MOTM

On 5/30/08, Jeff Laity put forth:
>Thank you. Part numbers are very helpful, especially for caps and
>semiconductors. (hint, hint)

Yes :)

>I think poly = polypropylene.

Afaik, the term "poly" when talking about capacitors refers to
polyester, meaning polyethylene terephthalate.

To a polymer chemist, polycarbonate (which is also used in
capacitors) and many other polymers are also polyesters.  To most
people, "polyester" means a polymer of one specific ester,
polyethylene terephthalate.  There are also different types of
polyethylene.  Mylar is a trade name of polyethylene terephthalate
film.

Polypropylene is not a type of polyester, because propylene is
an alkene, not an ester.  Neither is polystyrene, because ethyl
benzene isn't an ester either.  Both are used a dielectrics.

>They're dark red like kidney beans.

Yes, but they make terrible chile.

>I was trying to avoid using Digikey but I'll go ahead and order a
>bunch of components for my next three projects.

Jameco sells Panasonic ECQ-V.  They also sell OP275, twisted pair
wire, hook-up wire, and many other parts used in MOTM, at very
competitive prices.


>>From: "Paul Schreiber"
>><<mailto:pschreiber@...>pschreiber@...>
>>
>>Poly as in mylar? ACK (shudder!)

Sorry, I'm a bit confused by the "ACK (shudder!)" comment.  I know
that polyester is largely inadequate for many applications such as
VCO's, sample and hold, timing circuits, etc. due to its high DA and
poor temperature stability.   However, it seems that MOTM often uses
polyester caps for filters, coupling, etc.  The Panasonic ECQV are
listed as coated "metallized polyethylene terephthalate"  and the AVX
BF/BQ  "yellow box" caps are listed as "metalized polyester".