[hpsdr] LPU & Multiple boards on Atlas

[Alfred Green]

On 4/5/2011 3:20 PM, Bruce Beford wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
>
>
> >  Actually, the diodes will dissipate exactly the same heat as resistor(s)
> >  dropping the same voltage at the same current, unless the diodes are
> >  LEDs and thus converting some of the energy into visible light :-)
>   
> >  P=EI
>   
> >  73, Lyle KK7P
>   
> Lyle,
>   
> Thank you for stating clearly, what should have been obvious. B^)
>   
> 73, Bruce, N1RX
>
>
Actually, it's not quite that simple. Obviously the power dissipation 
will be the same in all cases, but that does not mean that the 
temperature rise will be the same.
The thermal characteristics will be different, expressed as degC/W 
depending on the ease of getting the heat into the air. A small diode 
will likely get hotter than a big resistor, but diodes mounted on a nice 
heatsink will outperform the big ceramic resistors. If the goal is to 
reduce the temperature of the circuit then some care needs to be taken 
to find an optimal solution.

73  Alf  NU8I
Scottsdale  AZ  DM43an

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