I would like to built a circut with some LEDs that they will light up for every lets say 250v. So for example if i want to charge a 2kv capacitor, 8 leds will be light up each one for every 250v. Any thoughts ?

Thanks in advance

 

An LED bar graph voltmeter circuit with suitable resistive voltage divider on the front.
have a look at this article. Fig 6 is a start.
https://www.nutsvolts.com/magazine/article/led-graph-circuits

 

Dendad than you for your reply. I was thinking also to make a 1/100 voltage divider since i got 2 of these voltmeters so when for example it displays 12v it would be actually 1,2kv. I would like to mention that i use 4 caps in series and they got some 10MΩ bleeder resistors each. Any idea the circuit i must built to take the above indication form that small voltmeter ?

 

You will need to find out what the sensitivity is, that is, how much current the meter draws to read 120 and then calculate the resistance needed to drop the aproprite voltage. Use multiple resistors to spread the voltage across them to keep it safer. For a start, feed 24V into the meter, then add series resistance until it reads 12V. Measure the resistor and that will tell you what the input resistance of the meter is.
Working from that, you can start to calculate what the series resistance needs to be for your high voltage.
But I must stress, BE CAREFUL!
If you are not experianced with high voltage, it may be a good idea to find qualified help. You are dealing with very dangerous potentials.
https://www.allaboutcircuits.com/textbook/direct-current/chpt-8/voltmeter-design/. may help you.

 

Ok dendad thank you a lot. i will post again when i will have done any progress

 

Division by 100 gives a voltage that can be measured and displayed by that voltmeter.

100 times the Displayed value is the actual voltage.

In all probability, the voltmeter will be using the LM3914 series having an input current of max 100 nA.

Use a 10 Mohm + 101 K Ohm (100 + 1) as a voltage divider should give what you want.

 

If you try a 10Mohm resistor, make it with at least 10x 1Mohm resistors. Using just one resistor will arc over, or at least fail going open. For some reason, high voltage across some resistors do that, even though the dissipation is not exceeded. That was a common problem in some switch mode supplies. I fixed many Mac Plus power supplies as the start up resistor would go open. At least it did on 240V versions. The fix was to replace it with 3 resistors in series, each 1/3 of the value.

 

Ok i just did some tests and i will post them here. i got an old mobile charger that it got an output of 4.94v according to that small vmeter. Here is what i got from various resistors and a potentiometer at a desired resistance.

0k --> 4.94v
1k --> 4.81v
2k --> 4.69v
3k --> 4.57v
4k --> 4.46v
10k --> 3.87v
20k --> 3.17v
40k --> 2.30v

 

I found online this circuit that it is said to be a voltage divider 1/100. Is that going to work?

https://gr.pinterest.com/pin/846395323697617901/