But you are running audio, not CW power, so your average power is going to be much lower then 120W, general audio design assumes 1/8th maximum power for thermal calculations, so heatsinks can be lot more reasonable.
Thanks for answers.
So 120W of maximum output only dissipates 15W (1/8)?
Like this build here:
http://www.diyaudio.com/forums/chip-amps/79303-chip-amp-photo-gallery-231.html#post3287193
Surely it can not dissipate 120W, or even 60W.
These ones seems to be quite a typical size:
http://www.diyaudio.com/forums/chip-amps/79303-chip-amp-photo-gallery-225.html#post3236454
http://www.diyaudio.com/forums/chip-amps/79303-chip-amp-photo-gallery-227.html#post3259479
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I presume if I have build dozens of these things, I can take a look at a heat sink and tell if it is enough.
Yes, pretty much.
But it includes both the practice, looking at data, and learning the basics.
Pretty of the chip amp datasheets is that they include both graphs and examples to calculate the heatsink C/W number.
Picking the heatsink still means going through data, not pics.
(a couple of heatsink manufacturers have catalogues, of their entire range, that can be downloaded)
Do it often enough, and you'll know a lot of standard heatsinks by type number & C/W range, plus able to tell in a second that the first reply you got was incorrect.
Here are a couple of calculators that will help you.
One is for forced convetion and the other is for natural convection.
Heat Sink Calculator
Heat Sink Calculator
The temp. data is inputed as Kelvin so you will need a celsius to kelvin calculator.
Celsius to Kelvin conversion
or
Celsius to Kelvin (K) degrees conversion
jer
One is for forced convetion and the other is for natural convection.
Heat Sink Calculator
Heat Sink Calculator
The temp. data is inputed as Kelvin so you will need a celsius to kelvin calculator.
Celsius to Kelvin conversion
or
Celsius to Kelvin (K) degrees conversion
jer
Here are a couple of calculators that will help you.
One is for forced convetion and the other is for natural convection.
Heat Sink Calculator
Heat Sink Calculator
The temp. data is inputed as Kelvin so you will need a celsius to kelvin calculator.
Celsius to Kelvin conversion
or
Celsius to Kelvin (K) degrees conversion
jer
Thanks. Very useful.
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