hybridfree/eevblog-posts huggingface dataset:
To float or not to float.... - Page 1
Forum section: electronics / testgear

author: cybertronicify
author_rank: Regular Contributor
timestamp: September 04, 2014, 04:04:44 pm
content: Hello people!I was wondering what is the best option on my Korad KA3005D. It has +/- and Earth binding posts and should Earth be shorted out to GND? If you can, please explain to me what does floating ground mean and what does earthed ground mean.Thanks!!The Korad will be powered by a 110vac to 220vac transformer.http://www.ebay.com/itm/Goldsource-STU-300-W-Watt-Step-Up-Down-110V-220V-Voltage-Converter-Transformer-/160733095687?pt=BI_Circuit_Breakers_Transformers&hash=item256c706707

author: macboy
author_rank: Super Contributor
timestamp: September 04, 2014, 04:59:54 pm
content: There is no correct answer to this question. A lot depends on what you will be powering with this power supply.If it is a simple circuit with just this one power supply, and you won't be making measurements with a scope, then often, the - terminal is grounded so that the circuit ground is equal to earth ground.If you use multiple supplies, then often, only one has a terminal grounded. This prevents ground loops. Same idea when measuring using an earth-ground-referenced instrument like an oscilloscope. The ground lead on the probe is directly connected to ground. If you float the circuit, then you can connect this toalmostany reasonable point in the circuit, not just a 'ground'. But if you ground reference the power supply - terminal, then youmust onlyconnect the scope ground probe to a true ground. And even then, you are creating a ground loop which may or may not cause problems.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: September 04, 2014, 06:52:34 pm
content: In simple terms, a floating ground is relative to the circuit being used and does not necessarily always have to be 0V. A floating ground should not have a physical connection to an earth ground. An earth ground will always have an electrical path to the physical earth where voltages can be referenced and a return path for electricity.

author: cybertronicify
author_rank: Regular Contributor
timestamp: September 04, 2014, 11:34:10 pm
content: So ill just keep it grounded until i need to measure something or series the power supplies?

author: sleemanj
author_rank: Super Contributor
timestamp: September 05, 2014, 04:43:09 am
content: You should watch Dave's video on not blowing up your oscilloscope, the concepts are the same...

author: cybertronicify
author_rank: Regular Contributor
timestamp: September 05, 2014, 11:55:17 am
content: I've watched the video and it helped alot! I was wondering if i can use this as a isolation transformer.http://www.ebay.com/itm/Goldsource-STU-300-W-Watt-Step-Up-Down-110V-220V-Voltage-Converter-Transformer-/160733095687?pt=BI_Circuit_Breakers_Transformers&hash=item256c706707I have that step up/down and it does have a 110v in 110v out.
HP Power Supply Question - Page 1
Forum section: electronics / testgear

author: George_Race
author_rank: Regular Contributor
timestamp: September 03, 2014, 07:00:34 pm
content: I have an HP-E3611A that has a problem.The power supply works perfectly except for the Amps Display. It just keeps putting up sets of random numbers on the display, no matter what the Volts and Amps level controls are set at, all the way up, or all the way down. The volts indication is nice and stable and easily adjusted.I can setup a load for either CC or CV, and the proper LED lights up.Does anyone have any suggestions for a solution?Thanks,George

author: George_Race
author_rank: Regular Contributor
timestamp: September 05, 2014, 10:49:12 am
content: Problem solved! Half of the display board was setting there just counting up and down. No repair possible, all surface mount micro technology! New board is still available for $124.00Sold it on eBay last night for $50! If the new owner replaces the display he will have a like new power supply for a good price.George
Can newegg legally sell fake Saleae Logic Analyzers? - Page 1
Forum section: electronics / testgear

author: os40la
author_rank: Regular Contributor
timestamp: September 04, 2014, 08:27:04 pm
content: Is this legal? I can't believe Saleae would allow this.http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&Description=saleae&N=-1&isNodeId=1

author: Fsck
author_rank: Super Contributor
timestamp: September 04, 2014, 08:47:20 pm
content: pretty sure they can't sell a clone.maybe if it was just unbranded hardware with no mention of saleae, they might be able to.however, technically newegg isn't the one selling it, it's just newegg acting as an intermediary with their "marketplace" crap.

author: dannyf
author_rank: Super Contributor
timestamp: September 04, 2014, 08:56:55 pm
content: Is it newegg selling or someone selling through newegg?

author: Macbeth
author_rank: Super Contributor
timestamp: September 04, 2014, 09:05:45 pm
content: Clicked on the link and can't find any mention of "salae". Perhaps they have acted

author: os40la
author_rank: Regular Contributor
timestamp: September 04, 2014, 09:30:41 pm
content: They seem to be selling thru newegg. But still, it is their website they should validate that... I guess they don't...

author: os40la
author_rank: Regular Contributor
timestamp: September 04, 2014, 09:35:41 pm
content: Quote from: Macbeth on September 04, 2014, 09:05:45 pmMust be your location... The link still works for me...Here is my screen shot ....

author: Macbeth
author_rank: Super Contributor
timestamp: September 04, 2014, 10:45:28 pm
content: Yep, with my destination being UK, a search of saleae returns nothing relevant. Change it to USA, and do a new search, I get the same as you. However, I don't know enough about these things to know it is a fake / clone?

author: German_EE
author_rank: Super Contributor
timestamp: September 05, 2014, 10:05:09 am
content: I have one of these (or something very similar) It just about works but nine times out of ten I spend greater effort making it function than taking measurements. I suspect that the original item would be a better purchase.
Leader 8060 oscilloscope  - Page 1
Forum section: electronics / testgear

author: XenonFlash54
author_rank: Contributor
timestamp: August 30, 2014, 01:37:13 pm
content: Hello Everyone!I have been thinking about getting a oscilloscope for a while, and when a Leader 8060 popped up on ebay I decided to buy it. I attached a photo of it's face.Now it seems to not be working right. Like when I turn the 'V mode' switch to the CH1 position it displays all three traces. And when I flip it to the CH2 position, it displays all three traces too. But when I turn it to the dual position, it only displays two traces. When I flip it to CH1/CH2 position, shouldn't it only display one trace?Also, you have to turn the intensity all most all the way up to get a nice looking trace. And at higher frequencies the trace is really dim, even at full intensity. And also there's a 'Delay Time Mult' on the 'scope, does anyone know what that is? Because I have tried adjusting it in all most all the settings, and nothing has ever happened.Think it's a dud? I have got fourteens days to return it if it is.Although on the positive side of it, the horizontal time base seems to be spot on!Thanks for your time!!Dan

author: Andy Watson
author_rank: Super Contributor
timestamp: August 30, 2014, 02:10:16 pm
content: That dark line just below the third division on the graticule, is it dirt, a trick of the camera, or is the screen burnt? If it's the last option I would be sending it back.

author: XenonFlash54
author_rank: Contributor
timestamp: August 30, 2014, 02:31:13 pm
content: It's screen burn. Is there anything wrong with that except it being annoying?Thanks for your time!

author: David Hess
author_rank: Super Contributor
timestamp: August 31, 2014, 06:42:59 am
content: I doubt it is suppose to operate that way. The vertical mode switch might be damaged or worn or there could be a problem in the logic.Given that it also has a screen burn indicating misuse or long operating time, I would return it.

author: XenonFlash54
author_rank: Contributor
timestamp: September 06, 2014, 04:49:03 pm
content: OK, I guess I will return it then.Thanks for the help guys!
Flir E4 - Page 1
Forum section: electronics / testgear

author: Reegan
author_rank: Newbie
timestamp: September 04, 2014, 09:54:19 am
content: Hi guys, im in the market for a thermal imager and have been reading about the E4 hack etc. My question is, how does one check the firmware?The distributors here in South Africa said that once I purchase the E4 I register it using the serial number and download the firmware for it? Not sure what that means, but my main question is, how do I check to see what version firmware a unit is running? Id just like to know how to identify a units firmware before purchasing so I can see if its hackableCheers

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 04, 2014, 10:09:36 am
content: The only way is to turn on & look at the info screen.Your distributor is probably assuming you want the latest version.....Probably the best bet is to talk to the distributor and tell them that you will order only if they can supply a V1.22 or earlier FW version. Unless they've had units in stock for quite a while chances are it will be a more recent version

author: Reegan
author_rank: Newbie
timestamp: September 04, 2014, 10:46:36 pm
content: Thanks Mike, will try that. Considering this is South Africa im praying that they have some older units in stock, thermal doesnt seem to have really taken off here.
Rigol DS1074Z-S Maths A+B Function - Page 1
Forum section: electronics / testgear

author: Dave Turner
author_rank: Frequent Contributor
timestamp: September 04, 2014, 06:01:10 pm
content: Whilst On my Rigol I fed a10MHz sine wave from channel one of the inbuilt signal generator into channel one of the scope and another 10 MHz signal lagging at 90 degrees from channel two of the inbuilt signal generator into channel two of the scope.So far so good I see exactly what you'd expect to see. Two sine waves 90 degrees out of phase with each other.However when I enable the A+B math function the output is inverted to what is expected.Has anyone else seen this, is it an error with Rigol or have I possibly done something daft?

author: Dave Turner
author_rank: Frequent Contributor
timestamp: September 04, 2014, 09:30:35 pm
content: OK sorted - I found that the math function had a buried invert facility which I hadn't previously seen.Math button -> Math (Right Down) -> Options -> Invert
Rigol Scope - Page 1
Forum section: electronics / testgear

author: Xplosiv166
author_rank: Newbie
timestamp: September 04, 2014, 01:53:30 pm
content: Hi,I am after a new DSO for home use, mostly low voltage analogue stuff (PSU design, small signal sensors for etc) I have no interest in any of the digital logic analyser features as I already have a very good standalone Logic analyzer for this.After some research I have decided on either the Rigol DS2072A or the Rigol DS2102A so before I actually buy one I thought I would ask the community if there was anything else worth looking at in my price range, which is between £700 to £1200 (i maybe go a little higher).NOTE: it is to replace my crappy Hantek USB oscilloscope which is no good for accuracy ......Thanks for any help you maybe able to give me.Andy

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 04, 2014, 04:00:36 pm
content: Quote from: Xplosiv166 on September 04, 2014, 01:53:30 pmHave a look at the Siglent SDS2000 Series, i.e. the SDS2074. Reports suggest it's a very good entry level scope, and unlike th Rigol DS2000 it's also available as four channel variant which should be right within your budget.

author: tautech
author_rank: Super Contributor
timestamp: September 04, 2014, 08:23:46 pm
content: Quote from: Wuerstchenhund on September 04, 2014, 04:00:36 pmFor more information see the best review on the net by membermarmad:https://www.eevblog.com/forum/testgear/review-siglent-sds2304-a-comparison-of-features-with-rigol-ds2000-series/
New Siglent Support Email Address - Page 1
Forum section: electronics / testgear

author: Unknown
author_rank: Unknown
timestamp: September 04, 2014, 03:12:19 pm
content: Greetings to all.Effective immediately, we have a new general support email address that comes to our new office here in the the United States. The address is:info@siglent.comWe look forward to hearing from you!Thank you.Steve
too good to be true? - Page 1
Forum section: electronics / testgear

author: kt315
author_rank: Regular Contributor
timestamp: September 05, 2014, 01:09:17 am
content: I've ran a quick search, but could not find anything in the older post. My apologies if it have been discussed before.Does any anyone have one of these:http://www.ebay.com/itm/261499015291?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT?It looks rather interesting, but I do not see the temperature coefficient specified anywhere.Any ideas what part it is based on?Cheers.

author: Bored@Work
author_rank: Super Contributor
timestamp: September 05, 2014, 05:34:31 am
content: Quote from: kt315 on September 05, 2014, 01:09:17 amEh, no. More on the expensive side. Seehttps://www.eevblog.com/forum/beginners/t17704/for an alternative.

author: kt315
author_rank: Regular Contributor
timestamp: September 06, 2014, 05:20:08 am
content: Thanks. Appreciate the pointer.

author: tszaboo
author_rank: Super Contributor
timestamp: September 06, 2014, 09:57:22 am
content: Since it settles in five minutes, it cannot be a heated zener reference. Since it is not a heated zener reference, the +/-6 PPM and the claimed "Temperature drift is 0.3ppm/C" in the other auction by the same seller just cannot be guaranteed.I would assume it contains a ADRxxx reference. I would not buy any voltage reference (on this level) which I don't know the internals, or the supply chain is not verifiable.

author: kt315
author_rank: Regular Contributor
timestamp: September 07, 2014, 03:39:33 am
content: Thanks for the responses. I actually bought this unit (before posting the question here): "more money than brains" syndrome.Have I found the part of the discussion on LTZ1000 thread earlier I probably would refrain ...I came across a Fluke 335A a few weeks ago, which was "pulled from a working environment", but have not been recently calibrated. I was looking for a way to get at least some idea how much out of calibration it is.I contacted the seller to get the tempco of the mysterious reference. He asked me for the serial number, which implies the part has changed at some point, and came back with TI REF102 for my unit:http://www.ti.com.cn/cn/lit/ds/symlink/ref102.pdfI compared the difference between the little black box and the fluke at a couple of temperatures (26C and 18C, which it was calibrated at). Nothing scientific -- just was trying to reproduce the conditions it was nulled at as close as possible. The difference between two measurements was a few 10s of uV. The Chinese reference deviate quite a bit more.At the time I did not write down all the numbers, but all in all, the little black box seemed to be more stable than product of Far East. I'd have to go thru the same process to get specific numbers though.All in all, at 18C the difference between the fluke and the little black box end up bing around 270 uV. Which is way better than I hoped it would be.
Hantek - build additional kernel modules from GPL source - Page 1
Forum section: electronics / testgear

author: gicho
author_rank: Newbie
timestamp: September 04, 2014, 02:01:55 pm
content: First post here, but - I've got the GPL sources for kernel 3.2.25 of DSO5102P, made some small tweaks and everything builds fine. Then I re-configured the kernel and got some additional modules - usb lan, usb wireless, bt, etc.Now I am looking for some assistance to use them on the scope. Ultimate goal is to get automatic "dropbox upload" of screen captures ("save") over LAN/WiFi/BT. Maybe I will need USB HUB to be able to connect a storage stick and the wifi/bt/lan? But maybe I could skip this - I suppose that one ("current") screen capture could just fit in /tmp and be uploaded from there?Any ideas about a simple console style linux tool for "cloud" uploads? Or to network file system?Any notes on rcS modifications and maybe wifi startup would be helpful too.
Hooking up a multimeter to 240v mains on DC mode - Page 1
Forum section: electronics / testgear

author: ninjastrike
author_rank: Contributor
timestamp: September 03, 2014, 06:55:09 pm
content: Hello,I recently acquired a Uni-T UT61T multimeter. I hooked it up to the mains to test meter out.I mistakenly left it in DC mode, and got the smell of "burning" electronics.The meter works fine from the basic tests that i've carried out.Took it apart and saw no visible charring on the pcb.Is this a problem ? Could it cause my meter to go off calibration?Cheers,Ash

author: Wytnucls
author_rank: Super Contributor
timestamp: September 03, 2014, 07:10:42 pm
content: As long as you didn't measure anything above 1000V, the meter will be fine.

author: ninjastrike
author_rank: Contributor
timestamp: September 03, 2014, 10:10:03 pm
content: Thanks mate!
Uni-T Ut61e: Strange problem after trying to mod it - Page 1
Forum section: electronics / testgear

author: ghild
author_rank: Newbie
timestamp: September 02, 2014, 12:41:00 pm
content: Hi folks, i'm new to the forum. Sorry for my poor english, it is not my first language.After trying to mod my DMM to put backlight function and auto power off, my DMM is behaving exactly the same way as seen on this video from another person:http://youtu.be/zaFsA8M0edII've cleaned the legs of the IC with isopropyl alcohol, checked for solder bridges, three times already, and nothing changes.Readings on mV, Ohm, Capacitance and Frequency are not working anymore. If i put the meter on the Ohm scale and press the blue button, nothing happens, only random readings.Any help to fix it is appreciated. Thanks!

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: September 02, 2014, 01:54:37 pm
content: Re-check your connections, solder.If there are any elastomeric connectors, check the alignment, clean if necessary.If all else fails, remove the mod and check to see if operation returns to normal. If not, then maybe some damage occurred during the mod.

author: ghild
author_rank: Newbie
timestamp: September 03, 2014, 02:58:58 pm
content: Thanks for your reply Terabyte,I've already removed the mod, checked and re-checked for solder and conections. Any chance the chip got burned only on these operations mods?Thanks!

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: September 04, 2014, 06:39:21 pm
content: Quote from: ghild on September 03, 2014, 02:58:58 pmIt's possible that something was damaged during the mod. Depends on the malfunction, but partial operation or lack thereof can happen.
Trinocular + C-Mount USB-CAM as an alternative to DIYIHK 1080p scope - Page 1
Forum section: electronics / testgear

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: September 03, 2014, 09:35:54 pm
content: As theDIYIHK 1080p microscopeis somewhat tempting but not really a bargain, I wondered if it would make sense to combine an affordable Trinocular microscope with a fast C-mount camera instead for SMD soldering/inspection/documentation.E.g. something like this for the Trino could be usable:http://www.euromex.com/gb/catalog/euromex-stereoblue/1396/euromex-stereoblue-trino-zoom/8205/orhttp://www.amazon.de/NECTARIS-Trinokular-Stereo-Mikroskop-7-45x/dp/B002YSZ7JUIt took a bit of searching around, but finally I found a fast C-mount camera based on an AR0130CS sensor:http://www.teleskop-austria.at/shop/index.php?lng=de&m=2&kod=foto-asi-120-mikThere is an USB3.0 version on the way which even claims to reach 60fps at 1280x960:http://www.zwoptical.com/Eng/Cameras/ASI120S/index.aspSo for ~700€ (including VAT), you could get a zoomable stereoscopic microscope plus a fast (>30fps at full resolution) and reasonably hires (1280 x960) USB scope.Admittedly, this is about three times the price of the diyinhk scope, but still somewhat affordable and with quite a few benefits (zoomable, usable as normal stereoscopic microscope,better refresh rate at only slightly worse resolution).
Acqiris/Agilent PCI Digitizers  - Oscilloscope card - Page 1
Forum section: electronics / testgear

author: psykok
author_rank: Frequent Contributor
timestamp: September 04, 2014, 08:41:15 am
content: Hi,I just found an old Acqiris DP250 (now Agilent) PCI Digitizers card im my stock:http://www.keysight.com/en/pd-1183048-pn-U1069A/acqiris-8-bit-high-speed-pci-digitizers?cc=US&lc=engIt seems that this card can just turn any pc in a nice DSO.Has any one some experience with such systems?Regards,Alex

author: andy_silicon
author_rank: Regular Contributor
timestamp: September 04, 2014, 06:47:19 pm
content: Yes - I have a couple of 500Mhz versions in a box.I used them a few years ago - depending on the configuration they can have large memory and the ability to perform interval captures. I.e. Multiple frames of high speed capture with delays between frames.They have a 50ohm input ( well mine do )Linux was my OS of choice for those.The SDK came with a simple oscilloscope app as far as I recall.
VIDEO - AADE LC Meter - Page 1
Forum section: electronics / testgear

author: Aaron D. Parks
author_rank: Contributor
timestamp: September 02, 2014, 08:23:54 pm
content: Hi! Long time reader, first time poster.This isn't a tear-down video, but rather a build-up video since it's a kit.It's the first video I've done in this style, so any feedback or comments would be appreciated. I noticed when editing that I sound like I haven't had my coffee. Well, I hadn't!I'll try to be more animated in the future.
Agilent 54622D MSO Digital 16 channel port pinout - Page 1
Forum section: electronics / testgear

author: jeremyabel
author_rank: Newbie
timestamp: September 01, 2014, 10:35:05 pm
content: Hello all,So, I got a 54622D last week, for about $250 off ebay, but it didn't come with that weird cloth logic probe pod thing, and I see that prices for that bit alone are $250, which seems like a bit much, considering the manual states that they're passive. Would anyone happen to know the pinout of the 2x20 connector on the front? There is of course no schematic available, so I'm just hoping maybe someone knows it off hand, or had a logic probe pod they could look at and see where the wires go? Might have to open this thing up otherwise; my multimeter was giving me weird readings in continuity mode between most of the pins...Thanks!

author: alex.forencich
author_rank: Frequent Contributor
timestamp: September 02, 2014, 06:04:45 pm
content: One row is all grounds. The other row has a couple of supply voltages along with all of the logic inputs. Just take a clip lead and a resistor (say, 10k), clip the resistor to the probe compensation test point, turn on digital channels, and start touching the other resistor lead to the pins one at a time and see what shows up on the scope. Shouldn't take all that long to work out. As for the grounds, turn the scope off and get a multimeter. Then find the biggest block of pins that are all shorted together.

author: nctnico
author_rank: Super Contributor
timestamp: September 02, 2014, 06:07:48 pm
content: I'm pretty sure the pods contain some circuitry. At least a passive divider network to match the impedance of the braided wires.

author: alex.forencich
author_rank: Frequent Contributor
timestamp: September 02, 2014, 06:13:38 pm
content: True. See page 12 of this PDF for a schematic of the 'standard' flying lead probe:http://www.transcat.com/PDF/E5383A.pdf. Looks like 250 ohms in series with 90.9k in parallel with 8.2 pF.

author: MarkL
author_rank: Unknown
timestamp: September 02, 2014, 07:04:42 pm
content: And see further in that same document on page 38. It lists all the signals on the 40-pin connector. No guess-work needed.

author: PaulAm
author_rank: Frequent Contributor
timestamp: September 02, 2014, 08:12:16 pm
content: The LA probe is gawd awful expensive if you can find it. However, you can look for an HP 54620a LA with cables. Nobody wants these things because they're only 16 channels, old technology, no LCD, yada yada, but the cable is compatible across the 546xx line. I found one with all the cables and grabbers that I use with my 54645d that was $55 shipped. Heck, you could pay more just for the grabbers.Actually, the 54620a isn't a bad LA for $55 either.HP used that braided cable on a lot of their LA cabling. Unfortunately, it's almost impossible to find just the cable for any reasonable amount of money.
Multimeter LSD count error repeatability - Page 1
Forum section: electronics / testgear

author: tomlut
author_rank: Regular Contributor
timestamp: August 29, 2014, 12:48:38 pm
content: I was explaining why a multimeter was no good for measuring low (less than 1 ohm) values because the count error dominates like this:QuoteNow, my question: How repeatable is the count uncertainty error? Can a DMM's relative measurement function be used to remove it's effect or is it time, temperature and/or battery voltage dependent?

author: Lightages
author_rank: Unknown
timestamp: August 29, 2014, 05:44:28 pm
content: The LSD error stated is the worst case for all meters in production and that each will have its own maximum error. The LSD error will depend conditions at the time of the measurement too. My guess, I don't know for sure, is that each meter will have its own characteristic error that can be determined and used to at least partially correct for the error but it will have to be characterized for all conditions of use. For example you might need to log the temperature, humidity, electrical environment, and all against the voltage range and function being used. It would be rather cumbersome IMHO.Probably you can characterize a general environment and make at least a partial correction to the reading.As I said the above is all a guess based on some experience. For me, I wouldn't rely on such a correction unless it was checked and rechecked with some real statistical analysis over many measurements.This could be a good experiment for somebody with a few multimeters, a good reference, and a lot of time on their hands

author: Artraze
author_rank: Contributor
timestamp: August 29, 2014, 09:22:11 pm
content: Looking at the HP 3457A (a 6 1/2 digit meter) specifications for the 30 Ohm range:24hr Accuracy, @ Tcal +/-1C: 215 counts (and 0.003%)90day Accuracy, @ Tcal +/- 5C: 315 counts (and 0.0065%)1year Accuracy, @ Tcal +/- 5C: 315 counts (and 0.0075%)So while clearly there is additional error accumulated over time and environmental changes, there exists a baseline amount of error that is simply an unknown. Indeed, most of the long term drift appears in the form of % error, while the count error tends to remain fairly constant.In the case of this meter, where the short version of the specs (which would consider a 1 year calibration period) might say "315 counts", you could get 215 counts of usable precision within a 24hr period at the same temperature, but not more.

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: August 30, 2014, 04:03:48 am
content: In my personal experience, short-term LSD repeatability is EXTREMELY high with even crappy meters. I'd be willing to bet the accuracy specs there are driven by tempco.

author: tomlut
author_rank: Regular Contributor
timestamp: September 02, 2014, 10:40:51 am
content: Thanks for the replies. Interesting, didn't think it would be that repeatable.It's a moot point now anyway as I built a precision 100mA constant current source to measure the sub Ohm resistances.
Blue esr meter from trans electronics - Page 1
Forum section: electronics / testgear

author: baconsteak
author_rank: Contributor
timestamp: September 02, 2014, 03:12:11 am
content: Hi has anyone here had dealings with trans electronicshttp://www.blueesr.transelectronics.com.au/?Their website doesn't work. I shot them an email on sunday but haven't got a reply.Does anyone know if there is a difference between this and the altronics unit (http://www.altronics.com.au/p/k2574-esr-meter-kit/) besides power supply?

author: baconsteak
author_rank: Contributor
timestamp: September 02, 2014, 04:33:00 am
content: Found both schematics. They are almost identical. I ordered the one from altronics and it's marked shipped already.http://members.ozemail.com.au/~bobpar/k7214.pdfhttp://www.blueesr.transelectronics.com.au/Blue_ESR/Blue%20ESR%20assembly%20manual.pdfI guess something different could be updated in the micro.Edit: Arrived today at 830am. Not bad for Sydney to central coast on 6 bucks postage.Brilliant quality. Glad I got it from Altronics.
Tektronix 492 Spectrium Analyser - Page 1
Forum section: electronics / testgear

author: Psi
author_rank: Super Contributor
timestamp: August 31, 2014, 11:04:44 am
content: I have the chance to buy a tektronix 492 spectrum analyser. Price unknown at this stage but i think he wants around NZ$600 so ~500USDHas anyone used one of these and have anything to say about them?http://72.29.85.210/~radioama/instruments/TEK%20492%20user%20manual.pdfQuoteI know they are old but any spectrum analyser is better than none.I need the 5.8ghz band which means the bottom range of modern analyzers aren't of any use to me. And the rest are too expensive

author: bingo600
author_rank: Super Contributor
timestamp: August 31, 2014, 02:52:40 pm
content: Searchhttps://www.eevblog.com/forum/testgear/tecktronix-492p-spectrum-analyser/msg499484/#msg499484/Bingo

author: G0HZU
author_rank: Super Contributor
timestamp: August 31, 2014, 09:47:09 pm
content: For $600 it looks very good value (if you need a basic >5.8GHz analyser) as long as the RF performance meets your needsI'm not really that experienced with the 492 but I did skim through the RF specs and a few things may be an issue. The std spec has no limiter protection for the first mixer up to 1.8GHz. So the damage level could be as low as +13dBm on low (typical!) attenuator settings.Option 1 adds the limiter.If you want to do any work on narrow spans then option 3 adds the phase lock option on narrow spans. This would be a very attractive option because it also includes a 100Hz RBW filter.Unless you hit lucky and bag something like an HP8592 (or the vastly superior HP8561/3) for a stupidly low price then I think you will struggle to get better value for money than the $600 Tek492 even if it has no options fitted.The other alternative is to get something like a Rigol 815 and build a simple external downconverter from 5.8GHz.

author: Psi
author_rank: Super Contributor
timestamp: September 02, 2014, 12:53:30 am
content: Thanks guysLooks like the only module fitted is Option 2, digital storage and averaging
Help with repair on Rhode & Schwarz SMG w/ options B1 & B2 - Page 1
Forum section: electronics / testgear

author: wattw
author_rank: Newbie
timestamp: August 31, 2014, 07:39:24 pm
content: I have new-found respect for the complexity of high performance signal generators! I am working my way through the error codes on a disappointing eBay purchase and I think that I am down to the last issue which is a dead 50 Mhz osc. on the A2 FRN Loop module.As these modules are highly shielded, and I lack the service extension cards/cables to hot-test the module outside the "frame" - does anybody have any experience that may short-cut the "blind testing of cold components? Thanks, Bill

author: tautech
author_rank: Super Contributor
timestamp: August 31, 2014, 08:45:42 pm
content: You may have to make your own extension cable.I have had to on occasion, one such: an old PC IDE drive ribbon cable, a custom made PCB edge to slide in to the socket and a modified PCB card socket from the junk pile.Rough, but got the module powered up and the fix done.

author: nctnico
author_rank: Super Contributor
timestamp: September 01, 2014, 11:21:28 pm
content: In these cases I solder wires to the boards (long enough to stick outside the shielded case) and probe from there.
Editing Agilent MSOX Arbitrary Waveform - Page 1
Forum section: electronics / testgear

author: jstarr
author_rank: Regular Contributor
timestamp: August 29, 2014, 03:58:27 pm
content: I stored a serial bus data 10 byte data packet (9600 Baud) as an Arbitrary waveform. I now want to have it outputted --- pulsed every 1 second. However when I use the Wavegen editor the only option I see is to change the frequency or period but doing this simultaneously stretches out the individual bits which of course distorts the BAUD rate between bits badly. I used the maximum number of data points to capture the data packet (about 10 msecs long) so I can't add a 990 msec lead or tail to the waveform. Can anyone tell me how to do this on the Agilent 2000x scope?thanks

author: alex.forencich
author_rank: Frequent Contributor
timestamp: August 31, 2014, 05:55:19 pm
content: Can you put it in external trigger mode and then trigger at 1 Hz with another generator?

author: MarkL
author_rank: Unknown
timestamp: September 01, 2014, 04:29:55 pm
content: The wavegen feature on the Agilent/Keysight 2000/3000 scopes is weak compared to a real arb generator. It's either in free-run or off, and has no external inputs that allow trigger/sync or modulation. It also has a very small number of points (8192). (I suspect Agilent doesn't want to cannibalize their arb generator sales by giving it more functionality.)I think the best you can do for simulating your data stream is to manually rebuild your 10-byte packet using the full 8192 point memory and arrange the timing so that you place one bit per arb point. This would use up 10 bytes x 10 bits/byte = 100 points for the packet, and you would leave the other 8092 points at idle.Still, this doesn't get you a full second, but it's close: 8192/9600 = ~0.85secs per repetition.An easier alternative is to use a computer and a serial dongle or one of these FTDI serial dev boards (scroll down about half way):http://www.ftdichip.com/Products/Modules/DevelopmentModules.htmI use the FT4232H Mini-Module which gives you 4 channels of RxD/TxD for serial data injection and monitoring.

author: MarkL
author_rank: Unknown
timestamp: September 01, 2014, 04:49:00 pm
content: Actually... Does the 2000X series even have arb capability?Maybe it does, but I don't see it in the datasheet or manual. The only cababilities mentioned are pre-programmed waveforms.
Tektronix SC501 o'scope - got her working - Page 1
Forum section: electronics / testgear

author: crusader66
author_rank: Contributor
timestamp: September 07, 2014, 10:00:24 pm
content: I decided to take a crack at getting my SC501 working. It turns out all it needed was patience and CRC QD Electronic Cleaner. The blue LEDs beneath are the guts from my 4 year old son's cheapy carnival toy.
Buying new multimeter PHILIPS PM2524 - Page 1
Forum section: electronics / testgear

author: Simon123
author_rank: Regular Contributor
timestamp: August 31, 2014, 09:54:09 pm
content: Howdy!On flea market i saw this multimeter selling for 25€.(dont know if its working)It looks in pretty good condition.My offer was 20€ but seller didnt like it.So my q is if i should pay that extra 5€?How good it is, i read its good and precise, but does any of you have any experience?How fail proff it is?

author: markce
author_rank: Regular Contributor
timestamp: August 31, 2014, 10:09:51 pm
content: Hi Simon,I've had a meter like that. It's rather basic but if in good condition quite accurate.I do not like the switches, the corrode over time and are not so easy to clean.Front panel is basically plastic with thin metal cover. Due to aging this is not very strong.Sold mine for Eur 25 in favor for a PM2528 which I still have.

author: Simon123
author_rank: Regular Contributor
timestamp: August 31, 2014, 10:15:11 pm
content: Thanks!If he will still have it il buy it.What about some 5V battery power supply?Could a battery with 7805 be used, cause i will also need a meter in school(till i get some hand held model)?

author: markce
author_rank: Regular Contributor
timestamp: September 01, 2014, 08:08:41 am
content: Battery supply for the meter is a PM9216 rechargable pack, which is no longer available.Accuracy of the meter is good in DCV, but average in other ranges. The meter has a fixed 2A current rangeand adjustment pots all over the place! There is a free service manual for it on the net.Check the meter you buy.

author: Simon123
author_rank: Regular Contributor
timestamp: September 01, 2014, 03:49:04 pm
content: Yea, thanks didn't knew whats up with battery.I already checked the schematic and looks serviceable except some custom parts.There is also nicely described adjustment step by step.
BK 1739,  Maynuo M8831 or other low current power supply - Page 1
Forum section: electronics / testgear

author: kwass
author_rank: Frequent Contributor
timestamp: August 30, 2014, 03:09:12 am
content: I'm looking for a low current/low voltage, simple (no need for programming) power supply with high resolution settability and readback. The BK 1739, comes pretty close to my needs but seems incredibly expensive for what it is:http://www.bkprecision.com/products/power-supplies/1739-low-current-high-resolution-dc-power-supply-30-v-999-9-ma.html.Is BK just re-branding something that's much less expensive?I'm considering the Maynuo M8831 as well. I really like the excellent resolution on this but the display seems very small. Are their other options that I should be considering?Thanks,Katie

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: August 30, 2014, 03:53:01 am
content: It seems that by "high resolution" you mean 10mV and 10mA, which really isn't super duper high. That said, good linear supplies with the kind of low noise and ripple to make that resolution worth something tend to be on the expensive side. And supplies with 3.5digit displays are much less common than 2.5 digits. I'd look at second-hand top-tier supplies - I picked up an Agilent U8001A the other month for $200, that meets your specs nicely. There is, for example, this:http://www.ebay.com/itm/HP-Agilent-66312A-/181506988271?pt=LH_DefaultDomain_0&hash=item2a42a8d8ef

author: kwass
author_rank: Frequent Contributor
timestamp: August 30, 2014, 04:28:58 am
content: Thanks for those suggestions. The 10mV readback is okay, but I need at least .1ma readback. The old Aglient 661xC (or 66312a you mention) series are a possibility because they have a low current range, but the displays on many of the used ones can be dim. The U8001A looks really nice, but its readback is only 10ma.

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: August 30, 2014, 04:48:23 am
content: 0.1ma? That's definitely SMU territory. Even the 3631a only has 1ma resolution, and that's $5-600 used.

author: Fsck
author_rank: Super Contributor
timestamp: August 30, 2014, 04:57:38 am
content: how much current do you need?if you can live with 100mA max, a used keithley 220 is a great buy.

author: Warhawk
author_rank: Frequent Contributor
timestamp: August 30, 2014, 11:25:13 am
content: Quote from: kwass on August 30, 2014, 03:09:12 amHave a look at Twintex TPM-3003. I haven't had a chance to do a proper review and tests but my first impression is very good.

author: kwass
author_rank: Frequent Contributor
timestamp: August 30, 2014, 04:27:40 pm
content: Quote from: Warhawk on August 30, 2014, 11:25:13 amThe TPM-3003E looks like a good alternative, not sure where to buy one in the US however. It looks pretty new maybe they'll be more available soon. Where did you get yours?QuoteI really need something more versatile than a current source with 1 volt steps, but I do like the old Keithley equipment.

author: Warhawk
author_rank: Frequent Contributor
timestamp: September 01, 2014, 10:10:57 am
content: Quote from: kwass on August 30, 2014, 04:27:40 pm
Best cleaning solution for faceplates, knobs, switches, etc. on vintage scope? - Page 1
Forum section: electronics / testgear

author: Electro Fan
author_rank: Super Contributor
timestamp: August 30, 2014, 11:32:44 pm
content: Just checking to see what is recommended for removing grit and grime from vintage gear without taking off finishes and lettering on metal and plastic faceplate parts? Plain old mild soap and a damp soft cloth or something else?

author: tautech
author_rank: Super Contributor
timestamp: August 30, 2014, 11:54:33 pm
content: Just a search in the forum for "restoration" should deliver all the info you need.Here's a few to get you started:https://www.eevblog.com/forum/testgear/tek-7603-scope-w-7a18-amp-7b53a-timebase-restoration/msg172135/#msg172135https://www.eevblog.com/forum/beginners/old-test-gear-restoration-questions/msg86113/#msg86113https://www.eevblog.com/forum/reviews/old-'scope-preventative-maintenance-and-restoration-ideas/msg90544/#msg90544

author: 4thDoctorWhoFan
author_rank: Regular Contributor
timestamp: August 31, 2014, 12:08:59 am
content: For metal & certain types of plastic, I highly recommend Simichrome Polish. It's fantastic stuff that really cleans & shines without damaging the finish or lettering or at least it has not damaged any finish and lettering on equipment that I have used it on so far.For all plastics, I have to go with Novus #1 for normal cleaning or Novus #2 for a little more muscle. Excellent products.For example, I just restored a Sansui 1978 G-8000 receiver and the faceplate on this thing was filthy. I tried numerous different products and Simichrome was the only thing that brought it back to life. I also used Novus #1 to clean the glass & plastic parts. Not much plastic on this beast as it is mostly aluminum.Here are some pictures, the first being a BEFORE & the 2nd picture is AFTER cleaning: (the BEFORE picture does not really show the true filthiness of the faceplate:

author: kwass
author_rank: Frequent Contributor
timestamp: August 31, 2014, 12:38:45 am
content: Quote from: 4thDoctorWhoFan on August 31, 2014, 12:08:59 amI'll second that! Avoid Novus #3, it's way too abrasive.

author: Stray Electron
author_rank: Super Contributor
timestamp: August 31, 2014, 01:59:54 am
content: Check your cleaning solution in an inconspicuous place first! I took all the display lettering off of my first GRC DigiBridge just using water and a bit of soap!
Agilent 34970A sampling rate - Page 1
Forum section: electronics / testgear

author: tcsaba101
author_rank: Contributor
timestamp: September 01, 2014, 09:56:47 am
content: Based on the forum discussion I have set up my ATE.here:https://www.eevblog.com/forum/testgear/how-to-build-an-ate/msg479564/#msg479564Yesterday I have made my first "serious" data logging: a Car battery current measurement in the car from opening the door, starting, charge, etc, .The setup:34970A34901A 20ch multiplexerE2050A LAN GPIB converterHp notebook + crossover cableBenchlink software for 34970A300A shuntOfficially the 34901A can work at 60samples/sec.That gives less then 100ms for 5 channel and less then 20ms for 1 channel.First I have made 5 channel test programmed to 500ms sampling that gone flawless.Then programmed 100ms sapling rate, but it has made at 300ms sampling (precisely 287ms).Finally I made 1 channel sampling when no relay open/close time needed, one channel connected permanently but didn't gone under 42ms the samling rate. (see pictures on two cars)Originally I wanted to ask why not get the specified rate?But immediately I have get in my mind why I couldn't go faster: because the specification is for 4,5 digit readings and I had 5,5 digit resolution programmed.Still the single channel 42 ms is too much.1 PLC integration is 20ms, a bit more sampling time would be acceptable.I have programmed a second channel setup in the Benchlink program a calculated channel, that one calculates the current from the one measured shunt voltage, maybe that calculated channels takes the second 20ms?Is there info existing what is the expected sampling rate for 5,5 digits and 6,5 digit readings with 34901A or 34902A?

author: tszaboo
author_rank: Super Contributor
timestamp: September 01, 2014, 12:26:06 pm
content: Csaba, do you have auto zero on? That aproximately doubles the measurement time, as it will make a zero offset measurement before sampling the real signals.

author: tcsaba101
author_rank: Contributor
timestamp: September 01, 2014, 02:01:13 pm
content: Quote from: NANDBlog on September 01, 2014, 12:26:06 pmThat looks to be a good idea.After reading the regarding users manual section:Definitely the Autozero is on, because it is the default state, and cannot be disabled from the front panel.When the integration time is set to less than 1 PLC, it is disabled. This is the only way to control from the front panel.It has to disabled from the remote interface, and also possible to make a remote commanded "one time autozero cycle".The Autozero params are stored in a volatile memory, so after every power up it has to be done.Next time I will try using disabled Autozero!Thanks.
Sonic level meter recommendation - Page 1
Forum section: electronics / testgear

author: davorin
author_rank: Unknown
timestamp: August 30, 2014, 11:15:29 am
content: As I'm currently in the works replacing noisy fans in my measurement equipment I though I look around on ebay for some sonic level meters...See plenty of low cost handheld ones probably from China....are those $10 - $20 meters any good just for measuring noise in my lab? (o;

author: tautech
author_rank: Super Contributor
timestamp: August 30, 2014, 09:09:10 pm
content: Quote from: davorin on August 30, 2014, 11:15:29 amCould you not achieve a quantitive measurement with just a mic and a DSO p-p reading at a set distance?

author: davorin
author_rank: Unknown
timestamp: August 30, 2014, 09:17:17 pm
content: I thought of that as well....but the only mic I have is a Grundig capacitive microphone from the 50s...requiring 100V DC bias voltage (o;Ordered now tonight some new fans for testing in my 9354AL DSO....
SIGLENT SDS1102CML - Page 1
Forum section: electronics / testgear

author: kaveendra
author_rank: Contributor
timestamp: August 29, 2014, 07:29:48 am
content: I bought an Oscilloscope!Even though I have used Oscilloscopes many a times, this is the first I ever bought for myself. One of the main constraints were the price, of-course, which was under AU$500 and was searching for the best deal out there. I have found TRIO (http://www.triotest.com.au), a local dealer, who gave me a very good price over the other stores. Roland, the nice gentlemen there were very helpful all throughout.If any body in Australia looking for test equipment, I would highly recommend TRIO, as they carry an impressive range of test equipment including the Agilent/Keysight line.Will post my view and experience on the SDS1102CML, as it goes. The first impressions are very good and probably the best deal out there for the price point AU$389.00 Ex GSTThis is a clear winner over the RIGOL E series (DS1052E /DS-1102E), based on specifications

author: Rick Law
author_rank: Super Contributor
timestamp: August 30, 2014, 02:18:09 am
content: Quote from: kaveendra on August 29, 2014, 07:29:48 amCongrats...
Oscilloscope in Las Vegas - Page 1
Forum section: electronics / testgear

author: jeanguypataterub
author_rank: Contributor
timestamp: August 28, 2014, 12:58:08 pm
content: Does anyone know where I could buy test equipment in Las Vegas? I'm looking for an oscilloscope and a power supply.Thanks advance for your helpPierreSent from my iPad using Tapatalk

author: kwass
author_rank: Frequent Contributor
timestamp: August 28, 2014, 03:46:08 pm
content: I've never been there, but there's a Fry'shttp://www.frys.com/ac/storeinfo/las_vegas-location-frys-electronics-hours-maps-directionsand they should have a small selection of power supplies and o'scopes in store.

author: jeanguypataterub
author_rank: Contributor
timestamp: August 28, 2014, 04:38:32 pm
content: Thanks for the info I'll check it out.Sent from my iPad using Tapatalk

author: true
author_rank: Frequent Contributor
timestamp: August 29, 2014, 11:52:11 pm
content: The Las Vegas Frys has a pretty poor selection of 'scopes (Teks with floppy drives and such) and their PSUs are wildly overpriced. But they have a ton of components if you really need to prototype something basic RIGHT NOW.As far as what to get - I got most of my stuff online, not locally. The only thing I've purchased local in Vegas is a used Fluke 189.