hybridfree/eevblog-posts huggingface dataset:
got my stencil, now what do I do with it ? - Page 1
Forum section: electronics / beginners

author: Simon
author_rank: Unknown
timestamp: August 27, 2015, 11:57:31 am
content: So I have my PCB's and stencil. but how do I use the stencil. Surely I will need something to hold it down with, some sort of adjustable jig (I've seen some on ebay but can't remember the name). So what should I use ?

author: matseng
author_rank: Frequent Contributor
timestamp: August 27, 2015, 12:27:38 pm
content: Maybe something like this - but only if you made holed for the tooling pins....http://www.hoektronics.com/2012/10/27/super-simple-smt-stencil8/

author: deephaven
author_rank: Frequent Contributor
timestamp: August 27, 2015, 12:45:03 pm
content: Assuming it is a frameless stencil, just a thin sheet the I do the following:Find a nice flat surface and get together some spare boards of the same thickness as the board you want to paste.Arrange the spare boards around all for sides of the board you want to paste so that there is a continuous flat surface.Tape down the surrounding boards. Then align the stencil with your board and carefully tape it down at one end.Now apply paste using a squeegee. If you don't have a proper one, a credit card will do. Try to apply the paste in one stroke. Some people say you can't do repeated strokes, but I find you can if you're careful. Probably need to do a few practice runs to get it just right.

author: RogerRowland
author_rank: Regular Contributor
timestamp: August 27, 2015, 02:39:53 pm
content: This guy has some hints:https://youtu.be/qyDRHI4YeMI

author: Simon
author_rank: Unknown
timestamp: August 28, 2015, 06:48:15 am
content: Right seems simple enough. what do I do with the paste that ends up all over the stencil, how do I clean it off and dispose of it properly ? after all we are talking unhealthy metals.
Gould DSO 4092 Eye Diagram or Eye Pattern (Persistence) - Page 1
Forum section: electronics / beginners

author: stojke
author_rank: Regular Contributor
timestamp: August 09, 2022, 08:12:45 am
content: Is it possible that these high end models from early 90s, even tho costly then, do not support something as simple as an eye pattern?I have recently purchased a Gould DSO 4092 oscilloscope , rebranded as Siemens Oscillar D1052 , and simply can not find any settings relating to getting a proper Eye diagram for checking Compact Disk players and etc.What ive read is that digital oscilloscopes , older ones, do not have this, and that newer ones use something called persistence (I guess it just keeps the trace on the screen for a little while longer after drawing it).Should I sell this thing and get an analog scope , there is one Hitachi V-1085A here I can get.

author: m k
author_rank: Super Contributor
timestamp: August 20, 2022, 01:16:48 pm
content: Your alternative is 100 MHz analog, Gould DSO 4092 is 8 bit 800 MS/s.What kind of, say 50MHz, when DSO has 16 dots/cycle, comparison that will generate on screen?Maybe early DSO makers didn't believe it doesn't do harm if some functions are sort of low freq. only.Can't you have both?

author: stojke
author_rank: Regular Contributor
timestamp: August 29, 2022, 05:11:35 pm
content: These devices are too bulky and take too much space, one is too much... The scope comes close to making an eye pattern if only I could slow down the display to keep the traces on a while longer, dont know if it is possible to program it to do so as it has programming via Serial.

author: stojke
author_rank: Regular Contributor
timestamp: October 12, 2022, 03:23:57 pm
content: Anyone?
GP5 Multi-Effect IC identification help - Page 1
Forum section: electronics / beginners

author: nadavb
author_rank: Newbie
timestamp: August 21, 2025, 05:31:10 am
content: Hi,Just disassembled a Valeton GP-5 multi effect (for all you guitarists out there....) neeed some help with an unfamiliar IC.The MVSILICON is a BL enabled processor and probably also the audio codec. I don't know if it does the actual DSP (it is not that powerful).the other one: JAT S24PQ maybe an MCU or the DSP. Any ideas?Thanks
GPIB practical sampling speed Qn - Page 1
Forum section: electronics / beginners

author: 3roomlab
author_rank: Frequent Contributor
timestamp: November 15, 2015, 03:39:27 am
content: i am curious to know @ 10 NPLC or 100 NPLC. how fast a sampling rate can you fetch readings (specifically NPLC 10 / 100, on GPIB only), could it do so effortlessly at 5Hz or more?

author: bingo600
author_rank: Super Contributor
timestamp: November 15, 2015, 08:23:19 am
content: Do the math100 NPLC@50Hz = 100 * 1/50 = 100 * 20ms = 2 sec100 NPLC@60Hz = 100 * 1/60 = 100 * 16.667ms = 1,667 secIt would be hard to match 5Hz at that rate.@10NPLC it is "just" possible (50Hz) , and GPIB certainly isn't the limitation./BingoRef:http://cp.literature.agilent.com/litweb/pdf/5989-4879EN.pdf

author: 3roomlab
author_rank: Frequent Contributor
timestamp: November 15, 2015, 08:48:07 am
content: ok i forgot NPLC is based on AC cycle as base "clock" thanks (me getting very very forgetful)i was curious because, on RS232, max i could do on NPLC 10 is about 1.5Hz. i guess thats about it.

author: bingo600
author_rank: Super Contributor
timestamp: November 15, 2015, 09:08:07 am
content: Quote from: 3roomlab on November 15, 2015, 08:48:07 amAre you having a filter/avg on ?Could that slow down things ?I'd check the triggering , and maybe consider reading samples to "Mem" , and offload from mem via rs-232 or GPIB.@9600 bps , you'd get ~900 chars/s , and if a reading takes up 10..15 chars , that would bea lotmore than 1.5Hz.For relally fast xfers , most meters have binary readouts.Saves cycles in converting to ascii (float) , and saves byes as they're usually shortern than the ascii representation./Bingo

author: 3roomlab
author_rank: Frequent Contributor
timestamp: November 15, 2015, 09:37:17 am
content: nope, no filter, no averagingwhen i first succeeded in using python - RS232 - DMM, i thought it was bitrate, it did help in 1NPLC. i am using 19.2kbps btw.but in 10 NPLC, when remote set it up, the internal delay is very slow, to get readings out it seems. so i was wondering if other K2000/2015 users see its reaction similarly.hmmm i didnt try binary/mem mode. maybe i will study it.in RS232/python, i find that longer NPLC seems to require more delay for the MCU to compute readings. so i was wondering if other keithley users are also experiencing it the same way

author: Kleinstein
author_rank: Super Contributor
timestamp: November 15, 2015, 12:52:08 pm
content: In many DMMs there is also a auto zero cycle. This can be as long as the reading itself and add an extra delay.Usually GPIB is rather fast (near 10 MBit/s if I remenber right), in the old days there where even hard disks with GPIB interface. Some Interface cards (especially via UAB) may be slower, but this schould not be a problem even at 1 NPLC.
gpib project - Page 1
Forum section: electronics / beginners

author: N9SXF
author_rank: Newbie
timestamp: January 12, 2020, 05:57:01 am
content: hi everybody,After some consideration on the level of, 'well, why not?' I took the plunge and decided to go down the GPIB rabbit hole. It began by mending a filter cap on the +5 volt rail on an hp3455a that fell in my lap, then finding a hp3478a to keep the other one honest. After some research on here- particularly reading about the knockoff agilents usb-gpib- I figured an ni pci-gpib (n114 on board, exact model number to follow) would be a safe bet... until i began to seriously look into software. Now I'm bewildered by the vast array of driver and os combinations and instruction sets for each particular bit of equipment.The good news is I am learning that ko4bb, ke5fx, ulrich bangert, and even the NI ftp website (with particular thanks to precaud on here from his contribution pointing out where to find older drivers) have things comprehensively covered, assuming you've got the experience to avoid a newbie's mistakes... Which is the reason i'm here. See, my attempts to install the ni-488.2 driver version 2.5.2 on the machine stopped when it prompted for labview and a few other things. I didn't even get as far as looking over if I have GPIB32.dll installed.Um... to add a layer of (your choice- ridiculousness, frugality, masochism, not knowing any better, or fill in the blank)...the platform for said NI pci-gpib card was originally intended to be an old linux box which happened to be the only desktop in the house with pci slots- a dell dimension 8200. This was until I found that for some reason, dell decided to build a super dock for my old latitude c840, with space for two pci cards and a storage drive expansion slot- which once I found out about it i went and found one for all for twenty bucks shipped and now the gpib card is in there without a driver.So now my lab bench has the potential to be state of the art for...2002. For this reason, i have included links to related discussions on the AntiqueRadio forums...At a minimum this should consolidate all the loose knowledge across very many postings here and elsewhere to help jumpstart discussion on the topic.So to summarize, what can i use for free given the combination of winXP os and ni pci-gpib?n9sxfBibliography:https://www.eevblog.com/forum/chat/a-big-thumbs-down-to-natl-instruments/msg1793855/#msg1793855https://www.eevblog.com/forum/beginners/gpib-getting-started/msg686062/#msg686062http://ko4bb.com/Test_Equipment/GPIB.phphttp://www.ulrich-bangert.de/html/downloads.htmlftp://ftp.ni.com/support/https://www.cl.cam.ac.uk/~osc22/tutorials/gpib_usb_linux.htmlhttps://linux-gpib.sourceforge.io/https://www.antiqueradios.com/forums/viewtopic.php?t=139236https://antiqueradios.com/forums/viewtopic.php?f=8&t=324831

author: WastelandTek
author_rank: Frequent Contributor
timestamp: January 12, 2020, 06:19:03 am
content: gonna watch this
GPIB to USB adapters: Are they all the same?  - Page 1
Forum section: electronics / beginners

author: Zondar
author_rank: Regular Contributor
timestamp: August 05, 2025, 04:08:15 pm
content: Hello,Most first-party GPIB to USB adapters, e.g. from Keysight, are absurdly expensive. The cheapest from reputable sources include one from B&K Precision ($245) and one from Siglent ($167), but both are out of stock everywhere. Then there are the many found on the usual bay, etc., but most of these should be presumed to be counterfeits.I need to talk to an Agilent 3458A, which only has GPIB I/O. Are all GPIB adapters totally interchangeable? What about all those inexpensive "Agilent" models, etc., that are quite likely to be countefeit - are those effectively just the same too?Thank you.

author: m k
author_rank: Super Contributor
timestamp: August 06, 2025, 01:54:42 pm
content: Technically yes, but.It's a bridge and not very standard one.If you have a GPIB to RS232 hardware adapter you have a standard to standard bridge.You can also have a GPIB to RS232 through USB, but then you also have a non-standard non-hardware USB to RS232 bridge.So for non-standard converter you need an extra converting software, like a driver.Usually driver converts unknown to known from operating system's point of view, but not necessary.It can also stay known to certain application only.It's also possible that application knows it without any extra software.So any device can have what ever that prevents its use.Even RS232 device can have a password.

author: BennoG
author_rank: Frequent Contributor
timestamp: August 07, 2025, 09:18:09 am
content: did you seehttps://www.eevblog.com/forum/projects/poe-ethernet-gpib-adapter-open-source-project-now-public/msg5762141/I have 2 of them and 3 more in order.They are not expensive and work like a charm (you will need a POE switch to use them)Benno

author: coromonadalix
author_rank: Super Contributor
timestamp: August 07, 2025, 10:12:10 am
content: somme fake(s) did work fine for many users, but it is always a riskyou have many open projects here based on arduino usb to gpib cost is very low, even as mentioned network to gpib .... and their support is very goodhttps://www.eevblog.com/forum/projects/ar488-arduino-based-gpib-adapter/you have free software to control such istruments, and some can backup the calibrations constants or do morei have some of theses designs, worked very well with keysight softwares, Rhode schwartz ... wingpib or others ...
Gpio in cpu2 TMS32F28379D - Page 1
Forum section: electronics / beginners

author: Apollo1234
author_rank: Contributor
timestamp: October 15, 2024, 01:52:22 am
content: Hi there,I'm trying to use GPIO31 on CPU2 of the TMS320F28379D. I've set the ownership to CPU2 using GPACSEL4 = 1, but it's still not working. Can someone help me figure this out? it works if use only the cpu1, im also respecting the time line
GPIO unpowered IC - failsafe? - Page 1
Forum section: electronics / beginners

author: Tantalum
author_rank: Regular Contributor
timestamp: March 22, 2019, 10:37:18 am
content: HelloI'm wanted to use an PCA9539 I2C IO expander and power it with 3.3V. The IO's will be connected (sink) to 5V (+resistor of course).The IC is "5V tolerant".https://www.nxp.com/docs/en/data-sheet/PCA9539_PCA9539R.pdfNow, i'm asking me if there might be a problem if the PCA9539 is unpowered and that a 5V signal is applied to it's IOs.Won't the body diode of the internal mosfet conduct? In other words, won't the 5V pass though Vdd to the 3.3V power rail???
GPRS Shield V1.0 - What am I doing wrong? - Page 1
Forum section: electronics / beginners

author: M84AB1
author_rank: Contributor
timestamp: June 11, 2014, 04:03:13 am
content: Hi fellow electronic enthusiasts & professionals,I have a question around the GPRS Shield v1.0 module that is built around the sim900 chip. Over the past 2 days I have tried just about everything to get this thing to work (interact with it through terminal software) but without any luck. After doing all of the things that I will list below, I am starting to believe that the module may be faulty and I was hoping that one of you guys has one of these same modules and could help me with referencing a few things ie. check voltages or observe RX/TX pins on oscilloscope purely for presence of data bits.- inserted SIM card- assembled the antenna- connected the device to external 5V (2A)- hit the power on button- device fails to register to a network, never gets to 64ms on, 3000ms off even after 1 hour- tried different locations - no luck- tried different sim card - no luck- thought, surely I should be able to communicate (via terminal software) to this device even if it does not register to a network- interfaced the GPRS module to my PC via RS232 & max232- tested that same interface with a PIC microcontroller and it works perfectly. I can use Hyper Terminal to send and receive data between PIC and PC- although not necessary (as proven by PIC to PC communication), checked serial / voltage levels (max232) on oscilloscope. all are good- set the jumpers to SWserial on the GPRS module- connected pin12 on max232 to pin8 (db7) on GPRS module- connected pin11 on max232 to pin9 (db8) on GPRS module- tried different terminal software (hyper terminal, rs232analyzer, terminal, SSCOM3.2)- all establish a connection with my COM port (COM1)- tried different baud rates across all software- when I send a command ie. AT, I observe a serial or should I say UART signal on my oscilloscope on db7 of the module, so it is definitely getting a signal- I get no signal or message on db8 at any point and therefore also no data received on any of the terminal software- I measured the voltage across db7 and db8 and both have the same voltage as VCC (about 4.9V), not sure if this is correct!!- tried swapping db7 and db8 connections around but as expected it does not work- the voltage regulator outputs 4.1V, is that correct?So I have tried just about everything but just dont seem to be able to get the module to respond. Is there something that I may be missing?
GPS antenna cable right beside power cable? - Page 1
Forum section: electronics / beginners

author: FriedMule
author_rank: Frequent Contributor
timestamp: February 19, 2020, 03:24:05 pm
content: To avoiding to drill to many holes in my ceiling I want to run both my GPS timing antenna RG400 coaxial cable, bundled with the 5 leads (3 phases, ground and neutral). Will it work just fine or do I have to add some extra shielding?

author: brabus
author_rank: Frequent Contributor
timestamp: February 19, 2020, 04:23:26 pm
content: No problems at all.

author: FriedMule
author_rank: Frequent Contributor
timestamp: February 19, 2020, 11:50:08 pm
content: Thank you a lot:-)

author: amyk
author_rank: Super Contributor
timestamp: February 22, 2020, 12:53:58 am
content: GPS signal is >1GHz, mains is 50Hz.

author: Ian.M
author_rank: Super Contributor
timestamp: February 22, 2020, 11:13:21 am
content: That may well breach local electrical wiring regulations. Check any requirements for physical separation or barriers between mains power cables and low voltage (e.g. signal) cables.
GPS antenna on the aluminum enclosure - Page 1
Forum section: electronics / beginners

author: Vcky_electro
author_rank: Contributor
timestamp: July 29, 2019, 07:00:04 am
content: Hi ,I would like to use GPS chip antenna. Where i would to use the antenna on the pcb which is inside the aluminum enclosure. Please suggest me the better GPS antenna. WIll it work inside the enclosure ??Thanks,Vicky.

author: hagster
author_rank: Frequent Contributor
timestamp: July 29, 2019, 07:39:36 am
content: A GPS will not work inside an aluminium enclosure unless there is some form of RF transparent material for the signal to get through.You have lots of options, but the simplest is to get a panel mount GPS antenna and drill a hole in the box.

author: Vcky_electro
author_rank: Contributor
timestamp: August 02, 2019, 04:25:09 pm
content: Thanks..Is there any off the shelf PIFA antenna for GPS ??

author: hagster
author_rank: Frequent Contributor
timestamp: August 02, 2019, 07:01:48 pm
content: Probably lots, but why do you want a PIFA antenna?Have a look through the Taoglas catalog and pick one that suits. They are mostly stocked in digikey.https://www.taoglas.com/product-category/gps-antennas/

author: Vcky_electro
author_rank: Contributor
timestamp: August 03, 2019, 03:20:03 am
content: PIFA antenna will be easily mounted on enclosure. So I want PIFA antenna.

author: hagster
author_rank: Frequent Contributor
timestamp: August 03, 2019, 07:44:41 am
content: I haven't seen too many PIFAs or IFA antennas mounted externally on metal enclosures. The occasional multi and car antenna uses this type of antenna, primarally because the PIFA can be made to cover multiple bands, eg GPS + cellular.A PIFA antenna mounted on a metal enclosure needs to be at 90° to avoid being shorted.If it's just for GPS, a straight patch antenna is normally more easily mounted and has the advantage of circular polarization.Obviously I don't have any details on your application or enclosure, so I may be wrong.If you want something really low profile antenna you could just make a slot antenna using the enclosure. Just cut a half wavelength thin slot in the lid and connect your coax across it. You will need to experiment to tune the feed point correctly. You can seal the slot with silicon or something if needed.

author: vsmplast
author_rank: Newbie
timestamp: September 17, 2019, 07:44:10 am
content: As mentioned byhagsterA GPS will not work inside an aluminum enclosure unless there is some form of RF transparent material for the signal to get through.RF transparent materials are materials where RF fields can penetrate with no heating happen. So far, I know plastic polymer material like Teflon, PPL,PVC, andABSwhich are made of plastics and have almost 0 dielectric loss factor.You have other plastic enclosure options like polycarbonate,Fiberglass (FRP)which also are RF transparent material

author: Vcky_electro
author_rank: Contributor
timestamp: September 24, 2019, 06:37:05 pm
content: Thanks @hagster and @vsmplast for detailed explanation.
GPS UART activity LED issue - Page 1
Forum section: electronics / beginners

author: kevin8
author_rank: Newbie
timestamp: April 19, 2021, 06:58:45 pm
content: Hello guys,I've been trying to make an activity LED for my GPS module.Main idea is to trigger the LED whenever the GPS module is sending data thru TXD pin.Circuit works well when the LED is powered from 5V supply (fig 1), but when supplied from 12V (fig 2) the LED is on all the time :/ just some slight dimming occurs.GPS module is supplied from 7805, and 7805 is attached to the same 12V supply as the LED.Please check the attached images for more details.Thanks!

author: mvs
author_rank: Frequent Contributor
timestamp: April 20, 2021, 08:26:55 am
content: UART is usually active low signal. In your circuit LED will be on in an UART idle state.You can insert additional common emitter stage to act as an inverter.You can make also a pulse extender for better visualization, for instance with a 555 timer in a mono-stable configuration.
GPS Week Number Rollover error in Navman Jupiter Pico T GPS - Page 1
Forum section: electronics / beginners

author: carver
author_rank: Contributor
timestamp: January 10, 2020, 04:49:21 pm
content: Hello.I have lot of equipment in which are installed Navman Jupiter Pico T GPS.TU36-D400-020 ver.14.00 - work OKTU36-D400-020 ver.73.08 - has GPS Week Number Rollover error.https://en.wikipedia.org/wiki/GPS_Week_Number_RolloverI waiting connector and cable for it,but maybe someone solved this problem ?or knows how to copy firmware from one device to another ?i has approx 20 failed units. Sirf Scorpio 11577 inside.Thanks.

author: jimdeane
author_rank: Regular Contributor
timestamp: January 13, 2020, 03:49:23 pm
content: I would be surprised if you are able to copy firmware from one to another. We had this problem on a fleet of deployed Connor Winfield units in some physics equipment. The tech people came up with a firmware update procedure we could use in the field, but step one was downloading the appropriate firmware update file from the Connor Winfield manufacturer site.A cursory search didn't reveal a download site for your device. Perhaps you'll have more luck?

author: carver
author_rank: Contributor
timestamp: January 28, 2020, 10:19:42 pm
content: thanks.I didn't receive a notification and I just saw your answer.I know that this is a real problem, and many manufacturers,even GARMIN/Apple didn't solve it.although garmin may have already decided,I have'nt such models.

author: LateLesley
author_rank: Frequent Contributor
timestamp: January 29, 2020, 02:22:02 am
content: Are you sure it's Juniper, not Jupiter?If it's Jupiter, I found this which may or may not be helpful.http://gps.0xdc.ru/static/sirf/doc/SirfStar/gpsd.berlios.de/vendor-docs/jupiter/LA010105A_TimingAppSoftware_AppNote.pdfIt says it uses the Zodiac GPS chipset, and I found this on it -https://www.gpskit.nl/documents/rockwell/zodiac.pdfMaybe it can provide useful leads to update it?It may be possible to find a way to update the time yourself, but it may not remember the change. I found some info in the appendix of this page.http://www.jrmiller.demon.co.uk/projects/ministd/faq.html
GPS with antenna requirement - Page 1
Forum section: electronics / beginners

author: Vcky_electro
author_rank: Contributor
timestamp: August 02, 2019, 08:15:03 am
content: Hi,Im looking for a GPS module with antenna. Similar to L80 from Quectel. With I2C supported. But there is available in ublox CAM-M8C.in CAM-M8C they are using chip antenna. Since chip antenna uses linear polarization its performance will be lower than circular polarised patch antenna.Anybody can suggest !!!Thanks..Vicky.
GPSDO question - Page 1
Forum section: electronics / beginners

author: liais73
author_rank: Newbie
timestamp: October 31, 2014, 07:46:39 pm
content: Which forum would be the best to field questions for specific make of GPSDO ?Brandywine GPS-4Don H

author: mazurov
author_rank: Frequent Contributor
timestamp: October 31, 2014, 08:01:14 pm
content: Time nuts ->http://www.leapsecond.com/time-nuts.htm

author: liais73
author_rank: Newbie
timestamp: October 31, 2014, 08:22:08 pm
content: I have not had much luck withtvb's site. My question is for someone who has experience with the Brandywine GPS4 specifically.Thank you for your replyDon H

author: VK5RC
author_rank: Unknown
timestamp: November 01, 2014, 11:26:45 am
content: Have you tried the "Time Nuts" forum athttps://www.febo.com/mailman/listinfo/time-nuts?I would be very surprised if someone there doesn't have experience with your GPSDO, sorry I can't help, my limited experience is with Thunderbolt or old HP.Best of luck.Robert

author: liais73
author_rank: Newbie
timestamp: November 03, 2014, 12:48:37 am
content: Hi Robert: I have tried time-nuts with no response. I am afraid the Brandywine gps-4 may be somewhat of an orphan.Thank you for your reply.Don H

author: rf-loop
author_rank: Super Contributor
timestamp: November 03, 2014, 02:48:32 pm
content: Quote from: liais73 on November 03, 2014, 12:48:37 amI can not see any fresh message about Brandywine in time-nuts archive.There is lot of old messages about Brandywine in timenuts archive (but mainly many years ago). Just for starting one click and find 58 msg. There is many peoples with they names etc. Easy you can find who have experience with it, then just letter... what you need what can not find from this equipment documentation where can find all normally needed things. (I do not have experience with Bw-4, I have only experience with symmetricom-HP's and Trimble's)https://www.mail-archive.com/search?l=time-nuts%40febo.com&q=Brandywine+GPS-4&submit.x=12&submit.y=15
gpsdso adding an rs232 port - Page 1
Forum section: electronics / beginners

author: ME
author_rank: Frequent Contributor
timestamp: February 26, 2025, 08:41:31 am
content: I have just ordered this gpsdso from aliexpress, I see on some videos that some have an rs-232 port on the rear, the one i ordere doesent have one, Is it possible to add one and has anyone tried one of these things, I want it to cal my freq counters.https://www.aliexpress.com/item/1005007363524269.html?spm=a2g0o.order_detail.order_detail_item.3.2aa5f19c9PosZO
GPSLDO Cannot stabilize - Page 1
Forum section: electronics / beginners

author: Moriambar
author_rank: Unknown
timestamp: June 01, 2021, 07:02:29 pm
content: Hi,in my recent spree of failing equipment (I just broke a microcurrent and no replacement is in sight), my gpsldo is starting to behave weirdly.It's connected to a distribution amplifier and then to my signal gen (and occasionally I use it on a board).Nothing's changed recently in any of my setups, but the oscillator locks on gps and the alm light stays on. What's worse is that the signal is sh*t, as per the attachment.Is this one gonsky too?Cheers

author: jpb
author_rank: Super Contributor
timestamp: June 01, 2021, 07:52:51 pm
content: If your GPSDO is an old one or a new one made with an old OCXO then it might be that the tuning range of the OCXO has drifted beyond the range that the disciplining circuit can supply and perhaps it keeps starting at the low end and covering its whole range and still can't reach 10MHz and does this over and over.If you can measure the applied voltage on the OCXO that might give you a clue.If this is the problem then you might be able to get a cheap replacement for the OCXO on ebay. I think someone on the forums has posted doing that a little while ago. It might even give you an opportunity to improve the OCXO.

author: Moriambar
author_rank: Unknown
timestamp: June 01, 2021, 09:00:03 pm
content: Quote from: jpb on June 01, 2021, 07:52:51 pmIt is quite new actually, it has a date code on the case of oct 2020.I'll try the measurements

author: dl6lr
author_rank: Frequent Contributor
timestamp: June 02, 2021, 05:55:49 am
content: Quote from: Moriambar on June 01, 2021, 09:00:03 pmI assume your screenshot is from the GPSDO, not after the dist. amp?Your signal shows amplitude and phase jitter, I would check the power supply first. Noise from the PSU will do harm to the PLL lock.

author: Moriambar
author_rank: Unknown
timestamp: June 02, 2021, 06:43:45 am
content: Quote from: dl6lr on June 02, 2021, 05:55:49 amyou think the cheap psu is what has gone?The signal is the same before and after the amp.BUTafter unplugging, unscrewing, weeping at the idea of replacing the osx, rescrewing, replugging… well today the signal is clean as a whistle!It fixed itself.Maybe I'll investigate the psu though…
Graph of Input Voltage against Output Voltage - Page 1
Forum section: electronics / beginners

author: fx991ex
author_rank: Contributor
timestamp: October 01, 2020, 11:05:19 am
content: I am trying to figure out what is the easiest way to create a graph of input voltage against output voltage.The circuit that I am analyzing acts pretty much like a regular DC-DC converter.Input voltage goes from 0 to 5 VDC. Output voltage goes from 0 to 8 VDC.I want to measure with a resolution of 0.01 V.I have access to multiple power supplies, multimeters, an Arduino, and ROHDE & SCHWARZ RTB2004 osciloscope.Here is an example of a graph:https://www.researchgate.net/figure/Graph-of-Output-Voltage-V-against-Input-Voltage-V-for-Finger-2_fig9_312019343

author: palpurul
author_rank: Regular Contributor
timestamp: October 01, 2020, 12:02:01 pm
content: You basically have to control your power supply and get the measurement data from your multimeter.I think you gotta look at what kind of connection you can establish between your PC and your equipments.

author: bob91343
author_rank: Super Contributor
timestamp: October 01, 2020, 07:17:58 pm
content: Do youi want to plot the graph manually, or have it displayed on an oscilloscope screen?

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: October 02, 2020, 08:20:11 pm
content: How about an old style flat bed X-Y recorder such as HP 7045 or 7035

author: SilverSolder
author_rank: Super Contributor
timestamp: October 03, 2020, 06:08:56 pm
content: Use the oscilloscope in X-Y mode. Input on X, output on Y. Set the vertical and horizontal scales to suit. No matter how slowly you crank up the power supply, the graph will look right (assuming no noise etc. interfering!)
Graph results of common source amplifier. - Page 1
Forum section: electronics / beginners

author: magnumX
author_rank: Newbie
timestamp: December 08, 2017, 06:51:42 am
content: Hello, guys. I'm wondering is it the value of resistance R1 and R4 won't affect the output voltage of amplifier ? For original design, R1 and R4 resistance is 1K respectively. For 2nd design, i have changed their value to 500. After that, I have compared the output voltage between them. I found that there is no different between them. Why? Can anyone provide some opinions ? Thank you . Your help is greatly appreciate.Ps: Attached here is the design circuits and the results of each design.Ps: I'm using Mentor Graphic to design these circuits.

author: danadak
author_rank: Super Contributor
timestamp: December 08, 2017, 10:29:44 am
content: You have a DC source connected to gate, so R1, R4 are irrelevant to thevoltage at the gate, except when they are 0 ohms.Regards, Dana.

author: magnumX
author_rank: Newbie
timestamp: December 08, 2017, 01:52:37 pm
content: Quote from: danadak on December 08, 2017, 10:29:44 amThank you so much, sir. It helps me a lot. By the way, can i know is it possible to get the value of transconductance, gm and small-signal output resistor, ro based on this design circuit ? Got any formula to calculate it ? Thank you

author: danadak
author_rank: Super Contributor
timestamp: December 08, 2017, 05:38:11 pm
content: The amplifier you have shown is a common source MOSFET amplifier.This will help you calc the parameters of interest -http://www.prenhall.com/howe3/microelectronics/pdf_folder/lectures/mwf/lecture12.fm5.pdfRegards, Dana.

author: magnumX
author_rank: Newbie
timestamp: December 09, 2017, 01:44:14 am
content: Quote from: danadak on December 08, 2017, 05:38:11 pmOk. I got it. Thank you very much for taking the trouble to answer all my questions.
Graphic divisor - Page 1
Forum section: electronics / beginners

author: marc1996
author_rank: Contributor
timestamp: August 22, 2018, 09:48:22 am
content: Hello to everyone,I have one voltage and current waveform graphics and I would like to divide them in order to get the resistance value in time domain. Do you know if this is possible with any software or something?Voltage and current waveforms are not proportional. Values from both graphics are taken in the same moment and the graphics are exported from LTSpice.Thanks for your help!

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 22, 2018, 10:31:11 am
content: I normally use command-line tools likeawkandgnuplotfor such things, and was going to write an answer on how to do it, but then I vaguely recalled that LTspice's plot view ought to have an expression editor. (I'm not even sure if I've used LTspice except for some experiments, however, so the following is basically all I know; hope it helps.)Looking atLTspice Tipsat Digikey, you can add a new trace to the plot in the WaveForm Viewer, and change its expression toV/I(assuming the voltage trace is namedVand the current traceI). So, you should be able to do this in LTspice WaveForm Viewer.

author: Unknown
author_rank: Unknown
timestamp: August 23, 2018, 09:55:31 am
content: If you are using LTSpice then it's easy to do by adding a new trace.With the plot window selected, press <Ctrl> A to add a trace (or right click in the plot window or select from the plot settings menu).Select the voltage node you want to use from the list, type / after it then select the current from the list and click OK. The new resistance trace will be added to the plot complete with an ohms scale.

author: Zero999
author_rank: Super Contributor
timestamp: August 23, 2018, 12:33:05 pm
content: Yes, it can be done in LTSpice. Label the voltages and use V(label)/I(component) in the graph properties window.https://www.eevblog.com/forum/beginners/passive-components-in-guitar-pedal-input-stage/msg1753601/#msg1753601
Graphical LCD with Alphanumeric mode - Page 1
Forum section: electronics / beginners

author: PedroDiogo
author_rank: Regular Contributor
timestamp: July 10, 2012, 09:08:33 pm
content: I need to use a Graphical LCD for my thesis work. Initially the idea was using a regular graphical LCD, the cheaper the better, for the board I'm trying to design. However my adviser said it would be preferable to use a graphical LCD with an alphanumeric mode so it can be used just like a regular text LCD too, and they are supposed to be fairly common.However I'm having trouble finding any on the market, but most likely I'm missing something.Does anyone know any LCD that does this?If I can't find any I might create a software library to emulate it but I rather not do it if I don't have toThanks!

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: July 10, 2012, 09:43:06 pm
content: The Hitachi HD61830B and Toshiba T6963C based LCDs have an integrated ASCII character set.Then again, it should be no problem to paint some bitmap font to a pure gfx mode LCD e.g. with a Samsung KS0108 controller. Indeed you'll find several libraries for this purpose if you google a bit...

author: johnmx
author_rank: Frequent Contributor
timestamp: July 10, 2012, 11:08:40 pm
content: Hi Pedro,In my last project I used a graphical OLED LCD. According to the data sheet it can work in both ways, graphical or alphanumeric. I didn’t try the graphical mode because of lack of time, but it works well in alphanumeric mode. Because is OLED the image quality and the contrast are the best in the market. I will never buy transflective LCD’s anymore.OLED rocks!!!!Link:http://pt.farnell.com/midas/mcoc0802awmye/oled-2x8-yellow-green-on-black/dp/2063144?Ntt=2063144

author: EEVblog
author_rank: Unknown
timestamp: July 10, 2012, 11:14:14 pm
content: You can use graphical modules like the ones from 4Dsystems:http://www.4dsystems.com.au/Dave.

author: PedroDiogo
author_rank: Regular Contributor
timestamp: July 11, 2012, 10:15:11 am
content: I found a couple good LCDs using the 6963 controller but they were a little big for what I wanted (one was aprox. 10mm*10mm and the other 75mm*70mm). I'm yet to find a good 128*64 COG LCD (which appear to be much smaller) with character generator built-in.What I think I'm going to do is, as the board will have a modular design, create two separate modules, one with a standart 4x16 HD44780 LCD and the other with a cheap graphic LCD.Thanks everyone it helped a lot!
Graphics card current measurement - Negative current ? - Page 1
Forum section: electronics / beginners

author: berwick53
author_rank: Newbie
timestamp: April 19, 2017, 04:52:51 pm
content: Hi, I'm taking some power measurements from an AMD graphics card using a PR30 current clamp on a +12V PCIe 6-pin power connector and It appears that I have current going in the other direction occasionally when not at load..I've 'zeroed' out the clamp meter when the PSU was turned off and have removed the remaining bias from my data but I'm still seeing values below 0 with the largest (negative) reading being -1.68A. I'm measuring the result on a Rigol DS2702A with it recording data at 100kS/s which is far more than I need so it this just high frequency noise ? As this appears to be rather large?The attached graph is Power (W) vs Time (s) and the blue line is a 1000 point moving average.Current clamp datasheet:http://www2.elo.utfsm.cl/~elo382/wp-includes/images/PR30.pdf

author: wraper
author_rank: Unknown
timestamp: April 19, 2017, 05:23:36 pm
content: 100kS/s is certainly not enough, and will cause aliasing. On top of that1.68A in this case is only about 1.5 bits of scope ADC resolution, basically below the noise floor of oscilloscope.EDIT: That said according to the scale on the picture attached.Dunno if 1.68 is according to those numbers as 100+ amps current is an order of magnitude too high.EDIT2: Well, those are watts obviously. What goes negative should be noise + likely aliasing. Average is not that negative at all as is about those 1.5 bits of resolution mentioned.

author: berwick53
author_rank: Newbie
timestamp: April 20, 2017, 02:07:50 pm
content: Quote from: wraper on April 19, 2017, 05:23:36 pmThanks for answering, I've done some more digging and have taken some pictures of the system when idling at a much higher sample rate (500.0 MS/s & 2.0 GS/s) and with setting the BW limit to 20 MHz vs 300 MHz. I can see from this when applying the BW limit that some of the noise disappears but the negative part of the waveform still appears. Do you still think this could be due to aliasing or something else?I'm thinking that I may need to measure via a current shunt if I can't explain why.
Graphing calculator.... sort of? - Page 1
Forum section: electronics / beginners

author: rocksteady
author_rank: Newbie
timestamp: November 10, 2017, 07:03:50 am
content: Hello folks,I'm curious if anybody would be able to point me in the right direction on this. If any of you are familiar with the Mandelbrot Sets, I basically want to build a little(or big if need be) box that will output them onto a screen and allow for zoom in/out control. The screen doesn't have to be built into it, but I don't know if having it set up to output to a TV/Monitor would be any easier to handle.I know this is likely well beyond my skill level at the moment, but I like to fail at stuff to keep me humbleAny wisdom you guys could impart on me would be greatly appreciated.

author: kripton2035
author_rank: Super Contributor
timestamp: November 10, 2017, 07:06:32 am
content: raspberry pi and its hdmi output ?any linux program on it to display mandelbrot sets

author: rocksteady
author_rank: Newbie
timestamp: November 10, 2017, 07:22:59 am
content: That's more simple than I was expecting... And painfully obvious now that you said it.I sometimes forget computers are tiny nowThanks

author: bd139
author_rank: Super Contributor
timestamp: November 10, 2017, 07:23:23 am
content: Definitely PiSoftware to use is xaos:https://github.com/xaos-project/XaoS

author: hendorog
author_rank: Super Contributor
timestamp: November 10, 2017, 07:25:57 am
content: Bit more ambitious but the result should be better (i.e. fast boot, no OS needed)https://ultibo.org/

author: rocksteady
author_rank: Newbie
timestamp: November 10, 2017, 07:36:11 am
content: Cool! Thanks a lot for the suggestions, guys. This is gonna go a lot quicker than I expected.

author: Ian.M
author_rank: Super Contributor
timestamp: November 10, 2017, 08:01:01 am
content: I also vote for using a SBC like a Pi. There are few MCUs with FPUs and integrated graphics, and the cost in development tools and time would be grossly excessive for a one-off project. Of the possible SBCs to use, a Pi the the most hobbyist-accessible.
Graupner Polaron Wireless Module Project - Page 1
Forum section: electronics / beginners

author: kelchm
author_rank: Regular Contributor
timestamp: January 21, 2018, 03:36:58 pm
content: I have a Graupner Polaron EX charger that I've been using for a few years. Graupner recently released a wireless module for the charger that piqued my interest. I knew this module had some limitations that I didn't like, such as being required to use an Android or iOS app and not being able to join an existing wifi network.I went ahead and purchased the module, planning to reverse-engineer the communication between the charger and the module so I could create my own.Some of the things I'd like to add:- Join to an existing wifi network- Integrated management webpage (replacing the app)- Persistent datalogging- Ability to backup/reload charing profilesAs a first step, I've taken a look inside the module. As expected, it's some variant on an ESP module.

author: Nioko
author_rank: Newbie
timestamp: April 21, 2022, 07:03:53 am
content: Hello kelchmDid you achieve anything with this? I just bought a Polaron Pro charger - will take a while until I get it. But cannot find the WIFI Module anywhere on sale. Thinking of at least DIY the original module, not sure if it needs some kind of firmware on the ESP though.
Great And Helpfull Site For Beginners - Page 1
Forum section: electronics / beginners

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: May 03, 2013, 11:23:09 pm
content: Hello i recenlty found this sitehttps://www.circuitlab.com/By googling : online circuit emulator.When you sign up you can search for circuits that you would like to build or take examples , search for components or even make a usefull circuit and publish it.This will be helpfull for me and i hope for you too thank you.

author: mateuszrjzr
author_rank: Newbie
timestamp: May 04, 2013, 06:39:37 pm
content: If we're talking about simulating, I think thishttp://www.falstad.com/circuit/is better. Or rather i like it more
Great bunch of video's on SMPS - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: May 12, 2018, 01:17:37 am
content: Most of what I learned lately EE wise was from Sam's videos like this 1However, I'm watching this stuff more as entertainment, so I'm not doing the maths and I forget 80% of any eq's. I wish I was back in high school/university doing this stuff, I used to love doing most equations.Hey I learned about the resetting of inductor core's, now I recognize what some other windings and diodes are for.
Great Scott's trailing edge dimmer circuit, DC Gnd conneciton to AC Mains - Page 1
Forum section: electronics / beginners

author: jwhitmore
author_rank: Regular Contributor
timestamp: July 21, 2019, 05:28:55 pm
content: I'm looking at this youtube video  and the circuit detailed in it. I've attached the screenshot of the schematic.It's an interesting circuit, but as someone who has worked almost exclusively in DC circuitry I find the sub-circuit in the lower right a bit concerning. The mains AC is switched through the two IRF840 MOSFETs but there is a connection from between the two sources to Ground of the DC Circuitry. OK so I assume that if there is no connection between the DC Ground and the AC Earth so everything should work just fine but it seems like a mistake could easily happen measuring a voltage relative to Earth.I was thinking of using a logic level MOSFET , but even then instead of using a uC to control the gates, of the MOSFETs, I was thinking to just connect 5V DC between source and gate from a bench top power supply. Then given the mains voltage connected to DC Ground I'd be afraid of blowing up that piece of equipment. I guess DC ground is just riding the sine wave of the AC Mains and so long as it's isolated everything should work, but should I be worried about my bench top power supply? Again so long as I don't plug into 'Earth' connection everything should work. Might be better sacrificing a uC that's easier to replace if this does go wrong.https://youtu.be/BhQWOv10Oaghttp://www.farnell.com/datasheets/2284028.pdf

author: DannyTheGhost
author_rank: Contributor
timestamp: July 21, 2019, 06:25:46 pm
content: Each time I look on this circuit I see more mistakes, even potentially lethal ones. If I were you, I would not try to build it.Or it's unfinished circuit, who knows.Optocoupler, which is driving MOSFETs, does not perform its function - isolation. Even if you supply right-side (with phototransistor) with separate isolated power supply, it still does not include 'turn-off' function for switches, only that 10k pull-down resistor can actually close them, which is bad for transistors.Returning to your question, if you dare to build it, do not connect anything earthed to it.

author: jwhitmore
author_rank: Regular Contributor
timestamp: July 23, 2019, 04:46:19 pm
content: Thanks for your answer. I'll leave that one and maybe keep an eye out.
Green & Orange Ceramic disk capacitors - Page 1
Forum section: electronics / beginners

author: CircuitQuest
author_rank: Contributor
timestamp: October 24, 2023, 08:51:56 pm
content: Attached are images from a radio I'm trying to fix. I have a simple question. I know blue disk capacitors are for AC or high voltage circuits. Orange I assume is for low voltage, however what are the green one's for?They are both 22nF btw.If I were to replace them can I use any low voltage 22nF capacitors?Like these>>https://m.media-amazon.com/images/I/51tmReuPAlL._SL1001_.jpgThanks

author: TimFox
author_rank: Super Contributor
timestamp: October 24, 2023, 08:57:38 pm
content: I would not trust those color code assumptions.Sprague disc ceramic capacitors (now made by Vishay Ceramite) were all orange, regardless of dielectric or voltage rating.(Sprague liked orange, just like Kermit the Frog liked pigs.)

author: Thunderer
author_rank: Regular Contributor
timestamp: October 25, 2023, 02:59:24 am
content: Quote from: CircuitQuest on October 24, 2023, 08:51:56 pmIt would be simpler to say what radio are you fixing (mains supply, battery supply). This way we can guess the voltage level required.Quote from: CircuitQuest on October 24, 2023, 08:51:56 pmWhat makes you believe these caps are faulty, so they require replacing? This kind of caps usually outlive us, no reason to replace them unless cracked by mistake.

author: floobydust
author_rank: Super Contributor
timestamp: October 25, 2023, 03:17:37 am
content: The toad green/orange brown ceramic disk caps are reliable and don't just change them out.Instead- the electrolytic capacitors fail with age - that is the blue and the sea green tubular, grey Shoei in your pics. My practice is to outright change them past past 40 years, they are usually dried out and low value. Radio might motorboat or have weak bass etc.It better to troubleshoot a bit, if you can say what the radio is doing.Measuring DCV at IC (don't short probe to the metal strap!) pins can reveal a lot, but we don't know its part number or the radio make/model. That can help too. You can look for the IC datasheet if you don't have the radio schematic diagram.