If all wall warts have the same plug but deliver different voltages, what havoc
will occur among consumers who grab the wrong wall wart and burn up (or
undercharge) one of their devices? Could all devices have a voltage regulator
circuit in them? Would these regulators cause RFI?
73, Ed, AA9OZ
-----Original Message-----
From: "Dale Svetanoff" [svetanoff@earthlink.net]
Date: 01/05/2011 11:35 AM
To: "Jim Brown" <jim@audiosystemsgroup.com>, rfi@contesting.com
Subject: Re: [RFI] Cell Phone Charger Duracell made in China
At long last, the IEEE Standards Association, of which I am a member, is in
the process of convening a standards working group to attempt
standardization of power supply connectors for electronic devices. The
stated reason was to reduce the vast number of incompatable connection
iinterfaces in use, thereby reducing the need for multiple power sources or
chargers among those have the same power output, but non-mating interface
connectors. To me, I find it hard to believe that this hasn't come to pass
years ago, but I suspect that a major reason is that many manufacturers
love proprietary connectors so that consumers are forced to buy specific
power supplies and chargers. I'll be watching to see if the working group
actually gets off the ground and if so, which manufacturers actually
participate.
One thing: I seriously doubt that there will be any improvement in the
performance of switchmode wall warts from this action. Only now, if this
work goes forward, one noisy wall wart can mess up operation with even more
devices!
73, Dale
WA9ENA
> [Original Message]
> From: Jim Brown <jim@audiosystemsgroup.com>
> To: <rfi@contesting.com>
> Date: 1/4/2011 1:03:46
> Subject: Re: [RFI] Cell Phone Charger Duracell made in China
>
> On 1/4/2011 8:46 AM, Dale Svetanoff wrote:
> > If ther unit is that "dirty", I have to wonder if this is one of those
> > instances in which parts (used for EMI control) are being omitted from
the
> > production version of the item.
>
> One of the most problematic elements of chargers like this is that the
> connector that connects to the cell phone is non-standard and the
> charging voltage and current are unknown. This makes it a bit of a
> challenge to home brew something to replace it.
>
> I'm seeing an increasing number of chargers and/or power supplies like
> this, shipped with everything from cell phones to UHF/VHF mast-mounted
> preamps! Have not yet tested them for RF trash, but it's on my to do
list.
>
> 73, Jim K9YC
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