[sdiy] dual output DC-DC converters

[John Luciani]

On 4/21/06, Nicholas Gregorich <nicksdsu at mac.com> wrote:

> What is the best way to measure the noise levels of these supplies?  I've tried
> unsuccessully with a scope comparing the PT and bench supply.  I see the same
> environment noise on both supplies.

To measure noise I usually place a coax jack on my vector board or
PCB. The jacks I use are made my Johnson and the part numbers are
129-0701-301 (horizontal) and 129-0701-201(vertical). Both are
available from Digikey. This will allow you to do your noise
measurements without the ground lead of your probe. You may want to
verify the size of your probe sleeve before you order. I seem to
recall Tek probes coming in multiple sizes. Always seemed to be the
wrong size for the adapter on my board ;-)

On boards where I could not place an RF jack I try to place two Vector
pins (K24A) spaced so that the ground sleeve of the probe would rest
against one and the tip would rest against the other.

There is good application note about noise and EMC at

http://vicor.mondosearch.com/cgi-bin/MsmGo.exe?grab_id=0&page_id=158&query=noise%20measurement

(* jcl *)

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