hybridfree/eevblog-posts huggingface dataset:
pwm vacuum tube - Page 1
Forum section: electronics / projects

author: Marduk
author_rank: Newbie
timestamp: August 06, 2012, 03:35:31 pm
content: Hello im working on a PWM power supply and thought to may self it would look cool if i could have some Vacuum that i could use for this. well i look around and found my self lost. i was thinking of using a Power amp tube to make the PWM but i can't fine anything that works with 12v or 24v. anyone out can give me a hand or is this just a lost cause
PWM voltage overshoot issue - Page 1
Forum section: electronics / projects

author: Allen_Du
author_rank: Contributor
timestamp: October 05, 2022, 09:21:41 am
content: Hi All,A 380V DC power supplier controlled by a 24V PWM singal, to supply a coil. max current 6A.The pwm pulse is 10-40us.measured overshoot on the 380V voltage, attached is the waveform picture.can you help suggest how to improve the overshoot issue, is it a solution to add high voltage film capacitors on the load coil? like Metallized Polypropylene Capacitors (MKP/MFP).Any comments are appreciated.
PWM dimming / Potentiometer ideas? - Page 1
Forum section: electronics / projects

author: mickc
author_rank: Contributor
timestamp: April 24, 2016, 01:30:12 pm
content: Hi,I am partway through construction a full flight simulator, and have an issue where i need to make one pot control 3 separate dimmers.Item 1 is a standard 12v LED PWM dimmer that uses a 1k potItem 2 is a 5v Incandescent dimmer that uses a 50k potItem 3 is a CANBus dimmer that uses a pot, but doesn't really care about the value too much. A different pot value will just alter the dimming curve.I got a quote on custom made pots with different values per gang, but there was a $530 USD charge for the low volume required.So, Question 1, are there any cheap modular pots out there?and question 2, does anyone have a better idea on how to do the dimming?The pots need the following features* Linear Curve* Smallest possible body size* 1/4" (6.35mm) D-shaft* SPST Switch at the off position.For further info, the first dimmer is powering 12v DC LED strips that backlight the panels,the second dimmer is powering 5v DC backlighting bulbs in original instruments that have been converted for sim useand the third is controlling backlighting on other CANbus devices.

author: uncle_bob
author_rank: Unknown
timestamp: April 24, 2016, 02:16:34 pm
content: HiOne simple approach would be to redesign the dimmers so they all function with a single chip. I would do it with some code in an MCU, but there are other ways.The era of "snap together" pots is long gone. Even when that was a common approach, you paid a lot to do it ($1 pot cost 3 X $10). Unless you were building < 5 gizmos, it made no sense at all.Probably the *best* solution is to simply convert all the lights so they can run off of a single dimmer.Bob
PyDSA - spectrum analyzer for rigol scopes - Page 1
Forum section: electronics / projects

author: hammy
author_rank: Unknown
timestamp: September 22, 2015, 05:40:02 pm
content: Found an article about PyDSA, a spectrum analyzer for use with an DS1054z scope.It looks like a nice low cost solution for hobby purpose.http://hackaday.com/2015/09/22/a-better-spectrum-analyzer-for-your-rigol-scope/QuoteCheershammyPS: Git sources:https://github.com/rheslip/PyDSA

author: adam_b
author_rank: Newbie
timestamp: August 14, 2016, 02:07:54 pm
content: I tried to run spectrum analyzer with my DS1054Z and it's work but my Rigol displays all time during work with PyDSA error "Function limited!" and "Can Operate Now!". Is this normal ? I have test software with patch and version for 1054Z and make the same.?

author: technogeeky
author_rank: Frequent Contributor
timestamp: August 16, 2016, 04:52:40 am
content: Quote from: adam_b on August 14, 2016, 02:07:54 pmThis behavior is "normal" and it occurred before the latest patch.Please note that this software was written, I believe, before the "Memory" FFT mode was introduced. This software is equivalent to transporting the data gathered from the FFT "trace" mode and putting it on a computer.It would be interesting to see if it's possible to get the data from the "Memory" mode onto the computer and use that instead.

author: adam_b
author_rank: Newbie
timestamp: August 16, 2016, 08:19:21 pm
content: Thank you for your answer. I not fully understand, is possible the program with a patch for the DS1054Z works well with no errors ? I tried DS1054Z version by Kerr Smith and initial release with patch 1054Z by Marcus - both worked the same.
pyMaynuo - python "library" for interfacing with Maynuo Electronic DC Loads - Page 1
Forum section: electronics / projects

author: metalphreak
author_rank: Frequent Contributor
timestamp: June 05, 2014, 03:55:45 pm
content: https://github.com/MetalPhreak/pyMaynuoStarted putting this together last week. I'm using the python module minimalmodbus to do all the MODBUS heavy lifting (with some modifications to account for maynuo not following modbus spec for coil registers). You'll also need pyserial as part of the minimalmodbus dependencies.I still have to write a lot of the functions up, and I'm going to include some high level functions to do battery testing etc, rather than it just being a wrapper script for the commands.If you're interested, and have some python knowledge, check outhttp://minimalmodbus.sourceforge.net/for the general gist of it. This is written as an instrument sub-class, similar to the author's eurotherm example.If there's a decent amount of interest, I'll generate some documentation for it, and submit it to the python module repository so you can easily grab it with pip etc.(it's all written and tested for Python 3.4 - not sure if its code compatible with 2.7)I think you also get a greater number of digits for read back values than you do on the VFD display, but it's meaningless beyond the stated accuracy specs
Python alternative to TI's USB-2-MDIO for PHY configuration - Page 1
Forum section: electronics / projects

author: thosewhowish2b
author_rank: Newbie
timestamp: March 18, 2022, 07:30:06 pm
content: Hi there,I wrote a Python tool to substitute TI's USB-2-MDIO in my workflow and wanted to put it out there, just in case someone finds it useful:https://github.com/AvatarBecker/USB2MDIO_PYThis way we have an option that also runs on Linux, and where we can automate everything, including switching the PHY-address and dispatching many scripts in a row.The background:TI has this tool for configuring the registers of the PHYs on their evaluation boards:https://www.ti.com/tool/USB-2-MDIOIt's a pain, you have to click too much, you can't really script away the work, and it only runs on Windows.People have asked for an alternative, but TI would only provide hints on how the tool works for the user to implement their own:https://e2e.ti.com/support/interface-group/interface/f/interface-forum/653516/usb-2-mdio-re-usb-2-mdio-source-of-usb-2-mdio-would-be-very-helpfulI wanted to post on TI's e2e forum, but apparently you have to have a business email address to post there (wtf?).Best regards,Wesley Becker
Python CMSIS-SVD Parser - Page 1
Forum section: electronics / projects

author: twatorowski
author_rank: Newbie
timestamp: May 04, 2019, 09:41:04 am
content: Hey everyone!Just wanted to announce the release of my CMSIS-SVD to Dictionary Parser written in Python. If anyone wants to create their own header files from the SVD files provided by the chip manufacturers this is a nice place to start. The code provided deals with things like: derivations/inheritances/array-list generations among the set of peripherals/registers/etc.. so that the result is a plain, fully expanded top-down nested tree without cycles or other "computer science funny business". This helps A LOT with header files generation.Project linkhttps://github.com/MightyDevices/python-cmsis-svd-parserFeel free to use it in your projects.PS. I am currently working on my own *.h file generator for STM32 micros that will produce headers that match my coding/documenting style. All in all information from the SVD is not enough and some post processing needs to be done. I'll let you guys know how thing are progressing when I have something that is up and running.Kind regards.

author: jeremy
author_rank: Super Contributor
timestamp: May 04, 2019, 01:21:48 pm
content: Very interesting. Thank you for sharing!

author: Joebeazelman
author_rank: Regular Contributor
timestamp: August 31, 2024, 01:20:51 am
content: I tried to use your parser to output an expanded SVD from an ESP32s3 file, but it didn't work for entire sections like AES. The output still contained placeholders.

author: zapta
author_rank: Super Contributor
timestamp: August 31, 2024, 02:54:27 pm
content: Have you consider posting it on pypi.org? It will allow a simple installation using the pip install command. You can post any package on pypi.org, it doesn't have to be 'mature'.
Python code for YX_TCD1304 linear CCD module - Page 1
Forum section: electronics / projects

author: peterloron
author_rank: Newbie
timestamp: May 20, 2025, 06:18:43 pm
content: For anybody tinkering with one of the YX_TCD1304 linear CCD modules, I have some python code available which reads the module and displays a simple graph. Starting point for something useful.https://github.com/peterloron/YX_TCD1304
Python library for Rigol DS1000E/D oscilloscpes - Page 1
Forum section: electronics / projects

author: adeuring
author_rank: Contributor
timestamp: July 12, 2022, 07:18:00 pm
content: I worked in the last weeks on a Python library to remote control Rigol DS1000E/D oscilloscopes.The aim is an easy to use library that encapsulates as good as possible the more arduous details, like waiting until the change of some setting is finally applied by the device. (Unfortunately the DS1000 series does not implement the SCPI command `OPC`.)Source code:https://gitlab.com/adeuring/ya_ds1052/The README file has a few usage examples.A pip-installable package is also available:Code:pip install ya-ds1052For the "lower communication levels" the package relies on other libraries: It works with the Linux kernel usbtmc driver, as well as with the Python packages PyVISA (tested with the pyvisa-py backend and with the National Instruments VISA library for Linux) and python-usbtmc.I have not yet figured out a good way to specify alternative dependency packages in setup.py, hence PyVIDA or python-usbtmc must be installed separately via pip or some other Python package manager.RunCode:import ds1052help(ds1052)to get an overview of what is possible with the library.I had quite a few gotcha moments working with the DS1052. Tried to sum up the conclusions here:https://gitlab.com/adeuring/ya_ds1052/-/blob/master/gotcha/gotcha.md
Q about mcu Vdd/VBat/Charging VBat - Page 1
Forum section: electronics / projects

author: legrady
author_rank: Contributor
timestamp: August 19, 2025, 02:03:04 am
content: I have some experience with creating circuits, but this is well out of my league.I want to make a board using an STM32 MCU. It has Vdd and VBat, and internal circuitry selects the appropriate one for running the RTC.Examining circuits from Adafruit and the WeAct "Black Pill", I see solutions for +5 to +3.3V and for disabling VBat if +5V is present, but the battery will eventually discharge. How do I charge the battery, assuming it needs it, if +5V is available?The best suggestion will win a free beer poured into my monitor, so have a mug under your monitor to accept your prize :-)Tom

author: ataradov
author_rank: Super Contributor
timestamp: August 19, 2025, 04:01:04 am
content: What type of battery? LiIon charger ICs usually work fine when the input is removed (in terms of not draining the battery), so just a standard charger IC powered by the 5V input would do the trick. The battery will be trickle charged while power is available.
Q: LVDS, LCDs, TCONs, and PC motherboards - Page 1
Forum section: electronics / projects

author: rea5245
author_rank: Frequent Contributor
timestamp: March 24, 2017, 07:58:20 pm
content: Hi,I want to make a PC case with an LCD in it. Option one is to get a motherboard with an LVDS port (actually a Flat Panel Display Link, FPD-Link; some mini-ITX boards have one, presumably for people to make All-in-ones) and have a direct connection to an LCD. Option 2 is to get a motherboard with the standard HDMI ports on the back and have an HDMI cable plug into it, go through a hole in the case, and connect to a disassembled LCD monitor that supports HDMI.If I understand correctly, an FPD-Link cable goes to a TCON (timing controller) board which then connects to an LCD. What I'm not clear on is whether LCDs typically come with the TCON board or not.For example, there are a lot of LCDs sold for the Raspberry Pi with an HDMI/VGA driver board. Does that board include a TCON so that it drives the LCD directly, or is the board converting HDMI into FPD-Link, which then connects to a TCON that's part of the LCD module?It makes a difference in how I hook an LCD up to the LVDS connector on a PC motherboard. If the Raspberry Pi LCD has a TCON included, should I be able to hook it directly to the PC motherboard? (A side question is, is FPD-Link standard, or do I need to pay attention to which LCDs it's compatible with?) Or do I need an LVDS-to-TCON board?Thank you,Bob

author: amyk
author_rank: Super Contributor
timestamp: March 25, 2017, 05:01:50 am
content: Separate TCON is usually found in large TV-sized panels; laptop and typical desktop LCDs have it built in to the panel, which accepts LVDS signals.Your best option may be to disassemble a suitable laptop and rearrange its components.
Q: Nixie tube wires - Page 1
Forum section: electronics / projects

author: rea5245
author_rank: Frequent Contributor
timestamp: August 27, 2017, 12:22:34 am
content: Hi. I'm working with nixie tubes and the tubes I bought do not have rigid pins. Instead, they have long wire leads, sort of like what you'd see on a through-hole capacitor.Is there any sort of socket I can use with these? When I search for "nixie pins" on eBay, I see lots of rigid pins for sale, but I assume they're only used for vacuum tubes that have rigid pins themselves (so you're plugging one rigid pin into another rigid pin).Thanks,Bob

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 27, 2017, 12:31:46 am
content: Many Nixies were designed to be soldered directly to the PWB.This recent thread has a photo showing exactly this:https://www.eevblog.com/forum/repair/iskra-122-nixie-soviet-calculator-1979/msg1288897/#msg1288897All you require is a plastic standoff between the Nixie and the board itself.

author: danadak
author_rank: Super Contributor
timestamp: August 27, 2017, 09:56:19 am
content: If your pinout is inline you could consider using header pins as sockets.Regards, Dana.

author: Ian.M
author_rank: Super Contributor
timestamp: August 27, 2017, 12:05:56 pm
content: The wires are likely to be Dumet or Kovar. Both fatigue far more easily than copper wire, and there is a risk of cracking the seal if they are bent too close to the glass, so socketing them directly is likely to be problematic. Presumably you've got numeric Nixies so need 11 connections. The best option would probably be to solder them to 14 pin turned pin DIP sockets. Seehttps://threeneurons.wordpress.com/miscellaneous-projects/improvised-tube-sockets/You may then want to reinforce them with a 3D printed base shell, printed as two halves attached with electronics grade (neutral cure) silicone sealant.

author: bd139
author_rank: Super Contributor
timestamp: August 27, 2017, 01:20:47 pm
content: I've had those tubes before. Couldn't get any replacement ones that were original! This was a Heathkit DMM.I soldered them to the board and put high temp silicone sealant around the base and the board. This stops them bashing around. If they blow up you're going to have to replace anyway so I didn't want to put too much effort into developing sockets. Make sure you heat sink the wires when soldering; it's quite easy to overheat the envelope.

author: dexters_lab
author_rank: Unknown
timestamp: August 29, 2017, 09:01:13 am
content: PV electronics have small PCBs made for mounting nixie tubes on their QTC clockshttps://www.pvelectronics.co.uk/index.php?main_page=index&cPath=4_11
Q on board to board connections - Page 1
Forum section: electronics / projects

author: Jonathon_Doran
author_rank: Regular Contributor
timestamp: June 17, 2021, 03:01:06 am
content: I am inexperienced in PCB design, but have been a hobbyist for decades. I am finally giving in to the idea of having someone else manufacture a board for me. (I tried the do-it-yourself thing with a laser printer about 20 years ago, with mixed results).For my current project, it is a bit big (600x150mm). PCBShopper shows two vendors, with the US supplier the cheapest!I have more options if I were to chop the board into two chunks, but the cost goes up. That makes sense, setup takes time/money. That isn't the problem. This is a hypothetical, because I don't have enough problems right now.If I needed to chop boards into pieces for fabrication, would it be feasible to create board-to-board connections if the signal frequency was low? What would I need to take into account?Would some headers and a ribbon cable work? What if I put in Bus/Line drivers?My current project is running low frequency, 10-20Hz, low voltage (3-5V).

author: rx8pilot
author_rank: Super Contributor
timestamp: June 17, 2021, 03:10:20 am
content: It sounds like pretty much anything will work from what you are describing when you are pretty much DC low voltage and current.What 'line drivers' or 'bus' are you talking about? I design 12Gbps line driver boards and that is a very serious challenge. If you are talking about RS-232 - it is a totally different thing.I tend to choose the easiest to work with connectors that can still maintain signal integrity. Through hole headers are common and nice, but end up being manually assembled parts. There are SMT B2B connectors that are pick and place friendly, which can eliminate the hand assembly. That may or may not be a factor for you.Lots and lots to choose from.

author: Jonathon_Doran
author_rank: Regular Contributor
timestamp: June 18, 2021, 08:00:39 pm
content: Rather than use one large board, could I use two or more adjacent to each other with some connection. I was thinking of driving signals from one board to another.I was checking to see if this was a reasonable thing to do, and if I needed to do anything special.

author: Jonathon_Doran
author_rank: Regular Contributor
timestamp: June 18, 2021, 08:06:08 pm
content: Thanks for a great deal of information, that was exactly what I needed.I don't believe that I need to down this road now, but possibly in the future.
q. on GY-VL53L0XV2 (breakout for ST VL53L0X ToF module) - Page 1
Forum section: electronics / projects

author: TechieTX
author_rank: Contributor
timestamp: November 26, 2019, 03:48:22 am
content: I've been looking at building a handful of monitors for our CPR manikins to get immediate feedback on the quality of compressions (depth of compression, full release, and BPM). We have Prestan Ultralite manikins, and the spring force feedback tower in the chest looks like the only decent place for sensing. Pouring over datasheets, most sensors flat won't work, or are too complicated to derive accurate depth (accelerometers).The ST VL53L0X looks to be the winner, but the only boards I can find with decent mounting considerations are no-name clones sold as GY-VL53L0XV2. Looking at a couple of good res photos, I see what looks like a 3.3V Torex or Sunrom regulator on a board that should have a 2.8V LDO reg.Asking the China sellers is a waste of time, and I don't want to wait a month to find out the boards are junk. Anyone here have one that can verify the SOT-23 part is actually putting out 2.8V, and not 3.3V as the 662K marking suggests?If you're curious, here's the basic parts:Not shown: ESP8266 D1 Mini, 1.8" OLED display, and a battery pack (TBD).I like the GUI for theLaerdal CPRmeter 2, but at$700 a pop, they're out of their freaking minds when I can do the same with $15 worth of parts. Since the ESP has WiFi, I can monitor all 4 units from my phone while walking around and offering guidance & coaching during the practice session.

author: kathy
author_rank: Contributor
timestamp: January 05, 2020, 08:29:17 am
content: I think SOT-23 part is suitable forOLED displaymodule via the I2C port. the monochrome oled interface can be simple, spi or I2C interface are available.
Solderless connections for IC-FPGA connection - Page 1
Forum section: electronics / projects

author: rsridhar
author_rank: Contributor
timestamp: August 19, 2025, 05:07:39 am
content: I am working on a project that uses a FPGA demo board (DE0 Nano) to talk to an ADC and DAC. But, being a beginner and hobbyist, I am trying to do it with solderless connections. My main question is: Is this crazy?Longer story: I am using something like this to convert the TQFP64 ADC package to DIP pins:https://www.ebay.com/itm/365095557703And using cheap jumper cables to connect to an FPGA:https://a.co/d/c9DxWvZPower and Ground rails are on a cheap breadboard. The max digital data rate going across the wires is 12-25MHz. Attached is an image of the setup:I posted this question to another forum and the general response was that this is not a good idea, and I will run into communication issues. I was wondering if anyone would be willing to go into what some of these issues would be; and a little more detail on the cause (interconnects, length of wires, EMI, etc.).Thanks in advance!

author: EggertEnjoyer123
author_rank: Frequent Contributor
timestamp: August 19, 2025, 07:06:21 am
content: It could work at 10 MHz since that is comparatively a low frequency, and if you don't care about radiated emissions you could probably try it.The main issue is return currents. Any current going from the chip to the FPGA needs a ground wire to return back to the chip. If the loop formed by these wires is large (as it will be in your case) then it will pick up any stray magnetic fields, or it would radiate it and mess up other signals nearby. At 10 MHz you very well could get away with it though.It's still better to make a PCB. It is quite difficult to get Verilog to work sometimes, and ideally you don't want to go on a wild goose chase with all those wires only to find out your code was broken (or vice versa)Edit: the bigger issue is going to be decoupling capacitors. If you can't solder then close to the ADC your circuit won't work or it'll be extremely noisy.
QA sticker - creepage distance - USB power board - Page 1
Forum section: electronics / projects

author: adam1213
author_rank: Regular Contributor
timestamp: October 05, 2014, 11:29:46 pm
content: Can a sticker crossing an isolation slot in a board have an impact on the safety of a power supply?See photo* Note the capacitor at the top of the picture is a modification I made to the board. The capacitor is Class Y2 300Vac 0.022uF

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 06, 2014, 01:17:54 am
content: Not sure, seems careless though.You don't care about inspection anymore, so just cut / peel it off..Tim

author: rs20
author_rank: Super Contributor
timestamp: October 06, 2014, 02:35:21 am
content: Quote from: adam1213 on October 05, 2014, 11:29:46 pmIt must surely have an impact -- what could be better at collecting conductive crud than the sticky side of a sticker (assuming the sticky stuff isn't already a problem by itself)?

author: SeanB
author_rank: Super Contributor
timestamp: October 06, 2014, 07:33:01 pm
content: Peel the "it did not blow up, or we are going to just ship because too many did blow up so no longer test" sticker off, the paper will absorb moisture with time and become conductive, and the glue will too, if it is not already conductive from contaminants.Clean off the flux as well, so the USB charger multiplug will be slightly safer. I would not have bothered with the capacitor, just connected the USB connector housing to earth direct, or via a low value resistor.

author: kolbep
author_rank: Frequent Contributor
timestamp: October 06, 2014, 08:15:35 pm
content: Where did the middle bit of R12 go? Was it a screwdriver slip?

author: SeanB
author_rank: Super Contributor
timestamp: October 06, 2014, 08:43:07 pm
content: R12.R13 were cost cutted out, who needs balancing resistors on the capacitors in any case.

author: Neilm
author_rank: Super Contributor
timestamp: October 06, 2014, 08:51:56 pm
content: Creepage is the path between two conductors going along a surface. So the answer is yes - it does compromise safety.Also, the distance required is dependent on the CTI of the material. So not only would that sticker be breaching the creepage isolation slot, as it is hydroscopic it would require more distance to provide the same protection - and as it is paper, it could start to track and would then provide the starting fuel for a fire.

author: DanielS
author_rank: Frequent Contributor
timestamp: October 06, 2014, 11:09:57 pm
content: It takes about 1kV to jump 1mm through air so unless the PCB and sticker are significantly contaminated or conductive, there is no imminent safety risk.From a safety regulation or certification point of view though, the sticker across a gap does void its creepage gain.

author: adam1213
author_rank: Regular Contributor
timestamp: October 07, 2014, 10:49:21 am
content: Quote from: kolbep on October 06, 2014, 08:15:35 pmI was wondering the same thing. I have another version of the power board. In one version it changed from R12 to C12The other unusual thing about the board is that one of the pins for the bottom IC doesn't have a pad.
QFN reflow - Page 1
Forum section: electronics / projects

author: gaminn
author_rank: Frequent Contributor
timestamp: October 10, 2019, 06:59:33 am
content: Hi,I have some QFN's from TI, they have pads plated on the bottom of the chip and unplated on the sides (visible copper which will oxidize). During reflow (lead free paste, temperature 255 °C) I can't get sides of the pads covered by solder so one can't visually check the quality of the joint. However, all boards are working.In you experience, is it possible to solder these QFN also on the non-plated sides during reflow? And is it neccessary? At the moment, I don't think so, the only drawback is that the joint doesn't look well when there is no solder on sides of the pads.

author: ConKbot
author_rank: Super Contributor
timestamp: October 10, 2019, 04:17:01 pm
content: No need to worry about the side of the QFN leads except in special applications. Some ICs that are automotive rated come in a "wettable flank" QFN package. This gets rid of the stress-riser by letting a nice fillet form, but unless you're in a high vibration application in an un-potted module, it's no problem.As you said, they are unplated, so they aren't 'solderable' just a remnant of the lead-frame manufacturing process.

author: Berni
author_rank: Super Contributor
timestamp: October 10, 2019, 04:23:47 pm
content: Yep this is by design, all the soldering just happens underneath where you can't see it. But if you really want them to be soldered you can likley get them to do so by putting down a lot of flux and running your soldering iron over them a few times. There are also QFN designs that have no metal on the side at all, i don't like those but hey you get what you get.The ones that are plated are often marketed as a feature since it makes an even more solid connection and makes visual inspection easier.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 10, 2019, 11:57:03 pm
content: Should be PQFN (pullback) actually. Which is actually an LGA without the grid array. Follow LGA rules for the pads -- there's no toe fillet, and correct, no way to inspect them visually, you need x-ray for that.These can be sneaky to identify. I followed one particularly bad drawing thinking it was a QFN, turns out it was one of these. And indeed, inspecting the part, there's a 0.1-0.2mm web of plastic around the perimeter, invisible without a loupe. The pads don't actually come out to the edge, nor do they wrap around to the leadframe exposed on the sides. The soldering looked terrible -- I left what was supposed to be a generous toe fillet, which just ballooned up instead, what with no face to wick up. But it connected alright and I fixed the lands in the production revision.Tim
QFP solder mask expansion and min. width - Page 1
Forum section: electronics / projects

author: shadewind
author_rank: Frequent Contributor
timestamp: March 16, 2011, 07:34:55 pm
content: I'm learning to do PCB layout as of lately and I noticed a problem that I'm not sure how to solve.I have an ATMega8A in a 0.8 mm pitch TQFP package on my board and the spacing between each pad is well within the minimum clearance (6 mil) for iTead Studio which is the service I'm going to use. On the other hand, the solder mask between the pads is less than 0.1 mm which is the minimum width iTead Studio's rules allow. This is with a solder mask expansion of 4 mil which is the default in Altium.Now, 0.8 mm is a fairly wide pitch QFP I assume so it surely has to be possible to use QFP footprints with iTead, right? So what am I supposed to do? Reduce solder mask expansion? Ignore the warnings?

author: jahonen
author_rank: Super Contributor
timestamp: March 16, 2011, 07:55:26 pm
content: There is no requirement in PCB manufacturing that there must be solder mask between pins. It makes sense to open the mask entirely in pad area (four big openings) in this case. With denser pitches like 0.65 mm and below, solder mask is usually removed this way.In fact, very thin slivers of mask might cause problem, and it is another reason why PCB manufacturer might edit your gerbers, to remove the thin slivers in soldermask.Regards,Janne

author: shadewind
author_rank: Frequent Contributor
timestamp: March 16, 2011, 08:29:26 pm
content: So should I remove it or should I just send it as is?

author: jahonen
author_rank: Super Contributor
timestamp: March 16, 2011, 08:37:26 pm
content: I think it would be perhaps safest to remove it by yourself, that way you can be sure how it has been done. This can be done by just drawing appropriate rectangles in the solder mask layer, on top of the pads. Another way would be to enlarge the openings in the footprint so that they touch each other.Check the result with some gerber viewer, to view the final result (wise operation, which I'll always do).Regards,Janne

author: shadewind
author_rank: Frequent Contributor
timestamp: March 16, 2011, 08:53:57 pm
content: Allright, I've draw rectangles across the spaces between the pad. Will it be a lot more difficult to solder this?

author: jahonen
author_rank: Super Contributor
timestamp: March 16, 2011, 09:11:31 pm
content: I think not, the <0.1 mm wide mask between pads wouldn't been much of a help anyway, even if it would exist.Regards,Janne

author: shadewind
author_rank: Frequent Contributor
timestamp: March 16, 2011, 10:23:47 pm
content: Well, then, we'll see! Thanks for the help.The advantage of using iTead is that it isn't a lot of money if anything in the design is wrong.
Qi chargers explaination and min. circuitry necessary - Page 1
Forum section: electronics / projects

author: Yaro
author_rank: Contributor
timestamp: September 05, 2015, 01:00:08 pm
content: Hi all,I've read something about Qi charger, I can't find some pratical documentations but found that is enought 2 capacitors and rectifier to connect reciver to load. Additional IC is necessary for communications between transmitter and reciver via modulation. I've some doubts about coil and connection in a pratical application.Some questions I've are:How coil dimensions are related with maximum current trasfer? For example a 100x100mm coil and 20x20mm smartwatch coil have same efficiency? How can I determinate their max. current trasfer?I've found also FPC wireless coils that are very thin and flexible, they need a magnetic base or are they something like double sided pcb? What are differences between normal coils and FPC?Also, in reciver module and load connection, for example usb port, how this works? Can I directly connect coil to usb port?Thanks for any explainations!
Qi wireless power Tx/Rx pair - Page 1
Forum section: electronics / projects

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: February 18, 2018, 07:45:59 pm
content: Would anyone be able to recommend a Qi wireless power Tx/Rx pair?At the moment I want to try using NXQ1TXH5101J (Tx) & BQ51013BRHLT (Rx) but just want to see if there are better suggestions out there ;^)
QPROX QT511 alternative capacitive scroll wheel  - Page 1
Forum section: electronics / projects

author: glenenglish
author_rank: Frequent Contributor
timestamp: June 18, 2024, 09:47:58 pm
content: some people might remember this from 2006 - the QPROX QT511Does anyone have any known good modern suggestions ?https://web.archive.org/web/20060105003703/http://www.qprox.com/news/qt411-511.phpwe used this on a portable product and customers loved it. it just worked. and had good resolution and good behaviouralas atmel bought them , then microchip , no longer existsany ideas appreciated - glen
QPSK Demotulator: frequency and time recovery - Page 1
Forum section: electronics / projects

author: Gregory
author_rank: Regular Contributor
timestamp: September 01, 2014, 05:51:36 pm
content: Hi guys!In a QPSk demodulator I need to recover carrier frequency and symbol sample time. How can I do both if frequency error generation needs correct time lock and Gardner time recovery needs frequency correct lock?Thanks

author: David Hess
author_rank: Super Contributor
timestamp: September 01, 2014, 06:32:36 pm
content: Quote from: Gregory on September 01, 2014, 05:51:36 pmAlex, what is Costas Loop?

author: scatha
author_rank: Regular Contributor
timestamp: September 02, 2014, 09:44:01 am
content: If you've got access to Simulink, Dick Benson of Mathworks has written some pretty nice models showing how to perform symbol timing/carrier recovery of QPSK in the face of various impairments.Pretty much the standard text in this area is 'Digital Communication Receivers: Synchronization, channel estimation, and signal processing' by Meyer. The symbol timing error estimator on pp. 289-295 can be used in conjunction with a loop filter and fractional delay filter to correct for symbol timing, and from here it's pretty simple to correct for carrier offset.

author: danfo098
author_rank: Contributor
timestamp: September 02, 2014, 03:04:14 pm
content: A Costas Loop run completely independent without any feedback from the downstream demodulator and symbol timing recovery scheme and it can aquire a lock on the carrier frequency and phase if the initial frequency offset is not too large (half or a quarter of the signal bandwidth, not sure but something like that).If the initial frequency offset is too large the carrier frequency can be estimated (one method if FFT) and then you initialize the Costas Loop with the estimated frequency which should then be in the pull-in range.

author: coppice
author_rank: Super Contributor
timestamp: September 02, 2014, 03:23:22 pm
content: A Gardner TED does not require that the carrier recovery is locked. You can make it the first step in recovering the signal, and nail down the carrier phase and frequency by monitoring the symbol locked information that comes out of the TED. Other totally different strategies, based on estimating the carrier first are also possible. A lot depends on whether you have a distinct training sequence to work from, or if you need to recovery the signal blindly.
QSpice Forum - Page 1
Forum section: electronics / projects

author: moffy
author_rank: Super Contributor
timestamp: October 07, 2023, 11:16:09 am
content: I had a question about accessing the simulation time from within a C++ block, so I went to the QSpice forum:https://forum.qorvo.com/c/qspice/9and had two solid answers in a couple of hours, very nice. The answer is that the variable 't' for time is accessible within any C++ block.
QT LR2000 aka. Chroma 16502 Milliohm Meter - Page 1
Forum section: electronics / projects

author: sixtimesseven
author_rank: Frequent Contributor
timestamp: April 02, 2019, 11:56:30 am
content: I picked up a LR2000 Milliohm Meter (aka. Chroma 16502) from Ebay and apart from the usual wear and the missing cal. it seems to be in good condition.Below you find what I could come up with so far. I will save the firmware as soon as I get the required adapter and add it here. Firmware is v1.32.If sombody happens to have a newer version I would be very interested to update since my unit is a pretty early model. Also, pictures of the Temperature Sensor Board would be of interest since I do not have the hardware option...Pictures / Teardown:https://www.flickr.com/photos/137236105@N05/Datasheet & Manual:https://www.dropbox.com/sh/tfv1xtd4gajtjcj/AAClgmVPqishVaijVZMTUQhPa?dl=0However, strangely I cannot disable "LOCK" via keypad, only via rs232 (haven't tried GPIB yet). RS232 commands are (9800B 9N1 with carriage return) supposed to be identical to the manual above GPIB commands. And some things work like "*trg" but e.g. "system:local" is not one of themUPDATE: Figured out the Calibration PasswordThe password for Chroma 16502 aka QuadTech2000 Milliohm meters is:[ArrowUp, ArrowDown, ArrowLeft, ArrowRight, Trigger]

author: sixtimesseven
author_rank: Frequent Contributor
timestamp: April 02, 2019, 08:01:51 pm
content: Figured out that it is likely that there were some changes between my firmware v1.32 and the manuals v2 firmware.I could not get for example "system:local" work at all.What works is to send the GPIB GTL command message.Pyvisa example: lr2000_DisableRemote.py here:https://www.dropbox.com/sh/tfv1xtd4gajtjcj/AAClgmVPqishVaijVZMTUQhPa?dl=0What I am missing now is the Password to enter cal. data. Manual does not mention a default one so unless I find and some obvious ones do not work. Might have to look into the Firmware
QTDMM - Page 1
Forum section: electronics / projects

author: PsychoMaster
author_rank: Regular Contributor
timestamp: February 16, 2015, 03:18:36 pm
content: Hello AllMy son ordered me a Tekpower 4000 (I asked him to get a 2834R oh well next time) which has computer output.I use Linux so it meant righting my own software (no big deal I,ll have a go in Python) but I found someone had beat me to it with qtdmm which means Digital Multimeter written in QT obviously.Any how if any one else needs help installing this as not every one likes the command line then I,ll try and make it easy as possible.If I hand out scripts to beginners which experienced folk tend to do then that is no help either as they struggle with the executable bit and calling the file.I remember I did.It looks to work with most meters built around common chip sets so If it works under Windows then it should here.

author: c4757p
author_rank: Super Contributor
timestamp: February 16, 2015, 03:49:54 pm
content: If you're going to choose to use Linux, using the command line somewhat comes with the territory. Youcanavoid it, but it's silly to as many things are designed for it and it's a really powerful tool anyway. If you're going to write code, using the command linereallycomes with the territory. That's where all the good tools are. And if you're going to do either of those things, figuring out stuff likechmod +xalso comes with the territory...

author: PsychoMaster
author_rank: Regular Contributor
timestamp: February 17, 2015, 10:03:33 am
content: Yes I agree I am happy to use no window manager at all and if you don,t use command line then you are missing out but look how Linux as changed over the last ten years .To attract Windows folk you don't need to really .Actually they don't recommend going out side the package system.Getting qtdmm put into the repositories is the answer but for now if a user needs help then I'm offering.
Qtouch auto-repeat implementation - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: May 10, 2020, 02:22:47 pm
content: Hi all,has anybody implemented autorepeat for a QTouch sensor/ketpad?I am planning to use this IC (http://ww1.microchip.com/downloads/en/DeviceDoc/doc9634.pdf) but it does not mention anything about autorepeat or detecting if the user keeps the finger on the QTouch pad.Any ideas or alternatives?Many thanks

author: ivi_yak
author_rank: Regular Contributor
timestamp: May 10, 2020, 04:35:50 pm
content: hittp223 provide auto recalibration after 16 sechttps://radiokot.ru/konkursCatDay2014/53/01.pdf

author: ricko_uk
author_rank: Super Contributor
timestamp: May 10, 2020, 11:20:14 pm
content: thank you.Any other suggestions anybody? That IC does not seem easy to be sourced from the major European/US distributors.
QTouch Auto-repeat - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: May 10, 2020, 12:20:23 am
content: Hi,has anybody implemented a QTouch autorepeat?I am planning to use this IC but it does not mention anything about autorepeat or detecting if the user keeps the finger on the QTouch pad:http://ww1.microchip.com/downloads/en/DeviceDoc/doc9634.pdfAny ideas or alternatives?Many thanks
Qtouch on Microchip - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: April 13, 2020, 08:34:14 pm
content: Hi,now that microchip has acquired Atmel, are there any Microchip micros that use any of the Microship "classic architecture" (8, 16 or 32 bits) which also have Qtouch?I want to implement touch controls but want to stick to the Microchip micros and I don't particularly want to use external Qtouch ICs.Any suggestions?Thank you

author: dmendesf
author_rank: Frequent Contributor
timestamp: April 13, 2020, 09:40:04 pm
content: Microchip PICs usually have 2 types of hardware for capacitive sensing: CVD and CTMU. They're older than Microchip's Atmel aquisition, so not the same technology. I'm unaware of any later PIC with a different hardware for touch sensing.

author: ricko_uk
author_rank: Super Contributor
timestamp: April 13, 2020, 10:13:47 pm
content: Thank you Dmendesf,from memory they need a metal plate and they measure the microscopic displacement of the metal plate (inductive and/or capacitive) is that correct?Thank you

author: dmendesf
author_rank: Frequent Contributor
timestamp: April 14, 2020, 05:10:49 am
content: No, they can also measure self capacitance and mutual capacitance as qTouch. Just maybe without the same fancy tools to trim the results.
Qtouch PTC Slider Project. - Page 1
Forum section: electronics / projects

author: amitchell
author_rank: Regular Contributor
timestamp: August 25, 2016, 06:26:23 am
content: Hey, I am working on a Qtouch PTC Project that controls an LED boost driver. Though I would share what I have so far and see what improvements can be made.I am using an Atmega328PB for the Qtouch PTC and PWM output to the Boost driver TPS61165. I have 6mm of Z height to work this little puppy into, so sourcing some components has been a hassle.Input protection is LTC4365 Overvoltage, Undervoltage and Reverse Supply Protection Controller. This seems like a nice little unit. 12vdc normal input with an 11-13vdc allowable input controlled by the LTC4365.On the original boards I was seeing some 1.2MHz switching frequency noise in my MCU circuit, I decided to try out some 1uF feed through caps to soften that up on this go around.I think i am looking at about 45dB insertion loss per FTC at 1.2MHz.https://product.tdk.com/info/en/catalog/datasheets/eemc_3tf_yff-hc.pdf(this is the 1206 footprint also have an 0805)I am trying two LDO's (LP2985A) to smooth out the power further, One at each end of the 1mm pitch FFC cable. Previous board had one.On the boost board I was thinking it may be smart to isolate the ground at the Boost circuit all the way back to the GND input. Do you think it is wise to do this? I have already kept a single point ground under the boost controller. I am also unsure of the top pour, is this worth it? I am keeping a 25mil isolation on everything.On the MCU slider board I debated with myself about the 16MHz crystal isolation, I did remove a guard ring that I had in place. It seams alot of datasheets are contradictory in terms of crystal isolation/guarding.Any glaring errors or issues that I am missing?

author: DTJ
author_rank: Super Contributor
timestamp: August 25, 2016, 08:44:31 am
content: Just out of interest - what sort of SIL header are you using for the programming connector? It looks like alternate pins are offset a little.How are you mounting the boards - I don't see mounting holes.

author: amitchell
author_rank: Regular Contributor
timestamp: August 25, 2016, 01:41:37 pm
content: Quote from: DTJ on August 25, 2016, 08:44:31 amGood eyes.That is a "lock" footprint from the sparkfun eagle library actually. Offset is 5mils so a standard SIL header is held in place and not flopping around.I am using adhesive to attach the slider to the panel. I think I will clamp the Boost board in place using the outside edges. I cannot use screws through the z-axis. The panel is 8mm thick and I get to use 6mm of this for the boards.

author: DTJ
author_rank: Super Contributor
timestamp: August 26, 2016, 05:34:25 am
content: Quote from: amitchell on August 25, 2016, 01:41:37 pmThat's a good idea. It craps me off doing the odd hand assembly job and having to hold them in place and vertical and getting a hot finger as the pins warm up.
quad op amp pin outs?  - Page 1
Forum section: electronics / projects

author: loki42
author_rank: Frequent Contributor
timestamp: July 01, 2019, 06:34:01 am
content: Are there quad op amps, if possible similar or better noise performance to the TL074 that have a switched pin out with the inverting and not inverting input pins switched? I need it in a SOIC format. Currently I'm reworking the boards to fix my mistake but it'd be a lot faster to swap the chips.

author: David Hess
author_rank: Super Contributor
timestamp: July 01, 2019, 11:26:11 am
content: I am not aware of any with the inverting and non-inverting pins swapped.Most quads use the LM324 pinout but there are exceptions like the RC4136.

author: loki42
author_rank: Frequent Contributor
timestamp: July 01, 2019, 11:42:07 am
content: Not sure if this is the easiest option but I've just thought of something that might have been obvious to others... how about I make a board that has a SOIC format on the bottom and a TSSOP format on the top and put new op amps on? I guess I could have SOIC on both but then I think I'd have to hot air the PCB on the solder the top ones? Maybe still pretty quick.

author: David Hess
author_rank: Super Contributor
timestamp: July 01, 2019, 12:22:13 pm
content: Incidentally, there is some reasoning behind operational amplifier pinouts. The outputs are placed closer to the inverting inputs than the non-inverting inputs to prevent positive feedback through capacitive coupling. Comparators want the opposite leading to the very different LM339 quad comparator pinout. Dual comparators copy the dual operational amplifier pinout which is not optimal for them.

author: loki42
author_rank: Frequent Contributor
timestamp: July 01, 2019, 12:28:09 pm
content: Looking at the prices of castellated holes it seems a lot quicker and easier to just use it basically as a QFN style package, with all the leads underneath and solder the top one. Would it work to put down paste, heat a small adapter PCB with hot air to solder it onto the main PCB and then hand solder the op amp on the adapter? I assume the enough heat would get to the paste to liquefy it without damaging the adapter board but maybe castellated is safer.