Do i have to use a thermal paste?

[LM741]

Hey guys...

Have a 2 channel H bridge. Each channel allows a device to draw max. 2A. Needed to to draw 2.3A so i configured it in such a way that i can draw 4A max. obviously only one channel now...
Anyway ...the H bridge gets very hot! the data sheet says it can withstand temperatures up to 132 degrees celcuis , but i still feel the need to attach a heat sink to it... Can i attach the H bridge to the heat sink with a mere screw or do I HAVE to use that speacial thermal paste.?

thanks

John

 

[fargoth]

the heatsink won't be useful without thermal paste...
so i'd say, yes, you have to use thermal paste if you want your heatsink to work.
atleast that's the way it is with CPUs.

 

[LM741]

Thanks - do you honestly think its that imperative. I can't see how using another method of attachment will make the heatsink totally useless...perhaps it won't be as effective without the paste but surely it will still help to a certain extent...

 

[imabug]

the heatsink will still work without the thermal paste. The paste helps the heatsink work better though by improving the contact area between the two surfaces and maximizing heat transfer.

 

[fargoth]

ofcourse a heatsink is still better then nothing, it's a VERY big difference if you use a thermal paste...

my only experience so far with heatsinks is CPUs, but i can tell you that a heatsink with no thermal paste can't cool pentium4 to less then 75C-80C with ambient temp at 23, and that's when it's ideal (well, it won't get much hotter, because it will throttle to save itself).

if you'd use a good thermal paste, you can get it to 30C-35C... so, thermal paste is quite important for a heatsink to be effective.

 

[LM741]

Thanks fargoth and imabug!