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Voltage "divider" after PSU to highten the resolution?
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FriedMule:
Calvin yes they du fit better but it looks to me as if only the M8851 do have 0.1mV adjustable resolution.
Am I reading wrong?
rstofer:
The easiest way to handle these kinds of experiments is to pick a voltage that is 'about right' and measure it with a DMM.  Get as close as you can to the desired value.  Do the experiment while measuring everything with DMMs, preferably simultaneously.  All meters should be calibrated annually - and we KNOW that won't happen!  So, all of this supposed accuracy isn't traceable - it is pretty much meaningless but we carry on...

We pick another voltage nearby and measure again.  We rinse and repeat until we have enough points to make a graph.

It's a matter of choosing the tool.  A high resolution power supply is pricey and unless it is of the 4 lead Kelvin type of connection, the power leads voltage drop won't be included in the readings.  A DMM, OTOH, measures right at the load.  It doesn't care about voltage drops in the leads.  And it can measure voltage and current.  Some can do it simultaneously but they too are high $ items.  Current measurements change the associated voltage measurement due to voltage drop in the meter's shunt resistor.  So, measure the voltage after the current measurement.

High resolution DMMs are cheaper than high resolution PSs.  That's good because you need two or three of them.


FriedMule:
LOL yes, we all hope and believe that we are reaching precision even when all our meters do not agree completely.
What I hope is not to measure by what value a component do what, but more find out what it does, to do that, I'd need small steps, even if these steps may not be counted precisely. Not much luck in water your plants, if you only have a fire hose! :-)
Calvin:
Hi,

You might ask yourself, how come they state such high resolution, but ripple figure is more than a decade higher?
Ands still You haven´t told us why You think You ´need´ that high resolution in first place

regards
Calvin
tggzzz:

--- Quote from: FriedMule on February 16, 2019, 03:30:02 am ---I have a standard power supply with 10mV resolution and max 30V, what I need is a far better resolution.
My first thought was just to put two resistors on the output as a voltage divider, i.e. 1,000:1 but that would also reduce max voltage to 0.03V and that's fare less then the 10V I want and is wary inefficient!!

Is there an other way to increase the resolution by adding some circuit between the PSU and DUT?

--- End quote ---

You need to state why you need those features - the best answer will vary depending on your requirements.

I rather like my Power Designs 2020 PSU: 0-20V in 1mV steps, plus a pot for tweaking down to 10uV. Low noise too, since the internal reference is an LM399 :)

Good luck finding one, though. I'm not selling mine :)
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