hybridfree/eevblog-posts huggingface dataset:
Fluke Connect Protocol - Free your Fluke! (Implemented Third Party Interface) - Page 1
Forum section: electronics / projects

author: MajorEE
author_rank: Contributor
timestamp: August 11, 2024, 06:07:15 am
content: I was able to implement some software that interfaces with the Fluke Connect system. If anyone has a Fluke 376FC, or other Fluke connect devices in which they can post some captures I would like to build up the library to a fully functional application and not just a MVP test application for a single meter.Releasing a very basic example to get those interested in contributing up to speed while I work on polishing the application and adding primary features.https://www.lambdafox.com/clamp-connect/Those interested in helping can do two scans for me:1.https://github.com/hbldh/bleak/blob/master/examples/discover.py-> discover.py -> Run this and share the service_uuids line like this only for your fluke device(s):-> AdvertisementData(local_name='376FC', service_uuids=['b6981800-7562-11e2-b50d-00163e46f8fe'], tx_power=0, rssi=-71)2. Once you have a MAC address or name run theservice explorer tool:(In my case see the local name matches the name below:)->service_explorer.py --name 376FC3. Provide your firmware, and radio version numbers.Note: Please don't post your serial numbers or full MAC address just in case (but first 2-3 hex would be helpful). Any concern feel free to DM me directly.Python console version:Code:import asynciofrom bleak import BleakClient, BleakScanner# Define the device name and the UUID of the characteristic to subscribe to hereDEVICE_NAME = "376FC"CHARACTERISTIC_UUID = "b6982901-7562-11e2-b50d-00163e46f8fe"async def run():# Scan for devicesdevices = await BleakScanner.discover()# Find the device with the name specifieddevice = Nonefor d in devices:print(d)if d.name == DEVICE_NAME:device = dbreakif device is None:print(f"Device with name '{DEVICE_NAME}' not found.")return# Connect to the deviceasync with BleakClient(device) as client:print(f"Connected to {DEVICE_NAME}")# Define a callback function to handle characteristic updatesdef callback(sender, data):print(f"Received data from {sender}: {data}")print(data.decode('utf-8'))# Subscribe to the characteristicawait client.start_notify(CHARACTERISTIC_UUID, callback)# Keep the script running to continue receiving notificationsprint(f"Subscribed to characteristic {CHARACTERISTIC_UUID}.")await asyncio.sleep(120) # Run for 120 seconds, or adjust as needed. This is just for testing after all.# Stop notifications before disconnectingawait client.stop_notify(CHARACTERISTIC_UUID)if __name__ == "__main__":asyncio.run(run())
fluke pm3082 any hacks or upgrade i can do myself? - Page 1
Forum section: electronics / projects

author: Priestblood
author_rank: Contributor
timestamp: May 29, 2016, 06:36:04 am
content: Hi,i have a old fluke pm3082 100mhz scope are there any home hacks or upgrades i can do to make it a betteri have read a couple of easy upgrade on someone else's fluke oscilloscope not same model and was hoping there might be a way of upgrading mine thanks for readingWayne

author: RNA
author_rank: Regular Contributor
timestamp: August 15, 2017, 12:15:25 am
content: Great question. I am repairing one at the moment and have just realised there is no external trigger input. There are a few sockets with nothing plugged into it, SWEEP OUT, MTB GATE,DTB GATE. The external trigger section does not have a socket installed. I can't seem to find any info on the options and whats entailed. Does anyone have any info on this?
Fluke PM6669 modding [backlight] - Page 1
Forum section: electronics / projects

author: cprobertson1
author_rank: Frequent Contributor
timestamp: July 21, 2016, 05:45:16 pm
content: I've recently picked up a Fluke PM6669 while in the US, and after a brief repair at the PSU side I've not got it working!Granted, it's only the base model with no second channel, so it's limited to 0.1-120MHz but hey-ho, it's still useful!Lately I've been using it late at night and cursing it's dim LCD screen though, and I've decided I wan't to (try) to mod in a backlight.I'm thinking adding a row of SMD LEDs around the glass plate on the LCD panel and hoping enough of it will filter out - but figured I might as well do some research first!Has anybody had any experience adding decent-looking backlights to fairly standard LCD modules?

author: bingo600
author_rank: Super Contributor
timestamp: July 21, 2016, 06:43:39 pm
content: https://www.eevblog.com/forum/projects/hp-3457a-lcd-backlight-mod-(also-for-3478a)/msg227880/#msg227880/Bingo

author: cprobertson1
author_rank: Frequent Contributor
timestamp: July 22, 2016, 07:09:22 am
content: Ha! Perfect!When googling around I found a lot of gameboy backlight mods - but wasn't sure how it'd work with a long, relatively thin LCD ony my frequency counter as compared to the roughly square lcd of the gameboyThat's a sneaky idea thatonlookerguy had with cutting up ebay LED bulbs - I'll need to remember that one!My plan was to use a strip of copper-clad FR4 board with some scores across it to break the track into segments and then simply soldering some 0603 LEDs across the scores to make a series strip of LEDs.Dismantling that LCD Module to change the reflective backing around is going to be nerve-wracking; I'll need to find some other modules to practice on firstWill post pics here of the process and the end resultWill post pictures here once fini

author: cprobertson1
author_rank: Frequent Contributor
timestamp: July 30, 2016, 10:30:58 pm
content: Hmm, I've hit a snag! Actually, two snags, but I sorted one of them already!The contrast seems a bit off - looks fine when view it from above, but viewing it straight on or from below makes it unbearably pale.LCD bias looks to be controlled internally from thePCF8576driver IC, so Im not sure how to fix it! Any suggestionsI can live with it, but its very, very pale when the backlight is on =/As a side note, I discovered that if you put the polariser in backwards, it inverts the display, giving a black, opaque background with white, transparent text - which is a surprisingly nice effect! Reminds me of those midas transflective modules!

author: cprobertson1
author_rank: Frequent Contributor
timestamp: July 31, 2016, 07:59:11 pm
content: The plot has thickened! I reckon that by applying a voltage toPin 12 (VLCD)(which is currently tied to ground) I can get the PCF8576 to adjust the Bias: can anybody confirm that from the datasheet before I go adjusting anything?
Fluke resistor codes - Page 1
Forum section: electronics / projects

author: gbaddeley
author_rank: Regular Contributor
timestamp: July 17, 2018, 11:46:23 am
content: Hi,Does anyone have information about codes found on Fluke precision resistors, particularly in Fluke test equipment?eg. FL4P2 FL2P1 FL2P2 FL1N4 that I have seen on green tubular resistors and mica card wire wound resistors.Glenn

author: doktor pyta
author_rank: Frequent Contributor
timestamp: July 17, 2018, 07:11:11 pm
content: I measured tempco of two green Fluke resistors:one with marking 'P1' has approx. +1ppm/'C @30'Cone with marking 'P0.5' has approx. +0.5ppm/'C @30'C(https://www.eevblog.com/forum/metrology/t-c-measurements-on-precision-resistors/msg1209379/#msg1209379)But Your codes don't use comma.So it might be similar to Zener diodes marking (5V1= 5.1V)To make sure, please write if all these resistors have same size.

author: gbaddeley
author_rank: Regular Contributor
timestamp: July 18, 2018, 11:02:08 am
content: Tonight I foundhttps://xdevs.com/article/f720a_res/I think P and N mean positive and negative tempco.There are examples of designations after this letter being 0.5, 1, 1.5, 2, 3, 4This is almost certainly PPM / deg.CThe 8375A DVM (1970's vintage) has R5 and R6 in series in the input divider network.They are both 4.45 M ohm, one is GL1P4 and the other is GL1N4, giving a net tempco of zero !Newer resistors seemed to be marked directly with tolerance +/-0.02% +/-0.01% etcand don't have any codes like FL1 FL2 FL4 etc.I think these are older Fluke internal codes that represent the construction / power / tolerance.The first letters of codes I have encountered so far are:E = Small tubular and mica former, approx 0.5 - 1W rating (?)F = Medium mica former, approx 1 - 2WG = Big tubular, approx 2 - 5WSecond letter and first digit:H1, H2, H3, H4L1, L2, L3, L5, L6I suspect these relate to the tolerance, and are all below 1%.

author: gbaddeley
author_rank: Regular Contributor
timestamp: July 19, 2018, 11:48:37 am
content: Regarding second letter and first digit, I have only encountered H or L so far.Could this mean High and Low, like P and N mean Positive and Negative?I am fairly sure that L1 = +/- 0.02%.I have parts from an 887AB Differential Volt Meter, 4999.1 and 2499 ohms marked FL1 and they correspond to +/- 0.02% in the manual's parts list.Are there any Fluke gurus out there that can offer an opinion?
Fluke/Philips pm97  - Page 1
Forum section: electronics / projects

author: Rats
author_rank: Newbie
timestamp: March 09, 2016, 05:32:56 pm
content: Hi,So i just acquired a fluke/philips pm97 scopemeter. Resistance, continuity and scope all seems to work fine but im getting a 0 reading on all voltage readings ac/dc/mv.Any idea what could be the problem?

author: mij59
author_rank: Frequent Contributor
timestamp: March 09, 2016, 06:06:48 pm
content: Maybe a blown input protection, faulty relay, etc, hard tell.If you haven't got the service manual,http://www.opweb.de/nl/model.php?id=1177] http://www.opweb.de/nl/model.php?id=1177

author: 1xrtt
author_rank: Regular Contributor
timestamp: March 09, 2016, 09:46:31 pm
content: Well, I had a similar problem and found that it was just me not knowing how to use the meterand too lazy to read the manual. You may try yourself:If you press METER and then, the softkey for VDC, it only measures from the BNC inputs, but it autoranges to mV.If you press METER and the softkey for mVDC, it only measures from the banana inputs and it measures up to 3.5V
Fluorescent lamp ballast inductance / Fluorescent lamp clamping voltage? - Page 1
Forum section: electronics / projects

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: April 03, 2023, 12:29:08 pm
content: I want to know/calculate the inductance of an inductive fluorescent lamp ballast.What is the clamping voltage for T8 and T12 fluorescent lamps? with this I could calculate the current at that clamping voltage for 36w for example, then get the impedance of the ballast at 50hz with that, etc.

author: jonpaul
author_rank: Super Contributor
timestamp: April 03, 2023, 12:34:58 pm
content: Like any arc lamp, the hot cathode fluorescent lamps required a 300...1000 V starting voltage to strike the arc, then mercury arc drop perhaps 20..100V depending on the arc legnth ,diameter and condensed mercury température.see 1960s..1980s books and papers on fluorescent lamps,Philip's ,Ellenbas, IES,Jon

author: Ian.M
author_rank: Super Contributor
timestamp: April 03, 2023, 12:59:35 pm
content: From:https://www.repairfaq.org/sam/flamp.htmQuoteQuoteThat + the tube wattage should be enough for a 'ballpark' estimate of the figures you want.
Fluorescent light fixture - wiring question - Page 1
Forum section: electronics / projects

author: howdy
author_rank: Newbie
timestamp: September 14, 2023, 06:21:17 am
content: We recently had some fluorescent light fixtures in the garage replaced with new LED lighting. These fluorescent lights had been in place for over 30 years and were of the old magnetic ballast type.Out of interest I had a closer look at the wiring configuration of these old fittings and noticed that the ballast (i.e inductor) in all cases was placed in the neutral (i.e return) path. I found this rather intriguing as every schematic and explanation I have seen concerning the operation of magnetic type fluorescent fittings has the ballast installed in the live path. Obviously the old fittings had worked just fine but it leaves me puzzled whether the placement of the inductor matters in any way.Based on my limited understanding, either placement (i.e in the neutral or live path), would limit the current drawn by the tube (which is one of the reasons for the balllast in the first place), but I am less clear as to whether ballast placement would impact in any way the generation of high voltage required to establish the electrical arc across the tube electrodes. Is anyone able to provide an insight into this ?

author: Shonky
author_rank: Frequent Contributor
timestamp: September 14, 2023, 07:18:07 am
content: Swapping live and neutral just inverts the AC sinusoidal waveform so as far as the tube is concerned it makes no difference.

author: Ian.M
author_rank: Super Contributor
timestamp: September 14, 2023, 09:03:30 am
content: Maybe readhttps://www.repairfaq.org/sam/flamp.htm?

author: howdy
author_rank: Newbie
timestamp: September 14, 2023, 09:39:32 am
content: Thanks for that reference. Will have a closer look

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 14, 2023, 01:31:18 pm
content: AFAIK Which wire is hot with single phase AC power really only matters from a safety standpoint, like if you're wiring up an edison base light socket, you want the screw at neutral rather than live to reduce shock risk. The load can't tell the difference, short of having an earth connection and circuitry to check e.g. outlet tester. At least in the US you see a lot of L-N reversed outlets, it isn't right, but it's a common assembly fault because it still functions.
Flush connector recommendations? - Page 1
Forum section: electronics / projects

author: Things
author_rank: Regular Contributor
timestamp: February 12, 2013, 02:31:33 pm
content: Hey guys, I'm working on a huge digital clock project, not unlike the one Sparkfun did a while back, but with my own twists of awesomeness.One thing many people will know is that the human eye is insanely sensitive to small things like pictures at a slight angle etc. Well, with this clock project, I'll have 8 boxes to hang, and I couldn't imagine trying to get them all a perfect height!So, my idea was to actually use some sort of connector, or pair of connectors between each digit. I'm using some SPI based RGB LED controllers, so I'd need to transfer power, + 2 data lines to each digit. Conveniently the LED drivers are self addressing, so the digits could all be built identically and placed in any order (Except the first one, which will contain the drive electronics).As such, I was thinking it'd be nice to just implement a pair of connectors on each side of each digit, so they could lock into each other, and eliminate all wiring, and they'd all be perfectly straight. Being made of only styrofoam and thin sheets of plastic, the digits would not weigh much, and would probably only need 3 supports on the wall, vs 8.They would have to carry quite a bit of power, I'd be aiming for at least 6A at 12V, however I could probably have 2 connectors per side, just for better mechanical support, and separate for power and data.I was thinking of using maybe 1/4" jacks, which I could modify in a way to mount flush (No gaps between the digits), and could have 2 on each side to give extra support, however I don't think they'd be up for the current.Any other ideas?Dan

author: dr_p
author_rank: Frequent Contributor
timestamp: February 12, 2013, 09:33:23 pm
content: I would go for separate mechanical and electrical connections.
Flux Remover Pen Foam Vs Foam Free vs Non-Flammable vs Flammable - Page 1
Forum section: electronics / projects

author: pacmann
author_rank: Contributor
timestamp: December 21, 2023, 10:19:28 am
content: I want a flux remover pen but don't know which to get. Chipquik hasFlux Remover (Non-Flammable)Flux Remover (Fast Evaporating, Non-Flammable)Flux Remover (Foam-Free, Flammable)Flux Remover (Foaming, Flammable)All cost about the same price. Whats best for rosin flux remover?
Flux residue after smd reflow? - Page 1
Forum section: electronics / projects

author: miceuz
author_rank: Frequent Contributor
timestamp: January 07, 2014, 10:14:20 pm
content: Hi all,I'm trying to do a reflow dumb way - just watch till it reflows, then wait a bit and open. After a couple of tries I can see flux leftovers over solder joints. What am I doing wrong? Jumping over soak too quickly? Not reaching a reflow temperature? Both times thermocouple was in unfortunate position, so I don't know the exact reflow temperature. Reflow itself takes ages - about 20min - I'd guess pretty enough to soak? Components are quite similar - SOIC20 package and 0603 resistors/caps.The paste is this one:http://solderchemistry.com/en/pdf/SC170e.pdfI could not find it's reflow profile in it's "datasheet" but reflow happens somewhat about 170 - 190 degrees according to my not so precise measurements.

author: Kohanbash
author_rank: Regular Contributor
timestamp: January 07, 2014, 11:43:26 pm
content: HiI dont have much experience with a reflow over but with standard soldering methods seeing flux residue after soldering is normal.You should clean it off with some electronics cleaner (they also make some special flux cleaners) and an esd safe brush.

author: nanofrog
author_rank: Super Contributor
timestamp: January 08, 2014, 02:17:59 am
content: You should expect flux residue (it doesn't evaporate). If you don't want it on the board, assuming it can be left on without consequences (i.e. rosin or no-clean), then you'll need to clean it off to get a nice, pretty board.Water soluble flux will need to be cleaned off regardless if you don't want problems (not what you're using according to the datasheet you linked).

author: marshallh
author_rank: Unknown
timestamp: January 08, 2014, 04:01:06 am
content: I use Amtech leadfree paste and hardly ever get any sort of flux residue. It's very clean. The closer you can approximate the recommended curve the better. The soak period not only helps flux activation but it helps parts with different thermal mass get up to temperature.

author: DakLak
author_rank: Contributor
timestamp: January 08, 2014, 05:43:10 am
content: We use small ultrasonic cleaner baths for cleaning PCBs. They are easy to fabricate in the size you most likely require.
fly-back converter - Page 1
Forum section: electronics / projects

author: whatty
author_rank: Contributor
timestamp: February 22, 2023, 06:27:34 am
content: Hi,How to set the flyback converter work in dcm mode i mean how do i choose critical magnetizing inductance so that the converter operates in DCM mode.I found some equationLm critical =(vi * D * D * T)/(2 * Ii)if Lm>Ltotal its DCMif Lm<Ltotal its CCMif Lm=Ltotal its boundary conditionwhere Vi =input voltageD = duty ratioT = total time periodIi = input primary currentLm = magnetizing inductanceLtotal = Total inductance of primaryif above case then if i choose to calculate at minimum input voltage then i need to set maximum duty cycle and total time period in the above equation.I got confused on these please guide me or provide materials related.Thank you.

author: Zero999
author_rank: Super Contributor
timestamp: February 22, 2023, 08:50:06 am
content: Why start a new thread, rather than using the existing one?https://www.eevblog.com/forum/projects/flyback-converter/
Flyback Convert for consatnt current LED driver in BCM mode  - Page 1
Forum section: electronics / projects

author: Patrick66
author_rank: Regular Contributor
timestamp: December 17, 2023, 01:13:55 am
content: Hello everyone, the datasheet did not mention the capacitance and resistance value for the circled part (purple) based on the figure below. May I ask how to find all of those values? Thank you for your time.

author: moffy
author_rank: Super Contributor
timestamp: December 17, 2023, 02:43:39 am
content: They are snubber components(R13/C13) meant to absorb switching/spike energy and are more a matter of practical choice often dependent upon the particular layout. That being said the values you have from the example circuit are probably a good choice, just ensure that the snubber resistor has enough power rating.

author: Patrick66
author_rank: Regular Contributor
timestamp: December 17, 2023, 03:53:44 am
content: Quote from: moffy on December 17, 2023, 02:43:39 amHello Sir, I have simplified the circuit as shown in the figure below. The resistance and capacitance that I had removed did not affect the output current as it still maintained at 333mA as expected from the circuit. Actually, may I ask if can i do this?

author: moffy
author_rank: Super Contributor
timestamp: December 17, 2023, 04:46:39 am
content: Okay by joining COMP+ and COMP- you are bypassing the internal error integrator and replacing it with U2 and the current sense resistor R7. R19/C15 are important for the removal of switching glitches which can cause the overcurrent detection to switch falsely, leave them in, but they are very layout dependent so you can choose to put C15 in or not depending on the current/switching glitches encountered. That's all I can comment on at the moment.

author: Patrick66
author_rank: Regular Contributor
timestamp: December 17, 2023, 06:28:28 am
content: Hello Sir, is it possible to remove the external error amplifier and use the IC COMP- and COMP+ instead. Can you show me how to calculate the capacitance value between the COMP - and COMP +. Moreover, if I were to use the IC's error sensing then the CTRL1,2,3 need to include a combination of resistors. Can you teach me how to do that as well because the datasheet didn't teach me how to calculate it or they did mention it indirectly but I did not manage to catch on. Hope to hear from you soon. Thank you so far Sir for the guidance. Very appreciate it.
Flyback Converter Component Selection - Page 1
Forum section: electronics / projects

author: qstilly
author_rank: Newbie
timestamp: September 20, 2018, 07:21:24 am
content: Hey guys! I'm new to this forum and somewhat new to electronics but have a question about flyback converter design. My goal is to run 60-100 V off of a 9V battery for about 15ish minutes at a time (running a small scale gel electrophoresis). After researching some potential solutions it looked like a flyback converter could work, would this be possible? If so, it seems that these are the components I would need:Input capacitorPrimary switch (MOSFET)Coupled inductor - transformerOutput rectifierOutput capacitorSo my main question is, how do I determine the size/specs of these components that will allow for the 9V to 100V conversion? I assume there are a set of equations but am confused as to where to start. Thank you so much for taking the time to read through this and potentially help a newb.
Flyback converter for constant current LED driver  - Page 1
Forum section: electronics / projects

author: Patrick66
author_rank: Regular Contributor
timestamp: December 21, 2023, 12:48:07 pm
content: Hello everyone, I would like to ask how to design your own transformer with auxiliary winding if the duty cycle, frequency, and output voltage values keep on changing during constant output current operation? What are the equations required to identify the turn ratio, wire diameter, etc?
flyback converter regulation - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: February 22, 2016, 09:18:56 am
content: HI guys,I designed a flyback converter using uc3842, I need a small clarification. In flyback converter optocoupler and TL431 is used for regulation in application note , but the auxillary winding that feed power to the controller can be used to sense output voltage and this method is easy because no compenation and no optocoupler drift. then what is the advantage of optocoupler sensing over auxiliary winging sensing.

author: Andrey_irk
author_rank: Regular Contributor
timestamp: February 22, 2016, 01:48:34 pm
content: Also if you have two or more secondary windings, then optocoupler isn't help you. In this case use linear post-regulator and aux sensing.

author: Andrey_irk
author_rank: Regular Contributor
timestamp: February 23, 2016, 03:37:10 am
content: Quote from: AcHmed99 on February 22, 2016, 05:04:59 pmThanks, I never heard about that before. It uses interesting way to control output voltage.But these chips are quite expensive...
Flyback converter small signal AC model  - Page 1
Forum section: electronics / projects

author: Patrick66
author_rank: Regular Contributor
timestamp: March 04, 2024, 03:14:56 am
content: Hello everyone, I would like to ask why the small signal AC model is different in obtaining the transfer function of the flyback converter from the YouTube video that I saw (Link below) compared to the article (Article below) that I read? Are both methods of analysing able to be used or either one of the methods is wrong? Hope that someone can help me with this thank you very much for your time.Youtube Link:(explanation around 9:07)Article: Attachment below

author: moffy
author_rank: Super Contributor
timestamp: March 04, 2024, 03:54:40 am
content: So many posts on the same topic asking some very broad quesions e.g.this one.https://www.eevblog.com/forum/projects/pfc-modelling-in-dc-dc-converter/msg5355569/#msg5355569https://www.eevblog.com/forum/projects/type-two-compensator-in-flyback-converter-for-led-driver-in-dcm-mode/msg5369618/#msg5369618https://www.eevblog.com/forum/projects/how-to-obtain-the-specific-component-in-ltspice/msg5353199/#msg5353199etc.getting hard to keep track of.

author: Patrick66
author_rank: Regular Contributor
timestamp: March 04, 2024, 04:23:30 am
content: Sorry about that sir because I wanted to study how the whole system works through the YouTube video and there are a lot of things that I didn't understand from the video but thanks to this community, I was able to understand the video. Now the problem is I found an article which is similar to the Youtube video that I saw but the method of analysis of the system is different so now I'm confused about which method of analysing the circuit is correct or both will also produce the same result? Maybe because the method of analysis that they use is different? I'm not sure about that thus I wanted to seek help from the experts. Once again sorry for posting so many posts related to this study.
Flyback LED Driver Signal - Page 1
Forum section: electronics / projects

author: jman
author_rank: Contributor
timestamp: December 10, 2014, 12:41:16 pm
content: Hi Guys,anyone can pin point whats wrong with this SignalThanks in advance

author: jman
author_rank: Contributor
timestamp: December 10, 2014, 07:28:49 pm
content: Thanks for the replyyes its a DCM controller but i really want to get rid of the ringing its very high.I have a RCD snubber across the primaryC=4.7nFR = 33Kit seems that the ringing its not fully dumped.Any suggestion for the transformer?Im using EFD30 ferrite

author: rbola35618
author_rank: Frequent Contributor
timestamp: December 11, 2014, 03:33:48 am
content: Actually there are two ringing frequencies in the waveform. The leading edge has the higher frequency which is the resonant of the Leakage and the Cmosfet. The lower frequency happens when the transformer reset and its frequency is determined by Lprimary and the Cmosfet. You would need to separate snubbers to damp the ringing. The resistor values should be around Zdamp=Squareroot(Linductor/Cmosfet).Here is a video that I made a while ago where I damp the higher frequency (12:20)Hope this helps.Robert

author: jman
author_rank: Contributor
timestamp: December 11, 2014, 09:08:08 am
content: thank you for your replies help allot..

author: jman
author_rank: Contributor
timestamp: December 14, 2014, 04:05:47 am
content: hey guys here is the new waveform after adding RC snubber and keeping the RCD

author: rbola35618
author_rank: Frequent Contributor
timestamp: December 15, 2014, 02:45:04 pm
content: Hi Jman,The plots show that the waveform is properly damped. This looks good.Robert

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 15, 2014, 03:13:58 pm
content: That looks well damped, but I would be concerned if the damping components are getting quite hot.Seems like the transformer could use higher inductance (or the controller to a higher frequency), and lower leakage (to reduce the spike).Tim
flyback mosfet problem - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: September 11, 2014, 01:10:51 pm
content: I tried to design a 48 v to 12v fly back converter using PWM controller. When I connect the transformer and power up the circuit even when the gate to the mosfet is removed the mosfet conduct and short the source.I used 34v dc from a transformer and rectifier. I tried different voltage mosfet eg IRF840 , IRF540 , IRF44n ctc also ex-bit the same characteristics. can somebody spot out

author: Marco
author_rank: Super Contributor
timestamp: September 11, 2014, 01:24:51 pm
content: "even when the gate to the mosfet is removed the mosfet conduct"You need to short the gate to source to be sure it is off and stays off.

author: Seekonk
author_rank: Super Contributor
timestamp: September 11, 2014, 05:18:53 pm
content: That is called phantom switching. Even if you short the gate, a FET will draw power when it is first applied. This is due to the Miller Effect. Generally it is not a problem. In really high power switchers it can be overcome by using a negative bias in the gate. The "phantom gate voltage" pulse still happens but it remains too low to turn on the FET.

author: planet12
author_rank: Regular Contributor
timestamp: September 11, 2014, 10:22:42 pm
content: It's very hard to know what's going on without seeing a schematic - can you provide one?Along with the miller capacitance pulling the gate up, as discussed above, the other option is possible reversal of the drain-source pins, meaning the body diode will conduct - this would also cause the symptoms you're seeing.
Flyback SMPS transformer...interleave wound or bifilar wound? - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: December 20, 2017, 09:00:37 pm
content: Hello,We need to wind a flyback transformer on a Ferroxcube PQ3535 former. We need 20 primary turns interleaved between two layers of 10 secondary turns (ie Np = 20, Ns = 20)Irms(pri) = 0.77ArmsIrms(sec) = 1.4ArmsThe PQ3535 bobbin is 20.8mm in winding length.As such, we would need the Secondary wire diameter to be 2mm in order to arrange its layers to span along the full length of the bobbin (as you know this is necessary to reduce leakage inductance). However, 2mm Enamelled wire is too unwieldy to wind easily. Therefore, we will instead simply scrap the idea of winding right across the bobbin, and simply wind 20 turns of bifilar TEX-ELZ triple insulated wire for primary and secondary. (we will use 7/0.17 TEX-ELZ)Do you think that this bifilar winding (primary and secondary twisted together then wound together) will give as low leakage inductance as interleave winding of primary and secondary, even if it doesn’t quite span the full length of the bobbin.?Ferroxcube PQ3535 bobbinhttp://www.ferroxcube.com/FerroxcubeCorporateReception/datasheet/pq3535.pdfTEX-ELZ triple insulated wirehttp://www.furukawa.co.jp/tex-e/en/product/texelz.html

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 20, 2017, 11:28:11 pm
content: What's the switching impedance? (Vpeak / Isw(pk))?Tim

author: chris_leyson
author_rank: Super Contributor
timestamp: December 20, 2017, 11:46:08 pm
content: Winding it bifilar on two layers will give good coupling as I don't see interleaved windings as being very practical with so few turns, also don't bother twisting the wires together that will only reduce the coupling. You've just got to try it and see and redesign the magnetics if it doesn't work. Don't see any problems with triple insulated wire for both primary and secondary.

author: nctnico
author_rank: Super Contributor
timestamp: December 20, 2017, 11:57:51 pm
content: Quote from: treez on December 20, 2017, 09:00:37 pmWhy not use a premade transformer from Wurth? It seems you need a 2:1 ratio so I guess this is a DC-DC converter application. If you are going to wind your own transformer anyway you'll probably need multiple parallel conductors otherwise the skin effect losses will be huge.

author: ocset
author_rank: Super Contributor
timestamp: December 21, 2017, 06:09:41 am
content: Thanks, all the wurth ones we've seen have really high leakage inductance.Sorry i shoudl have said, We cant do LLC as its a PFC'd flyback, with as you know, no large bus cap.Vpk/isw =ipk(pri) = 3.66A...this is at mains peak, which is 339V.
FM modulator-demodulator  - Page 1
Forum section: electronics / projects

author: Mahyar-jafari
author_rank: Newbie
timestamp: September 14, 2018, 03:16:37 pm
content: Hi guys,I want to creat a fm modulator-demodulator .I want to use 1496 IC . The datasheet describes the fm detectorCan this IC be used as a fm transmitter?Do you suggest another IC for this applicaton ?I really appreciate any help.
Fm sweep generator choice? - Page 1
Forum section: electronics / projects

author: ttx450
author_rank: Regular Contributor
timestamp: June 23, 2023, 01:52:17 am
content: I am on my first FM sweep generator adventure. When I went to align a 70s FM receiver it called for sweep generator I thought my AWG would work, but no and have a older E-400 I am not sure is up for the task or works.What is a decent capable FM sweep generator for receivers less then 200? Many use HP 3336C, they are a little pricey. How about the HP 3325A or other units? thanks..
FM transmitter. take current dunt transmit   - Page 1
Forum section: electronics / projects

author: dave_j_fan
author_rank: Regular Contributor
timestamp: September 10, 2016, 05:19:24 pm
content: i took this small and handy circuit :http://electronics-diy.com/solar-powered-long-range-fm-transmitter.phpbut when powerd from 9v cell it is not sending any xmission ... is the schematic ok ?i feel like the trimmer from OSc is at wrong placehow do i debug it ?it will be part of walky talky for a low range like 100m

author: Audioguru
author_rank: Super Contributor
timestamp: September 11, 2016, 12:28:17 am
content: Your circuit assembly is missing all the important capacitors.The coil L1 connects from the oscillator collector to +9V and the tuning capacitor connects from the collector to ground. But at 100MHz the +9V is the same as ground so the tuning capacitor and coil are parallel.
FMC-compatible Molex connector? - Page 1
Forum section: electronics / projects

author: aylons
author_rank: Unknown
timestamp: March 06, 2017, 05:35:30 pm
content: Hi, everyone!I was trying to prototype a simple FMC LPC mezzanine design when I found that Molex also supplyFMC-compatible SEARAY plugs. Great, because Samtec is very hard to find atDigikeyor Mouser, and the Molex part is in stock atMouserHowever, I'm utterly confused by Molex documentation: thepart pagesays 400 loaded circuits, however, the FMC LPC only has 160 circuits. To add to the confusion, if you take a look at thelast two pages of the drawing, it seems that there are only 4 rows, which is consistent with a 160-circuit connector, assuming the usual 20 columns. This would be footprint-compatible with the tradicional Samtec part, however, I can't find any explicit mention to the number of columns for this part number and, of course, I'm still more confused.So, has anyone here used Molex 45970-4305 as a substitute for Samtec ASP-134604-01 or anything similar? Is it really footprint-compatible? My main concern would be having some vias below the footprint shorting with the unused solder balls of the FMC connector, connecting an unrelated signal to the carrier.Tried to send an email to Molex, but no answer so far.Thank you! If you pay attention, the first 4 pages of the PDF are a document and the last two are another, different document.
FMC LPC Breakout board - Page 1
Forum section: electronics / projects

author: xyrtek
author_rank: Regular Contributor
timestamp: January 04, 2019, 07:19:57 pm
content: Getting few of this made to test signal integrity and use in a project. Nothing special, 4 layers (Signal-Vcc-GND-Signal), length matched differential pairs and controlled impedance.May add a clock and few other things to use as a replacement to the HW-FMC-XM105-G when making some samples for testing.

author: iam_electronic
author_rank: Newbie
timestamp: January 05, 2019, 03:54:32 pm
content: Hi,the design looks good, but if you break out the FMC pins to pin headers for loose cables, matched lengths and impedances aren't that important.For more inspiration please look here:https://fmchub.github.io/projects/FMC_LPC_BREAKOUT/Datasheet/FMC_LPC_BREAKOUT_datasheet.htmlThis FMC board breaks out the ANSI VITA 57.1 LPC connector on 2 layers.Tests for signal integrity above 1 GHz are also shown in the data sheet, and it is open source hardware!Eye scan at 1.350 GHz with loose cable connection

author: xyrtek
author_rank: Regular Contributor
timestamp: January 05, 2019, 10:45:06 pm
content: Hello iam_electronic,Thank you for taking the time to reply, it is greatly appreciated.Couple of noteworthy items:1- the final product will have no headers or FMC connector.2- to optimize cost the design is constrain to Zynq-7000 AP SoC (Low-End No GTP Transceivers)3- using differential pairs is not only about bandwidth but EMI, signal integrity, etc.There are some other design considerations as well.I added the headers since at the end of the development cycle there will be plenty of leftover PCBs, may as well use them as breakoutI noticed the user name, do you have any leftovers blank PCBs on hand?Once again thank you for your great reply.Regards.

author: xyrtek
author_rank: Regular Contributor
timestamp: January 07, 2019, 08:36:40 pm
content: Update.

author: iam_electronic
author_rank: Newbie
timestamp: January 07, 2019, 10:38:41 pm
content: I still haven't quite understood why you designes an FMC board when the final product will have no headers or FMC connector at the end!And yes, we have blank PCBs on hand. But as a said, this ones are two layer PCBs with no differential routing and no impedance control. E-Mail me with your details: i n f o ( a t ) i a m e l e c t r o n i c . c o mRegards

author: xyrtek
author_rank: Regular Contributor
timestamp: January 07, 2019, 11:22:11 pm
content: Eventually all components will be on the same board, sorry that wasn't clear.
"Foam" holding displays.  - Page 1
Forum section: electronics / projects

author: nike9307
author_rank: Contributor
timestamp: November 13, 2024, 09:26:08 pm
content: Hi all,I'm designing a project with a screen and i was looking for ways to hold it in place. Fortunately i stumbled into "EEVblog 1650 - Sequre HT-140 SMD Desoldering Tweezers REVIEW" and at around the 6 minute mark i saw that they were keeping the display pressed up against the front glass using some sort of foam material that had double sided tape on both sides.I've seen this being used on other products and i was wondering what this material is called and where can i get it. I was guessing it would be made by tape manufacturer, but i was unable to find anything similar on 3M's website.Any help would be highly appreciated.

author: reboots
author_rank: Regular Contributor
timestamp: November 13, 2024, 09:49:58 pm
content: I've had good luck holding glass OLED panels and other items with 3M VHB foam tape. It doesn't look exactly like what's in your photo, but it comes in a variety of formats and performs very well.https://www.3m.com/3M/en_US/vhb-tapes-us/

author: nike9307
author_rank: Contributor
timestamp: November 13, 2024, 10:02:06 pm
content: we've used VHB tape to hold displays displays at my day job. It is very strong. While that worked great in that context, in this project i need something that is way thicker, but springier (if that's a word). The distance from the board to the display will be around 7mm and i'd like to hold it with just the foam. If i can't, I'll design a 3D printed frame to hold the display close to the glass and use the foam tape to keep it pushed in place. But i'd like to skip the 3D printed parts, if possible.

author: nike9307
author_rank: Contributor
timestamp: November 13, 2024, 10:08:19 pm
content: Actually i just found a good 10mm foam tape from RS PRO -https://uk.rs-online.com/web/p/foam-tapes/2050906. Its 10mm thick and it has 30% Compression Set so it should get me the desired 7mm. Your suggestion led me to this. Thank you.I'll look a bit more and post the final tape i end up using.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 14, 2024, 12:40:44 am
content: I'm pretty sure that stuff is called "mounting tape", for attaching things to walls, etc. (I used to work in a hardware store and we stocked that in our 3M sticky-stuff display.)

author: Nominal Animal
author_rank: Super Contributor
timestamp: November 14, 2024, 11:23:16 am
content: Quote from: Analog Kid on November 14, 2024, 12:40:44 amAgreed.I have examined half a dozen different 0.91" to 3.5" display modules on PCBs, and they all used thin (typically 3mm wide, 2mm thick) "mounting tape" strips on the edges for attaching the display to the PCB. I've only taken one apart, but I could swear the double-sided foam tape feltexactlylike the 3M foam tape I've used to mount mirrors on a wall.
Focaltech ft6x36 datasheet - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 24, 2017, 07:51:16 am
content: Hi,I have a LCD that has this CTP chip for the touch panel, the problem is that there is a datasheet in the net which is incomplete,it's only 14 pages, and there is no info regarding how the register map is? Do you have a better datasheet for it? I want to write a driver with ARM Cortex M parts for this puppy, any hints are welcomed!

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 24, 2017, 09:57:41 am
content: Thanks body

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 24, 2017, 10:04:59 am
content: Body, means my Friend! I did not meant anything else

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 25, 2017, 08:58:49 am
content: Then we are friends now

author: strange_v
author_rank: Newbie
timestamp: December 02, 2019, 08:35:04 pm
content: Hi, I understand that this is a quite old topic but I'm currently writing a library for the same touch controller and, in my case, two features do not work correctly:1. According to chapter 3.1.4 of the datasheet, every touch should contain event information and it does. However, there are four event types: Press Down, Lift Up, Contact, No event. I'm getting only Press Down and Contact, no Lift Up.2. The controller support gestures Move Up/Down/Left/Right, Zoom In/Out but they do not work at all, the register responsible for storing gesture id is always zero. I tried to play with different min/max threshold/distance settings but without any luck.ali_asadzadeh, did it work in your case?

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 03, 2019, 06:24:42 am
content: Not eitherif you found something please share in here too.

author: strange_v
author_rank: Newbie
timestamp: December 03, 2019, 08:11:23 am
content: That's sad.As I can see it is a quite popular controller (at least I managed to find drivers for linux, android), strangely, none mentioned this "malfunction".Nevertheless, even in the current state it can be used but requires more software handling.I'll try to contact the official manufacturer to get some additional info.

author: strange_v
author_rank: Newbie
timestamp: December 04, 2019, 08:21:17 am
content: A small update.Issue #1 has been resolved. Now I can track Lift Up event.In case you interested in the library please checkFT6X36repo.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 04, 2019, 09:39:03 am
content: Thumbs up
Folding Workbench - Page 1
Forum section: electronics / projects

author: desolatordan
author_rank: Regular Contributor
timestamp: November 24, 2009, 05:21:33 am
content: So I "needed" an electronics workbench for my small apartment. Asked my Dad to put something together, and came up with this. The legs fold inward, and the top folds down, so it can fit into a car. Finally I have access to my "lab on a budget" at school now.Plan to add a top so I can mount my component cabinets to it.- There should be a "show off your workspace" thread here.Link to my website page regarding it:http://aquabunker.com/?p=elab

author: EEVblog
author_rank: Unknown
timestamp: November 24, 2009, 05:47:07 am
content: Nice!

author: septer012
author_rank: Regular Contributor
timestamp: November 24, 2009, 08:12:52 am
content: I agree nice. You should create a second folding tier above your component drawers for the lab equipment like the function generator and power supply, Leave the workbench for the project, the vice, and the soldering station.really cool that it folds though!

author: Simon
author_rank: Unknown
timestamp: November 27, 2009, 07:13:37 pm
content: thats a great idea for when you need to be on the move, I generally am ready to move out with all my equipment anytime (like when i go over to a friends to try out stuff on his car) but I don't have the bech, superb

author: EEVblog
author_rank: Unknown
timestamp: November 29, 2009, 10:07:43 pm
content: Technically the eevblog lab bench can fold too, but it's hardly portable being bolted into the brick wall on swing brackets.Dave.
Follow-up DO-160 LISN design - Page 1
Forum section: electronics / projects

author: BelgianEngineer
author_rank: Contributor
timestamp: January 30, 2021, 09:54:54 pm
content: Hey all,Inspired by this topic:https://www.eevblog.com/forum/projects/lisn-for-rtcado-160-aerospace-emc/I decided to give the DIY LISN a try. Mine is highly inspired from the one of the author with exception that 1uH, 21A (7443310100) are used and that the input capacitor is 1uF (actually 2x0.25uF + 1x047uF in parallel) to be in line with the 5uH MIL LISN at low frequency.Overall I am pretty happy of the layout work with exception that I fully flooded the bottom of the board with the chassis ground plane (I only realised later on that this was bad practice...). You can see an Altium picture of it hereby attached. Note that RC links to chassis are unmounted and 1kOhms are fitted in parallel with each inductor. Also note that for the sake of this measurement, the output was terminated at the capacitor lead with two R0605 100R in parallel.Today I mounted the first of the two channels and being very impatient I gave it a first S11 impedance measurement with a nano-VNA (1-port reflection). Setup consists of an SMA directly connected between the output and chassis ground (on the bottom) and input is shorted to the chassis ground. Unfortunately, results are pretty mediocre and out of the DO-160 tolerances on a big part of the range. We can also clearly observe a serious impedance drop starting from 20MHz.So here are my assumptions:The ground plane below the power path induces a lot of stray capacitance which eventually results in impedance drop proportional to the frequencyThe LISN board is not yet installed/fastened in its cast-iron board and somehow that affects the measurementsThe S11 impedance measurement is not accurate anymore at high frequencyI am not an RF expert so I am giving a shout to the forum to see if someone has a better clue of what might be wrong here

author: Andreas
author_rank: Super Contributor
timestamp: January 31, 2021, 06:45:14 pm
content: Quote from: BelgianEngineer on January 30, 2021, 09:54:54 pmI think: only if during your calibration (SOLT) something went wrong.I would also do a measurement of a individual coil with a SMA fixture if it is suitable above 20 MHz.with best regardsAndreas