Go Down

### Topic: Measuring High Voltages with a low voltage meter (Read 880 times)previous topic - next topic

#### Wawa

#30
##### May 21, 2018, 04:04 am
So the 6kV Fluke probe is using a voltage divider.
Thanks for posting that.

My very old Heathkit ~30kV probe only has one long ~1Gigaohm resistor inside.

The probe in post#23 also mentions an input impedance of 1000M.
So both are relying on the (10Megohm) input impedance of the DMM.
Leo..

#### TomGeorge

#31
##### May 21, 2018, 04:34 amLast Edit: May 21, 2018, 04:34 am by TomGeorge
Hi,
I noticed that the 40kV didn't have its circuit diag, so here it is;
It shows two resistors.

Tom..
Everything runs on smoke, let the smoke out, it stops running....

#### allanhurst

#32
##### May 21, 2018, 04:39 am
Electrostatic meters have been around for years, and take no current.

Allan

#### JohnRob

#33
##### May 21, 2018, 10:24 pmLast Edit: May 21, 2018, 10:30 pm by JohnRob
Quote
If the resistors have equal resistance the voltage will be divided equally.   That's Ohm's Law...  The voltage is proportional to the resistance...  That's how a voltage divider works.   (And that assumes no arcing.   ) [
This is absolutely true.

I apologize, I was remis in omitting my reasoning.

The OP seems to be new working with high voltage.  When building the divider, if the resistors are wired close together or some get contamination on the surface,  things could (not will) go bad.  Contamination could be finger grease solder rosin etc.   But in the end it is my opinion and how I would do it.

#### ChrisTenone

#34
##### May 22, 2018, 01:49 am
This is absolutely true.

I apologize, I was remis in omitting my reasoning.

The OP seems to be new working with high voltage.  When building the divider, if the resistors are wired close together or some get contamination on the surface,  things could (not will) go bad.  Contamination could be finger grease solder rosin etc.   But in the end it is my opinion and how I would do it.

When dealing with HV, you are always your own last arbiter. Cause a mistake could be fatal, or at least hurt a lot. That's why I am such a fan of the Vandegraaff and Tesla devices. As HV goes, they are both pretty benign.

ps, a full on shock from either IS painful, but usually NOT fatal. OP: What are you using as a power supply? Is it a transformer? Be real careful with those!
I'm not disparaging the differently abled. I'm stating the fact that thirty years of junior college has made me mentally retarded.

#### gwareloth

#35
##### May 22, 2018, 05:29 am
The OP seems to be new working with high voltage.
He's 15 years old, so bound to be.

From one of his other threads:

I am fairly new to arduino at age 15.

Go Up