Reasonably priced differential probes - Page 1
Forum section: electronics / testgear

author: McBryce
author_rank: Super Contributor
timestamp: April 07, 2015, 08:04:56 pm
content: Hi all,I'm looking to buy a differential probe without having to spend a fortune. I only need to test up to 240VAC, so I don't need a fat 1000V device. Happy to buy some Chinese device too as long as it is safe for me and my scope.Any recommendations?McBryce.

author: nctnico
author_rank: Super Contributor
timestamp: April 07, 2015, 08:21:59 pm
content: Look on Ebay for the brand Pintek (Made in Taiwan).

author: AndyC_772
author_rank: Super Contributor
timestamp: April 07, 2015, 08:25:06 pm
content: I have one of these:https://www.picotech.com/accessories/active-oscilloscope-probes/25-mhz-700-v-differential-probe

author: McBryce
author_rank: Super Contributor
timestamp: April 07, 2015, 08:55:25 pm
content: Thanks, I'll check those out.McBryce.

author: kripton2035
author_rank: Super Contributor
timestamp: April 07, 2015, 09:36:02 pm
content: Quote from: AndyC_772 on April 07, 2015, 08:25:06 pmalso have one of these, bought used on ebay for some 100€ some 5 years agothere are from time to time on ebay in europe , just be patient.

author: nctnico
author_rank: Super Contributor
timestamp: April 07, 2015, 10:25:07 pm
content: One of the things to decide on is whether to get a mains powered or battery powered diff. probe. Since I hate having test equipment with batteries I choose to buy a mains powered diff. probe.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 08, 2015, 12:04:45 am
content: Quote from: McBryce on April 07, 2015, 08:04:56 pmthats what you need, the fat 1000V device. 240Vac is ±330V or 660Vpp (differential), 1000V is the best and safer margin you can get. you seldomly see 660V devices.

author: bson
author_rank: Unknown
timestamp: April 08, 2015, 12:40:30 am
content: BitScope also has a sub-$300 differential probe...http://my.bitscope.com/store/?p=view&i=item+71.3kVpp, 25MHz, 9V battery or external DC adapter.

author: Someone
author_rank: Super Contributor
timestamp: April 08, 2015, 05:06:04 am
content: Quote from: Mechatrommer on April 08, 2015, 12:04:45 amThe peak withstand voltage for 240V mains in Measurement Category II (CAT II) devices in 61010 is over 2500V peak (I don't recall interpolation being allowed in that table).Reputable scope manufacturers already include this allowance in their probing solutions. Tek provide clean URLs so we can use them for example:http://www.tek.com/passive-probehttp://www.tek.com/oscilloscope-probes-and-accessories/differential-probe-high-voltageThe popular P5205A has a measurement range of +/- 1300V (differential or common mode), but carries a rating of 1000V CAT II. It will protect from transient over voltage events, but may not necessarily survive it. The comparable Keysight N2790A specifies a measurement range of +/- 1400V with a rating of 1000V CAT II, but also specifies a non-destructive absolute maximum of +/- 1500V and +/- 1300V RMS CAT II.Interestingly the P5202A is 300V CAT II with a +/- 640V peak.

author: mij59
author_rank: Frequent Contributor
timestamp: April 08, 2015, 06:14:16 am
content: I got the Testec TT-SI-9001 from Batronixhttp://www.batronix.com/shop/accessory/probes.html

author: tautech
author_rank: Super Contributor
timestamp: April 08, 2015, 07:26:50 am
content: Siglent do 2 models:DPB3050 50 MHz 800V US$483http://www.siglentamerica.com/prodcut-fjxx.aspx?fjid=408&id=-1&tid=1&T=1DPB4050 50 MHz 6.5 kV US$720http://www.siglentamerica.com/prodcut-fjxx.aspx?fjid=406&id=-1&tid=1&T=1This one includes a power adapter.Pricing may be plus taxes if any.

author: McBryce
author_rank: Super Contributor
timestamp: April 08, 2015, 07:46:55 am
content: Quote from: Mechatrommer on April 08, 2015, 12:04:45 amYes, what I meant is that I only need a lower voltage version (I think most start at about 700V), not one of those 10000V RMS big fat isolated ones that cost a fortune.McBryce.

author: electr_peter
author_rank: Unknown
timestamp: April 08, 2015, 08:01:40 pm
content: Quote from: nctnico on April 07, 2015, 08:21:59 pmLook for Pintek DP-25. Works well, no issues so far.Forum topics about this model:https://www.eevblog.com/forum/testgear/%27new-pro%27-differential-probe/https://www.eevblog.com/forum/testgear/teardown-pintek-dp-25-differentail-probe/

author: dadler
author_rank: Unknown
timestamp: April 10, 2015, 08:15:55 pm
content: Quote from: nctnico on April 07, 2015, 08:21:59 pmI looked into these and found this:http://www.ebay.com/itm/300710178863?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AITThis looks like a decent product with decent specs, but I wonder if it will match my use case.I am not all that interested in super high voltages, I mainly want ground isolation. Essentially, want to be able to measure the potential between points in a low-ish voltage circuit (under 30v absolute voltage). Right now I can do the subtract-channels thing, but sometimes the result is noisy and I lose the ability to use XY mode and math functions.Does anyone know if this differential probe in particular will match my use case, used with, say, a DS2072a or DS1054z? The attenuation and resulting low scope input voltages are what concern me, when used in a relatively low voltage circuit.

author: nctnico
author_rank: Super Contributor
timestamp: April 10, 2015, 08:41:07 pm
content: I have the diff. probe from the link above. In the x20 mode the maximum voltage is 35V. This is definitely in the voltage range you are looking for.

author: dadler
author_rank: Unknown
timestamp: April 10, 2015, 09:28:02 pm
content: Quote from: nctnico on April 10, 2015, 08:41:07 pmAhh I read the specs wrong. Thanks, and thanks for the suggestion. I researched around and found the teardown thread on the forum here and for the price it seems like a good deal.Just placed an order.

author: slurry
author_rank: Regular Contributor
timestamp: April 10, 2015, 09:30:30 pm
content: Still...the absolutely cheapest $0 solution is to use the tips of two probes, just inverting one of the channels, voilá

author: nctnico
author_rank: Super Contributor
timestamp: April 10, 2015, 09:48:06 pm
content: That consumes two channels and has severe limitations. You need to have the channels set to accommodate for the full voltage. If you want to look at a 500mV signal on a 30V offset from ground you'll need to set the scope to at least 5V/div which means the 500mV signal is almost invisible. With a differential probe you can set the scope to 20mV/div or 50mV/div and see the full signal.edit: type

author: slurry
author_rank: Regular Contributor
timestamp: April 10, 2015, 10:15:13 pm
content: Quote from: nctnico on April 10, 2015, 09:48:06 pmTrue... but the price is hard to beat

author: DanielS
author_rank: Frequent Contributor
timestamp: April 11, 2015, 08:40:16 am
content: Quote from: slurry on April 10, 2015, 09:30:30 pmAside from the sensitivity issues mentioned above, that only works if you have perfect gain and timing match between the two channels.Using the two probes method to measure voltage across a small current sensing resistor (my main use for differential measurements) is nowhere near as clean as using an instrumentation amplifier or equivalent opamp when possible.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 11, 2015, 03:52:25 pm
content: Quote from: slurry on April 10, 2015, 10:15:13 pmbut the performance is awful, its better to slap few opamps and volt divider into a active differential probe diy circuit. the diy circuit will be awful but 2dso probes setup is more awful.

author: DanielS
author_rank: Frequent Contributor
timestamp: April 11, 2015, 04:51:28 pm
content: Quote from: Mechatrommer on April 11, 2015, 03:52:25 pmInstead of slapping a bunch of opamps together, I would try looking at instrumentation amplifiers first: much simpler, far more accurate and possibly cheaper than attempting to match their performance using discrete opamps and precision resistors. You get 80-100dB CMRR with hardly any effort instead of fighting an uphill battle to go beyond 50dB using discretes.

author: SArepairman
author_rank: Frequent Contributor
timestamp: April 11, 2015, 06:23:14 pm
content: have you considered old tektronix p series probes? with attenuator.

author: Keylectric
author_rank: Contributor
timestamp: April 11, 2015, 10:25:45 pm
content: Quote from: AndyC_772 on April 07, 2015, 08:25:06 pmHi, first post for me!Agilent/Keysight have what seems to be the same product under their brand. A sign of ok quality perhaps if you feel Pico name is not a heavy hitter. Seems to be an ok basic diff probe. Pico pricing is lower.

author: Fsck
author_rank: Super Contributor
timestamp: April 11, 2015, 10:36:34 pm
content: Quote from: Keylectric on April 11, 2015, 10:25:45 pmthe OEM ishttp://www.sapphire.com.tw/

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 11, 2015, 10:55:41 pm
content: Quote from: DanielS on April 11, 2015, 04:51:28 pmpointless! your bottleneck will be in the attenuator (voltage divider) infact thats where the most work will be fought for, unless we have 1KV diff input capable ins-amp off the shelf.

author: grantbob
author_rank: Unknown
timestamp: April 11, 2015, 11:03:02 pm
content: Quote from: Fsck on April 11, 2015, 10:36:34 pmInteresting... the "Important Message" on their web site states:"Dear customers,GuangZhou Dekem Electronics Co., Ltd (brand name: Pintech,www.pintech.com.cn) has completely cloned ourproducts, including the appearances, cable material, nameplate layout. Even their online instruction manuals(www.pintech.com.cn/uploadfiles/201312103740873) are exactly the same as ours."Makes it even more fut to try to figure out what you're getting.-grantbob

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 11, 2015, 11:11:35 pm
content: the internal construction has become no secret several people have made the teardown, its just a matter of someone with the unit and the balls to make proper documentation about it. the stage of it being within reach of diy is very close. i havent time to get back to the project, there is no black magic in there, if there is, its in the input attenuator front end stage thats where the most mistake made (with some other things perharps)

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: April 11, 2015, 11:24:16 pm
content: Quote from: SArepairman on April 11, 2015, 06:23:14 pmThe P6046 is very difficult to get working properly and to meet its specs, but if you can do it it works well.Or for the adventurous, a 132 power supply and a 1A5 diff amp plugin with two probes works wonders. You can also connect a p6046 directly to a 1A5.

author: dadler
author_rank: Unknown
timestamp: April 16, 2015, 09:09:41 pm
content: Quote from: nctnico on April 10, 2015, 08:41:07 pmSo I received the PINTEK differential probe and it works as expected. As a test (not my primary use case) I was able to decode a CAN stream with differential trigger/decode using the probe. Works well, not too terribly noisy, sorry don't have any exacting description other than "works as expected". I'll try on higher voltage stuff soon.The build quality is decent. It's better than I thought it would be, the probe box is hefty and solid for the most part. For some reason, they cut the bottom 3/16" of the metallic serial number label off with an X-acto knife. Similar on the power adapter, not sure what they are hiding?The included power adapter leaves quite a bit to be desired. It's labeled 9V 300mA, but it's unregulated and reads 15v unloaded. It feels super cheap, so maybe a better power supply is in order, or I'll just run it off a 9V battery.I kinda feel bad that these probes are clones of the Sapphire products, but oh well?

author: nctnico
author_rank: Super Contributor
timestamp: April 17, 2015, 12:30:54 am
content: Perhaps Pintek is the OEM after all

author: pascal_sweden
author_rank: Super Contributor
timestamp: April 23, 2015, 07:58:52 am
content: Note that Pintek also has a low voltage differential probe with high sensitivity.Pintek DP-30HS:http://www.pintek.com.tw/files/pintek/DP-30HS-40LV-DM-frond.jpghttp://www.pintek.com.tw/files/pintek/DP-30HS-40LV-DM-back.jpghttp://www.pintek.com.tw/files/pintek/DP-30HS-40LV-MANUAL.pdfI read that Pintek is cloning Sapphire. Is the quality similar as Sapphire or much worse?Rigol has differential probes that look very similar as Pintek, but then again it could be an OEM from Sapphire, as Pintek clones SapphireDoes anybody know if the Rigol one is from Pintek or from Sapphire?I wonder if Sapphire has an "original" DP-30HS variant as well.

author: McBryce
author_rank: Super Contributor
timestamp: April 23, 2015, 08:45:20 am
content: Thanks for the info. After evaluating all the options, I think I'm going to go for the Pintek 40LV.McBryce.

author: dom0
author_rank: Super Contributor
timestamp: April 23, 2015, 09:36:51 am
content: Quote from: Mechatrommer on April 11, 2015, 10:55:41 pmThere are a few with very high common mode voltage ranges.- AD629: +-270 Vp common mode, protected to +- 500 Vp common *and* differential mode. 500 kHz BW.- INA149 is a similar part- INA148 too- AD8479: +-600 Vp common mode, +- 900 Vp for 10s AMR. 130 kHz BW.Of course none of these are isolation amplifiers!But that's okay for lab-use, if you aren't using an isolation/safety transformer to power your DUTs in the lab you're mad anyway.

author: nctnico
author_rank: Super Contributor
timestamp: April 23, 2015, 12:05:10 pm
content: An isolation transformer does more harm then good in a small lab which isn't setup to make sure everything is isolated. It is very easy to ground a DUT through test equipment or even a piece of steel from a bench. All in all isolation transformers are a thing of the past. Nowadays use a sensitive GFI and differential probes with the proper safety ratings.

author: nowlan
author_rank: Frequent Contributor
timestamp: April 23, 2015, 01:36:20 pm
content: Is that DP-40LV safe for switching supplies at 650v?I was interested in the DP25 but price is still to high for a rare use item.

author: pascal_sweden
author_rank: Super Contributor
timestamp: April 23, 2015, 01:46:50 pm
content: DP-40LV is actually more expensive than DP-25.While it has lower voltage range, it has higher bandwidth and better precision.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 23, 2015, 02:40:13 pm
content: Quote from: dom0 on April 23, 2015, 09:36:51 amyes but they are sub MHz BW, thats a thing of the past. otoh i agree with nctnico thats we seldomly see isolation transformer probe around, or maybe they are highly specialized purpose. when someone asking how to probe mains, everybody adviced go for isolated diff probe, and then go for [insert your fovourite cheap HV diff probe here], didnt they know that [insert your fovourite cheap HV diff probe here] is not isolated? the thing in between is just few big fat arse carbon or ceramic resistors. thats the isolator if ever you want to call it isolated.

author: Gromitt
author_rank: Regular Contributor
timestamp: April 23, 2015, 02:43:54 pm
content: Quote from: pascal_sweden on April 23, 2015, 07:58:52 amNo. it's not Pintek (Taiwanese company) that is cloning Sapphire, it's Pintech (Chinese company).

author: dadler
author_rank: Unknown
timestamp: April 23, 2015, 07:26:11 pm
content: Quote from: Gromitt on April 23, 2015, 02:43:54 pmAhh, I guess I feel better? Hehe. Geez.I found this comparison chart:http://www.pintek.com.tw/files/pintek/PROBE-COMPARISON-CHART.pdfAlso, PINTEK claims then DP-25 can operate fine on 5V. I am going to try using USB and see how the probe performs.

author: pascal_sweden
author_rank: Super Contributor
timestamp: April 23, 2015, 10:00:30 pm
content: Beginner's question:If you debug a low voltage circuit on a breadboard (e.g. amplifier circuit with transistor), and you power the circuit with a power supply which has an isolated DC voltage output, then your (-) on the circuit is not ground.Can you connect the ground clip of the probe on the scope to the (-) anyhow, to actually make the (-) of your circuit become ground?Or given that the (-) terminal as such does not define an absolute potential level, but only relative to the (+) terminal, could the potential level be high enough to actually cause a short, when connecting the ground clip of the scope?

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 24, 2015, 02:28:20 am
content: Quote from: pascal_sweden on April 23, 2015, 10:00:30 pmyes. for a floating circuit like you described, you can even plug the gnd clip to anywhere in your circuit to make that node gnd. so say you plug the gnd to +ve floating supply, you make that as gnd reference and rendering the rest of the nodes/circuits be measured as -ve voltages. you can also do this with not floating circuit but floating scope, but its dangerous when you connect gnd clip to say 240V, you render every gnded outer metal on the scope as 240V.

author: pascal_sweden
author_rank: Super Contributor
timestamp: April 24, 2015, 06:25:21 am
content: So if you are working on a logic circuit with a MAX232 chip to drive serial line, and you would connect the ground clip of your scope to the 12V point in your circuit, your metal house becomes 12V, which you can start feeling when you touch it?For 5V circuit it is no concern I guess, but the moment voltage becomes 12V or higher, it starts to get "hot".

author: Galenbo
author_rank: Super Contributor
timestamp: April 24, 2015, 01:55:03 pm
content: Quote from: pascal_sweden on April 24, 2015, 06:25:21 amSince when is 12V considered dangerous?30V is still safe, and 20 years ago people were stronger, 60V was safe then.

author: pascal_sweden
author_rank: Super Contributor
timestamp: April 24, 2015, 08:10:08 pm
content: Suppose you only work on low voltage circuits (e.g. 5V, 12V, 24V), and you use a power supply with isolated outputs.As indicated above, it is no issue to connect the ground clip of the probe with any point in the circuit, it just makes that potential level your ground from then on. That's clear.The case of the scope could become 5V, 12V, 24V. Not pleasant to touch, but not harmful.But I guess it still makes sense to have a differential probe anyhow, as you can still short your scope when you would connect the tip of the probe with the ground clip (not being actual ground, but having a higher potential level).The differential probe can not be shorted, it only measures the difference between two potential levels. The probe of the scope can be shorted, when clip and tip have different voltage levels and no resistor is in between. Is that correct summary?I told these observations to a friend with a 4 channel scope. He wondered why the manufacturers of scopes not just build this in as standard. This would make it cheaper as well, when it becomes mass production (a la Rigol). As there is no such scope, he is planning to buy 4 differential probes at once to avoid all the discussions and worries at once. Maybe Pintek offers a discount when buying DP-30HS differential probes in bulk

author: dadler
author_rank: Unknown
timestamp: April 24, 2015, 08:19:56 pm
content: Explained another way: A good reason to have a diff probe is that even if your circuit is floating, you can have one channel have a different "ground reference" than the other channels. With no diff probe, you are limited to a single ground reference potential and you may not be able to use the other channels on the scope depending on your use case.

author: dom0
author_rank: Super Contributor
timestamp: April 24, 2015, 08:33:29 pm
content: There are other reasons to use diff probes and amplifieres, too. Many lab supplies, especially cheaper ones and probably all people build themselves don't have a shield winding in the mains transformer, which means that there is a substantial capacitance (up to a few dozen nF for large toroidal transformers) between mains and the floating supply. This usually makes it undesirable to connect the ground clip to nodes that aren't low impedance.See attached screen grab for an example. Node impedance is about 250 k?.

author: tautech
author_rank: Super Contributor
timestamp: April 24, 2015, 08:37:21 pm
content: Quote from: pascal_sweden on April 24, 2015, 08:10:08 pmThe "general" issue of GND loop shorts is addressed by manufacturers withIsolatedchannel scopes. These are not cheap either, but you're dealing with preserving signal intregrity, not easy at higher BW's.For those that are examining 3 phase waveforms a lot, this is the best long term solution.Richard made a nice comment in another thread:https://www.eevblog.com/forum/testgear/best-practice-for-protecting-a-scope-that's-probing-mains-attached-devices/msg659425/#msg659425Where thereferencelead is attached is the root of all these problems.For noobs and the inexperienced it is called the GND lead, no doubt to remind us that incorrect connection will introduce a ground loop. But remember it is the "signal reference", first and foremost.Of course with the use of isolation techniques like Differential probes, Siglent ISFE or isolated channel scopes, risk of damage to the DUT or scope is minimised.

author: dom0
author_rank: Super Contributor
timestamp: April 24, 2015, 10:03:57 pm
content: The same circuit powered by a lab supply w/o a shielding winding and stacked windings, so with a transformer that has a large coupling capacitance.Whoops. A whooping 45 Vpp AC, enough to destroy more sensitive devices.So this is just another consideration when considering ground clip placement ; high impedance nodes... better not...

author: Keylectric
author_rank: Contributor
timestamp: April 25, 2015, 12:02:19 am
content: Quote from: pascal_sweden on April 24, 2015, 08:10:08 pmIf I get you right you are under the impression that there are no scopes with differential inputs?If so there are actually, however not that common.Picoscope for example have a four channel USB-scope with all inputs differential. Limited bandwith but anyway.

author: pascal_sweden
author_rank: Super Contributor
timestamp: April 25, 2015, 11:28:07 am
content: I know these scopes exist, but my friend really likes his current 4-channel scope and does not want to change it.I think that the decision about the need for a differential probe is already madeNow the question that remains is whether it should be a Pintek DP-30HS or DP-40L.Given that the voltage range is smaller for DP-30HS I would expect better sensitivity and accuracy, but according to the specs it actually isn't. The DP-40L seems to beat the DP-30HS in both BW and voltage range. Or do I miss something? Note that they cost the same!

author: akis
author_rank: Frequent Contributor
timestamp: April 25, 2015, 12:45:37 pm
content: Quote from: DanielS on April 11, 2015, 08:40:16 amThe most immediate and best way is this: If your scope is battery powered (like mine is) you can unplug it from the mains, and then use the probe + ground clip over the sense resistor or any other parts of the circuit you wish to measure. The "ground" clip of your scope is floating with respect to *anything* you will be trying to measure, therefore your probe is now differential by definition. This is immediate and 0 cost.Other people simply disconnect the earth from their mains pwoered scopes to achieve the same "floating" probe status, however this is dangerous because there may still be an internal path to the mains supply and then you can burn something or die.Trying to use the two probes is problematic not only in terms of offset voltages and sensitivity, but also of ability to read values off the screen easily and quickly - I have to use the Maths function which produces a third curve (the A-B or A + (-B)) but I then have to look really closely on the screen to take measurements on this third curve on the screen. Not convenient.Has noone thought of making a simple (?) circuit to convert a single probe to a differential probe? I am sure we can make a simple circuit to cover low voltages and low frequencies without much trouble.

author: pascal_sweden
author_rank: Super Contributor
timestamp: April 25, 2015, 07:30:59 pm
content: Good point!As the current market situation looks like, differential probes are only built for and in the budget of professionals.This is actually a bit of a contradiction, because beginners and hobbyists are the one that tend to make mistakes in connections, even when it only concerns low voltages and low frequencies.From that perspective, the suppliers should think about a beginner/hobbyist differential probe built for and in the budget of beginners/hobbyist.Here we just have found ourselves a gap in the market and potential business opportunity.Anybody up for the challenge? Beginnerprobe (R) or MyFirstProbe from TestSkool

author: dadler
author_rank: Unknown
timestamp: April 25, 2015, 08:10:54 pm
content: Do you consider the above discussed Pintek DP-25 ("economic model") too expensive? It seems reasonably priced for what it is.http://www.pintek.com.tw/product_detail/landersound/index.php?Product_SN=19265&Company_SN=6002&Product_Site_Classify_SN=17072I bet someone could reverse engineer it though, and sell blank PCBs for the DIY crowd. I'm not sure how the DP-25 is calibrated, but I'm imagining a bunch of trim pots

author: dom0
author_rank: Super Contributor
timestamp: April 25, 2015, 08:51:22 pm
content: Quote from: dadler on April 25, 2015, 08:10:54 pmProbably a few trimpots and caps for frequency response and one or more trimpots for CMRR. Calibrating diff probes is not simple.

author: pascal_sweden
author_rank: Super Contributor
timestamp: April 25, 2015, 09:21:40 pm
content: Aren't the DP-30HS or DP-40LV a better choice than the DP-25 for low voltage measurements?Best sensitivity: DP-30HS (1mVrms)Widest bandwidth: DP-40LV (40 Mhz)DP-25: 1000V, 25MHz, 20mVrmsDP-30HS: 65V, 30MHz, 1mVrmsDP-40LV: 650V, 40MHz, 10mVrmshttp://www.pintek.com.tw/files/pintek/PROBE-COMPARISON-CHART_2.pdfhttp://www.pintek.com.tw/files/pintek/DP-65-25-frond.pdfhttp://www.pintek.com.tw/files/pintek/DP-30HS-40LV-DM-frond.jpghttp://www.globalmediapro.com/dp/A01LT0/Pintek-DP-25-Differential-Probe-25MHz-1000V/http://www.globalmediapro.com/dp/A25XX7/Pintek-DP-30HS-Differential-Probe-30MHz-65V/http://www.globalmediapro.com/dp/A25XY5/Pintek-DP-40LV-Differential-Probe-40MHz-650V/Only a pity that they don't have the low voltage (65V) high sensitivity (1mVrms) differential probe in 100MHz version. If you would have 4 of those differential probes, you could turn your hacked DS1054Z into a fully-fledged 4-channel 100MHz digital isolated scopeThis would be a unique piece of equipment!I am going to order DP-30HS. More than one most likely.Additional plus: The white color suits better with the Rigol scope

author: dadler
author_rank: Unknown
timestamp: April 25, 2015, 11:15:34 pm
content: Yes, for low voltage measurements. But they are more expensive, and then you need a second one for high voltage. The 40-LV sits in the middle, but it's more expensive as well. I thought price was your issue, based upon your posts? The DP-25 is the lowest priced PINTEK diff probe.

author: pascal_sweden
author_rank: Super Contributor
timestamp: April 27, 2015, 07:51:53 am
content: I have contacted Pintek to bring up the suggestion of a new probe and they provided pleasant feedbackHere was my message:Hello,I read more information about the DP-30HS differential probe.Really nice feature set.Only a pity that you don't have the low voltage (65V) high sensitivity (1mVrms) differential probe in 100MHz version. If you would have 4 of those differential probes, you could turn an upgraded Rigol DS1054Z into a fully-fledged 4-channel 100MHz digital isolated scopeThis would be a unique piece of equipment!Why does high bandwidth (100 MHz) always go hand in hand with high voltages (+1KV)?Do you see my point about low voltage, high speed differential probe with 100 MHz?It could turn every hobbyist's 100 MHz scope into an isolated scope, without loosing bandwidth. Hobbyists working on digital design projects, need the bandwidth, and at same time can make mistakes when measuring in their circuits. So I believe it makes sense.Regards,PascalHere is their feedback:Dear Pascal,Thank you for your e-mail.I have passed your info to our engineer.We will develop a new model of different probe.The spec is:Bandwidth: 100MHz,Voltage: 65VSensitivity: 1mVrmsBy the way, can you please let me know your location? In Europe? Or US?Thank youPINTEK ELECTRONICS CO., LTD

author: akis
author_rank: Frequent Contributor
timestamp: April 27, 2015, 07:58:48 am
content: Could you guess the price for such a single probe?

author: tomy983
author_rank: Contributor
timestamp: May 04, 2015, 08:09:14 pm
content: Quote from: Galenbo on April 24, 2015, 01:55:03 pmI know this guy, he is now 70+. He used to work as an electrician on his own, probably doing a good enough job considering that he was doing it forever.He does not have any considerable education, he just probably learned on the job.Well, is not like I would do the same or I want to encourage anyone, but to look for the hot wire this guy used to lick his finger and touch the live copper until he felt it... Here we have 230V 50hz.Everyone who saw him doing it including myself, many many times, tried to persuade him not to, but he just kept going...He is still alive though.That is very dangerous though and no one should do it.

author: electr_peter
author_rank: Unknown
timestamp: May 04, 2015, 08:23:08 pm
content: Electricians are a special breed selected from people who have very resistive/thick skin and can touch live mains without dying.It is half joke, of course. But this statement is true in same sense as "marathon runners never die during marathon because everybody who can die already have done it or stopped running". Some people die running marathon, thus they cannot be marathon runners.

author: akis
author_rank: Frequent Contributor
timestamp: May 04, 2015, 08:44:31 pm
content: And professional gas men testing for gas leaks by running a lighter across the length of an old iron pipe I seem to remember.

author: Galenbo
author_rank: Super Contributor
timestamp: May 05, 2015, 06:24:27 pm
content: All this still doesn't make 12V dangerous.

author: DanielS
author_rank: Frequent Contributor
timestamp: May 05, 2015, 06:43:11 pm
content: Quote from: Galenbo on May 05, 2015, 06:24:27 pmUntil you accidentally weld one of your rings or other metallic accessories to 200A bus-bars or other high-current source.Low voltages are not necessarily harmless.

author: dom0
author_rank: Super Contributor
timestamp: May 05, 2015, 06:51:42 pm
content: Won't electrocute you, though. It's the hot, sparking, molten metal hurting you, not the current. Or voltage.

author: electr_peter
author_rank: Unknown
timestamp: May 05, 2015, 08:18:54 pm
content: Quote from: dom0 on May 05, 2015, 06:51:42 pmAdd fire (things get reallyHOT) to the mix.

author: Rupunzell
author_rank: Frequent Contributor
timestamp: May 06, 2015, 07:32:45 am
content: The vast majority of two channel Tektronix analog scopes or plug ins have the invert/add switch (select invert, add then drive the two probes common mode and use the gain adjust to optimize common mode rejection. This results in 60 to 20 db of CMR depending on frequency, probe match and ...). This effectively makes a single channel diff input scope. Many of the same Tek input amplifiers have up to 5volts/div, adding a 10x probe makes 50 volts per division with reasonable common mode rejection (keep increasing the gain until the input amplifiers complain). The tube Tek scopes aka 500 series plug ins often have 10volts/division or more and their over drive capability is something to behold. A few hundred volts on the plate supply goes a long way to help the dynamic range of vertical amplifiers.Bernice

author: akis
author_rank: Frequent Contributor
timestamp: May 06, 2015, 05:39:30 pm
content: How does that work. Do you get two traces on the screen?My digital scope does this by using the "maths" function so I choose, say X - Y, but it then plots a third trace which is not easy to see with another two traces already on the screen. Plus, it records no measurements on this third trace so you will have to count squares on the screen...

author: dom0
author_rank: Super Contributor
timestamp: May 06, 2015, 08:22:12 pm
content: Quote from: akis on May 06, 2015, 05:39:30 pmhttps://en.wikipedia.org/wiki/Operational_amplifier_applications#Summing_amplifier

author: Galenbo
author_rank: Super Contributor
timestamp: May 07, 2015, 10:28:23 am
content: Quote from: DanielS on May 05, 2015, 06:43:11 pmPlease express 200A as 'current', not as 'voltage'Even 1V 1mA can be dangerous, if you touch it and someone heated the surface up to 200 degrees celcius. Or if there's a dangerous chemical substance in the air around it. Please try to be specific.

author: pascal_sweden
author_rank: Super Contributor
timestamp: May 07, 2015, 11:19:09 am
content: I have ordered two Pintek DP-30HS differential probes, and I am waiting on their arrivalWill provide feedback on their performance after doing some tests.Pintek promised to keep me up to date on their new development of low-voltage, high-sensitivity, 100 MHz differential probe. Will keep you updated.

author: tautech
author_rank: Super Contributor
timestamp: July 18, 2015, 03:26:12 am
content: Quote from: pascal_sweden on May 07, 2015, 11:19:09 am@pascalAny updates for us?

author: dadler
author_rank: Unknown
timestamp: July 18, 2015, 10:46:51 pm
content: Quote from: pascal_sweden on May 07, 2015, 11:19:09 amWhere did you find the DP-30HS for sale?All I can find is this:https://www.globalmediapro.com/dp/A25XX7/Pintek-DP-30HS-Differential-Probe-30MHz-65V/Which seems ok, but these fine folks only take wire transfers as a method of payment.I haven't sent a wire transfer in at least 10 years... Makes me a bit uncomfortable but they seem reputable?

author: tautech
author_rank: Super Contributor
timestamp: July 18, 2015, 11:00:33 pm
content: Quote from: dadler on July 18, 2015, 10:46:51 pmBe aware there are 2 versions, the original Pintek and Pintech.RS sell them but out of stock.http://uk.rs-online.com/web/p/oscilloscope-probes/7296671/Na, most will send you a Invoice with bank details and you just set up a DC to their bank from yours and just pay the fees.

author: McBryce
author_rank: Super Contributor
timestamp: July 20, 2015, 08:22:48 am
content: Hi,I just picked up the July/August edition of Elektor Electronics and they have released a design for a "2GHz Active Differential Probe". I haven't had a chance to take a proper look at it yet (life gets in the way once again). Has anyone else checked this out yet? Any opinions on the circuit / design?McBryce.Side Note: For some reason Elektor have decided not to do the usual "Summer Bumper Edition" with 100+ circuits etc. as they have done since as long as I can remember. Pity really, Elektor seems to be offering less and less and costing ever more over the last few years.

author: McBryce
author_rank: Super Contributor
timestamp: August 31, 2015, 08:23:38 am
content: I finally managed to score a decent Differential Probe on Fleabay. It's a Pintek DP-100 (7KV 100Mhz). Not exactly the model I was after, but stupidly cheap (if I told you how much I'd probably get hate-mail), so I pounced on itI can do a teardown when it arrives if anyone is interested.McBryce.

author: tautech
author_rank: Super Contributor
timestamp: August 31, 2015, 09:17:50 am
content: Quote from: McBryce on August 31, 2015, 08:23:38 amIt would be just plain rude if you didn't.

author: McBryce
author_rank: Super Contributor
timestamp: August 31, 2015, 09:30:48 am
content: No problem. I won't be able to do it until sometime next week though.McBryce.

author: Shock
author_rank: Super Contributor
timestamp: September 01, 2015, 05:28:32 am
content: Quote from: McBryce on August 31, 2015, 08:23:38 amI'm interested in seeing a tear down as well. Tell us how cheap, noone cares if you get hate mail, besides you need to breath life into the people that are chasing the elusive bargain and never catch it.

author: McBryce
author_rank: Super Contributor
timestamp: September 01, 2015, 07:50:31 am
content: Let's just say it was extremely goodand it's brand new or extremely rarely used as far as I can tell from the pictures. Although I should mention that the probes aren't included, but this isn't an issue for me as I don't intend ever measuring anything that high a voltage.McBryce.

author: McBryce
author_rank: Super Contributor
timestamp: September 10, 2015, 01:48:47 pm
content: The device arrived this morning, I will do a quick tear-down tomorrow and start a new thread with some pics.McBryce.

author: HighVoltage
author_rank: Super Contributor
timestamp: September 10, 2015, 01:59:10 pm
content: Quote from: McBryce on September 10, 2015, 01:48:47 pmA while back, we had someone do a teardown of a similar Pintek probehttps://www.eevblog.com/forum/testgear/teardown-pintek-dp-25-differentail-probe/Will be interesting to see the differences to your DP-100

author: McBryce
author_rank: Super Contributor
timestamp: September 10, 2015, 02:10:21 pm
content: Thanks for the link. From the 10 second look I had inside it (was about to leave for work when it arrived) it's uses similar design aspects, but it's a completely different device / schematic. The case is also bigger and a slightly different shape. The build quality is top-notch. It also has an internal 9V batteryIf there are any specific details I should focus on, let me know.McBryce.

author: McBryce
author_rank: Super Contributor
timestamp: September 11, 2015, 10:56:03 am
content: Teardown here:https://www.eevblog.com/forum/testgear/pintek-dp-100-100mhz-differential-probe-teardown-mini-review/McBryce.