hybridfree/eevblog-posts huggingface dataset:
VDMOSFET 700W Push Pull Amplifier Design Questions - Page 1
Forum section: electronics / projects

author: Plasmateur
author_rank: Regular Contributor
timestamp: April 04, 2021, 07:14:16 pm
content: Hello, I am currently building broadband amplifier based on this design foundhere.Which uses 2 of theVRF2944VDMOSFET.Question #1 - I believe I need to use a matched pair for this push pull amplifier, is this correct to assume?Looking at the spec sheet I see it has 0.22 C/W junction to case thermal resistance.The best calculator I could find online to size the correct sink-ambient resistance ishere. I am using example #2, however I'm using the following valuesAmbient Temp - 22C (I am pulling air from outside my enclosure)Power - 700WJunction to Case Thermal Resistance - 0.11 C/W (I am halving this because 2 amplifiers are being used)Case to Sink Resistance - I do not know what to put here, but based on the example I am assuming it is relatively close to the Junction to Case Thermal ResistanceSink to Ambient - I calculated this value using another calculator, My value is 0.074 C/WThisis the heat sink calculator I used for the sink to ambient resistance.Question #2 & 3 - should I assume case to sink resistance is close to junction to case resistance, and should I half junction to case resistance because I'm using two amplifiers?Thank you
+ve reg sub - Page 1
Forum section: electronics / projects

author: p.larner
author_rank: Frequent Contributor
timestamp: October 11, 2023, 10:21:18 pm
content: can an lm7805 replace a AMS117-5v regulator,as long i can make it fit?.

author: TimFox
author_rank: Super Contributor
timestamp: October 11, 2023, 10:29:33 pm
content: Quote from: p.larner on October 11, 2023, 10:21:18 pmThe datasheet for the AMS117-5 indicates a maximum input voltage of 15 V.A 7805 can take 25 V.Different packages for the 7805 have different power ratings.Also, the drop-out voltage (minimum difference) for the 7805 is greater than the AMS117 series.What are your input voltage and output current requirements?Specifying a semiconductor isalwaysa quantitative problem.

author: langwadt
author_rank: Super Contributor
timestamp: October 11, 2023, 10:33:15 pm
content: Quote from: p.larner on October 11, 2023, 10:21:18 pmas long as the input voltage is more that ~7V probably

author: p.larner
author_rank: Frequent Contributor
timestamp: October 11, 2023, 10:42:04 pm
content: its to power a bt modual from an antenna analyser kithttp://www.foxdelta.com/projects/aaz-0914a.htm

author: TimFox
author_rank: Super Contributor
timestamp: October 11, 2023, 10:59:56 pm
content: Repeat:What are your input voltage and output current requirements?

author: amyk
author_rank: Super Contributor
timestamp: October 12, 2023, 02:35:47 am
content: I assume you're referring to the common 1117 series LDO, which since the schematic there specifies a 6-12V input, can't be replaced with a 7805 unless you revise that range to 7-12V since the latter has almost twice the dropout voltage.
VEC2315 P-FET Spice model - Page 1
Forum section: electronics / projects

author: veryevil
author_rank: Unknown
timestamp: October 21, 2018, 03:28:11 pm
content: Hi, having issues with the ON Semi VEC2315 dual fet spice model. I've added it to LTSpice and it runs and doesn't error but it seems to be hugely current limited.Made up a quick high side switch circuit into a 100 ohm resistor and 36v in but only a couple of mv when gate pulled low.Any help?Product page:http://www.onsemi.com/PowerSolutions/product.do?id=VEC2315Thanks

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 21, 2018, 04:04:05 pm
content: Look at the file -- you need to add these to the component statement:Code:* W = 1118585 E-6 m* L = 1.0 E-6 m* AD = 1118585 E-12 m2* RG = 3 ohm* RB = 0.019 ohmThat is, when you put in a .MODEL, you're just inputting process parameters. The instance of a component can be any size. A packaged component, of course, has fixed geometry, so it needs to know that.The default is 2u width and length, so actual width being a million times more kind of makes a difference, and yeah, that's why you got a microampere current sink.I forget if that's part of the component dialog in LTSpice, or if you need to put everything inside, say, a SUBCKT to encapsulate it.Tim

author: veryevil
author_rank: Unknown
timestamp: October 21, 2018, 04:13:31 pm
content: Thanks I didn't understand those values at all. Looks like I need to use the pmos4 part which allows all those to be specified.Thanks.

author: Wimberleytech
author_rank: Super Contributor
timestamp: October 21, 2018, 06:47:32 pm
content: Here is how I implement MOS models in LTSPICE.First, I create a file named models.txt and in that file, I put all of the models of interest to me. As an example, this model is instantiated in the models.txt file:.MODEL CMOSN NMOS LEVEL=3 PHI=0.700000 TOX=1.7600E-08 XJ=0.200000U TPG=1+ VTO=0.7657 DELTA=8.4040E-01 LD=9.0910E-10 KP=1.1805E-04+ UO=601.7 THETA=1.3140E-01 RSH=1.3840E+01 GAMMA=0.6434+ NSUB=4.8010E+16 NFS=5.9090E+11 VMAX=1.8680E+05 ETA=3.2550E-02+ KAPPA=1.3520E-01 CGDO=2.9000E-10 CGSO=2.9000E-10+ CGBO=3.9074E-10 CJ=2.94E-04 MJ=0.950 CJSW=6.05E-10+ MJSW=0.332 PB=0.56Place this file in the same place where your simulation file is stored.Inside LTSPICE environmentInsert the SPICE directive: .include model.txtAdd component and choose either nmos, pmos, nmos4, or pmos4.Drop this into the schematic.Then CTRL-rightClick on the component.On the "Value" line, enter the model name:CMOSN W=360U L=10UI suspect there may be other ways to accomplish the same goal.edit--LTSPICE syntax for instantiating a MOSFET:Syntax: Mxxx Nd Ng Ns Nb <model> [m=<value>] [L=<len>]+ [W=<width>] [AD=<area>] [AS=<area>]+ [PD=<perim>] [PS=<perim>] [NRD=<value>]+ [NRS=<value>]  [IC=<Vds, Vgs, Vbs>]+ [temp=<T>]You will need to add RG and RB to the model itself.
Vector graphics to Gerber - Page 1
Forum section: electronics / projects

author: ubbut
author_rank: Regular Contributor
timestamp: February 02, 2020, 11:01:13 am
content: I know there is at least one other - but old - thread about this topic. However despite quite a bit of research and trying several things I have not been able to find a good workflow.I want to convert vector graphics (format does not matter) into gerber files. I tried several tools but none proved to be reliably working so far. I wonder if there is a proven working method?I tried:Cenon(which could not even open my SVG files properly)pdf2gerb(but it does not support curves)PCBmodEcertainly looks promising, but seems to be overkill for just converting svg to gerber (or is there an option to do just that?)Circuit Studio image import (rasterized and with very low resolution)Circuit Studio DXF import (fails on complex shapes)Converting Artwork into a font and using it with CircuitStudio. This is the best I have so far but also fails on complex shapes or large artworks. (and correct scaling is painful)I have not yet tried:https://github.com/jaseg/gerbolyze(Looks very good, but does raster, not vector)Update:Tried this and it seems to work well! Needs Inkscape + Kicad but can work with complex shapes without issues:https://github.com/badgeek/svg2shenzhen(Inkscape Plugin, exports KiCad)Looking forward to your recommendations! Thanks!

author: mk_
author_rank: Regular Contributor
timestamp: February 02, 2020, 11:14:24 am
content: Quote from: ubbut on February 02, 2020, 11:01:13 amI usually try to convert (export) to DXF, check this DXF with an older version of AutoCad, import that DXF to a Gerberviewer (also very old Camtastic), scale and export it as gerber. Scaling is sometimes difficult, I normaly don`t catch it in the first run. Needs some time but works for company-logos and other customer-related stuff.

author: moffy
author_rank: Super Contributor
timestamp: February 02, 2020, 11:46:09 am
content: Have a look at:http://lasergrbl.com. It has internal graphics to gerber conversion.
Vectron 64 - Custom 6502 Computer - Page 1
Forum section: electronics / projects

author: nickbild
author_rank: Contributor
timestamp: April 26, 2019, 12:44:47 pm
content: I've built a custom 6502-based computer that anyone could replicate. Get the parts listed in the bill of materials, open the Fritzing diagram, start plugging in and wiring chips, and you can have your own Vectron 64 in a weekend!https://github.com/nickbild/vectron_64
Vectron C4550A1-0213 Reference Voltage - Page 1
Forum section: electronics / projects

author: monz
author_rank: Contributor
timestamp: February 25, 2025, 05:35:09 am
content: I used a Vectron C4550A1-0213 OCXO a while back and it provides a stable ~4V output to use as a reference for setting the frequency. This can be used along with a multiturn potentiometer to set the voltage that controls the frequency.Based on this, I ordered another project from ebay (actually 2). This time both do not provide the 4v. They output nothing on the reference pin.For my design I was planning on using it, for now I'm getting it from a 5v regulator that only powers the OCXO and and a couple logic gates. It works well and seems stable, but the built-in reference should be much more stable.The datasheet doesn't seem to imply this is always present. Maybe these were specially ordered without it despite the part number not changing? It seems like it's not connected - nothing measuring resistance or diode mode.Any ideas? These are pretty common it seems and readily alliable so hopefully someone has some info.This was encountered a a while by by someone here as wellhttps://www.eevblog.com/forum/testgear/updating-agilent-counter-53220a-to-option-010-ultra-high-stability-ocxo-timebase/msg4645651/?topicseen#msg4645651
Vectron VR - 6502 Virtual Reality - Page 1
Forum section: electronics / projects

author: nickbild
author_rank: Contributor
timestamp: June 14, 2019, 05:31:42 pm
content: Hello,I have built a virtual reality headset for an 8-bit 6502 computer.Previously, I built a 6502-based breadboard computer:https://hackaday.com/2019/04/19/a-nearly-practical-6502-breadboard-computer/Now I've created a virtual reality peripheral for that computer, called Vectron VR:https://github.com/nickbild/vectron_vrTo demonstrate the system, I've developed the 3D game "Asteroids VR". Put the headset on and you'll be sitting in the 3D cockpit of a spaceship blasting away at asteroids that appear to be floating towards you.I've got pictures, video, circuit diagrams, a bill of materials, and lots of descriptive text on my github page (https://github.com/nickbild/vectron_vr). My Vectron 64 computer (https://github.com/nickbild/vectron_64) is similarly documented, so it's possible for others to build their own complete system.I hope you like it!Nick

author: ebastler
author_rank: Super Contributor
timestamp: June 14, 2019, 06:39:05 pm
content: Wow!! That is impressive. (And only mildly crazy to build it all on breadboards.)How stable is the breadboard build (electrically, mechanically, and over time?) It seems that you have kept the computer gooing for a while already -- did it give you much trouble? And would you have any plans to convert this to a "regular" schematic and PCB layout?

author: nickbild
author_rank: Contributor
timestamp: June 14, 2019, 06:50:02 pm
content: It gave me plenty of trouble during the development/debugging phase, but that was just from the complexity and mistakes on my part. It's running rock solid, and signals look nice and clean on the logic analyzer.As for mechanical stability, well, it just sits on my desk, so there are no problems. I'd be concerned with moving it much more than across the room though.I'm not currently planning on making any "regular" schematics since this is a hobby, and that wouldn't be much fun for me. If there were a lot of interest I might be persuaded to do it.Thanks for the interest!
Velleman K8200 assembly tips - Page 1
Forum section: electronics / projects

author: Unknown
author_rank: Unknown
timestamp: January 02, 2014, 10:55:26 pm
content: Hi all,I'd like to share with you my thoughts I came across when I was assembling the printer.Please check my post here:http://ljwinkler.blogspot.ie/2014/01/velleman-k8200-assembly-tips.htmlI hope it will be useful.I'm more than happy to answer all your questions!
Velodyne CHT-12 service manual and/or help - Page 1
Forum section: electronics / projects

author: Nickthevoice
author_rank: Newbie
timestamp: December 12, 2024, 12:18:55 am
content: Hi !I Search for service manual of velodyne CHT-12 subwooferorIf Anybody have I tips about this trouble I have normal sound un the subwoofer for 2 secondes after that nothing ans no big humm noise when I short the input.

author: thm_w
author_rank: Super Contributor
timestamp: December 12, 2024, 01:17:01 am
content: Did you measure voltages/ripple?Check for blown/bad caps?Is servo coil ok? (I think it has onehttps://www.rythmikaudio.com/technology.html)I don't know if this is relevant:https://www.diyaudio.com/community/threads/velodyne-cht-headache.407493/https://elektrotanya.com/velodyne_cht-8_cht-10_sch.pdf/download.html

author: Nickthevoice
author_rank: Newbie
timestamp: December 12, 2024, 02:28:37 am
content: Thank you !
Vending Machine Simulator Board/Kit - Page 1
Forum section: electronics / projects

author: palpurul
author_rank: Regular Contributor
timestamp: May 04, 2021, 08:26:07 am
content: Hello a potential customer approached about his vending machine buisness. He basically wants me to develop a bluetooth module to his vending machines.The problem is it would be very difficult to develop a module for the vending machine if I don't have anything in my to lab to work on. Obviously, I can't carry a vending machine to my lab, and therefore I am looking for something that would simulate/mimic the controller board to see if the module that I developed is working or not. Can anyone suggest me a board/kit that can replace VMC (vendin machine controller) to save me from carrying a vending machine to the lab floor?I've found Qibixx on the internet, a company from Switzerland. If anyone had a similar experience in this field please let me know if there is any other company that I should aware of.Thanks in advance.

author: MDBSolution
author_rank: Newbie
timestamp: May 31, 2021, 09:44:45 pm
content: Hi. I design and build MDB VMC and device simulators, emulators and data logger. I've attached a few photos of my latest creations. The VMC Master is just that. It acts like a vending machine and will enable Changer, Validator and Cashless. I've also attached another of my later devices the Cashless Adapter. It will work with MDB Vending machine controllers that are not cashless compatible allowing you to add Cashless to these type of controllers. You can reach me at info@mdbtools.com if you are interested. I also have a bluetooth cashless device that will allow cashless payments via bluetooth communications.

author: JimmyMacRod
author_rank: Newbie
timestamp: September 19, 2021, 02:50:16 pm
content: Hi!I have been searching for an MDB-USB adapter to connect Bill and Coin Acceptors to a computer and found this post. Do you have or know about such item I'm asking about?Regards!
Vending machines - Page 1
Forum section: electronics / projects

author: David_AVD
author_rank: Super Contributor
timestamp: October 17, 2012, 07:27:36 am
content: Has anyone here had anything to do with vending machine hardware interfacing? Same for browser based implementations of auditing and control?A potential client has asked about remote access (coin count, free games, etc) for some non-standard game machines he has.I found a few protocols (ccTalk, MDB - ICP, etc) on the 'net. I'm thinking it would be better to utilise something existing rather than re-invent every part of the wheel.

author: JVR
author_rank: Regular Contributor
timestamp: October 17, 2012, 10:13:42 am
content: Does he want to remotely log in to the machines to see stock/money levels?Where are the machines situated? Is there usable IP infrastructure, or would you need to establish the link as well?

author: David_AVD
author_rank: Super Contributor
timestamp: October 17, 2012, 11:09:37 am
content: There will be an internet connection (either wired or wi-fi) in each venue.The machines to be monitored are battery powered (no wiring access at all) so the current draw from any additional electronics must be minimal. So.... I was thinking of a low power transceiver in each machine so it can be polled once in a while to get the latest statistics.A central unit could collate the data from each machine and present it as web pages. Now, all of this could use a custom protocol but maybe there would be an advantage in using an existing one.

author: deephaven
author_rank: Frequent Contributor
timestamp: October 17, 2012, 12:08:38 pm
content: Quote from: David_AVD on October 17, 2012, 11:09:37 amThis from Linear just fell into my in boxhttp://www.linear.com/product/LTP5900-WHMMight do what you need.

author: David_AVD
author_rank: Super Contributor
timestamp: October 17, 2012, 12:30:35 pm
content: That looks pretty cool.

author: JVR
author_rank: Regular Contributor
timestamp: October 17, 2012, 12:52:02 pm
content: Yeah, if you don't have wiring access Ethernet into the device is a no-go.Have a look at one of the RF+Micro packages maybe. Have that wake up every hour or so and report its numbers, then get the network master to do the TCP/IP link into the server.
Vendors for decent cheap class X & Y capacitors? - Page 1
Forum section: electronics / projects

author: cvanc
author_rank: Frequent Contributor
timestamp: February 02, 2019, 02:54:53 pm
content: Hi all-Want to replace very old ceramics at the AC power input. What brands are worth looking at?I'm not sure I'm searching correctly; Digi-Key seems to have almost none on offer, which just can't be right...Thanks.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 02, 2019, 04:17:37 pm
content: What are you searching for?Offhand there's ballpark ten thousand to choose from.Tim

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: February 02, 2019, 04:43:25 pm
content: Mouser seems to have many more. FWIW, when buying a safety capacitor, price wouldn't be my first parameter to look at.

author: cvanc
author_rank: Frequent Contributor
timestamp: February 02, 2019, 05:56:02 pm
content: Quote from: Conrad Hoffman on February 02, 2019, 04:43:25 pmAbsolutely.In further searching I found the Kemet C900 which looks good to me. Still, I'm curious what the go-to brands are for this part. Thank you.https://www.digikey.com/products/en/capacitors/ceramic-capacitors/60?k=&pkeyword=&sv=0&sf=0&FV=fffc018f%2Cffe0003c%2Cffec8a3a&quantity=&ColumnSort=0&page=1&stock=1&pageSize=100

author: TimNJ
author_rank: Super Contributor
timestamp: February 03, 2019, 08:48:19 pm
content: The safety-rated (line rated) caps are sometimes obscurely listed on Mouser and Digikey. On Mouser, they are not listed under Ceramic or Film Caps, rather under Safety Capshttps://www.mouser.com/Passive-Components/Capacitors/Safety-Capacitors/_/N-fb8xl?P=1ywpos4https://www.mouser.com/Passive-Components/Capacitors/Safety-Capacitors/_/N-fb8xl?P=1ywtgly
Verical - is it a reliable component source? - Page 1
Forum section: electronics / projects

author: tatus1969
author_rank: Super Contributor
timestamp: January 21, 2018, 06:27:32 pm
content: It is abouthttps://www.verical.com. The website states "An Arrow Company", so I dared to make a test buy from them. I ordered some ST SPBT3.0DP2 bluetooth modules, as these are currently difficulty to source. What I received was mostly scrap. The good thing about them is that they made a full refund after my complaint.I am a bit concerned now. On the one hand they have good prices, on the other hand I don't want to risk buying bad parts, or even fakes. Anyone having some experience with them?

author: ataradov
author_rank: Super Contributor
timestamp: January 22, 2018, 03:58:41 am
content: They are legit, but I believe they are supposed to sell leftover parts from production runs. Like if manufacturer minimum order is 5000 pcs to get a certain price break, but project requires 3k, those extra 2k parts go on vertical.What's do you mean by scrap? Like desoldered? That should not happen.
Verifying a controller memory map - Page 1
Forum section: electronics / projects

author: metertech58761
author_rank: Frequent Contributor
timestamp: March 14, 2025, 06:53:07 am
content: So, I'm getting ready to wind down a documentation project after tracking down most of the boards for a semiconductor wafer processing system I used to service years ago.One of the remaining loose ends is working out the memory map of the main controller in order to properly analyze the code dumped from the EPROM on the CPU board.If this was based on the 6800 family of MPUs (or even the trusty 6502), I would be able to pick out the addresses in the code, but this particular controller uses a pair of 8085s, and I still haven't had the time to get my mind around the intricacies of Intel assembly code.What does the IO/_M line (and its reciprocal, _IO/M) do?Anyway, here are the schematics I've worked out - and I just want to confirm my understanding of the address for each of these boards (upper 8 address lines only):These three boards all have the address hard-wired:290014 (Display): 1111 111x (FE)290055 (Comm): 1100 000x (C0)290077 (8253 timer): 1111 10xx (F8)290077 (RAM): 1110 0xxx (E0)These two, however, have the address selectable via DIP switch:290017 (I/O): 0000 00xx (00)But doesn't that conflict with the ROM space at 0000-3FFF?290020 (I/F): 1010 00xx (50)I've also attached the 'source dump' if it helps...

author: moffy
author_rank: Super Contributor
timestamp: March 14, 2025, 09:02:07 am
content: "These two, however, have the address selectable via DIP switch:290017 (I/O): 0000 00xx (00)But doesn't that conflict with the ROM space at 0000-3FFF?290020 (I/F): 1010 00xx (50)"The 8085 can have seperate 16 bit memory and adress spaces, the IO/M signal, hence the aparent overlap:https://www.tutorialspoint.com/memory-mapped-i-o-in-8085-microprocessor
Verifying ceramic capacitor voltage rating - Page 1
Forum section: electronics / projects

author: StefanHamminga
author_rank: Contributor
timestamp: January 25, 2019, 01:16:01 pm
content: So I bought some 100uF / 100V (supposedly) 5750 20% X5R capacitors from AliExpress. I normally buy my parts from Mouser, Digikey, etc, but I couldn't resist buying a few knowing the specs sound too good to be true. The item can still be found for sale here:https://www.aliexpress.com/item/5pcs-SMD-capacitor-2220-100UF-100V-107M-5750-20-X5R/32636203607.htmlSurprisingly the capacitance of the first few are in the 85-90 uF range, so not much wrong there. I'd love to find some indication of the voltage rating (and if possible other specs), preferably without any plucking of ceramic shards from my forehead. Any way to verify the voltage rating non-destructively?

author: OwO
author_rank: Super Contributor
timestamp: January 25, 2019, 01:26:29 pm
content: Quote from: StefanHamminga on January 25, 2019, 01:16:01 pmProbably not, but a simple breakdown voltage test should tell you if the rating is in the right ballpark. I'd expect breakdown voltage to be at least 20% higher than rating.

author: GreggD
author_rank: Regular Contributor
timestamp: January 25, 2019, 01:59:27 pm
content: Cap makers say they test to 2X the rated voltage but won't say just how they test them.Yes I too would like to know proper test for voltage.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 25, 2019, 02:21:17 pm
content: Just pull it up with a resistor, say 100k. Measure leakage current. Consider this a destructive test; if leakage increases suddenly and massively, throw it away.Bigger priority: measure capacitance under bias. Connect two in series, and bias the "center tap" with a large value resistor. Measure capacitance of the series pair. The point where C drops by, say, 30%, is a practical cutoff point for use.This tests saturation voltage. Capacitors are never rated in this way, despite it being fundamental to operation; you have to dig through the datasheet or mfg website to find this data, if they have it at all. Or buy some and characterize yourself.FYI, very large ceramics (over 1210 / 3225 size) are discouraged for reliability reasons: more likelihood of cracking under thermal and flex stress. (If you aren't doing anything horrendously expensive, or freakishly important, don't worry about it.)Tim

author: wraper
author_rank: Unknown
timestamp: January 25, 2019, 02:33:31 pm
content: You won't be able to get the actual voltage they were rated for with good confidence when measuring their breakdown. Ceramic capacitors often survive over 10 times of rated voltage. However you could measure capacitance under bias voltage. Type 2/3 ceramic capacitors drop a lot of their capacitance under voltage. Some of the worst ones (high capacitance and rated voltage for it's size) have less than 20% under rated voltage. So I'd say when around 25-30 % of capacitance is left, it likely would be somewhere around it's rated voltage.
Verifying that AP33772S I2C is 3.3V pull-up compatible? - Page 1
Forum section: electronics / projects

author: i509VCB
author_rank: Contributor
timestamp: March 30, 2025, 06:07:28 am
content: Hi, I am using a AP33772S with an i.MXRT1011.I believe that the I2C lines being open drain means I can just pull up to 3.3V. Since SCL and SDA are open drain, and the VI2C_HI minimum threshold is 1.4V for high. The threshold levels appear to be compatible with the i.MXRT1011 assuming 3.3V pull ups would work.The public reference besides the EVB (which does 5V pull-up) is the PicoPD Pro. The PicoPD Pro for some reason puts the I2C behind a level shifter. I can certainly see being conservative as a reason. However this appears unnecessary since open drain pins don't actually drive any voltage.https://github.com/CentyLab/PicoPD_Pro/blob/main/Hardware/PicoPD%20Pro%20Schematic.pdfThe INT pin is clearly 5V drive per the datasheet, so behind a divider it goes.In the vendor's infinite wisdom there is a user guide using the EVB with a Raspberry Pi 5. The I2C pins on the EVB are pulled up to 5V. I'm not sure if anything changed with the Pi 5, but the GPIO is not 5V tolerant on any Pi SBC boards from what I know.
vert. Card Guide - Page 1
Forum section: electronics / projects

author: richcj10
author_rank: Unknown
timestamp: October 05, 2014, 04:13:13 am
content: I am looking into using these.http://octopart.com/8647-keystone-29507450A lot of theses (from different companies) don't tell you how heep the well is for the PCB's. Is there a standard?Also, does anyone know what the cutout is for the retaining pins?Thanks

author: kizzap
author_rank: Unknown
timestamp: October 05, 2014, 08:32:34 am
content: took a bit to find it, but it is clearly there. The slot is 3mm deep, suitable for up to 1.8mm thick PCB.see this:http://datasheet.octopart.com/8647-Keystone-datasheet-15716776.pdf

author: richcj10
author_rank: Unknown
timestamp: October 05, 2014, 12:57:31 pm
content: Thank you so much! This is what I was looking for!
Vertical mount micro or nano SIM card socket - Page 1
Forum section: electronics / projects

author: DTJ
author_rank: Super Contributor
timestamp: April 25, 2018, 05:20:06 am
content: I'm looking for a vertical mounting micro or nano SIM card socket where the socket sits perpendicular to the PCB.I've looked on Mouser/Digikey/RS/Element14 and can't see one.Do they exist?Cheers.

author: mikerj
author_rank: Super Contributor
timestamp: April 25, 2018, 04:04:13 pm
content: I've never seen one, and I'm not too surprised; they are very thin compared to height and width so vertical mounting would be fragile. Could you mount a standard socket on a vertically mounted PCB daughter board?

author: DTJ
author_rank: Super Contributor
timestamp: April 26, 2018, 01:14:29 am
content: Quote from: mikerj on April 25, 2018, 04:04:13 pmI figured there would be low demand for one. The daughter board is one option. Thanks.

author: Gribo
author_rank: Frequent Contributor
timestamp: April 26, 2018, 01:06:20 pm
content: There are nano/micro SIM socket on flex PCB on Ebay/Alibaba.

author: DTJ
author_rank: Super Contributor
timestamp: April 27, 2018, 12:50:16 am
content: Thanks Gribo, I will take a look.
vertical  right angle slider switch array - Page 1
Forum section: electronics / projects

author: stern0m1
author_rank: Contributor
timestamp: June 24, 2018, 03:42:17 am
content: Hi,Im looking for a switch like this, but an array of 4. 1 piece with 4 switchesVertical right angle slider.Anyone come across something?Thanks

author: ebastler
author_rank: Super Contributor
timestamp: June 24, 2018, 07:13:48 am
content: Does it have to beDPSTSPDT? If a simple on/off switch is sufficient, angled DIP switches are widely available. (But may also be a bit smaller than what you had in mind?)Edit: Fixed the mixed-up switch designation...

author: stern0m1
author_rank: Contributor
timestamp: June 24, 2018, 04:09:09 pm
content: I need an on on switch. A switch with two positions each position connects 1 pin to a different one.Thanks

author: rdl
author_rank: Super Contributor
timestamp: June 24, 2018, 04:23:23 pm
content: Switches like the one in the picture exist and should be easy to find, but an array of four may be impossible to find outside of custom made. What do you expect to gain with an array vs. four single switches side by side?

author: stern0m1
author_rank: Contributor
timestamp: June 24, 2018, 04:35:22 pm
content: Price. The cheapest I found for a single switch was 65 cents us. The only switch I found at all this style was fromhttp://www.dailywell.com.tw/If you know of others please tell me.Thanks

author: rdl
author_rank: Super Contributor
timestamp: June 26, 2018, 10:05:21 am
content: Apparently those vertical style switches are pretty expensive, $3-$4. You might consider using the cheaper type and mounting them on a small piece of pcb attached vertically to the main pcb. I have seen this done in commercial products with 7 segment displays.Some ideas maybe here:https://www.eevblog.com/forum/projects/mount-pcbs-together-in-a-90-angle/
Very "Artesanal" LM399 Voltage Reference with Temp control - Page 1
Forum section: electronics / projects

author: dmmguy
author_rank: Contributor
timestamp: January 25, 2022, 01:00:42 am
content: Hi folks,Just want to share some pics of my crazy project, I would like to control the temperature around 35 Celsius inside the "oven". I am using just a heatsink with a couple of nichrome resistors... let's see hoe it goes
very bright LED JT but 0.4Amp taken from AA  - Page 1
Forum section: electronics / projects

author: dave_j_fan
author_rank: Regular Contributor
timestamp: March 21, 2017, 05:32:37 pm
content: THE Joule thief circuit i have made to give decent ligthtBut AMP draw is 0.400- 0.500Amp ...can we tweak to bring much lower , have seen many video where amp draw is lessany mistake i did herei use a 33uH choke as collectr side coil4turns on coil body as coil series to base resistorThe batt is AA NIMH 1 cell

author: Audioguru
author_rank: Super Contributor
timestamp: March 22, 2017, 01:40:48 am
content: How many ohms is 1.1E? If it is only 1.1 ohms then why not say 1.1 ohms instead? Then the battery is being shorted by the extremely low resistance in series with the base of the transistor.Joule Thief circuits use at least 1k which is one thousand ohms.Your transformer might be very inefficient and might not work with resistance in series with the base of the transistor..

author: dave_j_fan
author_rank: Regular Contributor
timestamp: March 30, 2017, 05:06:49 pm
content: thank u for the reply , yes that trafo is not that efficientswitched to toroid 1/4th current it is taking but not very brigth what to doi gave 5turns for coil to base and 20 for collectr

author: Audioguru
author_rank: Super Contributor
timestamp: March 30, 2017, 06:08:22 pm
content: The Joule Thief Projects and videos shown on Google show a transformer with many more turns than you have, yours is like a dead short.A Joule Thief circuit is supposed to operate from a battery cell that is almost dead then the current and brightness are very low. Maybe your LED needs a high current. Some LEDs are designed to be fairly bright when fed a low current.

author: Zero999
author_rank: Super Contributor
timestamp: March 30, 2017, 07:17:24 pm
content: Quote from: Audioguru on March 22, 2017, 01:40:48 amWhich is fine for a tiny 5mm LED but won't provide enough base drive for a Joule thief powering a high powered LED. I agree 1 Ohm does sound too low, even for a high power application.

author: dave_j_fan
author_rank: Regular Contributor
timestamp: May 14, 2017, 04:45:35 pm
content: yes , itz a little high current one ... thinking to go icbased solution
very complex ECD Corp 20930 C-Meter capacitance 1976 test teardown - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: August 07, 2022, 02:02:39 am
content: Here is the video :see how much electronics is needed to make this the good old NO MICROCONTROLLER way :https://youtu.be/nA5jsa_yBlk
very dangerous diy powersupply unit - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: December 16, 2022, 09:35:44 am
content: this is an amazing diy construction,I had the idea i have seen it all when it come to potential dangerous ..see here, what do you think is going to happenhttps://youtu.be/qIyc_DD2odUI dont know who designed it, or when, I got it some months ago from a local swap meet

author: bidrohini
author_rank: Regular Contributor
timestamp: December 16, 2022, 10:12:42 am
content: How did it perform in real life?

author: coromonadalix
author_rank: Super Contributor
timestamp: December 16, 2022, 11:03:07 am
content: Words like Amazing and Beautiful ...... sorry notDIY yesBUT mmmmmmm notToo cramped, and very very basic regulation ...Basic practicality
Very long lead times on a lot of products on Digikey - Page 1
Forum section: electronics / projects

author: Fusion916
author_rank: Regular Contributor
timestamp: March 26, 2020, 06:16:06 pm
content: First it was the pcb manufacturing that was affected by the Corona Virus, now I am noticing that a lot of products that I use that I am trying to restock on is out of stock with months long restock lead time. Other alternative parts are much more expensive.Anyone else having these same issues?

author: rfdave#gmail.com
author_rank: Contributor
timestamp: March 27, 2020, 02:29:14 am
content: Nope, I'm still getting my hand delivered packages daily, along with Fresh coffee

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 27, 2020, 03:32:51 am
content: Well yeah, the factories are shutting for, *checks watch on the pandemic*, a few months probably?Make do with whatever substitutes you can, alternate suppliers, stock, etc. It's not going to be business as usual. Just chill out, roll with it, and if applicable, notify customers of delays as needed. If you're low on cash, relief should be coming.Tim
. - Page 1
Forum section: electronics / projects

author: Unknown
author_rank: Unknown
timestamp: December 10, 2013, 01:38:35 pm
content: .

author: poorchava
author_rank: Super Contributor
timestamp: December 10, 2013, 02:35:19 pm
content: Either I'm missing something, or this hack is missing any kind of filter to keep the sucked in solder from killing the vacuum pump. Good idea though.
Very low idle power bluetooth module - Page 1
Forum section: electronics / projects

author: cyberfish
author_rank: Regular Contributor
timestamp: February 27, 2012, 08:49:21 pm
content: I'm thinking about making an Android app that changes phone settings (silence, etc) based on proximity to some "tokens".My current plan is to make those "tokens" out of small 9V battery-powered bluetooth devices.The biggest challenge is battery life. I would like the battery to last half a year at the very least, and with a 9V, 500mAh battery, that means the device must draw less than about 1mW, or ~300uA at 3.3V, in a discoverable (no need for pairing and connection except for configuration) state. This is assuming I can build a buck converter that's efficient at that current level (I never looked into it). If a linear regulator turns out to be more efficient, the power limit would be a lot lower.So does anyone know of any such bluetooth module? Must be hand-solderable, SMT is fine (I can solder TQFPs by hand).To recap:- 1mW max in a discoverable state- speed doesn't matter- range doesn't matter (few feet/meters)- hand-solderable- ideally less than $15 or soA module on SparkFun seems like a good fithttp://www.sparkfun.com/products/10253except I can't find any mentioning of the 26uA discoverable mode in the manual...

author: updatelee
author_rank: Contributor
timestamp: February 28, 2012, 05:55:30 am
content: http://www.rovingnetworks.com/products/RN_42under specifications it lists power usage in different modes. Ive been looking for a similar item this may fit the bill as well. time to read more datasheetsChris Lee

author: sonicj
author_rank: Frequent Contributor
timestamp: March 01, 2012, 07:21:46 am
content: 9V's suck.how about CR123? they'recheaper, lighter, smaller, long shelf life (10 years), much higher energy density, etc. unless youneed9v...-sj
very low leakage currents - Page 1
Forum section: electronics / projects

author: kars
author_rank: Contributor
timestamp: April 22, 2024, 01:55:42 pm
content: Hi all,for work (yes yes, i know) ive been diving into the wonderfully frustrating world of femto/pico amperes.For the past half year i've been trying to find the source of a leakage current that is both temperature dependent and different from device to device which makes pin pointing the source a pain.i am fairly certain the issue lies in our sensor bit i'm trying to read out. Unfortunately this makes finding information about potential issues rather difficult as most publications focus on the circuit board.What i think i can share: my main area of focus currently is a metal->ceramic->metal structure we use as an insulator.Does anybody have any experience in this area and/or can point me to more suitable literature?Are there any obscure effects that i need to take into account?Kind regards,Kars

author: Dr. Frank
author_rank: Super Contributor
timestamp: April 22, 2024, 04:18:11 pm
content: Hello Kars,that sounds similar to the technology of ceramic capacitors, MLCC, where you have the same layer structure.leakage currents are known there, as well, depending on the thickness, composition and quality / purity of the ceramic.The ceramic firing and annealing process as well determines the isolation.I propose that you search for technical papers of the known good ceramic capacitor manufacturers.Frank

author: jwet
author_rank: Frequent Contributor
timestamp: April 24, 2024, 03:36:18 pm
content: I worked on Ion Mobility Spectrometers for Bomb and Dope detection many years ago- 90's A radioactive isotope of Nickel bombarded the test sample and then would enter an electrode structure. This consisted of alternating sets of electrodes at progressively higher voltages up to a few kV that were used to accelerate the ions. There were some papers on this at the time- IEEE Instrumentation or Nuclear Methods. We settled on platinum plated electrodes and sapphire balls assembled by very patient assemblers. This is what is still used as far as I know. These techniques were published at the time- funding was DARPA, DEA or FAA, companies were SAIC, Oakridge, Berkeley, U of Tennessee and UW Pullman, IIRC. Spanned late 80's through mid 90's.
Very nice high quality switches - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: May 23, 2020, 05:21:58 pm
content: Hi,I am looking for PCB-mount switches (as alternative to touch sensors currently used) that:1) have nice tactile feel2) look very nice. i.e. you would put in a high quality good looking (think apple) product3) ideally have caps with different labels (enter symbol, ok, numbers etc)One I have been looking at is Apem's classic MEC series. Any other suggestions from other suppliers?Many thanks

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: May 24, 2020, 01:51:00 am
content: https://www.e-switch.com/product-catalog/cap-optionsThose I have explicitely remarked as having various actuator buttons available.https://www.knitter-switch.com/eng/Products/Group/4Schurter also makes such Switches and has good quality. You could also look at Mentor.

author: Renate
author_rank: Super Contributor
timestamp: May 24, 2020, 07:53:26 pm
content: I know that it's not very helpful, but back in ye old days the Honeywell Microswitch Series 2 was king.The pushbutton was illuminated by up to 4 #387 28V bulbs.You could split the indicator between upper and lower.The snap-on back end could have as many poles as you needed.I guess people got tired of needing so much back clearance and spending a fortune on switches.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: May 24, 2020, 08:42:14 pm
content: I used those. But I don't think they would mount on a PC board.
Very small coax connector ID - Page 1
Forum section: electronics / projects

author: PP3331
author_rank: Contributor
timestamp: May 19, 2020, 06:26:09 pm
content: Hi. Can anyone identify this very small coax connector plug? Thanks very much!

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 19, 2020, 06:39:48 pm
content: That picture is too small and blurry to be sure. Maybe it's a H.FL ?https://www.digikey.ca/en/products/detail/ksm-electronics-inc/1189-06/214179

author: Yansi
author_rank: Super Contributor
timestamp: May 19, 2020, 06:49:25 pm
content: Pick your enemy:

author: PP3331
author_rank: Contributor
timestamp: May 19, 2020, 07:01:57 pm
content: Here's a considerably better shot!

author: DaJMasta
author_rank: Super Contributor
timestamp: May 19, 2020, 07:09:33 pm
content: Still quite out of focus on the connector itself, but I'd expect H.FL as well - very common in smaller radio applications like wifi and such.

author: PP3331
author_rank: Contributor
timestamp: May 19, 2020, 07:27:52 pm
content: This is the best shot I could get. Looks like H.FL is the probable winner. Thanks all!

author: ejeffrey
author_rank: Super Contributor
timestamp: May 19, 2020, 07:30:28 pm
content: Looks like H.FL/U.FL or similar.These connector types are rated for 20-30 cycles but really only intended to be installed once -- such as a fixed antenna in a consumer electronics device. They are easy to insert but easily damaged during removal. They make an extraction tool that helps to lift the connector out without bending or breaking it.

author: PP3331
author_rank: Contributor
timestamp: May 19, 2020, 08:03:13 pm
content: In fact, since I'm seeing that most patch antennas seem to come with U.FL (MHF) that seems like an even higher probability. It's unclear to me what the difference is between the two (except perhaps size, of course). I'm not concerned about damaging the plug being removed, but if the female connector on the board is damaged when removing the original plug that would be depressing. I'll probably get hold of one of those patch antennas and see if U.FL is indeed correct. Thanks again!
Very small signals in LTSpice - Page 1
Forum section: electronics / projects

author: mc172
author_rank: Frequent Contributor
timestamp: March 31, 2024, 12:29:10 am
content: When trying to run what in my mind is a really simple simulation - a 1 Hz, 1 uV sine wave into a 100 k resistor - I get some pretty strange results in LTSpice:I'm expecting to see a sine wave but I see this bizarre triangle. Any idea what I'm doing wrong and/or how to manipulate LTSpice to properly simulate low voltages?

author: SiliconWizard
author_rank: Super Contributor
timestamp: March 31, 2024, 12:44:58 am
content: Yes, I just tried in LTSpice 24 and can confirm I get the same result as you do.The issue is a solver issue, more precisely, a timestep issue. The problem is that when using a sine voltage source with a very low amplitude and low frequency, the derivative of the signal respective to time is very small, and the basic solver behavior when faced with such a condition is to increase the timestep of the simulation to optimize it - that leads to, basically, aliasing in this case. (Conversely, the solver tends to shorten the timestep when the derivative of signals increases. That's basically done to improve the accuracy of integration.)The fix is to define a maximum timestep value (in the transient analysis options) instead of leaving it empty. In your case, 1µs for the max timestep works. But depending on the case, you may of course need to adjust it to a lower value.You can play with the max timestep parameter, and see that the higher you set it, and the fewer "points" the solver computes, so the "rougher" the simulated sine appears, until you get past a point where it aliases and you can't see a period anymore.Yes, Spice can be ultra confusing even with what seems like excessively simple simulations.

author: mc172
author_rank: Frequent Contributor
timestamp: April 05, 2024, 07:42:55 pm
content: Thank you very much!

author: Ian.M
author_rank: Super Contributor
timestamp: April 05, 2024, 09:02:48 pm
content: That's more of a kludge than a fix as it results in a rather slow simulation. The problem appears to be due to waveform compression. Turn that off with:Code:.opt plotwinsize=0or adjust its absolute voltage error limit with:Code:.opt plotvntol=1nand the original.tran 1leaving the timestep to default, will display a good waveform without significant loss of speed.
Very strange problems with SMD 3V regulator - Page 1
Forum section: electronics / projects

author: Powermax
author_rank: Regular Contributor
timestamp: March 05, 2017, 06:50:59 pm
content: Background:I had recently purchased a flight controller for my quadcopter based on a STM32F3 microcontroller. The chip is primarily a 3V device, but all of the power inputs to the board are 5V from USB, or power supplied from the "ESCs" (motor controllers with built-in 5V linear regulators). I have found that the board sometimes does not turn on (other than a single green LED wired directly to 5V) when powering from either USB or from the ESCs.The really strange problem:Instead of being a normal sane human being, and setting up a DOA return through amazon's A to Z policy, I decided to do everything in my power to get this specific board to work! I REFUSE to wait a week for a new board or use my F1-based alternative Naze32 board!Upon further investigation I discovered that when the board is in this dead state, the voltage being delivered to the 3v3 LED indicator is less than 1V. Furthermore, I found that if I use my multimeter to press hard on the physical chip, the board would come alive, my computer powering the board would recognize the USB device, and the red LED starting doing its thing when the software starts running. If I let the pressure off the chip, then it stops working. It after several times doing this it got worse and worse as I had to press harder and harder on the chipt to get it to work properly.Reflowing the pins on the package did not help, and the soldering job on them was as good as my Hakko FX888D would and clumsy hands could allow.Although messy with flux residue, it looked acceptable. This did not help. So in desperation, I then sacrificed and desoldered the package from the PCB, and salvaged a simalar-looking part on another 5V breakout board (3-axis accelerometer breakout board for breadboard/prototyping use) and swap that part to the board. I did check a couple of the pins (Vin, ground, and Vout) to ensure it has more or less the same pinout. The part number on the new part was different but I do know the breakout board has a "Vin" and a "3V Out" labeled on the pins, which as expected lead right to the regulator. After performing this surgery, the board came to life like frankenstein's monster!The actual question, what has caused this voltage regulator to fail in such an obscure way? not so much as fail, but DOA? I have never had a chip do such strange things, and my only guess is that the physical bond wires inside of the package have somehow broken. Looking at the chip closer under adequate light after being replaced, it is obviously concave given how much pressure has been applied to it to get it to work. When I was messing with it, I found that heat also made it harder to get working. Has anyone else ever experienced such strange behavior from SMT components?