hybridfree/eevblog-posts huggingface dataset:
Printer Teardown - Page 1
Forum section: electronics / projects

author: shriram
author_rank: Newbie
timestamp: June 21, 2014, 06:37:56 am
content: I recently took down a cannon IP2770 printer and got the main circuit board, I find many Integrated Circuits there, but I'm having a tough time finding them on the internet, could someone share their expertise in this small topic. [Sorry if the question is in the wrong section]The marking on the Chips are as followsa] 808520 611 A, says CHINA on it. A Quad Flat pack ICb] W9864G6JHc] 25Q16BVF1GI Searched them on google but couldn't get any productive result.Help!!!

author: lapm
author_rank: Frequent Contributor
timestamp: June 21, 2014, 11:58:48 am
content: Im not suprised that you dont find too much info on some of those chips... Some manufacturer order parts on their own markings to prevent competiotion or easy repairs...

author: amyk
author_rank: Super Contributor
timestamp: June 21, 2014, 12:52:41 pm
content: The last one in particular should be pretty obvious - 25(letter)(power of 2) is usually SPI flash, commonly encountered for BIOSes on motherboards.The first one is an NEC/Renesas CB-90M ASIC; UPD808520GM611GAA apparently is the full order code.http://am.renesas.com/products/soc/asic/cbic/lineup/cb90/index.jsphttp://am.renesas.com/products/soc/asic/cbic/device/UPD808XXX.jsp
Printing multiple pdf images on to one transparency to make several boards - Page 1
Forum section: electronics / projects

author: Chris Wilson
author_rank: Super Contributor
timestamp: February 12, 2015, 03:05:25 pm
content: I am trying to print about ten 1 to 1 scale images of the pdf in the attachment onto one A4 transparency to make multiple boards in one go, using photo etch PCB board. I can't work out how to retain the 100% scaling and get say 10 copies onto one transparency. I then want to UV light box them as all in one go onto a single sheet of photo sensitive single sided PCB and etch them all at once, then cut the boards off as individuals afterwards. I have Adobe Reader, but if I go to "Multiple Pages" it still shows the one one image, if you follow me?Thanks. OS is Windows 7 Pro 64 bit. Printers are elderly HP laser jets, one B&W and one colour. The B&W gives denser print.

author: dexters_lab
author_rank: Unknown
timestamp: February 12, 2015, 04:20:07 pm
content: you could load the pdf into photoshop and just paste the board multiple times onto a page... watch out to keep your dpis the same as your printer

author: Andy Watson
author_rank: Super Contributor
timestamp: February 12, 2015, 04:23:37 pm
content: LaTeX is your friend!

author: Lightages
author_rank: Unknown
timestamp: February 12, 2015, 04:26:24 pm
content: BTW, when exposing the boards, make sure you have the printed side of the transparency in contact with the board. You need to make sure that the image is printed mirrored of course. I am not sure if you knew these things but it is a good thing to know.

author: Chris Wilson
author_rank: Super Contributor
timestamp: February 12, 2015, 04:41:20 pm
content: Quote from: Andy Watson on February 12, 2015, 04:23:37 pmWhat a star! Thanks, now how do I get chummy with latex, this is where you tell me it's a Linux thing, isn't it?Thanks again Andy!!

author: Chris Wilson
author_rank: Super Contributor
timestamp: February 12, 2015, 04:42:30 pm
content: Quote from: Lightages on February 12, 2015, 04:26:24 pmYep, have done many boards, but thank you for the reminder, I'll do a sanity test before ruining expensive photo etch board

author: Andy Watson
author_rank: Super Contributor
timestamp: February 12, 2015, 04:57:32 pm
content: Quote from: Chris Wilson on February 12, 2015, 04:41:20 pmThere are windoze versions out there, but, paradoxically, if you're not happy using a command line you will probably not appreciate how quick and easy it is to use.http://www.latex-project.org/ftp.htmlI've only tried the Miktex version on windoze XP - can't say that I liked it.

author: tonyarkles
author_rank: Regular Contributor
timestamp: February 14, 2015, 03:20:26 pm
content: Quote from: Andy Watson on February 12, 2015, 04:57:32 pmAs a long-time LaTeX user, I don't know that I'd describe it as "quick and easy" on any platform. Ten years in, I'm pretty comfortable with it, but when I was first starting out there was a lot of cursing trying to figure out how to get a whole document to lay out properly without my images and tables ending up in ridiculous places.
Prior Projects on Capacitative Wireless Power Transfer - Page 1
Forum section: electronics / projects

author: 6E5
author_rank: Regular Contributor
timestamp: November 27, 2014, 06:23:58 am
content: Inductance coupled wireless power transmission has been a fairly popular project ever since WiTricity. However, I want to build a capacitively coupled system for my state science fair project. I have read numerous papers on the subject, however I haven't seen a hobbyist orientated, fully detailed project- something that would include the schematic, build, and any practical considerationsHas there been any previous projects on the forum? I would find them helpful in figuring out how to design my own.
Probe Master SMD test probes DIY - Page 1
Forum section: electronics / projects

author: wwjd1924
author_rank: Contributor
timestamp: February 23, 2022, 02:20:14 pm
content: I made my own Probe Master SMD test probes because the proper Probe Master test probes are hard to get in Europe.So I bought a 8162 Replacement Tip Pair whichwereon stock and soldered them to some Hirschmann 2mm gold plated female connectors I had in a drawer.I more details are needed, let me know. I figure there's not much interest in my DIY project but just in case I post it here.
Probing drain pin on power mosfets to observe switching operation - Page 1
Forum section: electronics / projects

author: zupta82
author_rank: Regular Contributor
timestamp: January 24, 2021, 02:44:50 am
content: I was wondering is it safely possible to probe the drain pin on mosfets to observe the switching on an oscilloscope. I was worried about high current damage to my scope. They are irfp450 FETs

author: ledtester
author_rank: Super Contributor
timestamp: January 24, 2021, 03:03:01 am
content: What kind of switching frequency are you expecting?

author: zupta82
author_rank: Regular Contributor
timestamp: January 24, 2021, 03:10:19 am
content: I’m thinking it’s got to be in the KHz range maybe 10-20.

author: TimNJ
author_rank: Super Contributor
timestamp: January 24, 2021, 03:38:03 am
content: You can definitely probe the drain-source voltage of a FET. What do you mean by high current damage? Is it a mains powered circuit? You need to be mindful of whether the source of the MOSFET is also at earth potential. If it’s not, make sure to use an isolated probe and/or power circuit through an isolation transformer. If it’s battery powered, then no worries. Many threads on this forum if you search for isolation transformer.

author: trobbins
author_rank: Frequent Contributor
timestamp: January 24, 2021, 05:01:50 am
content: 100:1 probe with sufficient voltage rating for the application.The capacitance of the probe may modify the waveform.

author: CaptDon
author_rank: Super Contributor
timestamp: January 24, 2021, 01:44:00 pm
content: Why would 'high current' matter?? Your scope measures voltage regardless of the circuit current flow. Would measuring the 12 volts at the car starter motor drawing 400 amps be any different than measuring 12 volts at the turn signal drawing 1.5 amps?

author: Ian.M
author_rank: Super Contributor
timestamp: January 24, 2021, 02:02:40 pm
content: Be aware that most x10 and x100 scope probes *MUST* have their voltage rating derated for frequency above a few tens of KHz. A nominally 600V rated probe may only be good for 60V at 10MHz.(from the Keysight Labs channel)Its *NOT* the switching frequency that matters for derating, its the slew rate as a 350ns risetime edge 'looks' like a 1/4 cycle of an approx. 1MHz sinewave, so even a 10KHz switching frequency can get you into trouble.
problem in bringing up a 440w LLC  - Page 1
Forum section: electronics / projects

author: mirbagheri1122
author_rank: Contributor
timestamp: February 17, 2015, 09:21:01 am
content: HiI have builded a LLC buck regulator based on datasheet of LCS708 from pi.and gave it 380 v directly but response that i get is 3v instead of 44v i attached my schematic and pcbmy ic draw 80 ma current.please check sch and pcbthanks for any guidance

author: mirbagheri1122
author_rank: Contributor
timestamp: February 19, 2015, 07:38:59 am
content: Hii changed ic and started to rise voltage with variac and no load.but in 30v (input) output starts to rise up slowly from 6v to 30 v that i turned it off but my hb voltage is rectangular.Frequency is 170khzStrange for me is secondary waveform that increases slowly and triple that compelled me to turn it off.Output cap is electrolytic that I will change it.Thanks alot

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: February 19, 2015, 12:21:52 pm
content: Hi,Please upload your design file spread sheet

author: mirbagheri1122
author_rank: Contributor
timestamp: February 19, 2015, 12:53:35 pm
content: Hithis is my spreadsheetand hb pin voltagethanks

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: February 19, 2015, 01:30:39 pm
content: Please upload the PI expert Spread sheet

author: mirbagheri1122
author_rank: Contributor
timestamp: February 23, 2015, 06:44:02 am
content: Hii reached to regulated voltage at 40 % of nominal input voltage.and output is very good.with load of 10w after 30 min my ic shut down happened.and after turning off input i saw my core is very very hot.ofcourse i changed turns numbers to 12.5 and 2.5.i think i found problem of core overheating.maybe is because of my low secondary turns that is 2.5 and BAC is 525.but in new spreadsheet that nurn number is 25 and 5 because of my new constant Lres that is 70uH and is about high.i cant satisfy other conditions.thanks alot.

author: mirbagheri1122
author_rank: Contributor
timestamp: February 25, 2015, 08:06:01 am
content: HiWhen i increase voltage more than 340v my device goes to off state and out put decreases to .4v[with 8w load].my ov/uv pin is disabled.Thanks
Problem in education FPGA Spartan III board(short circuit the AMS1117-1.2) - Page 1
Forum section: electronics / projects

author: rozeh
author_rank: Regular Contributor
timestamp: December 02, 2013, 05:24:46 pm
content: .....................................

author: hans
author_rank: Super Contributor
timestamp: December 02, 2013, 05:36:34 pm
content: Simple guess: check the soldering?I note that the via's are placed closely to the QFP pins from the inside. I suspect there is no via tenting applied because I neither see them at the bottom layer. Typically VCC and GND pins are located next to each other, so it is very possible there is short behind the QFP pins somewhere on the board.Have you checked the pinouts of all components? If one VDD/GND pair is off, you can also see a short on the entire rail.
Problem in Power integrity analysis on a two layer pcb. - Page 1
Forum section: electronics / projects

author: kumar
author_rank: Contributor
timestamp: April 24, 2013, 12:17:41 pm
content: I am new to emi/emc. So like to ask whether one can perform power integrity analysis on a two layer pcb ( both are signal layers and no plane). We tried but nothing worked. Can any expert guide me?

author: AndyC_772
author_rank: Super Contributor
timestamp: April 24, 2013, 06:26:24 pm
content: Yes, but it'll help to know more about your design. What kinds of circuitry are you using (ie. analogue, RF, digital or power management), how big is the board, how much power does it use, what's the nature of the problem you're seeing?Without specifics, you might get a lot of generic advice, but little or none of it could be applicable to your actual PCB.A good start is to post your schematic and some gerbers or PDFs of the board. Can you do that?
Problem of surge currents in PFC's sense resistor (LT1248 & LT1249) - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: November 18, 2017, 09:59:25 pm
content: The LT1249 and LT1248 are both CCM PFC controllers. They are very similar chips.Why is it that the LT1249 datasheet, on page 10, recommends a surge current bypass circuit (three diodes) for the sense resistor , but the LT1248 makes no mention of any need to protect from such surge currents?(eg the rush of current through the sense resistor if the PFC is switched on at Mains peak)Also, The LT1248 leaves one with a choice of what maximum sense resistor voltage to employ…but what is the maximum?LT1249 datasheet:http://cds.linear.com/docs/en/datasheet/1249fbs.pdfLT1248 datasheethttp://cds.linear.com/docs/en/datasheet/1248fd.pdf................

author: ocset
author_rank: Super Contributor
timestamp: November 18, 2017, 11:37:20 pm
content: Thanks, do you suspect that the LT1248 doesn't need a series diode chain bypassing its sense resistor for those current surges?

author: ocset
author_rank: Super Contributor
timestamp: November 19, 2017, 11:50:34 am
content: Hello,QuoteThanks, the thing is, our sense resistor is 1.2 ohms…so that’s 120V when a 100A surge flow through it. With the 4k resistor going into the MOUT pin, that’s then 30mA flowing in the chips ESD diode…that’s a lot.Do you think we in fact must have either a zener or a diode chain across the sense resistor?Why doesn’t the datasheet mention this?The attached shows the issus...LTspice sim and pdf schem attached.
problem recreating differentiator effect - Page 1
Forum section: electronics / projects

author: john23
author_rank: Frequent Contributor
timestamp: February 25, 2025, 10:12:27 am
content: Hello , I have built a basic PID circuit as shown below.I put a pulse as input.The integrator works good it converts the pulse into a ramp . but the differentiator is supoosed to convert the pulse into two spikes.Why its not happening?Ltspice file is attached.Thanks.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: February 25, 2025, 03:33:40 pm
content: Make C2 smaller and raise the gain of the stage (R3 bigger).

author: Grandchuck
author_rank: Super Contributor
timestamp: February 25, 2025, 08:35:08 pm
content: Have you seen this?https://github.com/HemakanthNatkunaraja/PID_controlerDesign_in_LTSPICE_Project/blob/main/README.mdhttps://github.com/HemakanthNatkunaraja/PID_controlerDesign_in_LTSPICE_Project/tree/main

author: john23
author_rank: Frequent Contributor
timestamp: March 07, 2025, 02:05:14 pm
content: Hello Conrad Hoffman, adding C2 adds ringing why it that?
problem identifying pin purpose on PMA5-83-2WC+ amplifier - Page 1
Forum section: electronics / projects

author: john23
author_rank: Frequent Contributor
timestamp: May 13, 2025, 07:30:07 pm
content: Hello ,In my PMA5-83-2WC+ amplifier I have Vg1 Vg2 Vdd and GND pins.So I need to see which amongst those 16 pins is GND which is Vg1 and Which is Vg2 and Vdd,There are writings near the pins of Vg1 these two pins are connected according to the DMM.But you said that DMM is not the proper tool to test shortcircuit here.in the documentation attached they also wont say at what exact pins I connect Vg1 Vg2 Vdd and Gnd.What could be done?Thanks.https://www.minicircuits.com/pcb/WTB-PMA5-83-2WC+_P02.pdf

author: eutectique
author_rank: Frequent Contributor
timestamp: May 13, 2025, 09:15:28 pm
content: Quote from: john23 on May 13, 2025, 07:30:07 pmWrite to the manufacturer of that evaluation board, ask them all that questions. They could provide a pinout for that kind of money.

author: Someone
author_rank: Super Contributor
timestamp: May 13, 2025, 11:09:27 pm
content: Quote from: eutectique on May 13, 2025, 09:15:28 pmNot this users style, they rather ask every little question (without any context or connection) to forum(s):https://www.eevblog.com/forum/projects/did-i-get-faulty-amplifier-question/https://www.eevblog.com/forum/projects/flat-cablepin-order-question/oh look:https://www.edaboard.com/threads/did-i-get-faulty-amplifier-question.414968/https://www.edaboard.com/threads/flat-cable-pin-order-question.414996/https://www.edaboard.com/threads/problem-identifying-pin-purpose-on-pma5-83-2wc-amplifier.415021/https://www.electro-tech-online.com/threads/problem-identifying-pin-purpose-on-pma5-83-2wc-amplifier.167741/and some other forum being more charitable:https://forum.allaboutcircuits.com/threads/did-i-get-faulty-amplifier-question.206603/Spam up the world! OP appears to learn nothing from their posts over the many years, and comes back with the same problems.
Problem unidentified in project - Page 1
Forum section: electronics / projects

author: Siddhat
author_rank: Regular Contributor
timestamp: April 28, 2019, 06:58:56 pm
content: Hey everyone. I have been working on a project namely, "Obstacle Avoiding Robot". The concept is to avoid obstacles and move left or right depending upon the obstacles on right or left of the robot respectively as the name suggests. IR module is used to sense the obstacles. The logic for the task was made using K-map and the circuit seem to worked fine in software until the hardware assembly part was in turn. When the circuit was assembled the motors did not rotate with constant speed but rather rotated not as desired. I could not find out the problem. Plus I was told to use a transistor to drive the motors with constant speed to solve the problem. But I could not figure out how to use the transistor to do so as the motor driver IC has two logic outputs.The circuit schematic is attached.

author: Benta
author_rank: Super Contributor
timestamp: April 28, 2019, 07:58:40 pm
content: You can throw R1 and Q1 away to start.Apart from that, it's impossible to say. The L293 is real simple, so it's up to your drive system to resolve this, and we don't see that.

author: OM222O
author_rank: Frequent Contributor
timestamp: April 28, 2019, 08:20:55 pm
content: that part allows you to drive 1A through the motors so it shouldn't be an issue ... you need to check your input signals and connections.
Problem using GBS-8200 to convert spectrum analyser RGBS output to VGA - Page 1
Forum section: electronics / projects

author: brian_mk
author_rank: Regular Contributor
timestamp: October 29, 2022, 11:08:26 am
content: I have an old (1986) but still very capable Marconi 2380 Spectrum Analyser that uses a CRT display. It also provides an RGBS output.To allow me to capture screenshots from it, I thought I would try using a GBS-8200 along with a Gracetop VGA->USB adapter feeding into a laptop running OBS.The composite sync output from the 2380 is 2V p-p ac coupled, so it needed a pull up resistor to 3.3v to work with the TVIA575 video processor on the GBS-8200.This gives negative going pulses that should be ok for 3.3V logic levels.Using the initial default settings on the GBS-8200 the image on OBS appears stable but slightly too large in the vertical direction.When I reduce the size using the GBS-8200 menu buttons, the missing lower part of the image appears but the bottom few lines are unstable / out of sync.The top and middle part of the display still look ok and remain stable.I can see nothing obviously wrong with the composite sync signal when viewed on a 'scope.I also tried hooking the GBS-8200 sync to an internal 5V TTL (inverted) version of the composite sync signal from the analyser (via a 1k series resistor because of the 3.3V TVIA575). This gives positive going pulses. It made no difference to the problem.The 2380 spec for the RGBS output indicates:- hsync: 15.625kHz, vsync: 48.2Hz, non-interlaced.Should this setup be capable of working or am I missing something?Could the problem be connected with interlacing or the frame rate?

author: brian_mk
author_rank: Regular Contributor
timestamp: October 29, 2022, 11:52:31 am
content: Here is a screenshot from OBS that shows the problem when the vertical size is reduced.

author: brian_mk
author_rank: Regular Contributor
timestamp: October 29, 2022, 02:26:43 pm
content: Composite Sync.Horiz: 50uS/div. Vert: 1V/div.
Problem with 16bit-ADC MAX11060 - Page 1
Forum section: electronics / projects

author: SerialCreators
author_rank: Newbie
timestamp: March 02, 2019, 08:22:18 am
content: HiI am using MAX11060 as a adc for my DC Monitoring system. However FAULT and OVRFLW pin are always go low as the chip startup. That mean voltage between AIN+ and AIN- are exceed the fault threshold. But Even if all AIN+- pins are leave floating. FAULT and OVRFLW still go low and DRDYOUT never goes low too.Anyway I can communicate with this chip through SPI and I can read or write any register. That mean the chip still working.I'm setting XTALEN bit to 1 and leave everything to default.I'm trying to measure voltage between AIN+ and AIN-. When the chip is not powered. I can measure the voltage as same as the the voltage source (around 0.124 V) but when chip is powered the voltage between AIN+ and AIN- were dropped to 0.034V and I think because of fault protection circuit in the chip. (this happen whatever I set FAULTDIS in configuration register to 1 or 0)I read all of the data sheet and in page 15 said thatQuoteSo I think that it must be something wrong with my Crystal or Capacitor Coupling so I change it from 20pF to 18pF and 10pF and I still have no luck.Here is my schematicADC Datasheet -https://datasheets.maximintegrated.com/en/ds/MAX11040K-MAX11060.pdf

author: iMo
author_rank: Super Contributor
timestamp: March 02, 2019, 01:50:12 pm
content: What is the absolute voltage at AIN0+ against AGND, and what is the absolute voltage at AIN0- against AGND??PS: when you leave the inputs disconnected they may float thus you get overflows..

author: SerialCreators
author_rank: Newbie
timestamp: March 02, 2019, 02:12:15 pm
content: Hi imo,When AIN- disconnected from GND and no voltage source between all of AIN+ and AIN-.Voltage between AIN+ and AIN- is 0.000V and voltage between AIN+- and GND is around 0.095-0.500V

author: SerialCreators
author_rank: Newbie
timestamp: March 03, 2019, 02:32:45 pm
content: Hi,After a very long debuging I found a mistake that I accidentally reset a config before waiting a DRDYOUT.It was a tiny mistake that took me a couple of day to debug. And I accidentally found a mistake after I use an oscilloscope to probe CLKOUT and CS pin.After solving that issue I found another problem that even I wait a DRDYOUT goes to low and read an adc value the adc value still not valid. They swing from -3000 to 2500 even no input connected. When I apply a 12.2V passing through voltage divider and voltage between AIN+ and AIN- should be 0.122V and ADC value should be 1817 (1817 * (4.4/65535) = 0.1219 V.) but the result was randomly from 25000 to -30000.
Problem with a Buffer Gate - Page 1
Forum section: electronics / projects

author: johnnyfp
author_rank: Frequent Contributor
timestamp: May 13, 2014, 12:06:59 am
content: Hi,I've got a SN74AHC1G125 Single Bus Buffer gate, and am at a loss why it's failing.I've got the buffer on the Dataout of a SPI slave (a CC3000 which does not release its DOUT so needs a buffer), and is enabled when the CS of the device is low, But what I'm seeing on the oscilloscope is in the first picture, The blue line is the output from the buffer, Purple is the input, then after a while I get the second picture, which is only a few hundred millivolts. It seems that the chip is either burning out or something else is going on, I can't seem to understand why it's happening.Current supply is 3.3v and all I have on the Y pin of the Buffer is the MCU, a SD Card Socket, Not Populated with a card. I measure the Supply at the time and cannot see any spikes or brownouts during the transfer.Any Ideas at what I should look at next?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 13, 2014, 12:19:45 am
content: You didn't stick 0.02uF on there by accident, by any chance...?!What does the pin do with nothing connected at all? Scope the supply pin? Verify the ground is actually grounded? Any bounce on /CS?Tim

author: johnnyfp
author_rank: Frequent Contributor
timestamp: May 13, 2014, 12:31:02 am
content: No Capactior on the output, Both power and ground seem sound. No voltage drop on the Vin of the 74AHCThis Y side of the SPI bus works with the SD Card, just when I activate the Wifi's CS does it not work. /CS seems OK for bounces (Purple line).
Problem with AD7194  - Page 1
Forum section: electronics / projects

author: nominal
author_rank: Newbie
timestamp: August 30, 2019, 11:49:09 am
content: I'm currently working with the AD7194 ADC and have problems reading the right input valueFor every channel i get the same Voltage. I've checked my code multiple times. has someone worked with them an can give me some advice ?thanks for every answer
Problem with BLheli_32 zeus (4 in 1 ESC) - Page 1
Forum section: electronics / projects

author: giotkesho
author_rank: Newbie
timestamp: April 04, 2024, 07:55:53 pm
content: i have 3 gimbal motors and i want to make my own gimbal. Can i somehow spin brushless motors both ways without changing its pins phisically with 4 in 1 ESC BLheli_32?

author: thm_w
author_rank: Super Contributor
timestamp: April 04, 2024, 09:00:15 pm
content: https://github.com/bitdump/BLHeli/blob/master/BLHeli_32%20ARM/BLHeli_32%20manual%20ARM%20Rev32.x.pdf
problem with BMI088 gyroscope - Page 1
Forum section: electronics / projects

author: jpittner
author_rank: Contributor
timestamp: June 07, 2019, 02:54:03 pm
content: Hello,I have been trying to use the 6dof IMU chip from Bosch BMI088, communicating via I2C 400kHz.The accelerometer works perfectly, but I get wrong results from thegyroscope. Already the chip ID register #0 reads out 0x0a, while it shouldbe 0x0f according to the datasheet and the registers with angularvelocities read out highly fluctuating 'random' numbers.I have tried two modules, one obtained from SEEED studio, and alsothe original Bosch sensor module with BMI088 purchased from Mouser.Both show the same problem. The code marking on the chips is:365/P1827/001 and 365/P1827/008 respectively.I am using STM32F37 MCU and code based on STM's library for I2C.Since the I2C communication with the accelerometer works perfectly,I wonder where would be problem with my I2C connection/software.I am using I2C address 0x19 for acc. and 0x69 for gyro (with appropriatepullups), 3V3 power.So I am really puzzled with the problem. Do you have any ideas,does anybody here have a hand-on experience with BMI088,did it work for you in I2C or perhaps in the SPI mode?With best regards,Jiri Pittner
Problem with Bringing up a Brushless motor - Page 1
Forum section: electronics / projects

author: amirkargar110
author_rank: Contributor
timestamp: April 01, 2018, 03:07:53 pm
content: Hi,I have read the ATMEL AVR498 appnoteQuote, I wanted to port it to STM32 ARM Cortex Parts, I have redesigned a PCB with STM32, and tried to port the Code to STM32,See the Motor in action!https://www.aparat.com/v/68buOThe producer for running the Motor is as follow, first of all the motor would run without a feedback with fixed delays, then it Measures voltages with ADC and activate the feedback, the problem is that the first part of my code is working as expected and I have checked the Zero cross detection logic inside my code, it seems it's doing OK, but as you may see in this video after the initial blind running of the motor, and after the first zero detection, the motor stops and since it would stop, there would be no zero detection, So do you have any Idea what might have gone wrong? How should I debug and find the problems in these kinds of Motor Driving projects?Any Ideas are welcomed!
Problem with capacitive touch sensing using TTP223/TTP233 - Page 1
Forum section: electronics / projects

author: kian0079
author_rank: Contributor
timestamp: October 14, 2022, 02:13:02 am
content: Hi all,I am working on a project which requires reliable and fast response to touch sensing. A physical button is not feasible for my application as I require to sense light touches on a flat surface (diameter of 20mm). My current solution uses the very popular TTP223/TTP233 capacitive touch IC. However, its seems to have a fairly slow response time as I am unable to sense multiple touches within 1 second. It works if I touch every approximately 0.5 seconds. But anything faster, it doesn't capture a touch. I have the output of the TTP233 connected to an interrupt pin of a microcontroller which prints out a serial message when touch. I don't think the lag is caused by the microcontroller side since its just a simple program that doesn't do anything other than waits for the interrupt to trigger. Does anyone who used the TTP223/TTP233 before encountered the same problem? If so, how did you overcome the slow response problem?Otherwise are there other alternative solutions (that are more responsive and reliable) that anyone can recommend?
Problem with charger IC - Page 1
Forum section: electronics / projects

author: hcglitte
author_rank: Regular Contributor
timestamp: April 27, 2017, 08:54:16 pm
content: Hello,I am using bq24272 in my project. The lithium polymer battery is specified to 4.2 V 2500 mAh.CC is set to 0.2C = 500 mA.I am setting the registers to enter CV phase @ 4.2 V. The termination is set to 0.02 C = 50 mA.After a while (sometimes) the IC will detect that the batteryhas a too high battery voltage, called battery OVP (overvoltage protection) and it will start to drain the battery as a safety precaution.The battery will then be drained too much (this I will still need to verify with a current logger).I am trying to figure out a way to cancel the charging if that fail occurs - assuming that it has reached maximum charge.Anyway, does anyone know why the battery will reach a higher voltage? I mean, the IC is supposed to decrease the current in order to keep the voltage at 4.2 V.I may have to write some code to check if it reached "charge done" before it enters the Batt OVP - so I don't need to lock at the LCD for 6 hours etc...But I can't imagine that the battery voltage will increase after the DONE state (since then no current is flowing into the battery).Any input is appreciated.
Problem with debugging - Page 1
Forum section: electronics / projects

author: amirkargar110
author_rank: Contributor
timestamp: February 03, 2018, 04:01:35 pm
content: HiI have a board with LPC4337 MCU.my board is programmed and work truely, but it doesn't debug.sometimes it debugs a few lines then stop, and sometimes it doesn't debug at all.i changed the micro and the 15MHz crystall but the problem still remains.what can cause this problem and what I should do to solve this problem?thank you.
Problem with DS1307 RTC - Page 1
Forum section: electronics / projects

author: Eddd
author_rank: Newbie
timestamp: October 22, 2014, 03:33:47 am
content: I have strange problem with DS1307 Real Time Clock. It is custom made PCB which contains Atmel ATmega 2560. When I run I2C scan test program to list all the devices on the I2C, I can't find DS1307 (which it should be at address 0x68), but other I2C devices are listed and work fine. But once I connect the battery, the whole I2C bus go down and nothing is listed. The schematics is shown below in the attached picture.What do think the problem is?

author: diegoterc3
author_rank: Regular Contributor
timestamp: October 22, 2014, 04:41:40 am
content: I assume you know you need pull-up resistors. Depending on the number of devices you will need to calculate the resistance value. Here is a link that can help.http://www.edn.com/design/analog/4371297/Design-calculations-for-robust-I2C-communicationsHad the same problem a while ago. Hope it helps.

author: SL4P
author_rank: Super Contributor
timestamp: October 22, 2014, 04:54:33 am
content: That would be my bet - as well s ensuring all ground refs are tied to the same 0V point.Programmer/external supply ground could be isolated from the 'real' uC 0V - so everything floats when not connected.
Problem with HMC253 - Page 1
Forum section: electronics / projects

author: electronicmonk
author_rank: Newbie
timestamp: August 02, 2017, 05:45:40 am
content: I am using the HMC253QS24 non-reflective SP8T switches for a project. While testing the switch with an input signal at the RFC pin varying from 1-10MHz, 20-100 mVpp from a USRP Tx, it was observed that the signal passes to all of the 8 RF outputs regardless of the control pins selection.I have tested the output with an oscilloscope as well as on the USRP Rx, with the same result in both the cases.I have tested, both, with and without the 100pf capacitors(as present in the evaluation board shown in the data sheet) at the input and outputs of the HMC253 but the results remained the same.Multiple HMC253 IC's were also tested to no avail.Thank you.

author: jmsigler
author_rank: Regular Contributor
timestamp: August 02, 2017, 05:57:27 am
content: You should post schematic, its pretty hard to say what the problem could be without it.

author: electronicmonk
author_rank: Newbie
timestamp: August 02, 2017, 06:23:06 am
content: The schematic is attached.This is exactly identical to the one in the datasheet.Thank you.

author: CJay
author_rank: Super Contributor
timestamp: August 02, 2017, 08:43:38 am
content: More than the schematic, the PCB layout is critical to achieve good performance from this or any other RF switch, are you using the evaluation board, a copy of the evaluation board or something designed with 50R impedance 'lines' because if you're not, it's going to be awful.You get a minimum 32dB isolation from DC to 1GHz so I *think* there will be some signal leakage no matter what you try and achieve, what sort of levels of signal are you seeing on the outputs?

author: electronicmonk
author_rank: Newbie
timestamp: August 04, 2017, 04:53:43 am
content: The problem was solved by using capacitors of higher capacitance on the input and output's,We used 1nF capacitors which resulted in considerably better results .The solution was suggested at the analog devices forum.link :https://ez.analog.com/thread/97697#comment-312139Thank you.
Problem with LM5030 - Page 1
Forum section: electronics / projects

author: MarkoAnte
author_rank: Regular Contributor
timestamp: November 27, 2015, 08:38:23 am
content: Hi,I made a isolated DC/DC converter based on TIDU355 (same circuit around the chip) and I can't get the LM5030 to work. The voltages on pins are : Vcc = 12V, Rt = 2V, Vin = around 11 V pin floating(tried tying it to 24V no difference), SS ramps up to 5V, Vfb = 0V tied to gnd, SC = 0V , COMP = 0V (Is this ok?) and both PWM = 0V.What I'm a missing. I tried 3 different chips and they all don't work in the exact same way. ( I have ofc measured all pins for shorts or bed solder connections). I find it strange that I measure 0V on COMP is this OK? In the data sheet shoves COMP connected to 5V via resistor - annotated at 1.4V)Best regards,Marko
Problem with MCP4021 Digital Potentiometer and PIC16F722 - Page 1
Forum section: electronics / projects

author: 8086
author_rank: Super Contributor
timestamp: November 17, 2011, 02:10:57 am
content: Firstly, I should say I seem to have solved the problem.But what happened was, I have a project with a PIC16F722 controlling a MCP4021 pot. The 2-wire serial (CS/UD) are connected directly to RA1 and RA2 on the PIC.I started writing the program in assembler and I thought it was correct, but it wouldn't work at all. So I hooked up my USB logic analyser to CS/UD to see what was going on.The waveform I saw was correct, and the pot went to the correct value when the LA was connected, but still failed to work without it.At first I thought maybe it was a missing ground, but that wasn't the case. Then I tried decoupling caps everywhere and that did nothing either.Finally I tried 10K resistors from VDD to CS and UD. This worked flawlessly!The issue is this. There's nothing I can see in either device's datasheet about any of the used I/O being open drain. The pot datasheet doe s say that CS has an internal pullup, but that doesn't seem to be doing it's job, as I need to pull it up myself for it to work. I know RA3 is generally open drain which is why I haven't used it. Could I get a sanity check from someone of whether it's actually mentioned in the datasheets because if this isn't its a pretty big omission.
Problem with NMOS device in LTSpice - Page 1
Forum section: electronics / projects

author: moffy
author_rank: Super Contributor
timestamp: November 10, 2016, 08:03:11 am
content: I have been trying to come up with a SPICE model for the 74LVC07, open drain inverter. I downloaded the Philips "lvcnom.lib" which includes an NMOS model for the output of the 74LVC07, but when I ran it in LTSPICE_XVII I got some strange results. With 0v on the gate of the NMOS output, it is not off but still has less than 10k impedance. Only when I apply about -0.5v to the gate does it turn off. I have included the relevant "Philips_74LVC_NMOS.txt" and a snapshot of what LTCSpice displays when the gate is driven by a 0 to 5v square wave. I know that SPICE sometimes has problems with modelling MOSFETS but if one of the experts could explain what is going on I would appreciate it.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 10, 2016, 10:31:27 pm
content: I discovered that little gem of a library. Discrete logic models for an entire family? Hell yes!But then, on closer inspection...The more complicated parts are completely empty, or use only placeholders (the 74HC74 has one inverter inside the whole chip!).There's no capacitance anywhere, so the speed is unlimited. Convergence problems, anyone? Not to mention nonphysical risetimes, and no representation of input loading capacitance or power supply consumption.Turns out the "gem" is no diamond, rather more like massive calcite: soft, fragile, unappealing, and not useful beyond its capability...I built a model for the 74HC7014, which can be modified for other basic logic devices in the family:http://seventransistorlabs.com/Images/AltiumBufferModel.pngIf you'd like a copy, it's available via PayPal and e-mail.Tim

author: moffy
author_rank: Super Contributor
timestamp: November 10, 2016, 10:39:34 pm
content: T3sl4co1l, thanks for the info and the offer. I was more interested in the behavior of the NMOS output transistor, so I borrowed from the LV.LIB an NMOS output transistor and put it in its place, should be fairly close, and the problem was solved, kinda. The LV NMOS transistor seems to behave much better!
Problem with power supply design - Page 1
Forum section: electronics / projects

author: jsfotografie
author_rank: Newbie
timestamp: December 22, 2017, 07:23:49 pm
content: hey all im trying to build a hybrid amp called alpha centauri v6 fromhttp://www.high-amp.de/html/frame.htmlusing this powersupplyhttp://www.high-amp.de/html/reg_pws_v5_eng.htmland i have a problem with the +400v chain would you mind taking a look at the circuit? i cant figur out whats wrong perhabs you can give it tip or a hint? when i turn on the transformer the led in the +400v chain flashes shortly and then goes out in the -400v its on all the time and very stable. im not that fit in unerstanding circuts so i need helpcheers and thx janosch
Problem with pulsed output rails on a Howland current source - Page 1
Forum section: electronics / projects

author: nitish111
author_rank: Contributor
timestamp: October 12, 2018, 04:27:14 pm
content: I am designing pulsed current source that can sink up to +/-15 mA with +/-100 V rails (schematics attached). I am getting a weird capacitive effect during switching of voltage rails. Then I probed the rails and I saw ripples on them when the current is switching polarity. On the oscilloscope image yellow is the voltage across a constant load of 4.22k @ +/-15 mA, Pink one is the 100V rail and blue one is -100V rail. Can any one please explain me what is causing the ripple and how can I reduce or even get rid of it.

author: TiN
author_rank: Super Contributor
timestamp: October 12, 2018, 04:41:35 pm
content: That's rather wierd arrangement. Why not use zener stage for opamp power rails to clamp for low voltages, and discrete power stage at the output to drive load?Also where are all the decoupling capacitors? It is common rule to decouple all power entry to opamps and regulators, this is good example when it's important.

author: coppercone2
author_rank: Super Contributor
timestamp: October 12, 2018, 04:47:16 pm
content: Did you try it on a lab supply first? Trouble shooting a custom PS and AMP at the same time might be hard.Did you try the hybrid op-amp without the complex feedback in a simple noninverting or whatever?but, why is the rail changing. it should be invarient lowz. Rail voltage change means impedance fail of some kind. your power supply is either doing something wrong or the chip is drawing a shit load of current.

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 12, 2018, 05:28:32 pm
content: I would test your flyback converter separately first with a pulsed load on either rail.You may have to increase the value of the output caps (C1, C3) a bit? Also I have no clue wether the transformer you chose is really adapted to this task - from the datasheet I got (Sumida), there is no CEP1110 model rated for an output voltage greater than 48V?

author: nitish111
author_rank: Contributor
timestamp: October 12, 2018, 06:15:35 pm
content: Quote from: TiN on October 12, 2018, 04:41:35 pmI cannot use decoupling capacitor on the VCC and VEE of op-amp since I am using a bootstrap circuit. I used circuit from following paper(figure 4).http://www.ti.com/lit/ml/slyy054/slyy054.pdfQuote from: TiN on October 12, 2018, 04:41:35 pmCan you please elaborate more what do you mean by this?Quote from: coppercone2 on October 12, 2018, 04:47:16 pmI do not have a lab equipment that can generate 100V DC. Yeah my guess is also same that somehow rail voltages are getting affected.Quote from: SiliconWizard on October 12, 2018, 05:28:32 pmI increased C1 and C3 to 1uF (CGA9P4X7T2W105M250KE), it help reduce it a little bit by 1Vpp. Increasing it to 2uF did not have significant affect. I ordered custom transformer samples from Sumida for the transformer. I am attaching the datasheet for the transformer.
Problem with simulating this circuit - Page 1
Forum section: electronics / projects

author: XaviPacheco
author_rank: Regular Contributor
timestamp: June 26, 2018, 09:23:32 pm
content: Hello,I'm using Proteus to simulate the circuit attached. According to simulation, when I give the signal to enable the optotriac, the capacitors start to charge extremely slow and don't even reach 60V. What could be wrong? The circuit or the simulation software?

author: Benta
author_rank: Super Contributor
timestamp: June 26, 2018, 09:35:41 pm
content: Your power triac is the wrong way round. Yes, it matters.

author: XaviPacheco
author_rank: Regular Contributor
timestamp: June 26, 2018, 09:39:05 pm
content: I just wired it like the datasheet says, look at the attachment. It still does the same.

author: Zero999
author_rank: Super Contributor
timestamp: June 27, 2018, 08:38:49 am
content: Quote from: XaviPacheco on June 26, 2018, 09:39:05 pmNo you didn't, wire it as per the data sheet, in your original schematic. It was backwards. Look more closely at the symbol.If you've now corrected it, then I'd suspect the model(s).
Problem with the Battery discharging circuit - Page 1
Forum section: electronics / projects

author: Harneet
author_rank: Newbie
timestamp: September 14, 2015, 02:50:45 pm
content: I have a circuit that aims to discharge a battery and hence monitors it's voltage.The circuit either drains 4 uA current through a 680k resistor or 20mA current which is driven by the DAC. The switching between these two scenarios is done using a 74hc125 ( have tried N FET as well)The circuit diagram is attached.Problem: When the switch corresponding to 680k is enabled it gets grounded but when switch corresponding to 10 ohm resistor is enabled it doesn't gets grounded.I'm unable to spot the problem with the circuit as I'm very naive in electronics.Please help!!

author: tree
author_rank: Regular Contributor
timestamp: September 14, 2015, 04:36:22 pm
content: If you're measuring the voltage at the "grounded" terminal of your 10ohm resistor you have to remember that you'll have some voltage drop across your transistor that's inside your 74HC125. What's the voltage when you measure at the output of each channel of the 74HC125?
problem with TLP250 mosfet and igbt driver  - Page 1
Forum section: electronics / projects

author: hussamaldean
author_rank: Unknown
timestamp: March 11, 2020, 09:37:14 am
content: Hi all,I have this IC which should be able to drive mosfet in low side switching. however, when I provide 1KHz PWM signal to the input side, the output remains zero despite I connected the Vcc and gnd of the IChere is the schematicsis there something wrong with the connection or what ?regarddsHusamuldeen
problem with Trans Middle Center - Page 1
Forum section: electronics / projects

author: amirkargar110
author_rank: Contributor
timestamp: July 19, 2018, 05:03:45 pm
content: helloI want to have a dc-dc transinput 5v 200maoutput = 4 separate 12v 20mai wrapped 2, 10 cycle wires around core for primary.and one 24 cycle for secondary as shown in the attached file.i changed 4 wires Respectively to change the direction of flow in core. so that i get the best gain.but unfortunately my output volt(in one output) does not exceed 2.58v.what should i do to improve my output voltage to 12v?

author: PA0PBZ
author_rank: Super Contributor
timestamp: July 19, 2018, 05:53:22 pm
content: You are shorting the primary coils with the diodes.

author: amyk
author_rank: Super Contributor
timestamp: July 19, 2018, 11:59:42 pm
content: L3 looks pretty much useless.

author: BrianHG
author_rank: Super Contributor
timestamp: July 20, 2018, 01:17:52 am
content: Q2 will also die, or, you are shorting out your 5v supply.
Problematic transistor in current shunt - Page 1
Forum section: electronics / projects

author: 22
author_rank: Contributor
timestamp: April 19, 2017, 03:51:14 pm
content: I'm working on my school project and I came to a problem. I design this schematic in attached image. The idea is that current pass through resistor R20 - R27 with one range and through R20, 21, 22, 24, Q3, Q7 at second range. This works perfectly for me but U$5 (purple) kept blowing up sometimes. Please note that FDN335N isn't used instead there are AO3400. I'm looking for reason why this transistor is problematic. Thanks.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 20, 2017, 04:42:39 pm
content: I don't see a really problem with the U5 FET. Spikes on the 12 V supply could be a problem. It is a good idea to have at least a capacitor at the 12 V.R1 and the source of U4 should go the GND and not towards the shunts - this would add an avoidable error, by sending the control current through the shunt too. The MOSFETs don't mind a slightly negative gate voltage to turn off - thus can actually even help to get lower leakage.

author: 22
author_rank: Contributor
timestamp: April 20, 2017, 05:36:24 pm
content: Thanks for reply. Yes that current throught R1 and U4 isn't that much of a deal. I correcting it by software. The color stuff add to schematic is modifications that I add later at troubleshooting state. The blue resistor hold gate voltage at around 6V and still doesn't help. After blowing up, the resistance at any pin at U5 is around 100R if that help to diagnose the problem.

author: w2aew
author_rank: Super Contributor
timestamp: April 20, 2017, 05:44:37 pm
content: Quote from: Kleinstein on April 20, 2017, 04:42:39 pmIs there any kind of an inductive load (solenoid, relay, motor, etc.) on the 12V that could be slamming the supply with transients when switched off?

author: 22
author_rank: Contributor
timestamp: April 20, 2017, 05:48:15 pm
content: There is also a PWM driven fan which works independently on that circuit

author: danmcb
author_rank: Regular Contributor
timestamp: April 20, 2017, 05:55:04 pm
content: I don't wanna be too critical - I did take a look at this to see if I could offer any useful advice, but I gave up because the way you have laid out the schematic is a bit of a nightmare. As a general rule - point ground nodes down, space things out a bit, label power rails ... that kind of stuff. It really is worth the hassle. Just a piece of friendly advice. If I was a lecturer or potential employer, I would definitely frown on this.