[Elecraft] K3 COOLING VENTS

[David Woolley (E.L)]

Guy Olinger, K2AV wrote:

> an INTERNAL reading.  If 110 F is a fault temperature, then you could
> destroy your K3 by leaving it out in the sun.

That's not a valid comparison.  The sort of temperature that will cause 
rapid damage is 150C for silicon semiconductors, something like 100C for 
electrolytics, 75C for the 1N34 germanium point contact diodes, if it 
uses them.  These temperatures are reached when the equipment is 
operating at full power and the insides of the devices are much hotter 
than the point at which the temperature sensor is placed.  If you leave 
the equipment out in the sun, powered down, and the case temperature 
reaches 45C, the inside of the semiconductor devices will also be at 
45C, well below 150C.  It may be lower, because of thermal inertia.

Typical consumer equipment is designed to tolerate an air temperature of 
45C whilst keeping the core temperature of internal devices well within 
safety limits.  If you actually operate at that sort of temperature, the 
case temperature and internal temperature will be significantly higher.

Leaving electronics exposed to the sun can, of course, result in 
destroying some of the more temperature sensitive components, as case 
temperatures can get a lot higher than 45C.   Having a large thermal 
mass will help protect the equipment as the sun should start to go down 
before the maximum temperature is reached.


-- 
David Woolley
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