100:1 probe can probe what max voltage?

[Flyback]

Hi,
We have a Rigol DS1074 scope.
We want to measure our flash tester output, as we believe it is going above 4kV due to resonance with Y caps.
Do you agree, we cannot use a 100:1 probe, as DS1074 only allows 30V at the terminals?

Page 6 of the datasheet says its ok to have 300Vrms into a 1MOhm channel. But that means with a 10:1 probe, so i am surprised they dont state that...because a 1:1 probe and 300vrms will blow the scope up.

DS1074

DS1000Z-RIGOL Technologies, Co. Ltd.

DS1000Z|

eu.rigol.com

 

[ZipZapOuch]

High voltage probes exist. Thy usually have fatter barrels to prevent arcing. Here's a 10kv probe...

https://www.digikey.com/en/products/detail/cal-test-electronics/CT4025/5882254?utm_adgroup=&utm_source=google&utm_medium=cpc&utm_campaign=PMax%20Shopping_Product_Medium%20ROAS%20Categories&utm_term=&utm_content=&utm_id=go_cmp-20223376311_adg-_ad-__dev-c_ext-_prd-5882254_sig-Cj0KCQjwq_G1BhCSARIsACc7NxogTJ1zeidiBsZ2xsCUvInRQFCsbf5GG10dAg3IPXEQcHmdKgDsDwYaAjIdEALw_wcB&gad_source=1&gbraid=0AAAAADrbLlgqL9GknIYj8ftZ_OgZ_eEsz&gclid=Cj0KCQjwq_G1BhCSARIsACc7NxogTJ1zeidiBsZ2xsCUvInRQFCsbf5GG10dAg3IPXEQcHmdKgDsDwYaAjIdEALw_wcB

 

[danadak]

The Rigol HV probes :

Accessories Oscilloscope current probes, differential probes, high voltage probes, and more | RIGOL

RIGOL Accessories including current probes for oscilloscopes up to 100 MHz or 100 Amps, high voltage oscilloscope probes, differential probes, attenuators, near field probes, options, and more

www.rigolna.com

https://www.tequipment.net/RigolDS1074Z.html

Regards, Dana.

 

[Flyback]

Thanks, they are too costly for us....we will just use a 100:1 probe i think... with a resistor ladder chain.?

 

[schmitt trigger]

No!
Unless you read the probe’s data sheet and find the derating specs. I have used premium LeCroy 100X probes and for continuous use they were only rated at 2.5 kV, and that was at low frequencies.
You may have a probe which could indeed withstand 4 kV, what is the make and model? Do you have spec sheets for it?

 

[ronsimpson]

they are too costly for us....we will just use a 100:1 probe i think... with a resistor ladder chain.?

Watch the data sheet on the resistors. They have a max voltage rating.
What bandwidth do you need?

 

[ChrisP58]

Have you considered renting a high voltage probe?

 

[For The Popcorn]

There are a lot of Fluke high voltage probes on ebay, for around 50 bucks.

 

[ZipZapOuch]

Hum, times have changed. Now it seems much more economical to have a team of engineers searching eBay and poking around forums for a few days to find a cheap solution than it is to spend $1000 on a good probe.

In my glory days, we would just spend the money and get the project done - with a probe that has a datasheet and produces results that can be relied on.

 

[ZipZapOuch]

There are a lot of Fluke high voltage probes on ebay, for around 50 bucks.

There are HV Fluke probes on eBay but, as far as I know, Fluke only makes OSCILLOSCOPE probes up to 1.5kV. The others are for volt meters - hence, $50 used.

 

[danadak]

I just bought a 50KV probe off ebay for $20 USD, seems to work fine.


Regards, Dana.

 

[ZipZapOuch]

I just bought a 50KV probe off ebay for $20 USD, seems to work fine.


Regards, Dana.

Did you buy an 80kV-rated fluke meter probe and use it as an oscilloscope probe for 4kV? Or was it a 1.5kV "HV" fluke oscilloscope probe?

Or wasn't it a Fluke probe at all?

 

[danadak]

This is probe :

rca voltohmyst hv probe at DuckDuckGo

DuckDuckGo. Privacy, Simplified.

duckduckgo.com

I use it with RCA VTVM.

I do not own fluke gear. My focus is HV supply repair old scopes.

 

[ZipZapOuch]

This is probe :

rca voltohmyst hv probe at DuckDuckGo

DuckDuckGo. Privacy, Simplified.

duckduckgo.com

I use it with RCA VTVM.

I do not own fluke gear. My focus is HV supply repair old scopes.

Right, there are many HV probes of all kinds on eBay and I'm sure they work fine. The point above was that a meter probe is not the same as an oscilloscope probe. And, since someone suggested the OP buy an HV FLUKE probe for is 4kV experiment, I was pointing out that the highest voltage FLUKE oscilloscope probe is only 1.5kV (that I'm aware of), that person's suggested was either IGNOrANT if they didn't know the difference between an o-scope probe and a meter probe or, MEAN and DANGEROUS if they did know the difference. Moral of the story, read the max voltage carefully on an HV probe and know its intended use.

 

[danadak]

HV Fluke Probe -

Fluke 80K-40 High Voltage Probe | Fluke

The 80K-40 is a high voltage probe designed to extend the voltage measuring capability of an AC/DC voltmeter to 40,000 volts peak AC or DC Overvoltage Category I.

www.fluke.com

However to ZipZapOuch's point, probes come as V dividers (generally speaking)
so the target instrument input Z has to be taken into account. Buyer needs to
examine specs of mating instrument and probe charactertistics.

Regards, Dana.

 

[ronsimpson]

My first HV scope probe:
R6 is a 500Meg ohm 30kV resistor made to load down the HV in TV sets and CRT monitors. It has HV wire on one end.
C5 is a gimmick capacitor. It is made by paralleling two HV wires.
C6 & C5 divides down the high frequency.
R6 * R7 divides down the DC.
I can't remember the exact schematic. There is a switch for 1M or 10M. The scope loads down the circuit with 1M ohm and 50pF while the meter is 10M and ?pF. Probably when the switch is in the scope mode R7=1M resistor and 1M scope to make 500k. When the switch is in the meter mode R7 // 11M = 500k.

Here you can see the resistor in white, metal box with 10M or 1M switch. The output was made to connect to a scope or meter.

Here is a better picture of the gimmick capacitor. Search gimmick capacitor if you need to.

The DC calibration was done against several HV meter probes.
The AC calibration was done at 100khz. I was making CRT monitors in the 32khz to 120khz range and needed to see the switching frequency ripple and see load/line ripple on 20-30kv power supplies. You could ac calibrate with a good signal generator and a 1:1 scope cable.

I hope this helps. It was used for years.