[TenTec] On Switching Power Supplies

[Jim Brown]

On 1/16/2014 6:35 PM, Robert Mcgraw wrote:
> I respectfully disagree with the general assessment regarding switching power supplies.

So do I, at least in principle.There is nothing in the nature of 
switching power supplies that makes it impractical (or even expensive) 
to make them quiet. EMC expert Henry Ott dedicates an entire chapter of 
the latest version of his definitive text on EMC to the design of 
switching power supplies. It's all a matter of good engineering 
practice, everything from controlling rise times to circuit layout to 
proper bonding and even shielding. The designer (and the manufacturer) 
simply have to do it right instead of wrong.

I own at least four switching power supplies that are RF quiet, but I 
own at least a dozen that are not. All of the noisy ones are a box 
labeled "noisy, junk," and have been replaced with linear supplies.

The same can be said of DC to AC inverters, charge regulators for 
batteries, and virtually any other product.

73, Jim K9YC