RFI
[Top] [All Lists]

Re: [RFI] Apple and Motorola Wall Chargers

To: rfi@contesting.com
Subject: Re: [RFI] Apple and Motorola Wall Chargers
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Fri, 16 Aug 2013 10:46:57 -0700
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
On 8/16/2013 9:54 AM, Dale wrote:
Actually making your own linear DC power supply to operate a device is not difficult - 
you can find filament transformers, diodes, filter caps, and linear regulator ICs in 
various output voltages, but the problem comes when you need to limit charging current to 
a battery pack.  That can also be true when "recycling" a charger wall wart 
from one device to another.

Yes, the linear supply must be carefully chosen. In general, linear warts are unregulated, so the open circuit voltage is typically 30-40% greater than the rated value. My approach has been to put Power Poles on both ends, insert metering to monitor voltage and current, and try to match the supply to the voltage the device wants to see, generally trying to be within 10-15% of nominal operating voltage.

73, Jim K9YC
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi

<Prev in Thread] Current Thread [Next in Thread>