Electronics > Beginners
Detect ~2kV
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Zero999:

--- Quote from: Gyro on September 08, 2018, 05:34:59 pm ---
--- Quote from: Hero999 on September 08, 2018, 05:07:34 pm ---My four year old nephew got a horrible burn on his chest from an electric fence.

An ordinary multimeter can measure up to 1000V, just add a 1kV rated 10M in series with it or perhaps 10 × 1M resistors if you can't get one rated to 1kV. The trouble is it's pulsed, so that might not work, as the meter might not respond fast enough. Perhaps a 2kV bridge rectifier and 100nF capacitor before the 10M resistor could be used to get a smooth DC voltage.

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I think you'd want a bit more protection for your multimeter than that - I'd go for a high voltage x10 divide (90M).

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I agree. There's no point in pushing the DVM to its limit and you'll get the same level of precision, i.e. decimal places, on the 0 to 200V range, as the 1kV range.
Mr. Scram:

--- Quote from: MarkF on September 07, 2018, 07:34:17 pm ---

Sorry.  I couldn't resist.

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You must be cold then.
rstofer:
I wouldn't use it to actually touch the fence but it should be able to detect the voltage from a small distance:
https://www.fluke.com/en-us/product/electrical-testing/basic-testers/fluke-1ac-ii
ahbushnell:

--- Quote from: JS on September 07, 2018, 06:44:15 pm ---A bunch of series resistors...

Build a divider, 2kV is not as much as you think, I don't know how much current you device puts but you can put 20 1MΩ resistors in series and measure upon the last one. If it's loading it too much twenty 10MΩ resistors could do better, or at least with both measurements you could tell the output impedance of the fence. Then read with your DMM, note than the DMM input impedance is probably about 10MΩ, so you can get a rough number with the 1M divider but for the 10M is a bit harder, the DMM could be the last resistor but you would need to measure it with a second DMM or you could try measure the current, 10µA would be your 2kV with the 20x10MΩ resistors.

The build of the probe is the more problematic matter, you could solder them in series in plain air and place them in a tube, The best choice will be to use some teflon spacers inside the tube, as using a teflon tube would be pretty expensive for your application. The tube could be PCV, or just use a PCV pipe with the end caps to hold both ends of the resistor string. In the 10MΩ version you just need access to the last one to measure current... well, this also applies to the 1M as you can do the same thing but now on 100µA for 2kV.

JS

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I think fences put out pulses. 
Mechatrommer:
this should warn you from some safe distance... no spark zap, no chest burn no pain whatsoever, the only sensation is the ears and the eyes. not cost more than your cheap unit..

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