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Using a DMM to measure output isolation/crosstalk

I'm making some PCB's that have some DC to DC converters on them with three 5 Volt converters, one 15 volt converter, and a converter with +/- 12 volt s DC. On the PCB the output pins are in a connector that are fairly close to each other. I want to make sure that there is isolation between all the supply outputs. The +/-12 supply shares the same common between them, but I"ll hav e to check to make sure that common isn't shorted to the +15volts for examp le. These components were from

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I need to be able to test about 20 of these boards.

My idea is I'm already doing line/load regulation on these supplies so I ha ve the DMM in VDC mode. After the line/load regulation test, I leave the po sitive lead of the DMM on the first supply, then I move the negative lead t o each supply. I should measure the supply voltage output of the first supp ly, then zero VDC moving the negative lead to each supply.

Then I move on to the next supply leave the positive on that supply, and te st all the negative pins making sure they are 0 VDC.

My question is, should I also do this for the positive pins for each supply ?

Example: Now leave the Negative lead on the supply, and move the Positive l ead to each supply making sure it is also 0VDC, or would this step be redun dant?

Reply to
Chuoiujk
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? 2016?8?8???? UTC+

8??4:45:31?Chuoiujk???

ee 5 Volt converters, one 15 volt converter, and a converter with +/- 12 vo lts DC.

ch other. I want to make sure that there is isolation between all the suppl y outputs. The +/-12 supply shares the same common between them, but I"ll h ave to check to make sure that common isn't shorted to the +15volts for exa mple. These components were from

formatting link
.

have the DMM in VDC mode. After the line/load regulation test, I leave the positive lead of the DMM on the first supply, then I move the negative lead to each supply. I should measure the supply voltage output of the first su pply, then zero VDC moving the negative lead to each supply.

test all the negative pins making sure they are 0 VDC.

ly?

lead to each supply making sure it is also 0VDC, or would this step be red undant?

[image]
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=844/image]
Reply to
Chuoiujk

? 2016?8?8???? UTC+

8??4:47:16?Chuoiujk???

C+8??4:45:31?Chuoiujk???

hree 5 Volt converters, one 15 volt converter, and a converter with +/- 12 volts DC.

each other. I want to make sure that there is isolation between all the sup ply outputs. The +/-12 supply shares the same common between them, but I"ll have to check to make sure that common isn't shorted to the +15volts for e xample. These components were from

formatting link
.

I have the DMM in VDC mode. After the line/load regulation test, I leave th e positive lead of the DMM on the first supply, then I move the negative le ad to each supply. I should measure the supply voltage output of the first supply, then zero VDC moving the negative lead to each supply.

d test all the negative pins making sure they are 0 VDC.

pply?

ve lead to each supply making sure it is also 0VDC, or would this step be r edundant?

ID=844/image] Here is the image. I hope this could help you understand my question.

Reply to
Chuoiujk

We test multi-channel isolated things by making a string-of-resistors voltage divider powered by some DC. Each tap on the string goes to one channel. We measure all those tap voltages to demonstrate isolation to ground and between channels.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com
Reply to
John Larkin

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