hybridfree/eevblog-posts huggingface dataset:
Shortage of Panasonic resistors? - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: July 27, 2017, 01:45:49 pm
content: For continuity sake I like to stick with a single manufacturer for jelly bean components. It seems like a lot of Panasonic's 0402 offerings have been bought out on Digikey.Which one of you did this?

author: Leo Bodnar
author_rank: Frequent Contributor
timestamp: July 27, 2017, 02:02:00 pm
content: Quote from: Pack34 on July 27, 2017, 01:45:49 pmThis does not compute!

author: Pack34
author_rank: Frequent Contributor
timestamp: July 27, 2017, 02:08:36 pm
content: It makes the BOM so much more aesthetically pleasing. All of the part numbers follow the same format. If JB MFG1 is out of stock, then board house is to order JB MFG2, etc.ResistorsMFG1 : PanasonicMFG2 : YaegoMFG3 : VishayCapacitorsMFG1 : SamsungMFG2 : MurataMFG3 : Kemet

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 27, 2017, 02:16:38 pm
content: They follow the same format if you use in-house part numbers too.

author: Niklas
author_rank: Frequent Contributor
timestamp: July 27, 2017, 02:16:47 pm
content: Yes, Panasonic has cancelled orders on some resistors. If I remember correct, the demand has increased and the production capability is not enough.The shortage is not limited to Panasonic and resistors.

author: calexanian
author_rank: Super Contributor
timestamp: July 27, 2017, 03:47:02 pm
content: Welcome to my life. Always doing the parts dance here. Many of our product designs have not changed in 20 years so I am also dealing with obsolescence. Logic chips are going through a big shake out right now as fabs are consolidating. Every day I get a process change or wafer cancelation notice on something.

author: jmelson
author_rank: Super Contributor
timestamp: July 28, 2017, 09:50:37 pm
content: Quote from: calexanian on July 27, 2017, 03:47:02 pmOh, man, the BANE of my existence. We are a small manufacturer, and not only do i have to find substitutes, and buy out remaining stock on things, but a number of times I've had to redesign boards to accommodate the newer part. A REAL pain!!Jon

author: Pack34
author_rank: Frequent Contributor
timestamp: July 29, 2017, 02:19:42 pm
content: Quote from: jmelson on July 28, 2017, 09:50:37 pmI used to have to do that every time I put in an order. But after I went through our library and added secondary and tertiary sources for everything available, all of that went away. I also started trying to stay as far ahead as possible with EOL issues by using tools like Silicon Expert to run our BOMs through once a quarter.

author: Neilm
author_rank: Super Contributor
timestamp: July 29, 2017, 04:40:23 pm
content: Quote from: calexanian on July 27, 2017, 03:47:02 pmThe worst thing I find with older products is the EMC requirements. They may have passed when first tested, but retesting them with new fab ICs suddenly shows that the newer chips have problems at frequencies the older chips didn't so an EMC redesign / remedial action is required.
Shorted IC on a NVidia display card. Need to find model. - Page 1
Forum section: electronics / projects

author: plazma
author_rank: Frequent Contributor
timestamp: February 19, 2016, 01:11:41 pm
content: Does anyone recognize the IC model? It reads AZ5 on top of the IC.One MOSFET was burned. Pins 6-8 are shorted on the IC. There are many parallel identical circuits so it was easy to compare.

author: Skimask
author_rank: Super Contributor
timestamp: February 19, 2016, 01:30:54 pm
content: Why yes.... I do want to spend my time scanning thousands of different types of nVidia cards to find one that matches the picture.No.....

author: plazma
author_rank: Frequent Contributor
timestamp: February 19, 2016, 01:54:35 pm
content: Quote from: Skimask on February 19, 2016, 01:30:54 pmI need to know the IC model so I can buy a replacement. I already know the display card model (GTX 770).

author: Skimask
author_rank: Super Contributor
timestamp: February 19, 2016, 03:05:09 pm
content: Quote from: plazma on February 19, 2016, 01:54:35 pmGreat.You know it.Nobody else did until now.

author: jdraughn
author_rank: Regular Contributor
timestamp: February 19, 2016, 05:36:32 pm
content: I had absolutely no luck searching on the web. We might have better luck however you posted some pics that showed more area around the IC in question. We can probably figure out what it does by looking at the components around it.

author: RR
author_rank: Contributor
timestamp: February 19, 2016, 05:55:38 pm
content: looks like mosfet driverhttp://www.onsemi.com/pub_link/Collateral/NCP5901B-D.PDF

author: plazma
author_rank: Frequent Contributor
timestamp: February 19, 2016, 07:45:07 pm
content: Quote from: RR on February 19, 2016, 05:55:38 pmThanksLooks like a match when comparing to a higher resolution image with clear traces. I'll still measure it.I knew I could trust you guys

author: dcarr
author_rank: Regular Contributor
timestamp: February 19, 2016, 09:37:18 pm
content: Well done.Inquiring minds want to know how you found that part?

author: Siwastaja
author_rank: Super Contributor
timestamp: February 19, 2016, 09:50:33 pm
content: Note that if the MOSFET gate driver is blown, most likely the MOSFETs it's driving are also blown, they are probably dead short now and will blow the new driver too.So measure and change the FETs too. They can be visually good and still blown into short circuit.Chances are that rest of the circuit is fine.

author: plazma
author_rank: Frequent Contributor
timestamp: February 20, 2016, 08:12:28 am
content: One MOSFET was visibly blown. It have been removed in the picture. I'll measure the rest.

author: Bud
author_rank: Super Contributor
timestamp: February 20, 2016, 08:32:42 am
content: Those puppies run hot. I just posted a thermal image of my EVGA videocard in the other thread, no wonder your MOSFET diedhttps://www.eevblog.com/forum/repair/my-experiences-reflowing-videocards-(so-far-100-success-rate)/msg874097/#msg874097
Shortest pin protrusion on opposite side of PCB for TH components - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: November 19, 2020, 03:51:31 am
content: Hi,for through hole components with pins up to 1mm in diameter, what is the shortest you can trim the pins protruding on the back of the PCB? I mean after soldering and assuming it is machine soldered in a production line?Thank you

author: TimNJ
author_rank: Super Contributor
timestamp: November 19, 2020, 05:41:50 am
content: I would not go less than 2mm, typically 2.5mm.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: November 19, 2020, 11:36:15 pm
content: I don't think it matters how the device works. You can completely level with the PCB to bite off.But when soldering with a wave, it is likely that too short conclusions will prevent.

author: Benta
author_rank: Super Contributor
timestamp: November 19, 2020, 11:45:28 pm
content: Single layer board with no hole plating: 2 mmAll other boards with hole plating: 0 mm.Do not cut leads after soldering, do it before.

author: tszaboo
author_rank: Super Contributor
timestamp: November 20, 2020, 09:59:29 am
content: IPC-610D defines minimum as (table 7-5):QuoteMaximum is 2.5mm or 1.5mm based on board classification.

author: ricko_uk
author_rank: Super Contributor
timestamp: November 20, 2020, 08:05:55 pm
content: Thank you all!
Shorting Terminals - Page 1
Forum section: electronics / projects

author: PsychoMaster
author_rank: Regular Contributor
timestamp: January 31, 2015, 12:11:15 pm
content: Hello AllI have bought some Chinese PSU modules with adjustable CC and CV based around a XL4006E switcher and they says to short out the out put terminals to set the current but this sounds a bit cruel.Any thoughts on this ?THANKSAMILLION

author: Circlotron
author_rank: Super Contributor
timestamp: January 31, 2015, 12:17:34 pm
content: Set voltage with open cct.Set current with short cct.Not unusual at all provided the psu really does have current limit function.

author: retrolefty
author_rank: Super Contributor
timestamp: January 31, 2015, 01:04:52 pm
content: Quote from: PsychoMaster on January 31, 2015, 12:11:15 pmNo harm will become the PSU if following it's instructions.

author: PsychoMaster
author_rank: Regular Contributor
timestamp: February 02, 2015, 02:53:31 pm
content: Thanks I have faith in you all.

author: Alex30
author_rank: Regular Contributor
timestamp: February 02, 2015, 02:58:21 pm
content: This is normal procedure for power supplies
Shottky diodes instead of germanium in old analog meter - Page 1
Forum section: electronics / projects

author: 001
author_rank: Super Contributor
timestamp: October 24, 2019, 01:55:34 pm
content: HiI`m working with vintage AC voltmeterThe rectifier is two germanium diodes blown with galvanometerI can buy new galvanometer but not new germanium diodesCan I replace germanium with new shottky?

author: iMo
author_rank: Super Contributor
timestamp: October 24, 2019, 03:34:11 pm
content: The closest alternatives would be the BAT42/43/45/46. Unless you'll find the germanium ones, when pretty luckyPS: those BATxx diodes are small signal, max 30V or so, not to be used as rectifiers for higher voltages. Good around the galvanometer movement, imho.

author: duak
author_rank: Super Contributor
timestamp: October 24, 2019, 05:57:58 pm
content: Pease had an article on various diodes' forward voltage characteristics. I can't find the link to it now but I've attached a chart.One thing to note is that large area devices, such as rectiiers, have a forward leakage current that can be significant at low voltages. This current could affect the accuracy of the meter.

author: 001
author_rank: Super Contributor
timestamp: October 26, 2019, 02:54:30 pm
content: awesome!Thanx1

author: bd139
author_rank: Super Contributor
timestamp: October 26, 2019, 04:54:42 pm
content: I just jam a 1N270 in everywhere a Ge diode is used. Easy to get and seems to work fine with similar characteristic curves plus breakdown voltage is much higher than the average schottky diode.

author: 001
author_rank: Super Contributor
timestamp: October 26, 2019, 05:51:01 pm
content: Quote from: bd139 on October 26, 2019, 04:54:42 pmThanx! Can You say about few examples?

author: bd139
author_rank: Super Contributor
timestamp: October 26, 2019, 05:55:10 pm
content: I've used them in RF detectors, good to VHF and to replace one inside a Micronta multimeter's AC circuit so similar use case to yours. I usually buy them from China. They are genuine Ge as they are much more temperature sensitive than an equivalent 1N5711 schottky. Main thing is if you have an analogue meter, you need a Ge diode rather than a schottky one as the scale is usually calibrated for the Ge diode curve.
Should I Change the Way My Xytronic I68-3C Iron Turns On? - Page 1
Forum section: electronics / projects

author: whirligig
author_rank: Contributor
timestamp: July 18, 2019, 08:01:15 pm
content: My Xytronic I68-3C soldering station has served me well for many years but, there is one thing that has always bugged me about the design. When plugged to the AC outlet, the transformer is always on even though the power switch is off. Opening up the unit, I see that the primary leads are connected directly to the AC cord. The secondaries are connected to the power switch which turns on the controller board. I don't see this station should be wired like this unless it's to avoid the cost of an AC rated switch. I am considering re-doing the whole switch assembly by using an AC rated switch, connect the hot line to the switch and solder the secondaries directly to the control board.Any thoughts?Thanks.
Should I Pour Extra Planes On A Star-Grounded Audio Board? - Page 1
Forum section: electronics / projects

author: algorhythm
author_rank: Contributor
timestamp: February 17, 2025, 06:13:58 pm
content: Hello fellow electron wranglersI have a star-grounded pi-hat audio board here with some power filtering, an ldo, two codecs, and some midi optoisolator stuff.It is a two layer board, no planes of any kind. The top barely has any traces ( they're just near the ics for caps, etc ), and the bottom is about 20% covered with traces. It sounds absolutely wonderful since the board was designed specifically around power/ground optimizations for the codecs. I cannot show the board due to an n.d.a.Before I order another batch of boards, I'd like to ask:Should I pour into the top and bottom empty areas?Should I put a via at the corner of each polygon to connect top and bottom?How do you think pours will affect the audio, if at all?Thanks!

author: RoGeorge
author_rank: Super Contributor
timestamp: February 18, 2025, 05:25:34 am
content: Quote from: algorhythm on February 17, 2025, 06:13:58 pm1. No.2. No.3. Most probably in a bad way.
Should I source this IC from China? - Page 1
Forum section: electronics / projects

author: iXod
author_rank: Frequent Contributor
timestamp: June 30, 2021, 02:06:39 pm
content: I’m repairing a HDD PCB. The motor controller, a TI SH6125B, is NLA. The only source I can find is from China sellers on eBay (US).Yes there are used PCBs available to replace the non-functional one, and donor boards that I can take a (maybe) functional controller IC from. But both these options are more spendy than this hobby project is worth.What’s the likelihood that these China-sourced chips are legitimate and not counterfeit trash?Thanks.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: June 30, 2021, 02:23:32 pm
content: If it cost nothing you can try,they recycle also, you will see fast enough after the mail arrives.

author: iXod
author_rank: Frequent Contributor
timestamp: June 30, 2021, 03:07:07 pm
content: I forgot about eBay's guarantee. If it's counterfeit, I get a refund. Thanks for the reminder.The only question is whether a fake IC would cause damage to the otherwise-functional (it seems) PCB?Thanks.

author: magic
author_rank: Super Contributor
timestamp: June 30, 2021, 03:21:29 pm
content: It could, if it's some completely different IC with fake markings. Such things happen, so always carefully inspect your eBay scores for signs of grinding, blacktopping, different font style, misaligned text, that sort of stuff.
Should I take apart a rubber connected LCD panel? - Page 1
Forum section: electronics / projects

author: PostaL
author_rank: Contributor
timestamp: January 18, 2013, 07:48:31 pm
content: I want to change the LED light on my car stereo to a different color. I just opened it and the LCD in it is the same kind of LCD panel as in common 16x2 LCD's: the LCD panel is communicating to the board viaa rubber connectorand is held to the PCB via a steal frame with itslegs twisted behind the board.What I want is to untwist those legs and take the LCD panel off, so that I can access the LEDs and change them.Now I remember from my young age, when I used to take apart all my Tetris games, which as well had their LCD connected in the same manner, that was close to impossible for me to put back the LCD-PCB assembly without loosing some segments from the LCD.So, is there a secret on reassembling this kind of LCD panel ? Or this is not meant for manual assembly ?Thank you!

author: plazma
author_rank: Frequent Contributor
timestamp: January 18, 2013, 07:51:35 pm
content: No problem. Just keep parts clean or clean with IPA.

author: SeanB
author_rank: Super Contributor
timestamp: January 18, 2013, 08:27:01 pm
content: Before diassembly take a permanent marker and mark the sides of the cover where the zebra strips are so you have alignment marks to get them back in in the same orientation as they came out. Note that the LED's on some modules are actually outside the module on the side, and if not then they are very thin units.

author: PostaL
author_rank: Contributor
timestamp: January 18, 2013, 08:37:00 pm
content: This one is like 3 times bigger than the normal 16x2, so let's hope is not that tiny. Thank you guys for all the advice so far!
Should the bottom pad of the FT2232 QFN-64 be connected to ground? - Page 1
Forum section: electronics / projects

author: zapta
author_rank: Super Contributor
timestamp: June 15, 2024, 06:10:26 pm
content: With the FTDI 2232H QFN-64 package, does the pad at bottom need to be connected to ground? I see a note for that affect for the VQFN-56 package but not for the QFN-64.https://ftdichip.com/wp-content/uploads/2024/05/DS_FT2232H.pdf#page=57Not having to solder the pad will make it easier to manually soldering the IC. Looking at the ICEZUM board as an example, the pad was left floating.

author: coromonadalix
author_rank: Super Contributor
timestamp: June 15, 2024, 06:24:10 pm
content: some designs do leave the pad unconnected, in this case not even sure it serve as heat transfert

author: tooki
author_rank: Super Contributor
timestamp: June 17, 2024, 06:22:46 pm
content: Quote from: zapta on June 15, 2024, 06:10:26 pmYou just missed the note, but it’s there for the VQFN-56 as well, two pages later (page 57, PDF page 59):“Note: The internal ground of the device is connected to the bottom side central solder pad whose dimension is 5.90 x 5.90mm. This central solder pad must be connected to the ground of the system.”

author: zapta
author_rank: Super Contributor
timestamp: June 17, 2024, 09:08:08 pm
content: Yes, are right, thanks.I sent the gerbers to JLCPCB earlier today and luckily it was connected. ;-)
should the LTC1043 voltage divider circuit be buffered? - Page 1
Forum section: electronics / projects

author: SArepairman
author_rank: Frequent Contributor
timestamp: June 14, 2014, 12:21:05 am
content: How should I look at the LTC1043 voltage divider circuits (divide by 2, etc) as a voltage source? what kind if impedance can it support?how is this analysis done?I figured something like 600 Hz oscillator frequency, 1uF charge on capacitor, 10k drain, so essentially the capacitor is losing X charge per second and it is restoring itself to full every 1/600th of a second? So its just a RC ripple that changes depending on load?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 14, 2014, 12:37:13 am
content: The output impedance is roughly Rds(ON) * 2 + Xc.Tim

author: Andreas
author_rank: Super Contributor
timestamp: June 14, 2014, 05:07:55 am
content: Hello,If you want to use it as precision device you should never load the output.Even the input bias current of a standard buffer amplifier creates a large error.Usually a LTC1050 buffer (10pA bias current) is used together with the LTC1043.With best regardsAndreas
Show us a quick and useful project - Page 1
Forum section: electronics / projects

author: Grandchuck
author_rank: Super Contributor
timestamp: January 03, 2025, 08:02:10 pm
content: Here is one: a fixture for testing two and three terminal devices plus two accessories ... a BNC T adapter and a BNC 50 ohm feedthrough.

author: RoGeorge
author_rank: Super Contributor
timestamp: January 04, 2025, 07:18:27 am
content: Nice!Here's a similar one:Pic fromhttps://www.eevblog.com/forum/projects/ad-hoc-zif-kelvin-probe-for-axial-tht-components/It's a Kelvin probe ZIF socket for axial components, from when I was testing a bunch of Ge diodes. The 2 golden pins placed like an X at each end of the diode do not touch each other, but they are both touching the terminal of the diode. It doesn't have wires yet in that picture, it was to be used inside a shielded can:Pic fromhttps://www.eevblog.com/forum/rf-microwave/(unfolds)-00-diodes-square-law-region/

author: Grandchuck
author_rank: Super Contributor
timestamp: January 04, 2025, 11:48:47 am
content: RoGeorge that is clever!

author: ComfyChair
author_rank: Contributor
timestamp: January 04, 2025, 02:08:43 pm
content: Solder spool holder:Just 2 chunks of wood and an appropriate length of copper pipe

author: RoGeorge
author_rank: Super Contributor
timestamp: January 04, 2025, 04:12:42 pm
content: Literally a hack.

author: westfw
author_rank: Super Contributor
timestamp: January 04, 2025, 11:04:42 pm
content: I've been getting a lot of products recently that are recharged with a USB-C cable, and come with short "charge only" USB-C cables. I should probably just throw those away, bu in order to check whether a given cable I pull out of a box is power-only or at least contains USB2 data signals as well, I built this little gadget...

author: RoGeorge
author_rank: Super Contributor
timestamp: January 05, 2025, 12:32:40 am
content: That reminds me of this USB Extender/Sniffer I've improvised once:It has all the USB wires and the shield connected through removable 0.1'' jumpers, 1:1 to the other end. Was made out of an USB header leftover from a former motherboard.Made it to easily insert an ammeter on the power lines, or to connect a Logic Analyzer in parallel with the D+ and D- for USB data sniffing. Also good to probe for EMI problems with or without the shield connected.
Show us you workbench/lab/workshop  - Page 1
Forum section: electronics / projects

author: MadScientist
author_rank: Frequent Contributor
timestamp: November 23, 2018, 06:21:14 pm
content: It’s always fascinating to see other people’s lab / workbench / workshop . Hence the call to see how you do itPs , I’m not posting mine till I tidy it upDave

author: georges80
author_rank: Frequent Contributor
timestamp: November 23, 2018, 06:28:03 pm
content: https://www.eevblog.com/forum/chat/whats-your-work-benchlab-look-like-post-some-pictures-of-your-lab/
Showcase Uno based PCB Pre-Heater w. active Temp Monitoring - Page 1
Forum section: electronics / projects

author: pcarew
author_rank: Contributor
timestamp: July 20, 2024, 06:56:07 am
content: I have developed an Arduino Based Pre Heater for PCB Rework that some may be interested in. This project has:Precise temperature controlSelectable Temperature ProfilesManual Temperature settingsHeater enable/DisableLED Indicator status profilesRotary menu selection / manual temperature settingTFT Graphing of measured temperaturesSerial streaming of Temperature readings for off-heater plotting and/or recordingFuzzy Logic / AI based Temperature control engineAll of this is crammed onto an Arduino Uno R3.For specific details see:https://github.com/pcarew/PaulsPCBHeater
Showing cool project to high school students at sci week? Tesla coil too chosen  - Page 1
Forum section: electronics / projects

author: timofonic
author_rank: Frequent Contributor
timestamp: October 24, 2015, 12:29:01 pm
content: Hello.I need to show an interesting, yet not so complex to do project in the science week. I would like to make something different, because most people are doing the typical Tesla coils and other typical electromagnetic circuits.I want to show something interesting, attractive for technological illiterate people and average layman.Any ideas?I would put all my retrocomputer machines, but that would worry most people. Maybe my Atari XL with Yoomp! could be interesting, as it's a quite addictive gameKind Regards.

author: daqq
author_rank: Super Contributor
timestamp: October 24, 2015, 12:41:35 pm
content: Lasers are fun! Coilguns are cool! DIY Spot welders look hacky, simple and produce great results. Induction heating looks impressive when you melt a screw driver.

author: Yansi
author_rank: Super Contributor
timestamp: October 24, 2015, 12:50:11 pm
content: Unfortunately induction heating is nowhere near easy to do in some "science week with technological illiterates", if it has to work at least little efficient. The only simple yet working induction heater I can think of is the modified Mazzilli's circuit often called "The ZVS driver". The advantage is it can handle quite some power and uses safe low voltage as a supply.

author: timofonic
author_rank: Frequent Contributor
timestamp: November 06, 2015, 07:09:06 pm
content: Unfortunately, there're lots of restrictions and I had health issues. Anyway, I'll take it as a future project.Thanks!

author: bitslice
author_rank: Frequent Contributor
timestamp: November 06, 2015, 07:16:00 pm
content: Quote from: Circuiteromalaguito on October 24, 2015, 12:29:01 pmsmash a 70's clock to bitsput in case? ? ? ?profit

author: f5r5e5d
author_rank: Frequent Contributor
timestamp: November 07, 2015, 04:18:11 am
content: is levitating pyrolytic graphite over NdFeB magnets "the usual" today? several tricks athttp://sci-toys.com/http://sci-toys.com/scitoys/scitoys/magnets/curie_engine/curie_engine.htmlhow about making the levitated graphite disc spin with laser or solar heat?http://birdstobosons.com/2012/12/19/a-new-twist-on-an-aging-trick/or the "Levitron":https://en.wikipedia.org/wiki/Spin-stabilized_magnetic_levitation
Showing my breakout board for IV-22 VFD Tubes - Page 1
Forum section: electronics / projects

author: Rolo
author_rank: Regular Contributor
timestamp: August 03, 2018, 03:07:01 pm
content: I'm into the vintage VFD display's but they are hard to experiment with. So I made a breakout board for the IV-22. I designed it before I had the tubes, based on the data I found on the internet. And, yes they fit!Now I can put them on a breadboard an ticker with these tubes.
Showing off my 16 output constant current LED driver project - Page 1
Forum section: electronics / projects

author: hamster_nz
author_rank: Super Contributor
timestamp: November 30, 2014, 10:58:19 am
content: I've just finished testing my constant current LED drivers, for a jumbo LED clock I'm making.If anybody wants a PCB just ask - I've got some more on order that don't need a bodge wire (guess who was the muppet gave the shift register's active-low OE signal a pullup resistor?)
Showing the final result of my pre-amplifier. - Page 1
Forum section: electronics / projects

author: _Steven_
author_rank: Contributor
timestamp: July 02, 2013, 10:27:32 am
content: Dear friends,After a lot of work I'm proud to show the final result of my pre-amplifier.greetings,Steven

author: free_electron
author_rank: Super Contributor
timestamp: July 02, 2013, 10:55:52 am
content: Oooh . Thats a very pretty case ! Where you gettit ?

author: _Steven_
author_rank: Contributor
timestamp: July 02, 2013, 11:22:40 am
content: it's totally a reuse of abandon parts. The case itself is an old amplifier for a car. And the rest is custom cut...out of old equipment. The thing you see above the toriod transo is something from an old CD player. beneath its something from the rest of the case.Totally junk parts...and figuring something out and make it nice. The two barrels left and right are a re-use parts.This case isn't on the market...just being creative. Taping holes for screwes etcetera.It's looking nice heI also sended the picture to Velleman....maybe they do something with it.The orange light on the backside is something not that succesfull. It lightens up all the time...also when the switch is "off"Here you see other things i've made:http://users.telenet.be/offie/voeding.htmlJust a hobbyIt takes some time....others go party with friends in the weekend...i like my soldiering ironOver time I also have a lot of spare parts. I just keep them organized in one closet. (otherwise my partner will by angry). My hobby don't has to be her'sWhy i posted this on this forum is that I really like Dave's video's on dumpster divingYou should do more with the things you find Dave:) Big hug from Belgium - Europe.I should send you a postcard. 2 years ago I was in Malaysie..not that far away from Australia. there were a lot of poeple from Australia @Malaysia.Some guy even told me that we should move to australia. (my wife is nurse....and i'm a physical therapist).They were from Melbourne.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: July 02, 2013, 11:42:11 am
content: Very nice use of junk parts

author: richard.cs
author_rank: Super Contributor
timestamp: July 02, 2013, 12:05:50 pm
content: QuoteThat can be fixed, it's just swapping the inlet and outlet pair of wires over so the power comes into the switch on the side without the neon

author: _Steven_
author_rank: Contributor
timestamp: July 02, 2013, 12:19:59 pm
content: thanks Richard! To simpel to be true....but indeed!!!! Thank you alotSometimes I'm that busy figuring out something and forget the smaller things. thank you alot.The neon on the second switch brake...offcourse! Switching the power cord to the other side is the solution.Thank you
showwx+ Laserprojector for pcb exposure - composite video quality issue - Page 1
Forum section: electronics / projects

author: Amper
author_rank: Frequent Contributor
timestamp: October 12, 2018, 02:45:08 pm
content: Hi!im currently doing a few experiments trying to expose some dry film with a showwx+ miniature laserprojector like the one mikeselectricstuff has done a teardown on. The first test with the testscreen of the device itself has shown promising results, not the very best quality, but still the 450nm of the blue laser is sufficient for exposure and the lines are clear enough. However now i ran into a pretty pathetic problem: These things seem to accept only composite video. I tried with a raspberry as the source but with unusable results. I suspect that the problem is the signal source, no so much the projector it self.Can anyone recommend a good source for composite video that allows me to show a single frame? b/w would be fine as only the blue will take effect anyways. I dont want to invest in some converters if they turn out to produce the same horrible quality.Or does anyone know if there may be a different way of feeding it some other signal?

author: Photon939
author_rank: Regular Contributor
timestamp: October 12, 2018, 08:26:09 pm
content: I have one of the original Microvision Showwx projectors - if you poke around on ebay you might be able to find a VGA dock for it, I got one for mine. It allows for much higher quality video input.
Shunt current measuring on a negative voltage rail.. tricky? - Page 1
Forum section: electronics / projects

author: aSmallGuy
author_rank: Newbie
timestamp: March 07, 2016, 07:03:49 pm
content: I'm trying to read a current using a shunt resistor on the high side of a negative voltage. I found a lot of high side integrated current shunt ICs (ZTX 3 pins with current output are the best), but they all assume they are placed on the high side of a positive voltage rail, hence they have a high common mode voltage, but only positive to their supplied ground (terminology correct?).Then I found this one, LT6105, where its Input common mode range extends 44V above V- indipendent of V+ (hence mobile).http://cds.linear.com/docs/en/datasheet/6105fa.pdfIn this barebone schema I omitted the Load part with a ready current source. The current flows from ground to -40V, the shunt is in high side on the neg. rail (load is grounded, and the shunt resistor touches the voltage supply).This looks like a huge life saver, the queston is: are there other similar chips? I was unable to find other components where the datasheet reported the input common mode range respect to V- (and the ability to have an explicit negative V-); to my untrained eye, they all reference to ground (in single or dual supply operations). A couple have something like -5/+60V, but it's not written if it's respect to absolute Gnd or V- pin applied voltage.Second point, what if I have a -60V supply? Should I forcifully go with a differential opamp design like LT1990? (but then I will have to add a second amplifying stage).I'm referring to Linear just because I have ready models in LTSpice to try (and the simulations actually converge); the bad is that it doesn't say if I'm violating component rating (max supply, common mode, etc).Let me know if I got current shunts the wrong way

author: dom0
author_rank: Super Contributor
timestamp: March 07, 2016, 07:15:11 pm
content: The usual current sense amplifier circuit also works here; you can place the output load resistor on a positive voltage to get positive outputs (e.g. buffered ADC reference).Edit: Attached image. ; gm = (Rg / Rf * Rs)^-1
Shunt Measurement Device - Page 1
Forum section: electronics / projects

author: Dreamer1
author_rank: Contributor
timestamp: December 25, 2013, 12:08:29 am
content: Hi guys, I'm trying to make an accurate shunt measurement device. I think I'm doing it the way most people would, running a known current through an unknown resistance and measuring output, anyway, i have attached what I have so far? Any thoughts before I start putting it together?http://imgur.com/D8BAr5E,QGdUi7g
Shunt Measurement of Capacitor ESR and Resonance Frequency with a VNA - Page 1
Forum section: electronics / projects

author: graybeard
author_rank: Frequent Contributor
timestamp: June 25, 2020, 03:41:06 pm
content: In this video I describe how to measure capacitor ESR (Equivalent Series Resistance) and resonance frequency using a vector network analyzer. I show my homemade fixture, describe in detail how the measurements are made, demonstrate several examples, and show how to convert the S21 measurement to ESR. Any VNA that covers 100KHz to 1GHz can be used.Here are printable versions of the |S21| to ESRconversion graphandconversion table.. . . Chris

author: graybeard
author_rank: Frequent Contributor
timestamp: June 27, 2020, 06:19:06 am
content: In this video I demonstrate ESR and resonant frequency and of some sample capacitors using the NanoVNA-F. The results are consistent with my previous measurements using the Siglent SVA1015X VNA.This is a quick supplement to my previous video "0012 Measurement of Capacitor ESR and Resonance Frequency with a VNA (Vector Network Analyzer)." If you want to see more details about the fixture, why this measurement works, and more example measurements please see my previous video

author: bob91343
author_rank: Super Contributor
timestamp: June 27, 2020, 09:18:08 pm
content: This all neglects ESL, which can by itself account for the tiny spike on the screen.

author: graybeard
author_rank: Frequent Contributor
timestamp: June 28, 2020, 08:41:13 pm
content: Quote from: bob91343 on June 27, 2020, 09:18:08 pmJust how does this neglect ESL? The series resonance of the capacitor is frequency at which the reactance of the ESL and the reactance of the C are equal in magnitude, but have opposite signs and cancel. I specifically discussed it in the first of the two videos.

author: cdev
author_rank: Super Contributor
timestamp: July 08, 2020, 04:23:17 pm
content: *Thank you!*I may be able to use a bnc to banana plug adaptor as a test fixture if I can find a noninductive (50 or 75 ohm?) resistor to use as my "load" - For through hole components, it would likely be better than some other means to testing these aspects of inductance and capacitance (LCR meter that tests at much lower frequencies)
Shunt opamp supply question - Page 1
Forum section: electronics / projects

author: teslinius
author_rank: Regular Contributor
timestamp: September 13, 2021, 07:04:42 pm
content: I have a current shunt and i'm using an opamp to amplifiy it, the only problem is that if i supply it to +12V which is powered by a 5w transformer the voltage drops by a couple 100mV and so the opamp output changes which changes the current readings. To prevent this i am planning to power it from +5V and -12V like in the picture, i just don't know if i can power it like this with different potentials?

author: Gyro
author_rank: Super Contributor
timestamp: September 13, 2021, 07:55:23 pm
content: Didn't you already ask this question?https://www.eevblog.com/forum/projects/help-with-current-shunt-amplifier/

author: Vovk_Z
author_rank: Super Contributor
timestamp: September 13, 2021, 09:29:31 pm
content: Quote from: teslinius on September 13, 2021, 07:04:42 pmIt is ok. Any typical opamp can work with any unsimmetrical power supply voltages.
Shunt resistor with only 2 terminals : how to use it ? - Page 1
Forum section: electronics / projects

author: Lunasix
author_rank: Regular Contributor
timestamp: April 10, 2015, 04:10:04 pm
content: Hello,I need to measure current, up to 20A, and I'm searching for a shunt resistor. I know how to use shunt with 4 terminals (some have 5, what for ?)http://www.mouser.fr/ProductDetail/Vishay-Dale/WSMS2906L5000JK/?qs=sGAEpiMZZMtlubZbdhIBIPNKsuXHpjQqyeLuBxEqI%2fE%3d.If I could find right value (around 5 mohms) with 4 terminals, it would be perfect but many shunts have only 2 terminals :http://www.mouser.fr/ProductDetail/KOA-Speer/PSEDTEL500F/?qs=sGAEpiMZZMtlubZbdhIBINcczzaXb4nbfTt0aoDXs6Q%3d!How is it possible to reliably measure current whith such a low value, when solder resistance will have similar values ? I don't understand. If somebody can help me, thanks.

author: nctnico
author_rank: Super Contributor
timestamp: April 10, 2015, 04:21:31 pm
content: For surface mounted resistors you can create a footprint with 4 pads.

author: DanielS
author_rank: Frequent Contributor
timestamp: April 10, 2015, 04:56:13 pm
content: On many PCBs with two terminal SMD shunts, they simply connect the sense line in the middle of the pad on the opposite side from the high-current traces so most of the current is out of the sense path. Not quite as good as four terminals but good enough for many applications.Unless you planned to rely exclusively on your shunt's 1% nominal value for accuracy, you will still need to calibrate the thing and that would cancel out a fair chunk of the shared pad issues.

author: ajb
author_rank: Super Contributor
timestamp: April 10, 2015, 04:57:38 pm
content: Analog Devices has an excellent app note on creating 4-wire footprints for two-terminal resistors:http://www.analog.com/library/analogdialogue/archives/46-06/shunt_resistors.html

author: paulc
author_rank: Contributor
timestamp: April 10, 2015, 05:02:16 pm
content: And another way from VISHAY datashhet:http://www.vishay.com/docs/30100/wsl.pdf

author: Lunasix
author_rank: Regular Contributor
timestamp: April 10, 2015, 05:50:56 pm
content: Thanks ! I was thinking at such things, but had doubt about result. In my mind, footprint was too small to divide pad in two smaller pads, but it is the way to do.

author: David_AVD
author_rank: Super Contributor
timestamp: April 10, 2015, 10:31:20 pm
content: That Analog Devices page has some really good information.
Shunt resistors for DMM6500 - Page 1
Forum section: electronics / projects

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: July 07, 2019, 10:13:28 pm
content: So I'd like to make some power measurements using the power script that has been written for the Keithley DMM6500 DMM using the DCV ratio.I would like to measure anything from small led's to power electronics drawing thousand + amp peaks (DC battery tab welder).Not sure if all shunts are built the same or if the ones I can get off of Aliexpress are good enough that go for a few bucks each.Will want to make the most accurate measurments possible so what range of shunts should I get?Also, if a Shunt is rated at 500A does that mean such a rating should no be exceeded or is it just to indicate that at that current level the burden voltage will be 75 mV?

author: Kleinstein
author_rank: Super Contributor
timestamp: July 08, 2019, 08:19:50 am
content: The rated current is usually the maximum current (it's different for very small currents). For short spikes below the thermal time constant (e.g. some 1-30 seconds, depending on size) the current can be higher. For best accuracy it may not even be a good idea to use the full rated current, as heating can add quite some error. This can especially be a problem with the cheap ones with high TC and poor cooling / exaggerated rating.
Shunts - Page 1
Forum section: electronics / projects

author: PsychoMaster
author_rank: Regular Contributor
timestamp: May 25, 2015, 02:48:29 pm
content: Hi FolkI have bought some ammeters off Ebay that require 75mv shunts.Well the ones supplied are uselessto the meters and I am asking what resistance is a 75mv shunt? How did they come up with that,where is 75mv relevent? How do I turn this into ohms?Thanks

author: AlfBaz
author_rank: Super Contributor
timestamp: May 25, 2015, 03:02:05 pm
content: It'll be 75mV at x Amps. You then use ohms law. To find out how many amps it is put 75mV of the meter and see how many amps it reads

author: DanielS
author_rank: Frequent Contributor
timestamp: May 25, 2015, 03:03:50 pm
content: An analog gauge has a full-scale current/voltage and the shunt is whatever resistance you need to have the meter's full-scale voltage at the desired full-scale current.Use a low-current/voltage power source, step it up slowly until you get full deflection, subtract that current from your max range, divide the full-scale current by the remainder of the current, that gives you your shunt resistance.
Shutting Off 120VAC Before Zero Cross - Page 1
Forum section: electronics / projects

author: ElectronKing
author_rank: Newbie
timestamp: August 23, 2016, 07:13:26 pm
content: Greetings:I have an application where I'd like to turn OFF a small inductive load (vibrating motor, 120vac, ~0.5A) immediately (within a few microseconds) after conditions are met within my microcontroller application, thus I can not use a TRIAC which would switch off but I'd have to wait for zero crossing.I was wondering if anyone has any suggestions on how to do this. Perhaps using a GTO??? I also realize I'll also need some type of snubber circuit since I'm often turning off before zero cross but not sure how all this would look. Really out of my wheelhouse here (I'm a microcontroller/firmware guy).Thanks.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 23, 2016, 07:22:33 pm
content: The alternative would be an bridge rectifier and than an MOSFET or IGBT between the + and - therminals of the rectifier.It is also possible to use a series pair of MOSFETs with source connected together.In Theory also Photomos could work, though the load could be a little high for the common types.Yes you need beefy snubbers. Depending on the switches this could be RCD or similar. Simple RC snubbers will not work well.

author: ajb
author_rank: Super Contributor
timestamp: August 23, 2016, 07:24:09 pm
content: A back-to-back MOSFET switch would be the typical alternative to a TRIAC. Two MOSFETS, connect the gates and sources together, one drain is the input and the other is the output. Note that your gate drive will be referenced to the source terminal, which is riding the AC voltage. How you manage that depends on your application, and what other connections to the outside world you require.Won't the mechanical inertia of a 60W motor swamp your microsecond timing, though?

author: Cyberdragon
author_rank: Super Contributor
timestamp: August 23, 2016, 10:03:33 pm
content: If you use IGBTs or IGCTs you won't need any snubber. IGCTs are still latching though, so you'd have to pulse the gate off.

author: wasyoungonce
author_rank: Frequent Contributor
timestamp: August 23, 2016, 11:01:03 pm
content: Quote from: ajb on August 23, 2016, 07:24:09 pmHe could plug brake the motor

author: ElectronKing
author_rank: Newbie
timestamp: August 25, 2016, 05:03:42 pm
content: Thx for the replies. Still trying to wrap my head around this.Ajb, good point about the mechanical inertia. I've been trying to quantify that for about a week now to see where limit is.As for IGCTs... did a quick search but couldn't find any that would meet my spec. Any idea where I would get something like this for 120v, 0.5A?As for back to back MOSFET switch approach, looking to drive gate with output of micro-controller. Not sure how to reference microcontroller side (DC) with MOSFETs.
SHV-02 diode equivalent - Page 1
Forum section: electronics / projects

author: Jordanch68
author_rank: Newbie
timestamp: June 27, 2021, 07:32:11 pm
content: Hello! I've been searching for an equivalent to the SHV-02 high voltage rectifier diode and I was wondering if anyone might know of one? A 2CL69 seems close but I thought I'd ask here for ideas.I did find one source for the SHV-02 online so that is my only option at this point.(This is being used on the power supply board of an Iwatsu SS-7610 oscilloscope which has ten of these)Shv-02 High Voltage Rectifier Diode datasheet:Vrm: 2kvIf (AV): 2.0mAIfsm: 0.3ATc: 100°CTstg: -40 to +120°CVf: 16V (max) / If: 10mAIr: (Vr=Vrm max) 1μAIr (H): (Vr=Vrm Ta=100°C max) 3μATrr: 0.18μS (If/Irp: 10/10mA) (Ta=100°C ---)Leads: 27mm x 2mmBody: 3mmPurpose: For general FBTEquivalent: possibility 2CL69Thanks,Chris
SHV connector question: Withstanding / working voltage - Page 1
Forum section: electronics / projects

author: balage
author_rank: Regular Contributor
timestamp: November 14, 2019, 01:28:08 pm
content: Hi All,There is a high voltage power supply that has a normal SHV jack. This supply can source up to 10kV. The factory supplied connector plug is the following:https://www.radiall.com/shv-straight-female-clamp-type-cable-5-50s-r317005000.htmlThe datasheet says that the dielectric withstanding voltage is 10 kV, while the voltage rating is only 6 kV. Am I right that this plug cannot be used on 10kVolts?The working voltage can be the highest applied, as this is the maximum safe voltage it can handle? Right? Regardless to the withstanding voltage.Thanks for your thoughts!

author: MagicSmoker
author_rank: Super Contributor
timestamp: November 14, 2019, 06:32:55 pm
content: SHV and MHV interconnects are often abused in this manner. It's not strictly acceptable to exceed the working voltage rating, but there are precious few options for HV connectors and minimal hazard for low volume products intended to be operated by trained personnel.If the connector is going to be subjected to 10kV continuously/long periods of time then I'd think twice about this, but if it is for intermittent use then I wouldn't sweat it.

author: jmelson
author_rank: Super Contributor
timestamp: November 14, 2019, 08:31:24 pm
content: Quote from: balage on November 14, 2019, 01:28:08 pmI think standard crimp SHV connectors are rated for 3 KV, but there are special SHV connectors rated for 5 and 10 KV, I think they are called SHV5 and SHV10. They have to be used with special cables with higher voltage ratings. I think REDEL makes some of these cables.Jon

author: balage
author_rank: Regular Contributor
timestamp: November 14, 2019, 08:53:02 pm
content: Yes, the SHV with the shorter center part is up to 5kV (SHV5) and the longer is up to 10kV (SHV10). Here is the longer one:https://www.newark.com/kings/1065-1-qd/connector-10kv-high-voltage-plug/dp/98F991For example I prefer cables from hivolt.de and connectors from Pasternack.