How Hot Is My F5?

[dantwomey]

Originally Posted by AndrewT

Dan,
you are either a wimp or your temperature measurement is wrong.

If you feel it burning in under 5seconds, then I suspect you are over 50°C

Tc is likely to be about 10 to 15C degrees above the sink interface temperature, the hottest part that you cannot get into.

I have no reason to believe that the tool I was using wasn't relatively accurate.

Regards,
Dan

[AndrewT]

I see two reasons
1.) you could hold on for 5seconds.
2.) another Member told you the temp measurement system needs calibrating.

I'll gave you a third reason.

[KatieandDad]

The original Pass amps run at about 78 Degrees I seem to recall.

[dantwomey]

Instantly measure temperatures from a distance without contact. Ideal tool for measuring temperatures in hard to reach or dangerous to access places.


Temperature Range -40° to 380°C (-40° to 716°F)
Accuracy ±2°C or ±2%
Distance To Measurement Spot Ratio 8:1
Response Time 500 mSec
Laser Specifications Laser wave length: 650nm, 2-5 mw
Unit of Measurement Celcius or Fahrenheit
Display Easy to read large LCD display with blue backlight
Battery Details 9V alkaline or NiCd battery

[jacco vermeulen]

Originally Posted by KatieandDad

about 78 Degrees I seem to recall.

Look Ma, it's a boy.

[Daniel(Del)]

What's better, more small ribs with less space between them, or less big ribs with more space in between?

[KatieandDad]

Heatsink design is a balance of factors. However, they are all trying to achieve maximum surface area with enough space for the air to flow, using the least amount of material.

[AndrewT]

wider gaps >=8mm suit passive airflow.
narrower gaps <=5mm suit actively blown airflow.

A flat plate rib will dissipate a certain quantity of heat.
A thin plate will run cooler at the tip.
A thick plate will run hotter at the tip.
A tapered plate will dissipate more heat relative to it's total weight than either of the parallel faced plates.

Similarly a thick backplate will be hotter further away from the emitting device than a thinner backplate.
For optimum use of material a tapered backplate would be better.
But most heatsinks are specified with the whole backplate face at an isothermal temperature at a fixed differential above ambient temperature. This specification does not show tapering of big backplate heatsinks in a comparatively good light. Some heatsinks use tapering and thermal travel distance to great effect to reduce the heatsink mass (and cost) relative to the dissipation capability.

[Nelson Pass]

Originally Posted by dantwomey

I have no reason to believe that the tool I was using wasn't relatively accurate.

True, but I have noticed that I get different readings depending on the
surface and the distance. Dull black surface at 1 cm is my standard.

[dantwomey]

Originally Posted by Nelson Pass

True, but I have noticed that I get different readings depending on the
surface and the distance. Dull black surface at 1 cm is my standard.

If my F5 smokes I'll ask about the warranty.

Regards,
Dan