Author Topic: Cheapest 100MHz oscilloscope probes hands on review  (Read 10123 times)

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Offline Spawn

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Cheapest 100MHz oscilloscope probes hands on review
« on: March 11, 2012, 01:16:29 AM »
First off all this is just a review how these things look like and how they feel when you use them, unfortunately I can’t test the limits of these probes since I don’t have the equipment to do so.

I ordered these 5 days ago and received them today, because the probes I got are not good anymore, while I was trying to calibrate the 10x compensation, the little screw of the adjustable capacitor went weird so it doesn’t change anything if I turn it (common problem on cheap capacitors).

 I write this down because I was pretty impressed about the build quality of these cheap probes.
The probes are probably cheapest ones on Ebay, I ordered them from UK so they cost little bit more, but I didn’t want to get in trouble with customs here by ordering from China.

This is the set I ordered from Ebay, it includes 2x 100MHz probes from UK seller
Price including shipment: 15GBP, 23.5USD or 18EUR

http://www.ebay.com/itm/1pcs-100MHz-Oscilloscope-Scope-Clip-Probe-Measurement-Test-1x-10x-/330605425145?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item4cf99e71f9]This is the same probe from China seller but then the package contains one probe.[/url]
Price including shipment: 4.79GBP, 7.52USD or 5.75EUR

Probes feel really good in the hand and build quality is surprisingly good, specially compared to my 50MHz probe which cost me 15 times more long time ago.

Specifications:
Attenuation: X1 : X10
Input Resistance: 1Mohm ±2%(X1) : 10Mohm±2%(X10)
Input Capacitance:  1Mohm ±2%(X1) : 10Mohm±2%(X10)
System bandwidth:  DC~100MHz
Max input Voltage: X1: 300VDC+Peak AC   X10: 600VDC+Peak AC
Net Weight:  55g
Cable Length: 120cm / 42.2 inches

Package includes: 2x  Probes, 2x Probe tips , 2x Ground leads, 4x Marker rings, 2x Tip locating sleeves and a Adjustment tool

See below some comparing pictures with these cheap TP6000 probes, black 50MHz probes (don’t remember the brand) and Tektronix P6109 150MHz probes.

The package, I got 2 packs (4 probes)



The connectors, from above TP6000 probes, 50MHz probes and Tek P3109 probes:



10x compensation adjustment is on the connector and not on the probe itself:



The probes, TP6000 has a nice tip and good grip unlike the black 50MHz one. TP6000 is cheap but it doesn’t feel cheap when you have it in your hands, the black 50MHz feels and looks cheaper, I am not going to compare it with the Tek probe because its just unfair to compare 8USD probe to a probe which probably cost an arm and a leg to buy when they where new:



Ground lead, same order as before in above pictures, its slightly shorter than Tek lead, to be honest I like longer ground leads like the 50MHz ones even longer if possible, that just gives you more play room:




Tip compared to Tek tips, I don’t have the tip for 50MHz one anymore, but as you see the tip is exact copy of the Tek tips and they work quite same, it also fits on the Tek probes of course, so if you need a cheap hooking tip for your Tek probes these tips cost 8USD and you get free 100MHz probes as gift :P



I tested the probes (all 4 of them)  on my 20MHz iwatsu ss-5702’s  calibration output (0.3v 1kHz) just to see if they work, nothing further like testing with high or low frequency’s or different signal waves and voltages:

Offline T4P

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #1 on: March 11, 2012, 02:51:16 AM »
Nice large CRO you have there , i'd better go down to my shop locally that sells second hand test gear to find a second hand large powerful CRO , probably heavy and would probably take up more space then i have now but oh well .

I have seen 1 probe on DX ( hongkong not china ) for 6.04$ and they have good ratings .
http://the4thpin.comeze.com <-- Rants and Reviews! sorry my english  :palm:

Offline saturation

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #2 on: March 11, 2012, 03:33:29 AM »
Great photos and review.  I think I have similar models; I did some rise time measurements and they perform as expected.  They continue to perform well.

http://www.eevblog.com/forum/product-reviews-photos-and-discussion/cheap-oscope-probe-quality/msg31749/#msg31749


Best Wishes,


Saturation

Offline Spawn

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #3 on: March 11, 2012, 05:26:43 AM »
Dave.S you would think it’s a huge oscilloscope specially on that picture, but it is one of the compact oscilloscopes in its time, you remember my newly bought Tek 2221A right?
This Iwatsu is only 6kg (13,2 pounds) and easier to carry around and Tek 2221A is 8.2kg (18 pounds) without its pouch on top of it ;)

I like my Iwatsu, the Volts/Div and Time/Div, buttons need some maintenance time to time and after that it works perfect again.

On topic again :)

Thanks saturation  and nice to see those tests, and good to know they perform well too.

Offline T4P

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #4 on: March 11, 2012, 09:43:22 PM »
Dave.S you would think it’s a huge oscilloscope specially on that picture, but it is one of the compact oscilloscopes in its time, you remember my newly bought Tek 2221A right?
This Iwatsu is only 6kg (13,2 pounds) and easier to carry around and Tek 2221A is 8.2kg (18 pounds) without its pouch on top of it ;)

I like my Iwatsu, the Volts/Div and Time/Div, buttons need some maintenance time to time and after that it works perfect again.
So it's compact longitudinal-ly ?  ;D
http://the4thpin.comeze.com <-- Rants and Reviews! sorry my english  :palm:

Offline Spawn

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #5 on: March 12, 2012, 01:34:28 AM »
lol, yeap it was compact in those days now it’s more like a long toolbox.
For example on the front it is 43mm less wide than a Rigol DS1052E and 6mm higher, lengthwise it’s 3.5 times (287mm) longer than Rigol.

A quote from the manual first words:
The SS-5702 is a compact and lightweight oscilloscope which covers a frequency bandwidth from DC to 20 MHz.

Offline The Electrician

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #6 on: March 22, 2012, 06:41:34 PM »
I also bought some of these Chinese probes for around US$12 on eBay.  They are better than you would think.  The are advertised as being 100 MHz probes, but they are much better than that.

To test them, I used a Tektronix tunnel diode pulser which outputs a 125 picosecond rise time pulse into a 50 ohm load.  My fastest scope is an Agilent DSO5034A, 300 MHz bandwidth.

I connected the pulser through a 50 ohm feedthrough to the 1 megohm input of channel 1 of the scope and captured the rise of the pulser.  The result is in the first image.

I then set the scope input impedance to 50 ohms and fed the pulser directly into that input.  This result is shown in the second image.

Offline The Electrician

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #7 on: March 22, 2012, 06:46:12 PM »
Next I connected one of the probes, labeled PP-150 near the BNC connector, to the output of the pulser, with the probe set to 10x and with the ground lead connected to the ground of the pulser.  The ground lead was positioned to occupy a nearly circular loop.  The first attached image shows the result of this setup.  You can see substantial overshoot and ringing.

Then I wrapped the ground lead around the probe tip, to minimize the loop area of the ground lead.  This result is shown in the second image.

Offline The Electrician

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #8 on: March 22, 2012, 07:05:17 PM »
For these tests, I disconnected the ground lead and connected the probe tip with the included spring adapter directly to the output of the tunnel diode pulser.  This shows the fundamental response of the probe.  The first image is taken with the PP-150 (manufacturer name unknown) probe.  This probe has enough overshoot to make the rise time measure less than 1 nS.

The second image shows the performance of the Aidetek P6100 probe.  It has less overshoot than the PP-150.

The overshoot these probes exhibit is due to the extremely fast 125 pS rise time from the tunnel diode pulser.  If a rising edge with more than several nS rise time is applied, you don't see overshoot (without the ground lead, of course.  With the ground lead in use you will get overshoot and ringing even with nanosecond rise times).
« Last Edit: March 22, 2012, 07:26:44 PM by The Electrician »

Offline The Electrician

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #9 on: March 22, 2012, 07:17:07 PM »
I also bought two 100:1 probes for US$70 on eBay; they are rated 250 MHz.  The first attached image shows the rise time of one of these probes driven by the tunnel diode pulser.  The output of the pulser isn't large to start with, and by the time it's attenuated 100 times, the signal is weak.  But we can still see that the rise time is 2.2 nS.

The second image here shows the performance of the Agilent 10073C probe, rated as a 500 MHz probe.  The rising edge with this probe is very clean, with almost no overshoot.

The two Chinese probes are much better than their rated 100 MHz; I would call them 200 or maybe even 300 MHz probes.

alm

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #10 on: March 22, 2012, 07:20:45 PM »
What's the loading at 200/300 MHz for these supposedly 200/300 MHz probes? How do they perform when driven frome a higher source impedance?

Offline The Electrician

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #11 on: March 22, 2012, 08:47:49 PM »
What's the loading at 200/300 MHz for these supposedly 200/300 MHz probes? How do they perform when driven frome a higher source impedance?

The specification says the input capacitance is 18.5pF to 22.5pF, which is quite similar to Tektronix and Agilent probes.

But, it occurred to me that I might be able to get a better answer to your question.

I set up a network analyzer to sweep 100 kHz to 300 MHz and display impedance on a Smith chart.  The probe was connected to the input of the scope and the probe tip was poked into the center conductor of the network analyzer's connector; I used a piece of braid to connect the shell of the analyzer connector to the ground of the probe tip.

In the attached image, the white curve is for the Chinese probe and the yellow curve is the Agilent 10073C probe.

Offline saturation

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #12 on: March 23, 2012, 07:03:20 AM »
Thanks the electrician,  these are the best tests I've seen on eevblog for probe performance!

I recently obtained a Tek 284 generator that uses a tunnel diode to generate ~70ps pulses [ which I can't confirm is so at this point...] for doing higher speed tests in anticipation of a better scope in the future, currently I just have a Rigol 1052e. 

The fastest Chinese non-name passive probes I've found are 500 MHz, they are about $70-85 each, delivered, but at those prices I'm skeptical about no-name performance.  I've found that for the same money, Picoscope's TA069 look like the no-name 500 MHz one [ and the same accessories!], but I hope Picoscope does quality control on them.   One problem with no-names and Chinese label, is quality control: one can't be sure if buying another of the same brand or a no-name if the >= performance can be expected.

Preliminary tests on TA069 vs no-name 100 MHz Chinese label and the Rigol 200 MHz P2200 probes, provides qualitatively cleaner looking pulses but rise times are all rate limited by the Rigol.  Screen shots to follow later.

http://www.ebay.com/itm/500MHZ-Oscilloscope-Probe-Hp-Tektronix-/320841226231?pt=LH_DefaultDomain_0&hash=item4ab3a097f7

http://www.pc-oscilloscopes.com/product_info.php/cPath/40_45/products_id/569

TA069


'Texas' labeled 500 MHz Chinese probes:
« Last Edit: March 23, 2012, 07:05:16 AM by saturation »
Best Wishes,


Saturation

Offline The Electrician

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #13 on: March 25, 2012, 09:27:22 PM »
You notice that the rise time of my 300 MHz scope was 1 nS when the tunnel diode pulser was connected directly to the scope.  The rise time through the Chinese probes was also essentially 1 nS, so I would need a faster scope to truly measure the probe rise time, which must be better than 1 nS.

For a price of 10 to 15 dollars, these probes are amazingly good.  The build quality is good and I keep the Agilent 10073C probes put away and just use the Chinese probes for everyday use.

I notice the 500 MHz probes you mention have an input capacitance of 11 pF; not much better than the probes I tested, and a lot more money.  If a person really wants to probe very fast rising edges on a node of relatively high impedance with minimal loading, I think you would have to use an expensive active probe.

alm

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Re: Cheapest 100MHz oscilloscope probes hands on review
« Reply #14 on: March 25, 2012, 11:07:06 PM »
The specification says the input capacitance is 18.5pF to 22.5pF, which is quite similar to Tektronix and Agilent probes.
300-500 MHz bandwidth Agilent/Tek probes would have something like 8-12 pF of input impedance, or about half of the HF loading.

I set up a network analyzer to sweep 100 kHz to 300 MHz and display impedance on a Smith chart.
How accurate would a network analyzer be for this measurement, given that the impedance is very far from 50 ohm?

You notice that the rise time of my 300 MHz scope was 1 nS when the tunnel diode pulser was connected directly to the scope.  The rise time through the Chinese probes was also essentially 1 nS, so I would need a faster scope to truly measure the probe rise time, which must be better than 1 nS.
Rise time doesn't tell the whole story, however. The cheap probes showed substantial overshoot, much more than with the direct connection or Agilent probe, indicating an over-peaked response. This results in a higher apparent bandwidth, at the cost of transient response (accuracy at and shortly after the rising edge). A CW sweep of the probe across the scope's bandwidth might show a dip in the frequency response somewhere far below 300 MHz.

I would expect the performance with a fast high-amplitude signal to be substantially worse than the Agilent probe, since capacitors and resistors in the attenuation network will likely have some voltage coefficient.

For a price of 10 to 15 dollars, these probes are amazingly good.  The build quality is good and I keep the Agilent 10073C probes put away and just use the Chinese probes for everyday use.
I can see why you'd rather kill a $10 probe than a $200 probe, but I would still keep some good probes around for when accuracy matters or you don't trust the cheapies for some reason. My experiences with durability of the cheap probes and their accessories (eg. Rigol) aren't too good, but I guess for $10-15 you don't care.


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