Jan,
The difference between G-10 and FR-4 is minimal and has to do with
flammability. G-10 is not self extinguishing in a vertical flame test
while FR-4 is. A strip of laminate is held vertically in a flame
until it ignites. When the source of ignition (flame) is removed the
G-10 will keep burning and the FR-4 will self extinguish. Check out
the Underwriter Laboratories test specifications. If I remember
correctly, this test is called the "UL 796 Vertical Flame Test".
I believe there are some slight differences in the velocity factor at
very high frequencies between the two types. This may also depend on
the specific vendor. G-10 laminate always has a white or grayish
water mark and FR-4 always has a red water mark. G-10 laminate is
kind of rare these days with most boards being made from FR-4. Hope
this information helps.
Tom
The difference between G-10 and FR-4 is minimal and has to do with
flammability. G-10 is not self extinguishing in a vertical flame test
while FR-4 is. A strip of laminate is held vertically in a flame
until it ignites. When the source of ignition (flame) is removed the
G-10 will keep burning and the FR-4 will self extinguish. Check out
the Underwriter Laboratories test specifications. If I remember
correctly, this test is called the "UL 796 Vertical Flame Test".
I believe there are some slight differences in the velocity factor at
very high frequencies between the two types. This may also depend on
the specific vendor. G-10 laminate always has a white or grayish
water mark and FR-4 always has a red water mark. G-10 laminate is
kind of rare these days with most boards being made from FR-4. Hope
this information helps.
Tom
--- In Homebrew_PCBs@yahoogroups.com, JanRwl@A... wrote:
> Can someone who know please explain the main difference between
(apparently
> older) G-10 and (apparently currently-used) FR-4? Thanks.
Jan Rowland
>
>
> [Non-text portions of this message have been removed]