but not for ceramic. Need help in writing 5000 words report on SMDs.
  • evanhevanh Posts: 15,917
    SMD's are intended to be used on pick'n'place machines on production lines and get soldered in reflow ovens and the likes.

    Hand soldering of ceramics is a hap-hazard affair with tweezers and a mounted magnifying glass.
  • LeonLeon Posts: 7,620
    edited 2016-02-16 11:49
    It can be done reliably with the right equipment, like the Metcal soldering station I use.
  • Peter JakackiPeter Jakacki Posts: 10,193
    Spamming in the sense not that he wants to sell but he wants help in writing 4,999 words of his assignment :)
  • evanhevanh Posts: 15,917
    Hehe, I'm happy to help on that account.

    Leon,
    Have you got a model name or link to product that you use?
  • Peter JakackiPeter Jakacki Posts: 10,193
    evanh wrote: »
    Hehe, I'm happy to help on that account.

    Leon,
    Have you got a model name or link to product that you use?

    I rarely would ever use an iron for SMD, I always use solder paste and toaster oven, always works, even 0603s are fine. Clean non-magnetic tweezers and room temperature solder paste in a syringe which I have loaded into a gun as it is much easier to dispense. Paste, load, check and realign, oven preheated, pop em in for 4 mins, and gently out to cool. Always works. Also I just run beads across pads for any fine pitch including Prop chips and it actually helps to smudge the Prop chip down as the reflow will suck up the bridging solder unless you panic and take it out before it is fully reflowed (don't). The same with resnets. I've posted plenty of "tips" (or non-tips, just ovens) like this over the years, don't know why anyone thinks it is hard or more complicated than that. You've seen my assembled boards, that's how they're done.
  • LeonLeon Posts: 7,620
    evanh wrote: »
    Hehe, I'm happy to help on that account.

    Leon,
    Have you got a model name or link to product that you use?

    I use a second hand Model 200 power supply (old but cheap) and new handpiece and cartridges. That's the 200, not the SP200, which isn't as good.

    It'll cost about £120. You will also need a handpiece holder and sponges.

    It uses RF heating at 13.56 MHz.

    Latest new equipment costs about £600.
  • rame12rame12 Posts: 3
    Thanks evanh, Peter and Leon
    This really helps to take my research in right direction. Oven soldering is new to me and will definitely fill some pages of my report regarding SMD capacitors :)
    Although I m researching on SMDs but your expert opinions are welcome, on "What is currently going on w.r.t to advancement of SMD capacitors". I just want some input, rest i will search.
  • User NameUser Name Posts: 1,451
    "What is currently going on w.r.t to advancement of SMD capacitors"

    The number of layers that can economically be built into a multilayer ceramic chip capacitor has increased dramatically, leading to 100 uF ceramic chip capacitors...unheard of a few years ago. OTOH, one has to consider carefully the specific dielectric being used. Some ceramic dielectrics have terrible voltage coefficients such that at 100% of rated voltage, the capacitance has dropped to less than 10% of nominal.

    Also, back in the day, the initial metallization layer used in ceramic chip cap construction was a precious metal alloy. Economics has forced the switch to a much cheaper nickel alloy, but that has exacerbated the voltage coefficient problem.

    Bottom line is that nothing is perfect, and there is always research being done on better and cheaper materials and processes.
  • Cluso99Cluso99 Posts: 18,069
    rame12 wrote: »
    Thanks evanh, Peter and Leon
    This really helps to take my research in right direction. Oven soldering is new to me and will definitely fill some pages of my report regarding SMD capacitors :)
    Although I m researching on SMDs but your expert opinions are welcome, on "What is currently going on w.r.t to advancement of SMD capacitors". I just want some input, rest i will search.
    Everything is getting smaller.

    BTW I can hand solder (soldering iron, thin solder, flux pen, tweezers) SMD parts down to 0603 with no trouble at all. The 0402 are getting a little on the too small size, and be careful you don't sneeze.

    But, I now have a nice IR Oven so boards look really good using solder paste and a stencil :)
    Oh, and Jewellers Glasses to see when placing parts (by hand).
  • Heater.Heater. Posts: 21,230
    Yep, even I can manage 0603 with a big clunky old Weller iron and bifocal specs.

    In fact I realized that at that scale building up SMD by hand is quicker and easier than messing with drilling holes in boards and poking wires through.

    I'm not ready to go really small, if I need to mess with solder paste and a reflow oven it all gets to much around here.

    Some decent tweezers for placement and a Jewellers Loupe for inspection are essential.
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