Along this line - can anyone tell me, a electronics hobbyist, how to do
calculations as far as how big a heatsink is needed for a SSR or triac?

For instance I found the power dissipation curves for a triac.  From that
and my system knowledge I know how many watts of power need to be
dissipated.  What I don't understand is what the C/W numbers are used for.

In one application I am kicking around in my head I am thinking of just
bolting an SSR to a big hunk of steel.  What I didn't know was how to
figure out if that would be sufficient or if I should use the piece of
scrap aluminum I have here instead.  I'm sure I could post it here and have
half the people yell at me for being stupid and saying it will burn up and
the other half saying no problem - but I'd like to be able to do the math
myself and have some level of confidence that it will work.

Please be gentle as I'm a newbie in this area.  Even a couple of good
references to books or web sites would be great.

Thanks,
Dan


>Yes, it will burn up and fail "on" unless you put a good-sized heatsink
>on it. The 40A is sort of a theoretical maximum, but it should be okay
>at 10A with an adequate HS. You need to keep the metal base plate of
>the unit as cool as practical, pick the number of degrees C/W from the
>maximum temperature spec and the maximum ambient, and try to do better.

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