Electronics > Beginners
Voltage "divider" after PSU to highten the resolution?
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FriedMule:
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?
beanflying:
First Question - What power supply because it matters a lot is it DC-DC or Linear what Brand and Model etc?
Second Question - What actual resolution and at what current and voltage?

As to a resistive divider for better resolution it then depends on the above factors and how 'stable' that supply is or can be made. They are also not good for regulation of a voltage due to what the unspecified load can and most likely will do to that ratio.
ejeffrey:
The easiest thing would be just to make a post-regulator on the PSU output like a LM317 or any number of more modern linear regulators.  You can adjust the supply voltage so that you avoid dissipating too much power in the linear regulator.

What is actually best depends on what you actually need in terms of current, accuracy, and stability.

Keep in mind that your 10 mV resolution is already 0.1% of your desired 10 V range.  This is not extraordinary, but your garden variety supplies and resistors won't be better than that.  It isn't hard to get 0.1 mV resolution but you won't get that much accuracy or long term stability without some effort.
FriedMule:
Thanks for your reply, I have a Korad KA3305P power supply it is just a standard, not wild unit but normally it is my best unit.
About the change on the PSU I have just found this circuit that looks wary interesting but can it be modded to my needs?
https://www.electroschematics.com/945/01v-50v-power-supply/

My needs is that I would like to make as high a resolution I can without having to call NASA, in other wird a "converter" that not have to reach the power sources 100nV but still a lot better then 1mV. Abut stability and so on, this shall be a "standard" PSU I can have on my bench when I want to play with more precise values.
beanflying:
Very quick check of it's spec shows it as fairly horrid for compared to what you actually want. So you either use it as an initial supply for an external board (easiest) or try and 'fix' it's specs (buy another supply long before this option).

Tied up at present but use your Google FOO to look at accurate variable linear regulators as a stand alone external option to tame the spec.
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