[TenTec] On Switching Power Supplies

[R. Eric Sluder - W9WLW]

Bob McGraw - K4TAX <RMcGraw at Blomand.net> wrote:
>A few weeks ago during a discussion of switching power supply and
>related noise, I made a comment that the charger for my laptop computer
>did cause noise.  
>
>Subsequently I did find need to replace that charger with a new one. 
>In comparing the two, one makes noise and one does not make noise.  Now
>the interesting observations, both were made in China, both have the
>exact same rating, both have the exact same symbols for certification.
>
>However, what's observed different is this;
>(a) The one that does create noise has the following statement; "(1)
>This device may not cause harmful interference."
>
>(b) The one that does not create noise has the following statement;
>"(1) This device will not cause harmful interference."
>
>Now the way I interpret those two statements is statement (a) "may not"
>can be also presumed to mean that it may or may not cause harmful
>interference where as statement (b) is firm in that it uses the words
>"will not" is much more definitive and restrictive.
>
>Apparently there is something to the different "certifications" as
>earlier identified, and the results of same.  In my case the one marked
>"WILL NOT" does not cause any RFI issues or noise issues with the HF
>reception.
>
>73
>Bob, K4TAX
>
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That is an observation Bob and something I will have to look for on my power supplies at home.

73-Eric
W9WLW
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.