[mythtv-users] HDHomeRun Prime iPad app
Mike Perkins
mikep at randomtraveller.org.uk
Sat Aug 20 17:36:15 UTC 2011
On 20/08/11 18:16, James Van Vleet wrote:
> On Fri, Aug 19, 2011 at 5:20 PM, Raymond Wagner<raymond at wagnerrp.com>wrote:
>
>>> it makes sense to remove as much unnecessary weight as possible. No,
>>> this is just some marketing weenie telling the engineers to use external
>>> supplies because a slightly smaller unit will be more appealing and sell
>>> more.
>>
>
> I did a brief stint in the appliance hardware thing and based on
> that experience I don't believe this is the case. The real reason I
> discovered is that it is *much* less expensive and painful from a UL (or
> other equivalent) standpoint to purchase an already approved UL external
> power supply and feed low voltage into your device. Doing this can make
> both the initial UL cert and the updates as the device changes a snap.
>
> Otherwise you are feeding 110-220 volts into your device and UL is MUCH more
> interested in those.
>
> Also there is the whole getting that heat out of our device thing, but in
> our case taking a lot of the UL headaches out of the system was the big win.
>
I'd sooner have the heat generated inside the box where the designed-in fan can
correctly dispose of it than have it generated by a lump of plastic sitting on
the furniture or on the carpet. (A typical 12v supply for a pico-PSU is a brick,
not a wall-wart.) Still, I agree with your reasoning as to why they do such things.
--
Mike Perkins
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