1000V power supply - advise needed

[e61_phil]

One could build something like a hammon divider.

I build a easier design with four resistors (Caddock HV ones) which builds, with another resistor and an OPamp, an inverting amplifier. At this point you can change the series configuration of the four resistors to a parallel configuration with a few jumpers. This way you can apply 1/16 of the voltage to calibrate this "divider". Which is 62.5V in this case. With good resistors (low voltage coefficient) and well measured 62.5V you can measure 1kV with low uncertainty this way.

[AlexResch]

8. I don't need "exactly" - whatever that means. I explained in the first post how. Did you actually read it ?

First post does not explain how you going to calibrate 1000V source.

1.  Division and comparing to REF still need calibrated meter to determine exact ratio of your divider , including voltage and temperature coefficients of it, to estimate the total error of 1000V output. Not even mentioning low voltage reference stability and accuracy, which also must be calibrated. So while it all can be done, based on questions and attitude in this post, sounds like in need of own research quite a bit, before any simple advice can help.

2. Why don't you start with something more simple, like 20VDC source first. Once that is done and verified, go up to 100V, and repeat same validation. Then perhaps 200-300V... Then you don't need much advice to build your 1kV box.

1. No, not at all.

2. I already did that.

[AlexResch]

You have the classic "chicken and egg" problem here.

1.  If you build a 1000V source, how do you calibrate it? With your meter?

2. By far the easiest and simplest solution is to send your meter in for calibration on a regular basis to develop historical confidence in its accuracy and drift rate... No, I don't do that either!

3. I don't know what your use case or budget are, but I would consider picking up a used Power Designs 3K10B Precision power supply on eBay. I have several I've picked up over the years for under $100 each. Like all the Power Designs precision supplies, these are amazingly accurate and stable. You can set any voltage between 10 and 3000 to the nearest 0.1v!

It will source up to 3000 volts at 10 mA. That's enough to ruin your day, so you need to be careful with it.

1. Yes, by using any meter as a null detector and precision 1:10 resistors.

2. I would like to keep an eye on some 5-6 digital meters and SIX AVO analog meters. Those are what I mostly use. Sending a meter for calibration is not an option where I am and not a long term and convenient solution either. I don't need that much "precision" but I would like to be confident in a couple of volts around 600V.

3. I am looking for one and for quite a while by now.

[AlexResch]

8. I don't need "exactly" - whatever that means. I explained in the first post how. Did you actually read it ?

First post does not explain how you going to calibrate 1000V source. Division and comparing to REF still need calibrated meter to determine exact ratio of your divider , including voltage and temperature coefficients of it, to estimate the total error of 1000V output. Not even mentioning low voltage reference stability and accuracy, which also must be calibrated. So while it all can be done, based on questions and attitude in this post, sounds like in need of own research quite a bit, before any simple advice can help.

One thing not mentioned is the input impedance of the meter used on the divider. This will have a significant effect on the divider ratio. Also, some meters have switchable impedences depending on the sselected voltage range - this causes havok if you calibrate the divider using a different voltage range to the one you actually use.

Also, the accuracy of the REF102 will mean you will have 0.25V error on you 1kV. Is that acceptable?

I do keep that in mind. The 608 is 10Mo on the 1000V scale. Also, 0.25V on 1KV is 10 times better than what I hope for.

[AlexResch]

... you can go one order of magnitude better, like here:

https://www.rhopointcomponents.com/components/resistors/networks-and-voltage-dividers/caddock-usvd-series

they have 0,01% in ratio. Not so cheap anymore, however.

Wow ! Those are super but I don't see a 10:1 or 20:1 ratio. I could of course use a single ref102 but  am guessing I will be substantially better with 5 or 10 of those in series and a lesser quality divider.

[Wolfgang]

... you can get ones with a 1/100 ratio, so that gives 10V of comparison voltage. Thats almost ideal, for comparison with a reference, or not ?

[AlexResch]

... you can get ones with a 1/100 ratio, so that gives 10V of comparison voltage. Thats almost ideal, for comparison with a reference, or not ?

True.

I thought that given I can not measure the actual voltage of the ref102 I will be better off ( more accurate ) by placing 5 or ten of them series. You are right of course and only one should be sufficient for my needs.