From: firstname.lastname@example.org (The little lost angel)
Subject: Re: How to make/solder a circuit fast?
Date: Sat, 28 Sep 2002 02:52:28 GMT
Organization: Yes please, I'm quite disorganized & lost at the moment
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NNTP-Posting-Date: Sat, 28 Sep 2002 02:51:47 +0000 (UTC)
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On Fri, 27 Sep 2002 19:44:39 +0200, Roger Johansson
>If you are not interested in DC and slow fluctuations, as it seems you
>are not, then there is no reason to measure it.
But I am too, the SMPS will be tested with a changing load, if it
works to spec, it should shift up and down within a certain range.
Those shifts should not spike, should not sag suddenly either, nor
should they be too fast. But a slow cyclical fluctuation is not a good
>It is maybe not the fault of the voltmeter, if you use cables suitable
Well, it IS. Because my Fluke measures it correctly. A 5A current
reads out 5.x mV on the Fluke. I get anything from 20mV to 40mV on
cheapo ones. I need like 3~4 of them for current readings, and 4
Flukes would really kill my budget.
>for such low level measurements that voltmeter might work as it
>should. You have to take special precautions to avoid noise from the
>environment when measuring such low voltages at high impedance.
>Keep the cables very short, use coaxial cable, screen off the circuit
>and voltmeter from electrical and magnetic fields, choose a suitable
>input impedance (by putting a resistor over the input terminals)
Erm, I'm measuring the drop over a 1mO shunt for the current. How does
all this apply?