hybridfree/eevblog-posts huggingface dataset:
building a power supply need suggestions on parts - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: November 05, 2010, 04:12:26 pm
content: Right, I found a heavy gem at a car boot sale: a 12V 200VA transformer. so I'm planning to use it to build a nice powerful bench power supply with a switch mode regulator.to ensure I get a good 15V out of it I may well use a doubling rectifier with very large caps but I'm yet to measure the output. I could also do a low voltage high current output/regulator using a full wave rectifier.Any suggestions on switchmode regs that can handle 12V 20A and maybe a 5V 40A ?I'm also looking to make each output current regulated as well so that the max current can be set, now I can do high side current sensing but how do I integrate the current control into the SMPS feedback

author: scrat
author_rank: Frequent Contributor
timestamp: November 05, 2010, 05:50:17 pm
content: For a voltage source, current feedback control can be an inner loop of the voltage controller.The voltage regulator generates a current reference, and the current controller generates the duty-cycle.Both controllers have limited output.That's what is usually done in variable voltage supplies with variable current limit. They can act as both voltage sources (until the current limit is reached) and current sources (until the voltage reference is reached), following the limit which comes first.

author: Murphy
author_rank: Regular Contributor
timestamp: November 06, 2010, 02:57:12 am
content: You're already using a big iron core transformer, what's wrong with linear regulation? Switch mode is so noisy.

author: Mr J
author_rank: Regular Contributor
timestamp: December 23, 2010, 05:49:03 pm
content: I've used a copy of astron's circuit in the past. Cheap, easy, simple. The iron transformer already has a huge loss, go linear
Building a quick and cheap solder paste printing jig - Page 1
Forum section: electronics / projects

author: blueskull
author_rank: Unknown
timestamp: September 06, 2016, 04:54:23 am
content: Yesterday I was trying to solder a board with OSHStencils stainless steel stencil for one of my projects. To my surprise, the solder didn't come off cleanly from small apertures, which left QFN packages pretty much unusable. The cause is my table. My working table is just a foldable 6ft dining table, which has quite a bowing angle especially at the edges.So, I decided to build a stencil printing jig that makes solder paste printing easier. After visiting Lowe's and Home Depot, I got a thin stainless steel plate and a ceramic tile. Using some crude tools I was able to cut the steel plate to the size of the ceramic, then epoxied them together. Then I attached a piece of OSHStencils jig to my steel plate, while the other jig is free to move to accommodate different PCB sizes.Attached are the photos of the completed work form top and side, as well as what I found interesting. The cutting wheel have shrunken to half its usable diameter just from cutting 15cm of steel. It was 24mm in diameter, and it is now 15mm.The total cost of the project is $6 worth of metal, $2 worth of ceramic, $2 worth of glue and $5 worth of OSHStencils jig set, totally $15 if you do not count the $0.125 cutting wheel, cheaper than a tube of paste.Also, a word of warning: if you want to do metal works, do not buy a Dremel micro. Its battery barely supported me to cut and polish 15cm of steel before requiring another charge.

author: andyturk
author_rank: Frequent Contributor
timestamp: September 06, 2016, 05:19:26 am
content: nice keyboard.

author: KL27x
author_rank: Super Contributor
timestamp: September 06, 2016, 05:57:14 am
content: Sooo....does it work? I'm surprised if a piece of thin sheet metal is very flat to begin with, and even if perfectly flat, I'm surprised when QFN stencil does NOT come out unuseable... what brand solder paste do you use where you actuallyexpectit to work?And what do you use for a squeegee?I gave up on no-lead oven reflow. I do those with solderwire, iron, and hot air. For solder paste "jig" I use 2" end grain cutting block lapped flat... so that not the problem.
Building a RGBW Controller with RF remote control - Page 1
Forum section: electronics / projects

author: PinheadBE
author_rank: Regular Contributor
timestamp: January 13, 2019, 05:37:01 pm
content: Hi,I bought a cheapo kit including an RGBW LED strip, a controller with its 40-keys IR remote control and a power supply.I installed it behind my TV, powered it up and....... it worked as intended !I was happy and looking forward to a good TV eveningAnd that was when the sh!t hit the fan: I turned on my WD TV Media Player, and... oh surprise .... the remote control of my WD TV was also commanding my LED stripsThe only workaround I can think of is to replace the controller and its RC with another one using a RF remote control insteadBut looking online for the available Chinese stuff, I didn't find a RC model which suits me: I don't need multi-zone control, I don't need all those flashy effects: I just want to be able to control separately each of the four color channels. A bunch of preset colors would be a bonus but this is not mandatory.And I did not find it yet.So, I thought of building one: remote control with at least 10 buttons (ON - OFF - one increase and one decrease button for each of the 4 channels)Any one would have seen a good design from which I could take some ideas ?Thanks for your input

author: PinheadBE
author_rank: Regular Contributor
timestamp: January 13, 2019, 06:22:54 pm
content: ... which in fact is a 4 channel PWM controller, controlled over a RF remote controlThe RGBW strips I use are not the WS2812 type, but have 5 connections: Common Anode, R, G, B and W

author: nsrmagazin
author_rank: Regular Contributor
timestamp: January 13, 2019, 06:31:46 pm
content: I can suggest you limit the range of the receiver or transmitter if possible(both is better). You need to change the location of 1 of the devices and put it as far away as possible and I don't know if they sell this, but a box around the transmitter or receiver will limit its range and point it more accurately. Unfortunately RF hacks are not my specialty so I can't tell you what the box should be made of exactly so it can do the job.
Building a Spektrum™ satellite based wireless RC simulator receiver - Page 1
Forum section: electronics / projects

author: kurt
author_rank: Contributor
timestamp: April 18, 2015, 12:20:36 am
content: Hi.I have built the hardware and are developing the firmware for a small device that makes it possible to use an RC flight simulator without tethering the transmitter to the PC with a wire.It has been done before, but here is my take on it:http://kavionic.com/blog/SimLinkFeedback, critisism, and help with the remaining protocol issues are very welcome
Building a step-up capacitor charger from ADP1613 - Page 1
Forum section: electronics / projects

author: aknaydenov
author_rank: Newbie
timestamp: October 04, 2015, 06:37:01 pm
content: Hello,I'm currently prototyping a device that will use capacitor discharges. The device must be compact and will use 2x1,5V AA batteries, but the capacitors must be charged at a higher, 16V voltage. So I thought of a DC-DC step-up converter and I found the ADP1613 to be convenient.I started reading its datasheet and I calculated all the parts values I need, except for the loop compensation resistor and capacitor values. And this is where my confusion begins.We all know that charging a capacitor at a constant voltage makes current decrease vs. time. So how the DC-DC converter will handle this? At the turn on, it will be at max current and it will go towards 0 current when the capacitors have charged.Regards,Alexander.

author: mikerj
author_rank: Super Contributor
timestamp: October 04, 2015, 09:59:46 pm
content: The ADP1613 has a 2 Amp fixed current limit which is probably too high for powering the part from a couple of AA cells; it will likely pull the cell voltage down so much that the low voltage shutdown will activate.For charging a large value capacitor I would either choose a part that has programmable current limiting, or provide an external current limiting circuit.

author: aknaydenov
author_rank: Newbie
timestamp: October 05, 2015, 05:15:15 pm
content: mikerj,But by saying 2A fixed current limit, I presume a maximum allowable one. Not necessarily used one. I will limit my charge current externally. Also, the IC has soft start.
building a tachometer - Page 1
Forum section: electronics / projects

author: Clear as mud
author_rank: Regular Contributor
timestamp: September 17, 2020, 06:59:39 pm
content: I've been thinking about building a tachometer, to use for lawnmower carburetor adjustments, but it would be nice if it had other applications too.So I searched for open-source designs and didn't find much. I was thinking of picking up the signal from the spark plug wire. Here are some of the interesting sites I found:Carburetor Sync Boardfor motorcycles, it mentioned something about a tachometer feature, but I think it is done by timing the pressure pulses from the air pressure sensors.Arduino Tachometertaps into the low-voltage side of the ignition coil for signal. That's the easy way to design a circuit, but would not be as useful for a diagnostic tool, especially for a lawnmower which has no low-voltage coil.AnotherArduino-Tachometerpicks up an optical signal. This project looks pretty neat, includes a custom case and everything.An oldEng-Tips Forum threadabout picking up the signal from a spark-plug wire. Doesn't make it sound too easy, but maybe it could be done with a sensitivity adjustment knob on the tachometer.I put the idea aside for a couple of months, and later when I came back to it, I ran across this:US Patent #5883510A: Tachometer system picking up ignition signals from vehicle ground. This looks very interesting, and I'm seriously considering building this. The patent is over 20 years old, so it should be OK to use freely. It makes a good case for being a more universally-applicable method of building a tachometer for any engine that utilizes sparks. Picking up the RPM signal from noise on the vehicle ground is safer and simpler than tapping into the high-voltage lead somehow. It still would require a sensitivity adjustment.I'm thinking of using thePIC16F1705/9. I'm somewhat familiar with this uC, since I designed a circuit using it when it was brand new. Now it is on the third silicon revision so some bugs have been worked out. It has peripherals that could probably be used in place of discrete circuitry for several of the blocks in the block diagram in the patent. I would still use discrete circuitry for the first signal-buffering op-amp, since it needs to be very sensitive, but then the uC has internal op-amp, comparator, CLC, and DAC, that could replace the other four blocks on the block diagram.For output, I was initially thinking of something like a character LCD display, but the other day I thought, why not a panel meter?I don't know, maybe nice ones are expensive. I haven't looked into that too much.I also haven't looked to see, is there some tachometer already available pretty cheap so I shouldn't mess around with building my own? I'm just kind of at the brainstorming stage here, wondering if others think this is a cool idea worth pursuing.

author: Benta
author_rank: Super Contributor
timestamp: September 17, 2020, 07:11:25 pm
content: Just buy one of the optical tachos that RC pilots use. They cost 20...30 US$. Place a couple of black stickers on the shaft you want to measure and you're done.
Building an AC current limitable, isolated, adjustable supply for the Lab. - Page 1
Forum section: electronics / projects

author: peteb2
author_rank: Regular Contributor
timestamp: October 18, 2017, 08:19:25 pm
content: OK done to death as a subject i am sure but i would really like to build mine in a similar vein to the sort Mr Carlson presented a couple years back. (See You Tube:).My question is to whether i can use a large chunk of 18mm thick clear acrylic sheet to mount the electrical components ( variac, isolation transformer, switches, outlets, hookup wiring etc) on rather that the normal brown coloured phenolic/ FR2 (synthetic resin bonded paper) fuse board panel you'd normally use (as Mr Carlson has done).... Of course there is a serious consideration of electrical safety issues at stake too annd i am really aware of that.I have access to plenty of heavy duty thick re-usable clear acrylic sheeting and like the idea of a single wall mounted panel setup next the bench in my Lab as opposed to having another set of shelf kit that would be occupying valuable space for real test gear.So the question is, is thick guage acrylic plastic safe to build mains (230Vac) projects on ? ? ?.... ok ideaor absolutely stupid....?Any input appreciated....
Building an ExpressCard  - Page 1
Forum section: electronics / projects

author: d.bocc
author_rank: Newbie
timestamp: December 12, 2017, 03:13:02 pm
content: Hello,I've been thinking about building some sort of addon card to be connected via the ExpressCard connector.I've found plenty infos about the pinout and such, but very little about the connector used, how the enclosure should be sized etc - basically, all the hardware stuff is a mistery to me.Anyone have some informations about how to physically build and design such kind of card?Thanks!

author: joshtyler
author_rank: Contributor
timestamp: December 13, 2017, 01:01:49 am
content: All the physical dimensions etc. are available inthe standard, e.g. p.36 for ExpressCard/54.The connectors and enclosures were previously all available but now all seem to be obselete/not stocked by suppliers because ExpressCard is pretty dead. You can find lots of non stocked connectors from suppliers e.g.this.The enclosure can be salvaged by purchasing a cheap USB 3.0 ExpressCard from AliExpress, and salvaging the enclosure, for a one off...
Building an original Philips pattern generator from scratch (video) - Page 1
Forum section: electronics / projects

author: inaxeon
author_rank: Regular Contributor
timestamp: June 14, 2023, 05:56:11 pm
content: Some may have already seen this. For those who haven't. Here it is:

author: Bicurico
author_rank: Super Contributor
timestamp: June 14, 2023, 08:23:25 pm
content: Cool!
Building Circuit for Testing One-way balance system with Lifepo4 cells  - Page 1
Forum section: electronics / projects

author: Gazza_au
author_rank: Newbie
timestamp: April 17, 2017, 02:36:41 pm
content: Hi,I am Building a circuit to test for any effect, of One-Way balance system on 17 Lifepo4 cells in series.Battery Bank17x "3.2v Lifepo4 100Ah Prismatic Cells" in Series.Connected to "Solar Charger" adjustable from 49.5 to 60v.The balance system I wish to test:Connects a charged Capacitor in Parallel with one of 17 cells.The capacitor will be tapped into a cell in parallel.During this time, any voltage it holds above the cell will transfer.Before being disconnected from cell and charged back up to a 1/17th reference.Repeat process for each cell.The 17 output sequence:Is done with Picaxe 28x2 - 17 Outputs operate relays:This part of the Test Equipment is covered.Op-amps and associated components I want to work on========================================Circuit Description:Recap- The "Solar Charger" is adjustable from 49.5 to 60v.A 1/17th voltage divider is connected across the Solar Charger for 17 Lifepo4 Cells.1/17th of the Solar Charger output = the average charging voltage across any 1 of the 17 cells.This voltage divider follows changes in supply rail during charging, on any set charging voltage.The 1/17th voltage is obtained with a 1/17 voltage divider connected to Op-amp as shown below.Capacitor Bank2 Capacitor are used in Series for good voltage tolerance.The Capacitor Bank is Charged at 1/17th the Solar Charger Voltage, in the range 2.9v to 3.529vThe second Op-amp divides this voltage, in order to efficiently charge the 2 series capacitors.By design, this equipment has no effect unless the capacitor is of higher voltage then cell.This equipment is to test the effect of a one-way balance system.I would like your opinion on Op-amp choice and divider/resistor choice/design.========================================Part Selection:Operational Amplifier (JFET-input) - TL082Mouser Part No: 595-TL082IPE4 (not sure if this is the standard pin version?)http://au.mouser.com/ProductDetail/Texas-Instruments/TL082IPE4/?qs=odmYgEirbwxFprZo7erKcw==Datasheet:http://www.ti.com/lit/ds/symlink/tl082.pdfDarlington - TIP100 60vhttps://www.onsemi.com/pub/Collateral/TIP100-D.PDFCollector CurrentContinuous 8APeak 15ACapacitor - Maxwell Technologies BCAP0350$16.07 AUDhttp://www.mouser.com/ds/2/257/Maxwell_BCSeries_DS_1017105-4-341252.pdf350 FESR 3.2 m?2.85 VLeakage Current 0.30 mAThermal Characteristics - Maximum Continuous Current 21A RMS @15C.-2x Maxwell BCAP0350 Capacitor in Series.175 FESR 6.4 m?5.7v10.5A RMS------------------------------------------Common Anode Dual Rectifier - MUR1620CTRG (Not sure if I need diodes or not?)http://www.mouser.com/ds/2/308/MUR1620CTR-D-79742.pdfAverage Rectified Forward Current 8APeak Repetitive Surge Current 16A

author: Gazza_au
author_rank: Newbie
timestamp: April 21, 2017, 08:57:47 am
content: EEVblog is hosted by David L. Jones, an electronics design engineer based in Sydney Australia.I see
Building Jim Williams Pulse Generator - What capacitors to use? - Page 1
Forum section: electronics / projects

author: JoeN
author_rank: Frequent Contributor
timestamp: September 12, 2015, 06:16:27 am
content: This project:https://www.eevblog.com/forum/blog/eevblog-306-jim-williams-pulse-generator/570/More info:https://entangledwaves.wordpress.com/2013/07/15/avalanche-pulse-generator/andhttp://zeus.phys.uconn.edu/wiki/images/Pulser_circuit_diagram.pdfJim William's schematic does not give voltage ratings for capacitors. I assume it should be at least 100V, right? My ceramic and electrolytic .47uF capacitors are 50V and tantalum ones at 35V. What do you all suggest? Also, do you think I can get away with 1N4937s instead of the MUR120s on the power supply section (that is what I have)? The reverse recovery time is 150ns instead of 35ns for the MUR120 but somehow I bet it will work OK. What do you think? I just put some on order but I don't want to wait.Thanks!Is this a good choice:http://www.newark.com/multicomp/mc1210b474k201ct/ceramic-capacitor-0-47uf-200v/dp/22T0152200V, 10%, cheapActually, their price on the suggested diode is good too.http://www.newark.com/vishay-general-semiconductor/mur120-e3-4/fast-diode-1a-200v-do-204ac/dp/76K7747I probably will just order both and wait for the parts.Ideas?

author: Kleinstein
author_rank: Super Contributor
timestamp: September 12, 2015, 06:57:01 pm
content: The 1N4937 is OK. The switcher should not be that extremely fast.With the first two caps one might in theory get away with 50 V ratings, but 100 V or more is definitely better. One should not use a tantalum cap close to the maximum rating and no way well beyound that. They caps may be a littel smaller for a first test, if the 1 M resistor is increased to reduce the pulse rate.
Building my first (proper) computer... - Page 1
Forum section: electronics / projects

author: peter.mcnair
author_rank: Contributor
timestamp: October 14, 2013, 12:09:37 pm
content: Let me introduce myself.My name is Peter and I am building an analog(ue) computer...http://analog-ontology.blogspot.co.uk/(I first saw one of these back in 1976 in London's Science Museum (I was twelve and as I recall it simulated a golf game); I have now got around to making one...it's early days but it's turning out to be something of a fascinating journey through analogue electronics...)

author: dannyf
author_rank: Super Contributor
timestamp: October 14, 2013, 01:32:54 pm
content: Analog computer, the future of computing!

author: alanb
author_rank: Frequent Contributor
timestamp: October 14, 2013, 03:05:13 pm
content: PeterYou need to read this thread.https://www.eevblog.com/forum/projects/home-brew-analog-computer-system/msg246348/#msg246348It's really inspirational!
Building my own wireless DAQ - Page 1
Forum section: electronics / projects

author: krapht
author_rank: Contributor
timestamp: January 21, 2016, 07:21:45 pm
content: So my board finally came back from China. Decided to get it assembled because I am not at all comfortable with QFN and 0402 by hand, which were a necessity in this design for decoupling reasons.Next step: gingerly power it on and hope I can at least talk to it over JTAG without magic smoke leaking out.

author: GekkoNZ
author_rank: Newbie
timestamp: January 23, 2016, 06:16:07 am
content: Let us know how it turns out. Thats a nice looking board, nice job on the layout.What company did the assembly? Cost effective? What were they like to deal with?

author: krapht
author_rank: Contributor
timestamp: January 27, 2016, 06:35:28 pm
content: So as it turns out the FTDI chip on the board takes forever to power on and settle. The bootloader on the MCU I'm using goes into a set of different modes based on the voltage on certain GPIO pins, GPIO pins which are glitching on power-up since they are also connected to this FTDI chip which is actually driving them with hard logic 1/0s, overpowering my pulldown resistors.I can fix this, but I have to cut the traces and write a program to flash the chip memory via JTAG, which is a little involved since the flash isn't memory mapped...I used an American company called Advanced Assembly. I don't actually know if they outsource to China, but I have a feeling they do since the manufacturing engineer I spoke with was Chinese and was writing me emails pretty late in the day. I forgot exactly how much I paid but it was around $600 for 1 piece, 6 day turn, turnkey, their standard 4-layer PCB stackup which is 1mm core and 2x2116 ply each side.
Building smart universal charging station - Page 1
Forum section: electronics / projects

author: ptricks
author_rank: Frequent Contributor
timestamp: March 19, 2016, 12:53:18 pm
content: After the SO became annoyed with all the different devices we have to keep charged, tablets,phones, laptops,mp3 players, etc she has tasked me to building something we can use to charge them all from one location in the house without a myriad of adapters.I got the laptop part covered but the other devices all use USB to charge and all seem to want different pin voltages on D+ and D- to do the fastest charging rate. I want to do this a smart way where a micro will work as a host , query the device, then select the best D+, D- combination for the device connected and any port can charge any device. I know about the short D+ D- thing , but that isn't always best as I had an older phone burn itself out because it pulled over 1.5A from that configuration.Apparently the manufacturer didn't employ protection, assuming only the approved charger or a current limited port would be used.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: March 19, 2016, 05:06:37 pm
content: Don't bother with a microcontroller. Who wants to program all the bizarre USB sub-sub-sub cases for proper detection? And you'll need a pile of supporting analog circuitry too.Instead just grab one of the ICs that manufacturers make expressly for this purpose. Off the top of my head, I know FSA832/BQ24392 are the device side chips for this. You should be able to easily find the host side ones. (Start with TI; they're not the absolute cheapest, but they definitely make what you want.) There are many, many, many ICs made just for this. I work on devices, not hosts, and I'm always coming across stuff that looks perfect for making a very smart device that can charge from anything... except it's actually a host-side part.

author: Kilrah
author_rank: Unknown
timestamp: March 19, 2016, 05:55:08 pm
content: Or just get a few of those things made specifically for that purpose and call it a day

author: technix
author_rank: Super Contributor
timestamp: March 20, 2016, 11:10:17 pm
content: Just grab a 7-port powered USB Hub, a 5V 10A power supply, and a Raspberry Pi. The Pi have adequate drivers allowing it to negotiate power delivery and put all devices into charging state, maybe rate limited.
Building some RGB LED strip lighting - Page 1
Forum section: electronics / projects

author: 8163jb
author_rank: Contributor
timestamp: August 22, 2013, 09:50:46 pm
content: Hey everyone, I recently kitted my room out with some RGB LED Strips and built myself a controller. So I thought I'd share the blog post I did about it with people herehttp://doayee.co.uk/rgb-led-strip-room-lighting-build-part-1/Comments would be greatly appreciated! I'm fairly new and would (obviously) like some feedback! Negative feedback (yes I own the T-Shirt) is good aswell as positive! Thanks!
Bulb socket type - Page 1
Forum section: electronics / projects

author: Medo
author_rank: Regular Contributor
timestamp: December 24, 2010, 08:27:33 am
content: Which socket type is used for bulb athttp://cgi.ebay.com/18V-BULBS-MAKITA-BOSCH-HITACHI-DEWALT-FLASHLIGHT-/160502879194?pt=LH_DefaultDomain_0&hash=item255eb793da#ht_1964wt_1135?I have few of bulbs but I cannot figure which socket to search for. My local supplier hasn't got anything similar to this.Is there any official naming for it so I can buy it online or is it proprietary to DeWALT?

author: GeoffS
author_rank: Unknown
timestamp: December 24, 2010, 08:51:58 am
content: It looks like a standard torch bulb so your best bet might be to salvage a socket from a torch.Do you have to use that particular bulb? Choosing a different bulb may give you more socket options.

author: Medo
author_rank: Regular Contributor
timestamp: December 24, 2010, 09:04:07 am
content: Quote from: GeoffS on December 24, 2010, 08:51:58 amI have quite a few of them alongside 18V power supply. It would be shame to waste it.

author: XynxNet
author_rank: Regular Contributor
timestamp: December 24, 2010, 01:59:53 pm
content: Looks to me like a P13,5S socket. To be sure, ask the suplier.

author: Medo
author_rank: Regular Contributor
timestamp: December 24, 2010, 05:39:34 pm
content: Quote from: XynxNet on December 24, 2010, 01:59:53 pmIt is. I checked dimensions and it fitsNow only task is to find some socket for it...
Bulging Polypropylene Capacitors - Page 1
Forum section: electronics / projects

author: Mario87
author_rank: Frequent Contributor
timestamp: June 13, 2024, 07:46:18 am
content: Hi all,Not sure where to put this, so thought I would try here...we have a production run of boards with a large (rated 1000VDC / 1uF) polypropylene capacitor. This is on a PSU which steps down from 400VAC to 65VDC and the capacitor is just after the bridge rectifier to smooth out the rectified AC.Boards are built, verification tested (NOT powered, just resistances / isolation checked), then sent for coating and now they have returned from coating we have at least 3 boards with the capacitors bulging. The boards have never been powered on and I don't believe any heat is used during coating (need to confirm this for sure incase they warm them to help dry it), but even if heat was used it can't be more than 60*c or so...not enough to cause damage.Anyone know what could cause this failure? I have seen many electrolytics bulging in my time, but never a polypropylene cap...any suggestions welcome!

author: ftg
author_rank: Frequent Contributor
timestamp: June 13, 2024, 07:55:06 am
content: Could a solvent in the coating be infiltrating the plastic case of the cap?

author: moffy
author_rank: Super Contributor
timestamp: June 13, 2024, 10:56:54 am
content: Is the coating a vacuum impregnation process? and could the caps be outgassing internally?

author: Mario87
author_rank: Frequent Contributor
timestamp: June 13, 2024, 11:29:41 am
content: Quote from: ftg on June 13, 2024, 07:55:06 amThis looks to be the most likely cause at the moment, however we have had 100+ boards made already with this coating and these caps, so its strange we now only get a handful with this issueQuote from: moffy on June 13, 2024, 10:56:54 amNo vacuum impregnation, just sprayed on and dries, its an acrylic based coating if memory serves correctly.

author: paul@yahrprobert.com
author_rank: Regular Contributor
timestamp: June 13, 2024, 06:01:11 pm
content: I would cut one open and see what's up. If you find anything wet then it might be a fake. Another theory is that those are polypropylene with oil soaked paper and the oil sucked up the solvent from your encapsulant.
Bulk-testing LiPo capacity at low (30-50mA) current draw? - Page 1
Forum section: electronics / projects

author: rt
author_rank: Regular Contributor
timestamp: January 06, 2015, 12:10:24 pm
content: Hi all,we are looking at producing 30-40 dataloggers to go in the field for a research project and want to qualify the 3500mAh Lipos that will be powering them. Previous editions of the project had a few dud batteries that failed in the field and we need to be reasonably sure on performance before we install.Current draws are 30-50mA and lifetime needed is minimum 1-2week but with safety margin for more in case retrieval is delayed.The plan is to build a set of 4 or 8 simple LM324/IRF540 based constant current dummy loads and monitor the cell voltage with a datalogging voltmeter & thermometer switching between the cells by relay.The aim will be to check ACTUAL capacity across a few temperatures (0deg, 10dg, 20deg) and through 2 to 3 discharge cycles.Are we over- or under-thinking this? Maybe simplify dummy loads to just 80R-100R resistors? Doe testing capacity at higher current draw gives same capacity information but faster?Any thoughts welcomed.RT

author: tszaboo
author_rank: Super Contributor
timestamp: January 06, 2015, 12:41:21 pm
content: What accuracy do you need? If the answer is anywhere in the x% region, you could just use a voltage regulator and a resistor to get a constant current sink. It is way easier to get it stable, and cheaper. It is possible that you dont even need a PCB just the two component.Also, there are battery tests with constant resistance.

author: bobcat
author_rank: Regular Contributor
timestamp: January 06, 2015, 10:57:30 pm
content: Your thinking is right on. Battery capacity changes with temperature and load. For your test load, use a constant current load because that will be closer to your design load type.
Bulkhead mounting a USB Type C connector - Page 1
Forum section: electronics / projects

author: Northy
author_rank: Regular Contributor
timestamp: October 23, 2020, 02:31:10 pm
content: Has anyone come up with a good way of siting a USB C connector onto a front panel that is:A) Not a fortuneB) Available from a reputable supplier for the foreseeable futureC) Looks niceMany thanks,G

author: Northy
author_rank: Regular Contributor
timestamp: November 01, 2020, 08:03:28 pm
content: I guess not

author: Hideki
author_rank: Frequent Contributor
timestamp: November 01, 2020, 08:36:52 pm
content: https://www.google.com/search?q=usb+type+c+panel+mount&tbm=isch

author: Pack34
author_rank: Frequent Contributor
timestamp: November 01, 2020, 11:53:12 pm
content: https://www.usbfirewire.com/c-panel-mount.html

author: Northy
author_rank: Regular Contributor
timestamp: November 11, 2020, 01:17:16 pm
content: I contacted a UK cable supplier asking for an off the shelf solution and ended up with a quote for custom toolingThese things are available from China cheap as chips, but I'm looking for a way to be able to guarantee supply as much as possible.Are there any companies out there that source from China but you can have some sort of agreement with?Thanks,G
Burden voltage - Page 1
Forum section: electronics / projects

author: Konkedout
author_rank: Frequent Contributor
timestamp: March 15, 2024, 11:27:42 pm
content: The video about burden voltage is true.But it is important to remember: "A burden hand is worth two in the bush."

author: Benta
author_rank: Super Contributor
timestamp: March 15, 2024, 11:50:39 pm
content: Time for your medication, I think.

author: Kim Christensen
author_rank: Super Contributor
timestamp: March 16, 2024, 12:35:44 am
content: You may want to post that joke here:https://www.eevblog.com/forum/chat/bad-electronics-jokes

author: Terry Bites
author_rank: Super Contributor
timestamp: March 16, 2024, 03:28:02 pm
content: He is on a tablet but I think the dose is too low.
Burleigh Instructional Scanning Tunnelling Microscope - Page 1
Forum section: electronics / projects

author: tggzzz
author_rank: Super Contributor
timestamp: June 19, 2019, 01:39:53 pm
content: A few of us at the local hackspace have got our hands on a Burleigh Instructional Scanning Tunnelling Microscope. Why? Just because; there doesn't need to be a whyIt looks in good nick, and we are slowly finding our way around it, but don't want to rush in like bulls in a china shop andunnecessarilyknacker it.We are hampered by some missing information. So far we have googled around and found some documents that give tantalising hints, especially one short "cheat sheet" and some that think the company is "Burly"!We would be grateful if anybody could point us towards:an actual manual, paper or electronicuseful techniques when cutting new tipsThe specific device is shown in the images below, but anything from the Burleigh company would be of interest.Thanks

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: June 19, 2019, 02:42:32 pm
content: Afraid I don't have any data, and it's been a lot of years under the bridge, but I worked at Burleigh and did some of the design work on those things! Feel free to PM me with questions and mysteries.

author: tggzzz
author_rank: Super Contributor
timestamp: June 19, 2019, 03:00:30 pm
content: Quote from: Conrad Hoffman on June 19, 2019, 02:42:32 pmThanks. We will do as and when we have any more specific questions.
Burn in board for references - Page 1
Forum section: electronics / projects

author: DavidKo
author_rank: Frequent Contributor
timestamp: April 17, 2022, 08:41:51 pm
content: I have created simple board to burn in references, primary I have intended to use it for LT1021, LT1019, REF0x ... references. But later I have created adapter (from universal PCB and pin headers) to use it also for zener diodes or LM399 type references (load resistors are not populated). The PCB size is 100x100mm and mine was produced by JLCPCB.Input voltage goes through protection diode to x7815 stabilizer. The voltage is distributed through top and bottom plane to each reference. The heat sink for the REF0x type references is probably not needed (I use 4k7 Ohm resistor as the dummy load). For the LM399 probably yes - I want to check the the power consumption with and without 3D printed "insulation" caps for references.Capacitors C1 ... C20 are dedicated for each reference (probably overkill and they do not need to be populated)Resistors R1 ... R20 are used as a dummy load for each reference (they are optional - SMD or through hole resistor can be used)LED diode with the resistor R21 for the ON indication are also optionalDB-25 connector can be configured to have on PIN 20 voltage from reference 20 or 15V voltage from x7815 - intention was that it can be used with 20 channel scanner. Power can be delivered or measured through this connector (both input or +15V).I have uploaded the KiCAD project and zip for JLCPCB toGithub.
Burned mosfets on a motherboard from an HP Laptop - Page 1
Forum section: electronics / projects

author: Hagis2k
author_rank: Regular Contributor
timestamp: May 30, 2014, 11:39:09 pm
content: Well i bought an older hp laptop most for parts to my other machine that i have like chassis and so...Anyway when i started dismantling it and removed the touchpad i saw one of the mosfets Q6070 it was fried completely and i just got my oscilloscope a few days agoand it was nice to probe the working and i had around 4.5-5V pp in square wave but on the gate of q6070 i had 4V DC no wonder that it burned out, and q6071 gets nothing on thegate also the gates on Q6012 and Q6017 get no gate drive at all i guess we could say the driver ic is faulty?Another thing im not that sure of should you still get the pulses on the empty pads where the old mosfets used to be? because q6070 gate = 4V and q6071 = 0Vi just wonder if they are out of the circuit would this prevent the ic from operating normally?The attachment with the screendump from the oscilloscope is on the left side on a working vrm Q1024 (not in the schematic) and as you can see the mosfet been turned on utilit did short circuit and fail im not to sure of shall i be able to see the pulses of each gate even when the transistors are removed?And its an old HP NC8430 my plans are to maybe try to bring this motherboard back alive i assume changing Q6070 will just kill it again as the driver seems faulty?

author: fluxcapacitor
author_rank: Frequent Contributor
timestamp: May 31, 2014, 12:34:22 am
content: Check voltage out of U2006 .Check voltage out of pin 19 ,that goes to pin 4 of q6071.

author: Electr0nicus
author_rank: Regular Contributor
timestamp: May 31, 2014, 03:46:20 am
content: The gate drive for the top N- Channel MOSFET Q6070 may not be switching when the MOSFETs aren't in place. Because the Q6070 is a N- Channel Mosfet the gate voltage must be higher than the source voltage. This is achieved using a charge pump (the diode is inside the controller chip and the cap is C7564). It's very likely that the gate drive for Q6070 is not able to work properly when the MOSFETs are missing.As you haven't anything to loose on that old motherboard, if I were you, I would use some appropriate MOSFETs, solder them in and then supply the motherboard from a current limited source, like a lab PSU. You may also simulate the battery pack with a lab PSU.If the fets get hot or you can't se a gate drive signal, then the driver would be where the problem lies.

author: Hagis2k
author_rank: Regular Contributor
timestamp: May 31, 2014, 09:30:29 am
content: Well the gate of q6071 has connection with pin 19 of the ic i shall order the parts and see where it leads
BurrBrown OPT301M why so expensive? - Page 1
Forum section: electronics / projects

author: PartialDischarge
author_rank: Super Contributor
timestamp: September 29, 2016, 06:36:05 pm
content: Why is the OPT301M from Burr Brown so expensive?It has only 4khz of bw and its like $88 a piece (at digikey), with todays op-amps why would oneuse one of these instead of a discrete solution?http://www.ti.com/lit/ds/symlink/opt301.pdf

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 29, 2016, 06:46:57 pm
content: Hermetically sealed, probably mil spec, low on quantity, high on paperwork, probably legacy support life cycle too.Tim

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: September 29, 2016, 08:01:41 pm
content: Yup,I was repairing old ~83-ish HP Voltmeter recently, every electrolytic cap that fits the size and capacity was x6 times the normal price

author: Kleinstein
author_rank: Super Contributor
timestamp: September 29, 2016, 08:48:29 pm
content: The opt301 is not just an OP, but an photodiode with TIA circuit. So it is a rather special low volume chip. The Bandwidth is that of the TIA, the OP itself is more normal 350 kHz GBW.The single chip solution is less sensitive to leakage and "noise" pickup. It might be used in low volume or 1 off circuits or in high humidity environments, where a discrete circuits would need sealing / complicated guards.

author: Pjotr
author_rank: Frequent Contributor
timestamp: September 30, 2016, 01:50:26 pm
content: It was never cheap. Used this one 20 years ago for a light meter for fluorescence microscopy because of its UV capability. It is simply not intended for mass market products but merely low volume instrumentation.

author: bktemp
author_rank: Super Contributor
timestamp: September 30, 2016, 02:02:52 pm
content: It looks similar to OPT101 (DIP8 package).

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: October 01, 2016, 12:13:21 am
content: UV sensitive photo diodes are expensive. Even used ones or Old Stock on Ebay - I don't see anything cheaper than $45.

author: PartialDischarge
author_rank: Super Contributor
timestamp: October 01, 2016, 06:15:44 am
content: Being a closed metallic packaged solution, low production volume, with UV sensitivity and specially from BB seems to explains the price.Thanks for the replies
Bus capacitor placement for 5kW inverter - Page 1
Forum section: electronics / projects

author: jonathan_nadar
author_rank: Contributor
timestamp: June 28, 2022, 11:53:54 am
content: Hi, I am currently developing a PMSM inverter rated for 5kW continuous power running off a 48V(nominal) Li-ion battery pack. I am using nine 330uF electrolytic capacitors across the bus along with few film capacitors and MLCCs. I want to understand the implications of using topology A instead of topology B attached to this post. Using topology A makes my PCB routing straightforward and I can keep the loop formed by the half bridge and the capacitor the smallest. I am using FOC, so current sensing is quite crucial to me. I am doing non isolated, differential current sensing across the shunt using TSV912.Thanks in advance.

author: Siwastaja
author_rank: Super Contributor
timestamp: June 28, 2022, 12:16:29 pm
content: With A, you cannot sense instantaneous current, only average current. With A, you can also just use one current sense resistor + amp instead of sensing 2 phases.Average current control is workable and some inverters do that, but I don't see the point when it's not much more expensive to sense the two instantaneous phase currents, i.e., topology B.I don't see large difference in layout. Just use shunt resistor as small as possible. I have used 1206 SMD parts up to some ~500W power level and 2512 rated for 3W up from there. But maybe the 5kW/48V needs a tad bigger, maybe not. It's about how much accuracy you need; but I wouldn't be scared of using some well-specified x100 shunt amplifiers just to get the resistor dissipation down, and package small. +/-10% current sense accuracy would be more than fine for basic torque control, after all.

author: Robotec
author_rank: Contributor
timestamp: June 28, 2022, 12:53:11 pm
content: I would go with B as well if Resistor disspation is a problem you can always put severall in parallel.

author: Siwastaja
author_rank: Super Contributor
timestamp: June 28, 2022, 12:56:43 pm
content: Quote from: Robotec on June 28, 2022, 12:53:11 pmYeah, OTOH paralleling makes accurate Kelvin sensing more difficult. There are ways to separately sense the resistors and average the small voltages before amplification, but this takes space and increases cost, too.So it's often best to use a single suitable resistor, even if that means you go to very small burden voltages and have to amplify more, sacrificing some accuracy, because alternative of parallel/series connection would also sacrifice accuracy just in different ways, plus have more power loss.

author: jonathan_nadar
author_rank: Contributor
timestamp: June 28, 2022, 01:22:41 pm
content: To add on to the information, I have place sense resistors for two phases, and a x10 gain. I'll share an image of the layout tomorrow.
buy from kynix ? - Page 1
Forum section: electronics / projects

author: sdouble
author_rank: Frequent Contributor
timestamp: February 12, 2017, 01:43:20 pm
content: dear all,I'm after an opamp from STmicro. Unfortunately, it's not produced anylonger. I was looking for the remainings available at mouser/digikey/arrow but not much left there.I just saw that there are 5k units left at kynix. I don't know that company. Is it legitimate ?does anybody hasve experience with that company ?

author: amyk
author_rank: Super Contributor
timestamp: February 12, 2017, 04:12:52 pm
content: This Kynix? I'm not sure if they're related to Hynix...

author: hendorog
author_rank: Super Contributor
timestamp: February 12, 2017, 06:37:53 pm
content: I got a Mini Circuits part from them which was not in stock from MC. Order was about $150They have MOQ of 1 compared with MOQ of 20 from MCNo issues with the parts or the shipping and the service was very good.(I hit a bug in their website which charged me shipping cost only when I placed the order, so we exchanged a few emails.)

author: sdouble
author_rank: Frequent Contributor
timestamp: February 13, 2017, 01:05:27 am
content: Quote from: amyk on February 12, 2017, 04:12:52 pmyep, that website. They seem not to be related to Hynix.

author: sdouble
author_rank: Frequent Contributor
timestamp: February 13, 2017, 01:06:41 am
content: Quote from: hendorog on February 12, 2017, 06:37:53 pmHi,thanks for your feedback. My order will be $5k. I wanted to make sure that my money won't idsappear.
buy wafer switches? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: July 05, 2021, 10:31:07 pm
content: Is it possible to buy exposed wafer switches like in old test equipment anymore? like a website with a switch configurator?or the parts to make your own from machined bakelite?

author: themadhippy
author_rank: Super Contributor
timestamp: July 06, 2021, 12:00:26 am
content: This sort of thing?https://uk.rs-online.com/web/b/nsf

author: bob91343
author_rank: Super Contributor
timestamp: July 06, 2021, 12:24:09 am
content: I got lots of hits with googling Wafer Switch.

author: Terry Bites
author_rank: Super Contributor
timestamp: July 06, 2021, 03:04:53 pm
content: Are you hard of googling?https://www.newark.com/search?st=wafer%20switchesmost suppliers seem to stock them still!

author: ogden
author_rank: Super Contributor
timestamp: July 06, 2021, 03:50:37 pm
content: Quote from: Terry Bites on July 06, 2021, 03:04:53 pmThis is not about googling but getting weird satisfaction when others google for you.

author: coppercone2
author_rank: Super Contributor
timestamp: July 07, 2021, 12:57:19 am
content: Quote from: ogden on July 06, 2021, 03:50:37 pmyeah thanks for the psychoanalysis Freud