Ceramic capacitor question

From: Peter C. Wallace <pcw_at_mesanet.com>
Date: Tue Jan 8 10:55:11 2002

On Tue, 8 Jan 2002, Pat Finnegan wrote:

>
>
> On Tue, 8 Jan 2002, Kent Borg wrote:
>
> > The voltage is something you merely need to meet, exceeding it is OK.
> > Assuming everything else matches, I'd go with the "104Z at 50V".
> >
> >
> > -kb
> >
>
> Quick lesson in capacitor markings:
>
> The number '104' indicates the capacitance, with the first two digits '10'
> being the 'mantissa' or value and the last digit being the exponent.
> Ceramic (and other caps marked like this) are all rated in pF or 10^-9 F.
> Therefore, this cap is 10x10^4pF or 100,000pF, or 0.10uF. The other
> capacitor, 224Z, would be 0.22uF (22x10^4pF). The 'Z' specifies a
> temperature range (IIRC) or something else that is not terribly important
> for most applications.
>
> -- Pat
>
>

A few minor additions


pf = 10^-12 F (10 ^-9 uF)

Z probably stands for Z5U - the particular dielectric used. Z5U is a very
temperature unstable material but with a high dielectric constant, often
used for bypasses. Its so unstable that if you make an audio oscillator
with a Z5U capacitor determining the frequency, you can hear the pitch
change by just warming the capacitor with your finger...

X7R is a newer, somewhat more temperature stable material used for
bypasses.

Peter Wallace
Received on Tue Jan 08 2002 - 10:55:11 GMT