Author Topic: resources for standard/common design conditions  (Read 1087 times)

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Offline ratioTopic starter

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resources for standard/common design conditions
« on: January 01, 2019, 05:25:37 pm »
Are there any standard guides for the ambient temp & design temp rise (& other environment conditions?) for like cheap consumer goods, or an automotive accessory? In particular I'm looking for the above for a (one-off DIY, not any kind of production) battery charger that's going to plug into a cigarette lighter, will not be under continuous use but will probably spend a summer day in the car operating from time to time.
 

Offline David Hess

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Re: resources for standard/common design conditions
« Reply #1 on: January 01, 2019, 07:44:01 pm »
One of my first audio power amplifiers failed via thermal runaway when my car was parked in the sun.

Knowing the power dissipation, junction-to-ambient thermal resistance, ambient temperature, and derating curves is enough but of course experience helps.  A good rule of thumb is a maximum 75C case temperature for reliable long term operation.
 

Offline spec

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Re: resources for standard/common design conditions
« Reply #2 on: January 02, 2019, 09:51:15 am »
Are there any standard guides for the ambient temp & design temp rise (& other environment conditions?) for like cheap consumer goods, or an automotive accessory? In particular I'm looking for the above for a (one-off DIY, not any kind of production) battery charger that's going to plug into a cigarette lighter, will not be under continuous use but will probably spend a summer day in the car operating from time to time.
The biggest killer long term is condensing humidity. And if you live by the coast, as I do, salt air.
 


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