hybridfree/eevblog-posts huggingface dataset:
Cheap Zetta NOR Flash - Page 1
Forum section: electronics / projects

author: unreal
author_rank: Newbie
timestamp: February 04, 2024, 12:07:35 pm
content: Hello EEVblog!I've been wondering about these sub-10c flash parts from Puya and Zetta. ZD25WQ/WD and PY25 series.They claim 100K program/erase cycles and 20y data retention as well as < 2V operation.Example:https://datasheet.lcsc.com/lcsc/2108150430_Zetta-ZD25WD20BNIGR_C2875855.pdfAlso, they supposedly achieve uniform erase times regardless of block size, which IMO is a bit unusual. Are they really conventional NOR memory?Anybody has experience using them in non-hobby settings? How reliable are they compared to e.g. GigaDevice?
Cheaper Crimper - Page 1
Forum section: electronics / projects

author: ezalys
author_rank: Frequent Contributor
timestamp: November 30, 2021, 12:17:16 am
content: Hi All -- I'm interested in making some 15 pin Micro-D cables, and the only connector/backshell that seems reasonable to use is from Norcomp, and uses pins 960-001-170L005With the following datasheethttps://content.norcomp.net/rohspdfs/Micro-D/960-001-170L005.pdfThe crimper they suggest is about $600 bucks, but I wonder if there's some alternative I might be able to use. Is there any chance there is some crimping hand tool with interchangable dies, with a suitable die? I'm fine with spending $600 or so for a tool and $300 or so for each additional pin type I want to crimp, but $600 is just too much. Is there a cheaper hand tool that requires a bit more finesse that might work, like the ENGINEER PA series?

author: Tomorokoshi
author_rank: Super Contributor
timestamp: November 30, 2021, 12:59:05 am
content: I have the ENGINEER PA-09, PA-20, and PA-21, although I've only needed to use the PA-21. It works okay, just note that the crimping area length is only about 1.5 mm, so you may need to crimp twice. For large pins, the short crimping area can split the wings that fold over. Otherwise it seems to work well. It's well made and doesn't feel loose. I probably did 100 of those large Molex pins and it still works fine.

author: daveismissing
author_rank: Contributor
timestamp: November 30, 2021, 02:25:36 am
content: We found the micro d contacts rather difficult to extract so do be careful

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: November 30, 2021, 05:37:47 am
content: Micro-Ds are quite finicky to crimp right, even with the 'official' crimper. ITT Cannon sells them with 26 AWG teflon insulated pigtails attached. I use those for low-volume/prototype stuff.https://www.digikey.com/en/products/detail/itt-cannon-llc/MDM-9PH003B/2403920

author: Terry Bites
author_rank: Super Contributor
timestamp: December 01, 2021, 09:19:32 pm
content: Dont scrimp on the crimper. Accidentally chopping one of your wires short will cause tears. Ask an aircraft mechanic.It take a bit of getting used to and some practice. Likewse the extractor.That said, the word Burgundy fills me with dread.Always buy ready made cable if you can. Or design your project around ready made cables- if you can.
Cheapest analog way to Vout = exp(Vin) - Page 1
Forum section: electronics / projects

author: king.oslo
author_rank: Frequent Contributor
timestamp: April 01, 2014, 05:34:54 pm
content: Hello there,I have been trying to satisfy:This may also be acceptable:What are my analog options which roughly does what I want? I found something called exponential opamp circuit which does:But I cannot do this because of constrains I cannot easily overcome, I need the correct sign.What are my options?Thank you for your time.Kind regards,Marius

author: IanB
author_rank: Super Contributor
timestamp: April 01, 2014, 05:45:41 pm
content: Probably you can make use of the fact that if:y = exthendy/dx = ex= yTherefore if you set up an op amp in an integrating configuration and make it integrate its output, you will get exponential growth.Most likely you will need suitable gain in the circuit to obtain the right time scaling.

author: robrenz
author_rank: Super Contributor
timestamp: April 01, 2014, 05:50:33 pm
content: Use a second unity gain op amp as an inverter to change the sign of the output or maybe the input.

author: IanB
author_rank: Super Contributor
timestamp: April 01, 2014, 05:50:48 pm
content: Actually, I see this is not quite what you are asking for. If you want a static exponential function of an input voltage, maybe you can make use of the diode characteristic equation in some way?http://en.wikipedia.org/wiki/Diode_modellingThis inherently has an exponential characteristic.

author: tszaboo
author_rank: Super Contributor
timestamp: April 01, 2014, 06:13:54 pm
content: If I remember correctly from the university "useless circuit collection" you have to put a transistor in the feedback of an opamp to get log, and on the non-inverting input for exp.After searching for 5 mins, here is some stuff:http://www.electronics.dit.ie/staff/ypanarin/Lecture%20Notes/DT021-4/6LogAntiLogAmplifiers.pdfI dont expect them to work awesomely.

author: dannyf
author_rank: Super Contributor
timestamp: April 01, 2014, 06:53:48 pm
content: Using a diode + resistor + opamp.

author: king.oslo
author_rank: Frequent Contributor
timestamp: April 01, 2014, 07:10:17 pm
content: Quote from: IanB on April 01, 2014, 05:50:48 pmHello Ian,I attempted that, but I failed. Perhaps you have some suggestions?What I did was to put a diode in series with a current limiting resistor, and then measured the voltage across it as a function of V_IN using a difference amp.As you can imagine, the resulting V_OUT is almost linear as dictated by the resistor. Do you have any suggestions?Thank you for your time.Kind regards,Marius

author: dannyf
author_rank: Super Contributor
timestamp: April 01, 2014, 07:17:15 pm
content: Using a diode (+ opamp) to convert the input voltage to current. Use a resistor to convert that current signal back to output voltage.Use two diodes if you want it to be bi-directional (+ and - voltage).

author: SArepairman
author_rank: Frequent Contributor
timestamp: April 02, 2014, 06:07:36 am
content: what are these kinds of circuits even used for now adays? the only thing I can think of is a voltage controlled gain signal in order to replace a logorithmic pot...
Cheapest store to buy Hakko FX888 today? - Page 1
Forum section: electronics / projects

author: Mint.
author_rank: Frequent Contributor
timestamp: December 18, 2011, 10:57:53 pm
content: Hey guys sorry for another Hakko FX888 topic. I am planning on buying this iron today, however I am not sure which online store or shop to buy it from that is a reputable dealer. Can somebody please point me in the right direction?

author: PeterG
author_rank: Frequent Contributor
timestamp: December 18, 2011, 11:10:37 pm
content: Where in Australia are you?Regards

author: johnboxall
author_rank: Unknown
timestamp: December 18, 2011, 11:11:47 pm
content: Quote from: MintyCondition on December 18, 2011, 10:57:53 pmMektronics are $176 inc but not sure about delivery charge.element-14 are $192 delivered. Order it today and get it tomorrow unless you're in the boondocks.

author: samgab
author_rank: Frequent Contributor
timestamp: December 19, 2011, 12:29:22 am
content: Don't just pay the retail online price. With RS Components and Element14 you can request a quote. Do that, and let them know you want the quote to be the best they can do... Go with the best quote. I did that and got a much better than RRP price from RS Components for the FX888 (and for the Fluke 87V FWIW).

author: Mint.
author_rank: Frequent Contributor
timestamp: December 19, 2011, 12:42:01 am
content: Quote from: samgab on December 19, 2011, 12:29:22 amHey Sam, thanks a lot for the suggestion.

author: EEVblog
author_rank: Unknown
timestamp: December 19, 2011, 01:52:02 am
content: $175 inc with free delivery from Vic:http://www.oritech.com.au/productDetail.aspx?productID=27313Not sure about stock though, I'd ask first.Dave.

author: Teknotronix
author_rank: Regular Contributor
timestamp: December 28, 2011, 02:37:17 am
content: Quote from: EEVblog on December 19, 2011, 01:52:02 amDamn! I bought mine from Oritech just before this free shipping came in. Could have saved $20.On another note, Oritech have a great selection of tips for the fx-888. I got myself a T18-I and T18-D12 with my order, as the FX-888 only comes with a standard conical.

author: joelby
author_rank: Frequent Contributor
timestamp: February 14, 2012, 12:29:07 pm
content: I just got anemail from element14 (Australia)with a buy two, get one free offer for the FX-888. It sounds like the free one is sent to you separately by the distributor, so there's no reason why you couldn't hit them up for a quote. Otherwise, pay 2 * 174.80+10%, which works out to $128.18 inc each, presuming you can find two other people who want one

author: ivan747
author_rank: Super Contributor
timestamp: February 14, 2012, 07:57:03 pm
content: Quote from: Teknotronix on December 28, 2011, 02:37:17 amStrange. My FX-888 came with a chisel tip when I ordered it from TEquipment.net. Maybe they make special orders to Hakko directly.

author: IanB
author_rank: Super Contributor
timestamp: February 14, 2012, 08:05:56 pm
content: Quote from: ivan747 on February 14, 2012, 07:57:03 pmWhen I bought my FX-888 in the US it came with a fine chisel tip. It looks conical from a distance, but has a very small double sided flat on the tip.
Cheapest way of measuring inrush current - Page 1
Forum section: electronics / projects

author: TheAmmoniacal
author_rank: Unknown
timestamp: June 23, 2016, 03:49:21 pm
content: I am interested in measuring the inrush current to a transformer, it's not a measurement I've done before or plan to do again - so won't invest in a clamp meter with that functionality. So can it be done cheaply? With tools I already have? (U1272A DMM and Fluke/Philips PM 97 scopemeter)Would a simple clip-on current transformer like thishttp://www.ebay.com/itm/SCT016-Split-Core-Current-Transformer-Input-0-01-120A-Output-40mA-1-3000-Black-/162103229324work? Hooked up to a the U1272A in min/max mode? Or put an appropriate resistor in series and trigger on the voltage across it with the scopemeter?

author: ebclr
author_rank: Super Contributor
timestamp: June 23, 2016, 04:46:59 pm
content: http://www.ebay.com/itm/30A-range-Current-Sensor-Module-ACS712-Module-Arduino-module-NEW-/281683074851?hash=item41959e9f23:g:W2IAAOSwBLlVSKtj

author: rob77
author_rank: Super Contributor
timestamp: June 23, 2016, 05:10:32 pm
content: just use a regular current transformer (e.g. Talema AC1010) - feed the wire in which you want to measure the inrush though it and terminate the output winding with a 100ohm resistor. then hook a scope across that resistor , set the trigger, hit one-shot and power up the load/transformer whatever. the CT i mention as an example has a ration of 1:1000 so for 10A current through the wire you'll get 10mA in the output winding - yielding 1V across that 100ohm resistor.

author: uncle_bob
author_rank: Unknown
timestamp: June 24, 2016, 12:16:45 am
content: HiIs this an AC transformer?The inrush current will vary a bit depending on where in the AC waveform the "switch" is closed. If you want to do a reasonable job of characterizing a part, the switch may be the most exotic item in the test set.Bob

author: Circlotron
author_rank: Super Contributor
timestamp: June 24, 2016, 01:13:24 am
content: Worst case inrush current to the transformer will be no higher than dictated by the DC resistance of the primary e.g. 120VAC and 2 ohms = 60 amps rms worst case. Depends on where in the AC cycle you switch it on. Zero crossing is worst. I used the word worst too much.
cheapest way of turning on many optocouplers based on a -+ common signal - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 03, 2018, 01:40:13 pm
content: Hi,I know it may sound very simple, I should use a bridge rectifier,but as I have only a common ground to about 1024 LED’s and it can be either positive or negative, since in some systems the common signal is ground or Positive ground, do we have a better way of avoiding 1024 individual diode bridges, see the sample circuit.

author: ajb
author_rank: Super Contributor
timestamp: December 03, 2018, 03:09:36 pm
content: Use AC input optocouplers?

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 03, 2018, 03:19:02 pm
content: Thanks, do you have any part number with similar prices to normal ones?

author: spec
author_rank: Frequent Contributor
timestamp: December 03, 2018, 11:14:57 pm
content: Hi ali_asadzadehYou say that the input voltage can be either positive or negative, depending on the system feeding the LED matrix. At any one time will there be a mixture of positive and negative inputs, or will they all either be positive or all negative- hope that makes senseDoes the LED matrix have any power of its own, or could a small power supply(5V @100mA say) be added- perhaps a battery (neither to power the LEDs).

author: DaJMasta
author_rank: Super Contributor
timestamp: December 03, 2018, 11:16:26 pm
content: I'm also sort of confused about what's going on, you say it's a matrix of LEDs but it's optocouplers? Are you actually sending data with something like a differential input signal, or are you just trying to drive a lot of LEDs?What is the device and what do you want to make it do?

author: spec
author_rank: Frequent Contributor
timestamp: December 04, 2018, 12:48:17 am
content: The way it reads is that they are LEDs inside an optocoupler. For the purpose of answering the OP's question we don't really need to know anymore in that area.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 04, 2018, 07:56:56 am
content: Thanks, we have 1024 optocouplers , so I meant the led inside the optosWe have one common signal and 1024 individual inputs, the inputs should be configured so that they could detect a positive or a negative common signal, because the customer have different sites with different common signal configuration.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: December 05, 2018, 05:46:02 am
content: I have a new Idea! maybe Padauk MCU's come in handy
Cheapest way to do  hi side drive for offline 230VAC buckboost converter ? - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: September 26, 2017, 01:26:47 pm
content: Hello,We are doing a single stage , offline PFC’d 150W buckboost led driver. For the high side drive, we can either do a pulse transformer drive, or just use an ISH1515 isolated power block to give us high side power for a hi side FET driver. –We’ll couple up to it with a digital isolator.Which is cheaper?The ISH1515A costs £5.17ISH1515A isolated power supply, 2Whttp://uk.farnell.com/xp-power/ish1515a/dc-dc-converter-15v-0-133a/dp/2484128

author: ocset
author_rank: Super Contributor
timestamp: September 26, 2017, 08:36:03 pm
content: Please find the schem...plus LTspice simIt is 100VAC to 265VACfsw = 65-75khzConstant off timeToff = 8usI think the ISH1515 could be a mistake since it has 20pF of pri-sec capacitance, which woudl be getting banged up and down as the switching node goes up and down...Do you agree?I think this would be a custom flyback for the gate drive anywayDo you know why such custom hi side supplies for gate drives are so uncommon?... i mean they're common for electric drives at say 10kHz and less...but not SMPS's at 100kHz or so...wonder why they're so rare?

author: strawberry
author_rank: Super Contributor
timestamp: September 27, 2017, 01:52:04 am
content: Yes you can wind low capacitance transformer with IR2153 push-pull or add additional winding to 12V auxiliary SMPS transformer, this solution could be the cheapest and simplestI have added damping capacitors parallel to flyback SMPS MOSFET, about 12pF/1kV and it somewhat gave 1W(don't remember) loss @520Vpk and 120kHz

author: jbb
author_rank: Super Contributor
timestamp: September 27, 2017, 07:01:02 am
content: If you don't need 100% duty cycle on the high side switch (seems unlikely given the AC line voltage zero cross).How about something with a bootstrap driver like theUCC27714? It could drive both switches for you.
Cheapest way to get higher density PCBs - Page 1
Forum section: electronics / projects

author: Unknown
author_rank: Unknown
timestamp: April 20, 2016, 02:57:38 pm
content: NOTE: This message has been deleted by the forum moderator Simon for being against the forum rules and/or at the discretion of the moderator as being in the best interests of the forum community and the nature of the thread.If you believe this to be in error, please contact the moderator involved.An optional additional explanation is:

author: IconicPCB
author_rank: Super Contributor
timestamp: April 20, 2016, 08:01:21 pm
content: You want to play with professional grade components You need professional grade interconnect system ( read PCB).Your other option is to mock up bga chips from lego blocks and use a phenolic single sided PCB.Quality is like oats.Once they have been through a horse they cost a little bit less.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: April 20, 2016, 08:10:03 pm
content: I don't know what's available in China, but in the US OSHPark has 4-layer boards with 5 mil trace/space and 18 mil vias (10 mil drill + 4 mil AR) for $10 per square inch for a set of 3. That should be fine for 0.8mm pitch BGAs, unless you need a bunch of impedance controlled traces, in which case the 4-layer and pre-preg thicknesses start to fight you. I can't imagine you are unable to beat those prices in China.
Cheater Dice - Page 1
Forum section: electronics / projects

author: ludzinc
author_rank: Unknown
timestamp: March 12, 2014, 01:59:32 pm
content: Just some blatant advertising of my latest project:http://ludzinc.blogspot.com.au/2014/03/getting-one-up-on-kids.html#moreIn all seriousness this is a follow up to the PCB offer JAKO made back in Decemberhttps://www.eevblog.com/forum/manufacture/trial-promotion!-free-pcb-fabrication-for-reviewers!/msg337361/#msg337361
check out my electronics load  - Page 1
Forum section: electronics / projects

author: franksterb92
author_rank: Contributor
timestamp: October 09, 2018, 10:02:50 pm
content: heres my load project lol its a dogs breakfast as dave would say. im a sort of newb meaning i have no formal training well long story short i blew up this power supply so i decided to put a load in the shell of said power supply still need some work tho so i can finish my power supply that im attempting to design working with opp amps can be confusing any tips or tricks out there destructive criticism is crucial in " getting better" so have at it

author: MarkF
author_rank: Super Contributor
timestamp: October 10, 2018, 05:13:57 am
content: Do you have a schematic?What power levels are you looking for (i.e. voltage and current)?Here's what I did. Max load voltage = 20V and current = 2.5A.Can be driven by internal potentiometer or 0-5V external signal.The max voltage across R4 = 0.5V. Hence, the max voltage across the sense resistor is 0.5V @ 0.2 Ω which yields a max load current of 2.5A.Edit: Updated circuit
Check out my home-made OLEDs! - Page 1
Forum section: electronics / projects

author: furan
author_rank: Newbie
timestamp: March 02, 2014, 09:34:17 am
content: A while back I decided to undertake making my own OLEDs. I did a writeup here:http://escapehatchlabs.com/blog/?p=155Let me know what you think and if you have any questions!Thanks!

author: cybermaus
author_rank: Frequent Contributor
timestamp: March 02, 2014, 10:09:48 am
content: NICEImage 13: By the looks of the similarity of your hair and the glowing die's. you wore this outfit on your2nd attempt

author: furan
author_rank: Newbie
timestamp: March 02, 2014, 10:11:05 am
content: LOL that's my standard hair right there.

author: plesa
author_rank: Frequent Contributor
timestamp: March 02, 2014, 10:17:02 am
content: Quote from: furan on March 02, 2014, 09:34:17 amNice!! Similar to Ben homemade LCD

author: DmitryL
author_rank: Regular Contributor
timestamp: March 02, 2014, 12:14:14 pm
content: Quote from: furan on March 02, 2014, 09:34:17 amVery nice! What's the role of the Soviet latching relay (RPS-20) in your setup ?

author: furan
author_rank: Newbie
timestamp: March 02, 2014, 12:35:36 pm
content: Thanks. If you mean the box with Cyrillic writing on it, those are some old single-digit LCDs from Russia.

author: furan
author_rank: Newbie
timestamp: March 02, 2014, 12:48:38 pm
content: You may have to scroll down a bit. The theme uses white space.

author: abdullahseba
author_rank: Frequent Contributor
timestamp: March 02, 2014, 04:47:25 pm
content: :-DDvery good

author: marshallh
author_rank: Unknown
timestamp: March 02, 2014, 07:33:31 pm
content: Nice

author: electrolux
author_rank: Regular Contributor
timestamp: March 11, 2014, 10:40:53 am
content: Who supplied you with the necessary materials?
Check out my latest (and pretty much first) project - Page 1
Forum section: electronics / projects

author: shadewind
author_rank: Frequent Contributor
timestamp: May 18, 2011, 05:23:44 pm
content: I asked around a bit on this forum about different things (decoupling, layout, power supply et.c.) regarding this TI Stellaris MCU dev board I was making. I got many helpful answers so I thought I'd share the results. Perhaps it can be useful to anyone else?This is pretty much my first design. It's a little dev board for TI's Stellaris MCUs, specifically the LM3S8933 (some other are compatible too). I've written about it a bit on my blog:http://blog.shadewind.net/?p=16http://blog.shadewind.net/?p=34Being a software guy mainly, there's also a lot of information on the software side of things. Hope it's of any use to anyone else.

author: mobbarley
author_rank: Regular Contributor
timestamp: May 19, 2011, 07:05:34 am
content: Looks good! I've wanted to use the stellaris chips a few times now for their ARM+built in MAC.. just havent taken the leap yet.
Check out this amplifier - Page 1
Forum section: electronics / projects

author: Fungus
author_rank: Super Contributor
timestamp: April 26, 2017, 11:09:46 am
content: I just saw this on eBay and couldn't let it pass:http://www.ebay.com/itm/252838069206How on earth can they sell that but not bother to put a $0.05 knob on the volume control pot? Bunch of cheapskates. And that transformer...?
Check twice when you use Chinese LCDs - Page 1
Forum section: electronics / projects

author: voja
author_rank: Contributor
timestamp: April 26, 2015, 12:27:11 am
content: Yes, I know that I had to RTFM, but who would expect that the new delivery of 2x8 LCDs will have +5 and GND swapped? Well, the type is ALMOST the same (DEM 08202 SYH-LY instead of DEM 082 SYH-LY), and I didn't pay attention, but...I had one more shock when I used the new type of 4x40 LCD in some other project. I simply copied the connector layout from my previous PCB projects, but I didn't notice that +5V and GND were simply swapped - not for backlite, but for logic supply. OK, some cutter and some wires healed the PCB (and the display module survived), but...All those modules use the same controllers, same connectors (with some extra pins added at the bottom) on the same place and the commands are equal, so why would anybody introduce those "creative" modifications?

author: David_AVD
author_rank: Super Contributor
timestamp: April 26, 2015, 01:25:12 am
content: I was almost caught on on this myself a few years ago.It pays to double check the pinout any new (unfamiliar) part.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 26, 2015, 01:47:08 am
content: Only thing worse: when the drawings are so poorly made that you can't tell which way the pins are. Feels like I have to do at least one rev every damn time I integrate one of those things [most often an I80 style parallel bus for a graphical type, not the character kind].Tim

author: amyk
author_rank: Super Contributor
timestamp: April 26, 2015, 08:46:16 am
content: I think it could be for the same reasons you can get slightly-different versions of ICs with reversed pinouts.
Checking drill file is aligned with gerbers  - Page 1
Forum section: electronics / projects

author: AndrewHodgson
author_rank: Contributor
timestamp: February 14, 2020, 01:47:55 pm
content: Hi,I'm a bit new to PCB design, so this might be a silly question, but how do I check that the gerbers are aligned with the drill file? I've been using Viewmate to import the files, and the gerbers align correctly, but the drill file is offset. I've done the same with a PCB I know is correct and the two are still misaligned, so i suspect the files are ok, but i'd like to know for sure. The files both have the spl extension and the drill file is an nc drill file.Thanks in advance

author: voltsandjolts
author_rank: Unknown
timestamp: February 14, 2020, 01:54:56 pm
content: Maybe this can help:http://www.pcbxprt.com/
Checking for Positive and Negative 3 Phase Sequence  - Page 1
Forum section: electronics / projects

author: raddie11
author_rank: Newbie
timestamp: March 08, 2019, 10:32:10 pm
content: Hello I am trying to get a high and low output on pin 11 to switch LEDs to identify both positive and negative phase sequence. I have found a circuit online have simulator using Multisim, however am running into error. Pins 14 and 7 have not been included in the schematic, however, pin 14 is for VDD(12V) and 7 is to ground. The simulation wasnt allowing me to put those to power the NAND gate 4011.

author: duak
author_rank: Super Contributor
timestamp: March 09, 2019, 04:56:44 am
content: This link may explain power supply connections in Multisim:https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000P8j5SACAlso, I would increase the values of the resistors in series with the LEDs. The 100R value is far too low and prevents the 4011 output voltage from rising high enough to cut the transistor off. I would also use a slightly different arrangement, however the exact configuration would depend on the current draw of the LEDs. If a few milliamps, the transistor would not be required at all.Cheers,
Checking my design for a portable cell phone charger - Page 1
Forum section: electronics / projects

author: geniass
author_rank: Newbie
timestamp: November 15, 2014, 11:33:55 am
content: Hi all,So I've been designing a rechargeable portable cell phone charger (or powerbank or something) that uses a lithium-ion battery to charge a phone. Here's the schematic:I got the circuit board made on a milling machine but it's double sided so the homemade vias are not great. Anyway when I connect the battery to the circuit (battery is JP3 in the schematic) LED1 switches on (which is not supposed to happen) and the battery makes a suspicious hissing noise. I haven't left it connected long enough to find out whether it explodes or not.I just want to confirm that my design is correct or if I've made some error.VINA, VIN_USB and JP2 in the schematic belong to this USB power multiplexer:http://www.pololu.com/product/2594/specs.It just switches between USB power from the usb charger and power from the battery.The step up converter to get 5V out of the battery is this:http://www.pololu.com/product/798and the charge controller is a MAX1811. The transistor circuit in the bottom-right corner switches the MAX1811 between high and low charge current.Thanks in advance

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 15, 2014, 08:19:29 pm
content: I don't want to stop your fun, buthttp://www.ebay.com/itm/Luxury-Portable-5600mAh-Battery-Backup-Power-Bank-USB-Charger-External-for-Phone-/301265152780?pt=US_Cell_Phone_PDA_Chargers&var=&hash=item4624cd6b0cIs it really worth the time and effort and resources?

author: geniass
author_rank: Newbie
timestamp: November 15, 2014, 09:22:53 pm
content: I know they exist, but honestly it was just to learn something about designing basic PCBs, and it's basically cost me nothing so far (I can get the components and PCB through my university at low cost). Anyway buying stuff through ebay is risky since our postal service is currently not functional.
chemical flow devices - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: March 22, 2024, 04:56:19 am
content: Has anyone here had any experience with chemical flow devices like batteries that require pumps, i.e. bromine battery flow cell etc?The idea is that there are two pumps that pump reactants together to make electricity or something else. The only other thing I can think of is pumping glowstick chemicals to make light for whatever reason.for instance,https://www.pv-magazine.com/2021/11/15/redox-flow-battery-with-capacity-retention-of-99-98-per-cycle/https://redflow.com/zbm3-batteryJust want to hear stories

author: MarkT
author_rank: Frequent Contributor
timestamp: March 23, 2024, 09:59:59 am
content: I know that large vanadium flow batteries are used commercially:https://en.wikipedia.org/wiki/Vanadium_redox_battery

author: jpanhalt
author_rank: Super Contributor
timestamp: March 23, 2024, 11:10:55 am
content: Quote from: coppercone2 on March 22, 2024, 04:56:19 amThere are countless examples of continuous flow systems to "make something.*" They date way back. Whether light is produced seems irrelevant. Whatever is produced is dependent on design.One 20th century example from the medical field is the Technicon Autoanalyzer. Circulatory systems in animals and plants date from even earlier. It's not new. The Autoanalyzer concept has now pretty much been replaced with discrete sampling in medical labs. Discrete sampling with modern electronics and data management can have advantages.On an industrial scale for a single purpose, continuous flow may have an advantage. Steel is still made in batches.*Just 2 examples:https://en.wikipedia.org/wiki/Flow_chemistryhttps://cbe.osu.edu/sites/default/files/uploads/scriven.pdf

author: coppercone2
author_rank: Super Contributor
timestamp: March 23, 2024, 04:41:47 pm
content: Well I mean along the line of EE not CElights an electricity are EE things. Once you start making materials for industry that's definitely CE. Making something that turns a turbine is ME or Aerospace.

author: jpanhalt
author_rank: Super Contributor
timestamp: March 23, 2024, 05:16:35 pm
content: Does electron transport count as EE? If so, air breathing animals are exquisite examples of electron transport where oxygen is the terminal receptor. Our heart is the pump.EDIT: You might also include electrophoresis where the "pump" is electro-endosmotic flow.https://acikders.ankara.edu.tr/mod/resource/view.php?id=58367#:~:text=When%20a%20high%20voltage%20is,Endo%20Osmotic%20Flow%20(EOF).

author: coppercone2
author_rank: Super Contributor
timestamp: March 24, 2024, 12:42:42 am
content: also possibly chemical lasersI like the idea of a glow stick chemical flow light though.
China feeltech Documentation, user manual, software - Page 1
Forum section: electronics / projects

author: qq354813374
author_rank: Contributor
timestamp: June 23, 2017, 08:56:29 am
content: Official website?en.feeltech.netGoogle Drive Web?https://drive.google.com/open?id=0B3N_NW8vylrmWU93b0EwRjhrQlE
China flange/panel SMA - can someone please measure dimensions? - Page 1
Forum section: electronics / projects

author: Yansi
author_rank: Super Contributor
timestamp: June 01, 2018, 01:47:01 pm
content: Hello,I am trying to design an enclosure for a project, that requires SMA connections. I'd find the flange type SMA connector suitable, however I can not find the dimension anywhere listed.If anyone of you have these, could you please measure the dimensions for me? Especially I am interested in the length of the teflon piece sticking from the flange and then the inner conductor length.Unfortunately these connectors have not arrived yet, so I can't measure them myself.Thank you!Y

author: edpalmer42
author_rank: Super Contributor
timestamp: June 01, 2018, 05:22:39 pm
content: You should wait until you get your connectors. A quick ebay search shows connectors where the length of the white insulator varies from zero to about 3 times longer than the one in your picture.

author: cowana
author_rank: Frequent Contributor
timestamp: June 01, 2018, 06:03:01 pm
content: The dielectric on those connectors is very easy to cut with a knife - I routinely cut down longer connectors (exposing more pin).If in doubt, order connectors that look much longer than needed (they come in virtually any length), and cut them down to whatever you need.

author: Yansi
author_rank: Super Contributor
timestamp: June 01, 2018, 06:26:56 pm
content: Well I am more concerned it will be too short rather then long. The wall thickness of the case is ~4mm, and the PCB has yet some clearance in between the case and itself. so...//EDIT: A quick crude measurement from the photo yields length of the insulatour about 4mm (which is great!) and the rod is about 2.5mm, which should be just enough to reach where it is supposed to.
china silicon chip manufacturing service - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: August 04, 2017, 02:28:52 pm
content: Hi,I was wondering if we have IC manufacturing services in china? do you know some companies? have you done any projects with them?Any ideas are welcome!

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: August 08, 2017, 05:18:20 am
content: So anyone has done it with china?
Chinese bucks - can they be used in series ? - Page 1
Forum section: electronics / projects

author: ez24
author_rank: Super Contributor
timestamp: December 31, 2017, 02:54:34 am
content: HiI am starting with a Dell laptop PS rated at 19v 6.5a and want to end up with : 12v, 9v, 5v, 3.3v, and var PS.To get 3.3v should I go from 19v to 3.3v with one buck or from either the 12,9, or 5v? ie bucks in seriesOr should I try all combinations and look at the ripple?The bucks can do 12v at 3a with no sweat, hardly gets warm. The ratings I want are 12v 3a, 9v 1a, 5v 2a, 3.3 1a. The var is rated at 3a (v?)The things I want minimize are heat loss and ripple.thanks

author: tooki
author_rank: Super Contributor
timestamp: December 31, 2017, 03:26:03 am
content: There’s no point in cascading them; they’re not linear regulators. Just run each buck converter directly off the 19V. (Assuming, of course, that that’s within their rated input range.)

author: ez24
author_rank: Super Contributor
timestamp: December 31, 2017, 05:04:55 am
content: Quote from: blueskull on December 31, 2017, 04:37:56 amHa haFrom a PHd to a DA (dumb ass - going to add this to my profile), this is going to take me awhile to understand. Tomorrow I will get pencil and paper and see if I can figure this out. Thanks for taking your time to help me

author: technix
author_rank: Super Contributor
timestamp: December 31, 2017, 08:29:12 pm
content: It is usually okay to cascade converters, as long as the filtering is adequate.19.5V is out of range for some good buck converter chips (like TPS563201 which I have been using a lot recently, goes only up to 17V but a lot cheaper than the 28V TPS54302.) So in my design I would cascade the 9V/5V/3.3V converters after the 12V one (since I can use the cheaper '563201) but use the higher input voltage converters for 12V (since I have to) and the adjustable (maximizing range.)Or if you can find a multi-phase or multi-output converter. That may likely be the best option.
Chinese dead cheap IC PFM flyback calculations - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: June 19, 2019, 11:36:28 am
content: Hi,I have bought some samples of LP3783, here I would attach it's datasheet PDF, the problem is that their website is some how down and it's in Chinesehttps://www.chip-hope.comI do not know why when I click the English version it would not load!is this their correct website?Also in the data sheet only a few parameters formulas are shown, so my question is how to design the passives including the transformer for this IC, any hints or a general calculator etc... is highly appreciated!
Chinese din 41612 connector manufacturers - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: July 12, 2021, 12:14:58 pm
content: Hi,I want to know if forum members know some Chinese manufactures that would make and sell din 41612 connectors.Thanks

author: Terry Bites
author_rank: Super Contributor
timestamp: July 17, 2021, 06:05:59 pm
content: knock yourself outhttps://www.alibaba.com/trade/search?fsb=y&IndexArea=product_en&CatId=&SearchText=din+41612+connectors
chinese electronic load - Page 1
Forum section: electronics / projects

author: p.larner
author_rank: Frequent Contributor
timestamp: October 24, 2023, 09:37:23 am
content: i got a chineese 150w electronic load kit sent in error,i ended up keeping it,it was ok untill i dumped 400w into it testing a psu,the fets went sc,would replacing them with igbt devices be better than fets?.

author: Vovk_Z
author_rank: Super Contributor
timestamp: October 24, 2023, 02:33:13 pm
content: It depends.

author: CJay
author_rank: Super Contributor
timestamp: October 24, 2023, 06:43:15 pm
content: Hey, is that you M3VUV ?

author: p.larner
author_rank: Frequent Contributor
timestamp: October 24, 2023, 06:57:21 pm
content: who is that?

author: MK14
author_rank: Super Contributor
timestamp: October 24, 2023, 07:00:50 pm
content: Quote from: p.larner on October 24, 2023, 06:57:21 pmQuote from: CJay on October 24, 2023, 06:43:15 pmQuote from: m3vuv on December 15, 2021, 02:10:26 pmQuote from: p.larner on October 19, 2023, 05:44:35 pmQuote from: m3vuv on January 21, 2021, 02:44:39 pm

author: wraper
author_rank: Unknown
timestamp: October 24, 2023, 07:17:53 pm
content: As minimum, using IGBT will render electronic load useless below about 2V. Also IGBT are slow, so feedback loop probably will not work correctly. Not to say their SOA suck in linear mode.

author: EEVblog
author_rank: Unknown
timestamp: October 24, 2023, 11:58:47 pm
content: Quote from: p.larner on October 24, 2023, 06:57:21 pmIt's you.a.k.a TekGuy, TekGuy2, m3vuvGive me a good reason why we shouldn't ban you again?

author: Konkedout
author_rank: Frequent Contributor
timestamp: October 25, 2023, 05:17:00 am
content: Quote from: wraper on October 24, 2023, 07:17:53 pmThat sounds accurate to me. Also....switching MOSFETs do not do well in stressful linear conduction. Individual cells within the FET (or small portions of the FET chip) can go into thermal runaway because threshold voltage goes down as temperature goes up. Safest to use a linear FET; certainly so if those were used in the original. But if it was a cheap design, maybe they did not take care of that.

author: wraper
author_rank: Unknown
timestamp: October 25, 2023, 09:06:07 am
content: Quote from: Konkedout on October 25, 2023, 05:17:00 amBut not nearly as bad as IGBT. Also while MOSFETs usually are not designed for linear operation, some of them are not that bad at it.

author: Siwastaja
author_rank: Super Contributor
timestamp: October 25, 2023, 09:12:35 am
content: Quote from: EEVblog on October 24, 2023, 11:58:47 pmGeez, why do you waste your time playing games like this? Just keep smashing the ban button.

author: Gyro
author_rank: Super Contributor
timestamp: October 25, 2023, 11:53:00 am
content: Quote from: EEVblog on October 24, 2023, 11:58:47 pmDouble posting under different names?https://www.eevblog.com/forum/repair/chineese-150-watt-electronic-load/
Chinese IGBT Supplier/Chinese Electronic Engineer with good english - Page 1
Forum section: electronics / projects

author: marc.hickling
author_rank: Contributor
timestamp: January 16, 2020, 12:22:03 pm
content: Hi i'm having some issues with my IGBT supplier in china, does anyone know of anyone? I want to find someone who speaks good english and understands electronics. I find the people I meet on aliexpress don't know electronics so their testing is much to be desired.ORAnother way of doing this is to find an electronic engineer in china who can speak good english that I can subcontract to find my parts.Anyone got any leads?
chinese iv curve tracer issues - Page 1
Forum section: electronics / projects

author: p.larner
author_rank: Frequent Contributor
timestamp: October 23, 2023, 12:58:03 pm
content: hi,i have one of thesehttps://www.aliexpress.com/item/1005005275876126.html?spm=a2g0o.productlist.main.5.42471040jeE8n7&algo_pvid=245513a5-790c-43de-9670-3045f102c800&algo_exp_id=245513a5-790c-43de-9670-3045f102c800-2&pdp_npi=4%40dis%21GBP%2126.07%2126.07%21%21%21225.50%21%21%40211b61d016980654854223821e87eb%2112000032451722093%21sea%21UK%212308464272%21&curPageLogUid=6DP7CNfeJcdqissue is it seems not to output an ac waveform,ie where a huntron tracker will show a diode junction regardless how ts connected,this will only work connected one way,its lke there is no v- swing on the test leads,is that normal?.
Terminal blocks from WANJIE - Any experience? - Page 1
Forum section: electronics / projects

author: AndersJ
author_rank: Frequent Contributor
timestamp: December 20, 2021, 10:18:48 am
content: Is anyone familiar with the WANJIE brand?I am looking for terminal blocks.Theirs are very similar to the green Phoenix terminal blocks.http://www.china-wj.com/En/product1/id/20.html
Chinese MOSFET logo = International Rectifier ? - Page 1
Forum section: electronics / projects

author: sdancer75
author_rank: Frequent Contributor
timestamp: June 03, 2019, 10:28:40 am
content: Hi,The 1st attached logo is from a Chinese MOSFET IRFZ44N bought from eBay.Could this be the logo of the International Rectifierhttp://www.irf.comestablished in the USA?

author: wraper
author_rank: Unknown
timestamp: June 03, 2019, 10:43:09 am
content: It is IR logo with a bit wrong diode placement and dimensions. I would not bet it's a genuine part.

author: sdancer75
author_rank: Frequent Contributor
timestamp: June 03, 2019, 10:50:10 am
content: I thought so...., but anyway, do you know (testing/experiment/replacement) if these Chinese MOFSETs are reliable?Regards,PS: Since the power supply is output a regulated DC voltage up to 24V, why the manufacturer selected to use a MOSFET with 100V Vds? I want to say it's ok to have a wide margin ahead from the working voltage but 24V to 100V the difference is too big!

author: wraper
author_rank: Unknown
timestamp: June 03, 2019, 10:54:06 am
content: Most of them are unreliable crap with a tiny die inside. Nothing to do with conformity to specs or original part.

author: Daixiwen
author_rank: Frequent Contributor
timestamp: June 03, 2019, 10:59:38 am
content: You could try and measure their RDSon, or have a high current go through them and see how warm they get. Fake parts usually have a higher resistance and therefore get a lot warmer.

author: magic
author_rank: Super Contributor
timestamp: June 03, 2019, 12:42:11 pm
content: If you need reliability buy from serious distributors. If it's for some hobby stuff which is allowed to fail, just put it in and see if it works.

author: Monkeh
author_rank: Super Contributor
timestamp: June 03, 2019, 01:13:02 pm
content: IRFZ44N being an International Rectifier part, it's not exactly a surprise that it bears their logo..

author: Siwastaja
author_rank: Super Contributor
timestamp: June 03, 2019, 02:00:23 pm
content: Standard power MOSFETs out of Ebay are almost guaranteed fakes.Actually, one of the first Ebay fakes I bought was exactly IRFZ44N. I paid the same as for genuine parts. Of course, free shipping was appealing. They worked, but had about four times the Rds(on), so a different MOSFET. I was able to use them in some hobby projects. The same cannot be said about many other Ebay fake semiconductors, which caused a lot of gray hair, such as fixed voltage regulators with any arbitrary printing on top, not reflecting the actual voltage.

author: strawberry
author_rank: Super Contributor
timestamp: June 03, 2019, 03:31:38 pm
content: I bought once on ebay IRF3205S no manufacturer marking on them. holded 10A wery well.But Toshiba ("made in japan")power bjt 15A was fake, half rated voltage , half die size and oscilate as well. Now I bought them from Mouser and I can abuse them as much as I want, no worrieslook up some new released part number on ebey, they all are more expensive than Mouser , digikey... why?
Chinese multimeter with ESR measurement function - Page 1
Forum section: electronics / projects

author: vehf277
author_rank: Contributor
timestamp: December 04, 2012, 11:20:23 am
content: Hi everybody!I found this one on ebay:http://www.ebay.com/itm/Transistor-Tester-Capacitor-ESR-Inductance-Resistor-Meter-NPN-PNP-Mosfet-/181030404166?pt=LH_DefaultDomain_0&hash=item2a2640c046Is it a scam and if not can it be used as in-circuit ESR meter?Thank you in advance.

author: darrylp
author_rank: Regular Contributor
timestamp: December 04, 2012, 03:09:23 pm
content: Resistance measurement from 0.5 ohms, hmm almost every other ESR meter I've seen go much lower. Ie. around 0.01 ohms upwardSent from my HTC One X using Tapatalk 2

author: nikifena
author_rank: Regular Contributor
timestamp: December 04, 2012, 06:09:30 pm
content: Based on how it looks I'm 99% that this is german transistor tester from here:http://www.mikrocontroller.net/articles/AVR_TransistortesterActually this is the new design concept based over this transistor tester:http://www.mikrocontroller.net/articles/AVR-Transistortester

author: Fraser
author_rank: Super Contributor
timestamp: December 04, 2012, 06:17:00 pm
content: No ESR or inductance specification.There is nothing apart from the Sellers title to show it is actually capable of ESR. I am unconvinced as many sellers list lots of key words in an effort to attract customers.Ask the seller specifically about ESR measurement before buying.Fraser

author: vehf277
author_rank: Contributor
timestamp: December 04, 2012, 09:36:39 pm
content: Thank you guys:)

author: Adler
author_rank: Regular Contributor
timestamp: December 06, 2012, 05:50:33 pm
content: This listing seems to confirm.http://www.ebay.com/itm/NEW-TRANSISTOR-TESTER-CAPACITOR-ESR-INDUCTANCE-NPN-PNP-MOSFET-RESISTOR-METER-/160921762374?pt=LH_DefaultDomain_0&hash=item2577af3a46
Chinese PCB manuf. vs TFBGA216 - possible or not? - Page 1
Forum section: electronics / projects

author: Yansi
author_rank: Super Contributor
timestamp: July 04, 2015, 10:26:18 pm
content: Hello,I've just came across interesting problem... Is there any chinese PCB prototyping service, which can deal TFBGA216? The device manual suggests this PCB pattern (see attachment please).Most China PCB houses can't do smaller than 12mil (0.3mm) holes / 24mil (0.61mm) outer dia. But this seems useless for this kind of a BGA beast. With the proposed dimensions, it seems also there is only 5mil clearance between pad and via.Can the pcb pattern be somehow altered to fit the chinese manufacturers? What do you suggest? Do you have any experience with these packages and china pcb houses?Thanx,Y

author: marshallh
author_rank: Unknown
timestamp: July 04, 2015, 11:00:53 pm
content: You need 10mil dirll/18mil overall to do 0.8mm bga.I can point you to a korean proto fab where you can get a few made for about $200. Or you can order just 3 at oshpark.

author: Yansi
author_rank: Super Contributor
timestamp: July 05, 2015, 12:04:04 am
content: OSH park allows 10/18 (0.254/0.46) vias. That should do it. Thanks for the tip. The price isn't the lowest, but at least we have small vias to do the job.