[RFI] Apple and Motorola Wall Chargers

[Jim Brown]

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