hybridfree/eevblog-posts huggingface dataset:
thin kilns? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: May 05, 2019, 04:39:51 pm
content: So I have read the kanthal wire equations for kilns and they specify a maximum surface load of heat for a furnace and the equations are typically volumetric, i..e you find surface area of kiln, use wire gauge, etc.Fairly easy if not a bit tedious to design a kiln. You can do it in a few hours.Do all these equations hold true for 'odd' shapes that you don't typically associate with kilns? My idea was to make a dissimilar sheet metal joiner, so say you want to make a copper-steel sheet bond,it would be like a panini press, so the kiln would be really wide but short.do you need to derate anything for this non convectional design?Or if you wanna build a kiln that conforms around some funny shape thats thin, like a U.The idea being so you dont need to heat up a giant volume to heat a thin bit of sheet metal.http://www.west-l.com/uploads/tdpdf/06080303.pdf

author: KL27x
author_rank: Super Contributor
timestamp: May 05, 2019, 09:20:06 pm
content: QuoteSurface area:volume goes up when you make your kiln elongated; hence, you have limited gains in making a kiln in a funny shape. Greater surface area means greater loss to the environment.Equations are fine for gross estimation. Make it. Then optimize.

author: coppercone2
author_rank: Super Contributor
timestamp: May 05, 2019, 10:46:09 pm
content: the idea was actually to make a kind of lego kiln that you can build around a object you want to make out of two layers, with little ceramic blocks that fit into pegs with ceramic rods wrapped in wire around them so you build up a kiln around your oddly shaped part.Like the X + Y would be variable but the Z would be set (perhaps make 3 different coil lenghts) so you can make a contour around whatever.The power supply would need to be a beast though to handle the various combinations. or just multiple suppliesit would only work on parts that are like a curve which is extended on 1 axis in a strait line though, anything more seems like the mechanical work would be difficult and you would need angle pieces and shit.So you can do a bimetalic bracket. If its just a thin bit your limited to working with flat sheets that you need to bend afterAfter the heating layer is assembled you would just put a buncha dummy insulator blocks to fill it into a solid cube.I imagined like a big work station with a buncha these bits in a tool chest and a big fire brick table top etc.
Thin NTC for measurement - Page 1
Forum section: electronics / projects

author: Siwastaja
author_rank: Super Contributor
timestamp: January 05, 2017, 11:06:06 am
content: Hi,I'm looking for thin NTC thermistors for temperature measurement in range of 0 degC to +80 degC. I can easily find products like this on Ebay:http://www.ebay.com/itm/5pcs-Mini-NTC-1B3950K-Precision-Thin-Film-Thermistor-Temperature-Sensor-TTF-103-/282268103962I'm looking for something similar, from a proper supplier, properly specified, reliable and non-drifting sensor in the <$10ea price range. No luck with Farnell or Digikey.http://www.vishay.com/docs/29132/ntcaflex05.pdf($2 on Digikey) seems rather nice, but the 1.4mm thickness is really a tad too much. I'd like to be able to sandwich the sensor between a li-ion pouch cell and a heatsink, or between some cells. The Ebay thing has 0.4mm thickness which is nice.Any suggestions are welcome. Even a digital parasitic powered 1-wire sensor could be considered.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: January 05, 2017, 05:07:19 pm
content: It's not exactly what you've asked for, but you can get 10k NTCs in 0402 and 0201 packages. The 0402 parts are even available in precision grades (<1% tolerances). You could easily mount them on a flex substrate and get something quite thin.Unfortunately they're not so easy to employ as the discs you linked above.

author: mycroft
author_rank: Regular Contributor
timestamp: February 05, 2017, 11:44:59 pm
content: Take a look athttp://www.tayao.com.tw/film.html, it may be useful.

author: mimmus78
author_rank: Unknown
timestamp: February 06, 2017, 12:05:02 am
content: If you just want one that does not drift you can get from temperature body thermometers ... at the end it you may have some broken spare somewhere.
thinnest pic micro package - Page 1
Forum section: electronics / projects

author: wreeve
author_rank: Unknown
timestamp: September 25, 2015, 08:22:51 pm
content: Does anyone know the thinnest package you can get a PIC micro in; would really like 8 pins but 6 will do at a push but it must be very thin! I would be open to other micros if they come in a thin package.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 25, 2015, 08:34:02 pm
content: DFN8 at a guess

author: ConKbot
author_rank: Super Contributor
timestamp: September 26, 2015, 01:36:35 am
content: The VDFN and UQFN packaged PICs are 0.5mm thick (at least the 16 pin ones). I'm surprised digikey doesn't have height as a metric you can sort micros by. They do for a lot of other items.

author: sarepairman2
author_rank: Frequent Contributor
timestamp: September 26, 2015, 01:49:28 am
content: i spy
Thinking of building a 4 to 6 channel USB LiPoHV charger, need some tips. - Page 1
Forum section: electronics / projects

author: John_Edward
author_rank: Contributor
timestamp: March 18, 2017, 06:24:08 pm
content: TL;DR:I need tips on how to build simple&inexpensive USB powered and MCU controller CC/CV source(s), and how to best measure current (high side, low side, opamp, dedicated chip ?) for a LiIo/LiPo/LiHV charger project.I fly micro quads and have slowly amassed a bunch of different 1S lipos between 100mAh to 800mAh, and I've used a very simple"Four TP4056 modules bolted together"charger for my on the field charges. It's worked okay but the charge rate has always been a compromise (as it's preset), and now I have LiHV cells as well (3.8V / 4.35V), so I need a new charger.As far as I know, there are no TP4056 type chips that could easily charge LiPo, LiIon and LiHV (3.6v, 3.7v & 3-8v) cells, and also need an electronics project for school, so I'm thinking of combining these two if possible.(research, custom pcb, tests and measurements, 20 page report, all the good school project stuff)My goals would be small footprint, USB powered, 4 to 6 channels of 1S LiPo/LiIo/LiHV charging, and around 1A max charge rate per channel (total limited by input power ofc).I'm thinking of using an Atmega328 / Arduino as the MCU and using an ADS1115 (15-bit ADC) to guarantee the 50mV voltage accuracy often cited with Lithium charging.Voltage measurement is easy, and for current reading, using a current shunt and amplifying the voltage with an opamp seems to be the solution, though I'm not sure what would be the best way.I'm completely lost on the CC part though, and my CV solution is elementary at best;I've previously used simple transistor CC circuits to drive LEDs, and I can create a Constant Voltage with selectable 4.1/42./4.35 volt output by using an LM317 toggling resistors with transistors, but I don't feel they are the solution in this.As this is a school project with research being one of the parts and learning being the end goal, I'd prefer to get resources and hints instead of straight answers or circuits, although anything to get me started would be a great help.So, how would I best do the CC/CV part, seeing as I would need to basically build 4 or 6 copies per charger, one for each cell, and what would be the best way to keep track of the charge current ?
Thinnest MOSFET Gate Insulator?  - Page 1
Forum section: electronics / projects

author: CaptnYellowShirt
author_rank: Frequent Contributor
timestamp: February 20, 2014, 04:23:05 am
content: Recently, I have been expanding my theoretical knowledge of semiconductor technology. I'd like to reproduce an experiment I have read about and need to find a commercial available MOSFET with a thin gate insulator. Since this parameter doesn't seem to be something that manufactures notability advertise, I am wondering what circuit-design-level characteristics might be linked with a thin gate insulator?The first parameter on my mind was V_gs breakdown voltage. But I am wondering if simply minimizing this parameter gets at the thinnest insulator? Are there other factors to consider?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 20, 2014, 04:51:45 am
content: Highest transconductance too, I think?They're always shooting for the best, so it's still not that you'll be searching for sheer numbers, they'll still be limited by Vgs(max) in that product class.I've haven't heard about actual breakdowns of low voltage types (e.g., Vdss <= 10V, which always have paltry ratings like +/-6V Vgs(max)), but ordinary types (+/-20V) usually break down in the 70-80V range.That, and RF devices, are about all I can think of?Tim
Third Times the Charm, Class D Amp - Page 1
Forum section: electronics / projects

author: gnuarm
author_rank: Super Contributor
timestamp: March 19, 2021, 10:14:39 am
content: I never did find a suitable class D amp to drive a ~1 watt speaker and detect if the speaker was open or shorted. I know, everyone thinks I should just go class AB because it's "so little power". But the entire board isn't using a half watt and I can't see wasting another watt or more on the inefficiencies of an analog amp.So I did manage to find a couple of motor driver chips to do the job. One from MPS was a good candidate. It actually will generate a 250 kHz PWM signal for setting the current into the load based on an incoming, slower PWM signal used like an audio signal. That's perfect since the signal is coming from an FPGA. It likely would be a good match to the job, but the data sheet doesn't describe the switching modes and when I asked the FAE he does everything but answer the question as if he thinks I am asking a wrong question.So I found another good choice from TI, DRV8876. It has a current mirror and direct control over the PWM complete with documentation on the operating modes. The simulation model has allowed me to properly design the output filter and I'm pretty confident it will work fine with very low power overhead. But the current mirror doesn't seem to work in simulation. I posted in the TI forum which is what they do for support these days and someone has replied, but not with anything useful as yet. I found an earlier thread on the same issue where the poster is concluding the model doesn't work in that regard (even though the file itself says it is supposed to work). The FAE in that thread simply replied they did "disbanded" the model writers and there will be no further work on it. What the heck does "disbanded" mean??? Laid off? Reassigned? Shot?So other than not knowing for sure the current output works or exactly how it works, this seems like a good solution. I'm hoping it is just the simulation that is broken and not the chip. It won't be the first time a chip has a defective feature that wasn't fixed.
This guy needs a little help on components for DC charge input protection - Page 1
Forum section: electronics / projects

author: viper
author_rank: Regular Contributor
timestamp: October 04, 2025, 01:24:10 am
content: I'm working on a protection circuit for a DC charge source going into my charger IC. I am designing for OC, OV, reverse polarity, and transient. It would be extremely odd and rare to see reverse polarity but gotta do it just because.So the circuit is this, poly fuse on +, then TVS paralleled on DC +/-, then a schottky on +. The question I need to solve is that TVS. Which direction and should I consider bidirectional? I mean, it would be a freak of nature to have both a huge transient and reversed charge port at same time, but....The issue here is that TVS, if a uni, would normally be placed with anode on the -? So if polarity got reversed, that is now a dead short and blow city for the fuse. Obviously moving the schottky so it is first is the right play, but then the schottky is 'maybe' subject to any transient?I any case, open to other ideas. I don't want to mess with a FET for rev polarity. The charge IC manages current so that fuse is just for whatever reason. As with all fuses, we expect them never to blow anyway.
Thorlabs AMP145 Photos - Page 1
Forum section: electronics / projects

author: electron_plumber
author_rank: Regular Contributor
timestamp: June 14, 2025, 09:24:02 pm
content: Had this transimpedance amplifier lying around long enough for curiosity to takeover. Thought I'd share.https://www.thorlabs.de/NewGroupPage9_PF.cfm?ObjectGroup_ID=7083

author: Benta
author_rank: Super Contributor
timestamp: June 14, 2025, 11:56:31 pm
content: Somewhat outside my knowledge, but seems to have something to do with opto measurements.Lousy hand soldering on the connectors.

author: UnijunctionTransistor
author_rank: Frequent Contributor
timestamp: June 15, 2025, 12:32:55 am
content: Interesting circuit.Several tantalum caps being used. Perhaps to filter the USB-sourced +5v.

author: electron_plumber
author_rank: Regular Contributor
timestamp: June 15, 2025, 01:47:56 pm
content: Input amplifier looks like it could be the OPA847. It must be in a transimpedance configuration, since its the first stage. Not sure about the resistor network on the input. Seems a little odd. Might have to grab the ohmeter and map the traces.

author: electron_plumber
author_rank: Regular Contributor
timestamp: June 17, 2025, 02:37:31 pm
content: Not a TIA expert, so this might be wrong.The resistors on the input appear to be zero ohms. The pads for the three terminal device on the input are interesting -- maybe a dark current cancellation scheme they abandoned?Feedback resistor is lower than I would have guessed... I'm measuring in-circuit, so perhaps a parallel branch is pulling it down. There seems to be an interesting ground-referenced resistor divider (like a common mode bias type of circuit) between inverting and non-inverting inputs.
Those 48V-input DC-DC power supplies...  What do you DO with them? - Page 1
Forum section: electronics / projects

author: westfw
author_rank: Super Contributor
timestamp: September 02, 2020, 12:37:24 am
content: When Dave talks about salvaging parts from his dumpster-diving find, he always says "I'd definitely save the DC/DC converters." An I always have as well... They're also widely available on the surplus market for shockingly low prices.But ... what do you DO with them? Usually they're "telco system" supplies, with a nominal 48V input. Which is generally NOT a very convenient voltage for hobbyist projects, or even prototyping anything (other than telco gear, I guess.) Also, *minimum* output current tends to be pretty high.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 02, 2020, 01:27:09 am
content: Quote from: westfw on September 02, 2020, 12:37:24 amVery convenient for home solar setups and small electric vehicles like bicycles and go carts. Audio amplifiers as well, although in that case it usually makes more sense to have a separate power supply for the logic.

author: digsys
author_rank: Unknown
timestamp: September 02, 2020, 01:53:33 am
content: Not to forget - everyone is moving to PoE and so are vehicles (4x12V). I already service many installations that are 48VDC bus - they've dumped 240VAC, and all other DC voltages. I make up several DIN rail 48VDC <> xx modules, which are becoming quite popular. Oh yeah, and solar as mentioned

author: TheMG
author_rank: Frequent Contributor
timestamp: September 02, 2020, 02:05:38 am
content: Another example, I'm building an HF linear RF amplifier (for amateur radio) which uses LDMOS transistor running at 50V, needed some DC-DC converters to provide the lower voltages for the control logic so the complete unit can be powered from a single (external) 48V nominal supply.
those sipp module edge pins... - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 08, 2015, 12:37:01 am
content: I'm trying to find these pins so I can make an edge plugged PCB adapter.http://images.thomann.de/pics/prod/214610.jpgI found thishttp://www.digikey.ca/product-search/en/connectors-interconnects/terminals-pc-pin-single-post-connectors/1442576?k=edge%20pinsbut it's too expensive. I guess I'm looking for a stamped thing, instead of a machined part.I just want something pretty and pin-looking, I know I could just jam in old LED pins or something.What were these pins called?

author: slateraptor
author_rank: Frequent Contributor
timestamp: July 08, 2015, 01:45:58 am
content: Bingo...Their websitehas a ton of prototype-related stuff.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 08, 2015, 01:47:13 am
content: Quote from: slateraptor on July 08, 2015, 01:45:58 amAw geez I searched for SIPP... duh.Thanks!

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 08, 2015, 06:09:08 am
content: Look up "pin header".
Thought this would be interesting to look at: The iButton 1Wire 64bit ROM - Page 1
Forum section: electronics / projects

author: Bobertsawesome
author_rank: Regular Contributor
timestamp: April 01, 2020, 08:51:22 pm
content: I went to replace a battery in my AstroPhysics remote control and found what looked like another battery that would need replacing. To my shock, it wasn't a battery at all, in fact, it was a type of serial key/unique id system, all contained in what looked like a fat button cell. Doing some research on it, I found that this was pretty advanced for the time (MFG date 2004). I thought this would be interesting enough to share.From the mfg:QuoteNote: These images below pertain to a different model of iButton, but probably the same construction.https://www.cl.cam.ac.uk/~sjm217/projects/ibutton/

author: ArthurDent
author_rank: Super Contributor
timestamp: April 01, 2020, 09:28:03 pm
content: Around the mid 1990s the company I worked for used these to uniquely identify units on a production line. One of these was paired with each unit until it got through final test. They were then reused the next day.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 01, 2020, 09:44:12 pm
content: Do i see a small coin cell inside the ibutton ?? i tought thes ibuttons had a parasite supply mode ?

author: todd_fuller
author_rank: Contributor
timestamp: April 04, 2020, 12:21:37 am
content: Depends on the model. Some are just crypto authentication or unique serial numbers while others log temp, humidity, etc.

author: ale500
author_rank: Frequent Contributor
timestamp: April 10, 2020, 06:18:22 am
content: I worked with them mid 90s, we had developed an application based on the DS1994, they had a lithium battery in them, because they had an RTC. They were called "Touch memories" in those times... Pretty neat devices with internal RAM and RTC and scratpads.

author: Bobertsawesome
author_rank: Regular Contributor
timestamp: April 11, 2020, 08:46:34 am
content: Quote from: ale500 on April 10, 2020, 06:18:22 amSo neat to hear about the past uses. I'm 20, so I grew up in the age of pushing Moore's law to its limits, I didn't get to really analyze the neat things coming out early 2000s. I can only imagine this was really high spec stuff that every company wanted their hands on. I think in this AP Keypad it's the device that holds the authentication data for the software, because back in the day this was the bees knees for telescope mount control. It still is, but the use of devices like the SkyFi where you can control movement with your iPad/iPhone has surpassed it. They were most likely really concerned about reverse engineering.Heres the keypad in question:
Thoughts on the selling of IoT data by companies, particularly in health arena. - Page 1
Forum section: electronics / projects

author: cdev
author_rank: Super Contributor
timestamp: January 26, 2018, 07:24:34 pm
content: I am worried that some of the IOT hardware has the potential to be used to expose large amounts of private data - whereupon it will be used in unexpected ways.The shift to ipv6 will result in loss of Internet privacy. Little known aspects of ipv6 behavior allows lesser known quirks of ipv6- such as ipv6 fragments and ipv6extension headersto be used to penetrate firewalls.Some similar holes seem to be made possible by abusing MDNS services discoveryA great many kinds of data can be collected and exposed by IoT devices.One example of information which will likely be sold is health data.Newer cell phones contain raw data capable GPSs that can reveal the users exact location to a few millimeters (typically less than 2 cm when outdoors with a clear sky view, not quite that accurately indoors but relative accuracy might be good enough to use the data to determine cardiovascular healthMost GPSs that people are used to may log the location at 1 Hz but some newer chips can log up to 20 Hz. (20 times a second)The use of location data by purchasers of exfiltrated data (often without peoples knowledge) can have far ranging repercussions. All of this information will become marketable data.Areas lived could also impact insurance rates because of polluters.Data retention will make it possible to look back in time to determine who was exposed to what retrospectively, and charge them accordingly.

author: Echo88
author_rank: Frequent Contributor
timestamp: January 26, 2018, 10:48:41 pm
content: Please, this is the technical section. Get your huge-battles/potential-storms to the General Chat.

author: westfw
author_rank: Super Contributor
timestamp: January 29, 2018, 10:12:28 am
content: Prescient, much?https://hackaday.com/2018/01/28/opt-out-fitness-data-sharing-leads-to-massive-military-locations-leak/
Thoughts/suggestions on this negative high-ish voltage regulator circuit? - Page 1
Forum section: electronics / projects

author: msat
author_rank: Regular Contributor
timestamp: February 13, 2024, 04:54:46 pm
content: I have a high-ish voltage multi-output unregulated power supply (see attached image), that's just a simple transformer + rectifier. I'd like a way to add some variable voltage control, and preferably regulation for both positive and negative rails independently. I intend on it being an external device that just gets patched to it with cables.Now, I'd be satisfied with simply using an LR8 adjustable high voltage regulator, but they don't have negative rail equivalents. I drew up the attached circuit that uses an LR8 ground referenced to the negative rail (VSS) that controls an emitter follower driving the load - with the regulator's feedback coming from the emitter. I suspect this is a bad circuit, but don't really understand why. Will noise on VSS not get rejected? Would that matter if none of the transformer taps were earth referenced? Is the regulator even being of any use?Thoughts/tips/suggestions are appreciated!

author: msat
author_rank: Regular Contributor
timestamp: February 13, 2024, 06:11:42 pm
content: Ok, I'm pretty sure the circuit is not tenable because in order for the input of the regulator to be at a higher potential than the output relative to it's ground reference, the output would have to be more negative than the input, which isn't possible. I need to come up with something else.
Thread to help on my gpsdo on instructables.com - Page 1
Forum section: electronics / projects

author: Yannick99
author_rank: Contributor
timestamp: November 21, 2018, 06:22:59 pm
content: Hi everyone, this thread is for all of you building my gpsdo.https://www.instructables.com/id/GPSDO-YT-10-Mhz-Lcd-2x16-With-LED/I received some questions. And the comment section is not the best way to do troubleshooting. So i start this thread here for that. Like that, anyone building or not the device can contribute.
Threaded-axle stepper motors as lock pins - Page 1
Forum section: electronics / projects

author: Nominal Animal
author_rank: Super Contributor
timestamp: September 23, 2018, 10:18:31 pm
content: Has anybody used the ubiquitous micro stepper motors with a threaded axle as electronic lock pins in their own projects?The usual suspects sell a variety of micro-sized stepper motors, whose axis/axle is a threaded rod. (One examplefrom fleabay, 4mm diameter.)I was thinking of sleeving the motor using a 3D print, so that it moves linearly in another 3D printed part in a hollow without rotating: the entire motor moves. At one end of the hollow the axle pokes out, and is sufficiently thick-walled to be threaded for that axle. (You might need something like a bit of thick brass sheet to make that hole keep the threads.)In essence, this would be a miniature solenoid-like device, with a pokey end that can extend/retract ~ 5mm, in a cylindrical shape of about 10mm in diameter, 15mm in length, including both the outer wall and the motor sleeve.Considering you can get a dozen of these for a dollar, and an ATtiny or similar is sufficient to drive one (perhaps with a couple of transistors or a Darlington array chip), this seems like an obvious way to implement "locking pins" to 3D printed and woodworking jewelry boxes and electronic puzzle boxes and similar. Unlike solenoids used in many locks, you cannot bump these or unlock them with a strong enough magnet. Anyone done this yet?
Threaded pogo pins - Page 1
Forum section: electronics / projects

author: negativ3
author_rank: Regular Contributor
timestamp: July 18, 2022, 10:22:42 am
content: Hey all, I am seeking advice regarding threaded pogo pins.Specs I'm looking for are M3 threaded male, 9-11mm PCB mounting height, so pogo operating length at 10mm would be ideal.I have searched many different sites and so far solder cup and smooth end terminations seem to be the most popular, seems to be for PCH TH application.Any pogo pin gurus out there?Thank you.
Three phase transformer conundrum - Page 1
Forum section: electronics / projects

author: woodchips
author_rank: Frequent Contributor
timestamp: April 03, 2020, 11:15:24 am
content: Apologies to all those who find some flat bits of steel and copper windings to be oh so ancient and boring.Needed a large transformer and bought several three phase ones to play with.Each transformer is a standard three limb three phase type, each limb is identical with a 230V primary and a 14V secondary. The primaries are connected in Wye to give a 400V 3ph 50Hz input. Similarly the secondaries are connected in Wye to give a 24V 3ph output.All windings have been isolated so no connection between any of them. All testing done with no load.One primary on an outside limb connected to 230V supply. What voltages would you expect to see across the other five windings? Why?Two primaries, one on an outside limb, one on the centre limb, are connected in parallel to 230V with the winding phasing such that the magnetic flux from each winding is adding, so in series. What voltages would you expect to see across the other four windings? Why?As previous connection except that the primaries are the ones on the two outer limbs. What voltages would you expect to see across the other four windings? Why?Have a think!

author: trobbins
author_rank: Frequent Contributor
timestamp: April 03, 2020, 12:19:11 pm
content: What's the point of double posting this here, especially when you don't offer the measured levels, or do any more supplementary tests to extend on what you did last week (or whenever it was on another forum).

author: duak
author_rank: Super Contributor
timestamp: April 04, 2020, 12:18:14 am
content: Well, since the flux generated by the driven winding is divided in two, the other legs each get half. Since the voltage on a winding is a function of dFlux/dt, the other primary windings will develop about half the voltage of the driven winding. The secondary windings will develop a voltage that is proportional to the voltage on the primary winding they share a leg with.

author: woodchips
author_rank: Frequent Contributor
timestamp: April 04, 2020, 10:09:26 am
content: Have I double posted it here? Where?Yes, as duak says, my conclusion was similar that there are two opposing fluxes in the third limb which cancel out.I just wonder if this was an exam question what the answers would be, whilst very basic, does anyone actually get taught the basics no or is is all on the internet?
Three-terminal capacitors for EMI filtering - Page 1
Forum section: electronics / projects

author: aylons
author_rank: Unknown
timestamp: January 18, 2018, 07:10:03 pm
content: Hi!I have an EMI problem that I've mostly solved. It is a teeny tiny noise noise coming from inside a ethernet PHY IC, around 500 MHz. By teeny tiny, I mean -130dBm after two 20dB amplification stages. But it really has an impact in out measurements, and I'm working on getting rid of it.Some strategically placed 100pf capacitors (not in the supply pins, which already had them!) really helped in the prototype, and now I'm designing the next iteration of the board. To get really safe, I'm pondering on using these 3-terminal capacitors from Murata:http://psearch.en.murata.com/capacitor/product/NFM15CC222D1A3%23.htmlThese are 2200pf caps with SRF above 1Ghz! Sounds almost too good to be true. I've already used some similar capacitors (even in the same board), but they were 0603 and not so big. Also, I have not yet tested them to their full extent, meaning, I'm not yet sure that they are truly better than some properly placed 100pf+10nf+friends.Does anyone here have experience on them? This is a short-run, high-stakes, short deadline design, so the increased cost is not an issue.Thanks!
"Three wattmeter averaging method" for measuring 4-wire Wye - Page 1
Forum section: electronics / projects

author: 741
author_rank: Frequent Contributor
timestamp: January 28, 2020, 04:59:36 pm
content: In "Power Metering Fundamentals" (http://spanglerprototype.com/pwr_monitor/Power_Measurement_Tutorial_v2.0.pdf) it is stated thatQuoteThere us not a phasor or algebraic proof, just some examples.I wondered whether there was a proof of this? I get one result (that same paper) on Google for this search termPower "three wattmeter averaging method"The paper indicates it was written while the author worked for Cirrus Logic.At present I'm wondering whether, for the CS5463, I will need to multiply any results read back by 2. I have not yet read the DS in depth, just finding my bearings. The DS does not seem to mention this.Also, I am unsure up to what harmonic the harmonic results are for, and whether I get a sum or need to read in each one separately. Clearly it is related to samples/sec & line frequency.For the end application though, measuring power consumed, I think I simply use the "Active (Real) Power Register".

author: capt bullshot
author_rank: Super Contributor
timestamp: January 28, 2020, 05:48:40 pm
content: What I can see from a quick glance over that paper:The author claims that 3 wattmeters connected without Neutral give the same result as 3 wattmeters with artificial Neutral. Just a little difference in final result calculation, for the latter case you just add the three readings (of real power), for the first case you'll have to add them too, but multiply the result by 2/3. This results from each wattmeter sensing phase-to-phase voltage instead of phase-to-(artificial)neutral voltage, that's plausible so far.For measuring 4 wire unbalanced loads, the correct method would be to connect each wattmeter voltage sense between the phase and the neutral. An artificial neutral is a workaround if the neutral isn't available, the described method saves the artificial neutral (if it is done in hardware). As far as I could see, nothing was said about a offset or "shifted" real neutral (that would differ from the artificial neutral), resulting in different phase to (real) neutral voltages. With the artificial neutral different from the real neutral, the results of both methods would be questionable in the first place.There's a lot of different power line systems in the world (from an European view the weirdest to be seen in the US of America) - but there's one simple rule: for correct power measurents under all conditions you need one wattmeter less than the wires and all wires connected to the correct arrangement of meters. Four wire installations give best results with Wye connection scheme including the real neutral. For three wire Delta configurations without a neutral, two meters do the job (Hint: Aron connection). For active (real) power, add the results of all involved meters.The author mixes the topic a bit with sampling, so the reference to averaging the results over a whole number of power cycles - usually you don't have to care about that if you just use a metering chip outputting results like "Active (real) power" and so on.
three way buffer replication of a special kind on pulse - Page 1
Forum section: electronics / projects

author: john23
author_rank: Frequent Contributor
timestamp: July 17, 2024, 12:27:05 pm
content: There is a pulse shown in the picture.The pulse voltage are -2V to -5V and the width is 200ns.Is there a component which could take this pulse and relpicate it three times?Three outputs which are equal to the pulse i entered.Thanks.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: July 17, 2024, 07:58:42 pm
content: You did not mention the load this drives, nor the spacing between pulses ?You have a 3V swing, so any MCU or logic put between -2V and -5V rails will give that.Most CMOS Logic / MCUs will be slightly faster rise times than your display.CMOS logic would need a sprinkling of parts - something like a HC4017 gives you some pulse choices.Or, almost any small MCU could do that, either use PWM + SW, or just SW alone bit-bang.A 50MHz Sysclk will have 20ns granularity in timing.

author: David Hess
author_rank: Super Contributor
timestamp: July 17, 2024, 08:35:06 pm
content: A current feedback operational amplifier, or fast voltage feedback operational amplifier, can replicated it exactly, including the leading and trailing edges.A differential pair of transistors, with resistors and diodes, could duplicate it.
Threshold Crossing Detector Help - Page 1
Forum section: electronics / projects

author: veryevil
author_rank: Unknown
timestamp: May 15, 2011, 05:35:03 pm
content: Hi, I've been trying for a while now to detect when a voltage crosses a threshold. I've been using comparators. First the LM311 and now theTL3016.The threshold I'm after is 2.5v and I've been trying to use a hysteresis of around 100mv but nothing seems to work. Either its very noisy with HF spikes or the hysteresis seems not to be centred.Ultimately I am try to detect zero current through a motor using a current shunt and current shunt monitorLT1999orINA282.These both give a voltage dependant on current and direction and is centred around 2.5v.I used the LT1999 with its reference voltage pin into the TL3016 but it loaded it and affected the reference voltage. I then passed the reference though a MCP602 as a voltage follower and then into the TL3016 and this gave me a perfect output that triggered when the motor current was at zero (LT1999 output at 2.5v) however it only worked when my motor was in one direction. My motor drive uses PWM through a H-Bridge and runs in both directions.Any ideas on getting the signal I need? Or another way of getting zero current through a motor?

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 15, 2011, 06:54:59 pm
content: show your circuit.

author: Zero999
author_rank: Super Contributor
timestamp: May 15, 2011, 07:35:18 pm
content: Is the power supply voltage regulated?What's the required tolerance?If your power supply has adequate tolerance just use a potential divider across it and a suitable feedback resistor, for example if you're running it from 5V, use two 12k for the potential divider and 300k for the feedback. The output impedance of the potential divider is 6k which with 300k will give 100mV of hysteresis: 5*6/300 = 0.1V

author: Rufus
author_rank: Super Contributor
timestamp: May 15, 2011, 07:42:06 pm
content: Quote from: veryevil on May 15, 2011, 05:35:03 pmIf you are trying to sense zero (or actually less than a small value of) current with a bipolar voltage indication of current you need a window comparator.That is two comparators, in your case with thresholds set at say 2.4 and 2.6v and the outputs ored together.

author: veryevil
author_rank: Unknown
timestamp: May 15, 2011, 09:41:26 pm
content: A window comparator seems to be the answer. I've set up a MCP602 as one with two trim pots for now and it seems to be working a treat. I should be able to shrink the window when its not on breadboard as there will be less noise.Thanks Steven
Through hole capacitive touch controller? - Page 1
Forum section: electronics / projects

author: lazarusr
author_rank: Regular Contributor
timestamp: March 12, 2017, 06:31:13 pm
content: Is anyone aware of a through hole capacitive touch controller that is currently available. I am working on a touch sensitive synth keyboard which I may wish to produce as a kit.My current best choice for the touch controller is the is the Microchip MTCH108 which is in a SSOP-28 package. I had hoped to go for the QT161 which is DIP28 as many kit builders are less keen on SMD parts but it is obsolete and I cannot find a source for NOS (having looked in all the usual places including UTSource, ICSeek, HKInventory, LittleDiode etc..I am not optimistic of finding something suitable. There is nothing through hole on Digi-Key, Farnell, Mouser or RS.But thought it worth a post here just in case.

author: mclemens1969
author_rank: Contributor
timestamp: March 12, 2017, 07:27:48 pm
content: If the quest for through hole is due to soldering, then worst case, you need to order an SMD chip on a through-hole carrier:http://www.proto-advantage.com/store/product_info.php?products_id=3100180Those guys will acquire digikey parts for you, solder them on, and send them to you.

author: lazarusr
author_rank: Regular Contributor
timestamp: March 12, 2017, 07:43:56 pm
content: Thanks. I wasn't aware of that service. However, it would be prohibitively expensive. With three chips required, it would increase the cost for these chips alone by over €38 per kit.If I am unable to source a through hole solution I was going to sell the kit with the TSSOP device (I don't personally think these are two hard to hand solder - and I can design the PCB with extra long pads to aid hand soldering) and offer PCBs with the SMD chips pre-soldered to those who don't feel able to do this.

author: lazarusr
author_rank: Regular Contributor
timestamp: March 12, 2017, 08:00:11 pm
content: Quote from: blueskull on March 12, 2017, 07:44:13 pmThanks. I will have a look at that. I will have to have two of these MCUs talking to each other as I need 24 touch keys and 4 more digital pins to talk to the sound chip.
through hole crimping tool - Page 1
Forum section: electronics / projects

author: Homer J Simpson
author_rank: Super Contributor
timestamp: November 08, 2012, 08:13:49 pm
content: A while back Dave did a video where they discussed a crimping tool that put a "kink" in the lead to keep the component elevated off of the PCB.I have done some searching but to no avail.Does anyone have a brand or a link?Thanks

author: SeanB
author_rank: Super Contributor
timestamp: November 08, 2012, 08:16:35 pm
content: Google Lead former...

author: Short Circuit
author_rank: Frequent Contributor
timestamp: November 08, 2012, 08:24:34 pm
content: Here's one at a dutch webshop;http://www.printtec.nl/contents/nl/d479.html

author: Homer J Simpson
author_rank: Super Contributor
timestamp: November 08, 2012, 08:35:22 pm
content: Thanks, "lead former" was the search I needed.Those Italian ones look nice. Anyone know a US supplier?I was thinking of this onehttp://www.amazon.com/gp/product/B000IBQEZQ/ref=ox_sc_act_title_1?ie=UTF8&smid=ATVPDKIKX0DERAnyone have one?Thanks

author: mariush
author_rank: Super Contributor
timestamp: November 08, 2012, 08:50:04 pm
content: See the thread here, and my comments in particular:https://www.eevblog.com/forum/manufacturing-assembly/ramping-up-through-hole-board-production/15/I've posted links to those Piergiacomi tools and the thread may give you other suggestions.ps. there are some pliers from them that trim the lead on the other side, bending it at the same time. Besides pliers that bend the leads in different shapes. Check the links.

author: Homer J Simpson
author_rank: Super Contributor
timestamp: November 08, 2012, 09:02:48 pm
content: Well I went ahead and ordered the Xuron 573L.http://www.amazon.com/gp/product/B000IBQEZQ/ref=ox_sc_act_title_1?ie=UTF8&smid=ATVPDKIKX0DERLooks like all I need.Amazon also has a great deal today on A Wiha micro bit driver, (made in Germany), for $21.77. Free shipping over $25.http://www.amazon.com/gp/product/B002PJ3IYE/ref=oh_details_o00_s00_i00Thanks
Through hole SMA connector to coplanar waveguide... Ground plane clearance? - Page 1
Forum section: electronics / projects

author: TERRA Operative
author_rank: Super Contributor
timestamp: January 12, 2024, 11:00:30 am
content: I'm finalising design for the optional 3GHz input on my HP53132A counter and have a question regarding the SMA connector.It is a through hole connector feeding a coplanar waveguide with ground, with the connector on the opposite side of the 2-layer FR4 PCB and I am looking for guidance on how to correctly space the ground plane from the through hole pad?See attached image for a relatively recent board revision. Connector on the left.Can anyone help shed some light on this for me?

author: tszaboo
author_rank: Super Contributor
timestamp: January 12, 2024, 11:18:53 am
content: I'm struggling with similar issue, and the lack of simulation software. Here is some reading material.https://www.we-online.com/components/media/o563287v410%20ANE012d_EN.pdfI would remove the thermal cutouts for the GND though.

author: TERRA Operative
author_rank: Super Contributor
timestamp: January 12, 2024, 02:58:42 pm
content: Yeah I saw that document. If only they would give a clue as to how far to pull back the ground plane.......I've made the modification to my design, the size of the hole in the ground plane is arbitrary at the moment until I can calculate it.

author: tszaboo
author_rank: Super Contributor
timestamp: January 13, 2024, 03:27:10 pm
content: Quote from: TERRA Operative on January 12, 2024, 02:58:42 pmThe pullback depends on your stackup. So there is no one good answer here.

author: TERRA Operative
author_rank: Super Contributor
timestamp: January 13, 2024, 05:55:35 pm
content: I'm just using standard 2-layer 1.6mm thick FR-4 with 1oz copper. Nothing special at all.

author: tooki
author_rank: Super Contributor
timestamp: January 13, 2024, 06:07:01 pm
content: Is your clearance between coplanar waveguide and ground plane guessed or calculated? If it's calculated, I'd use the same and call it a day (and make the pad as close as possible to the size of the CPWG).
Thru-hole soldering with thick board substrate - Page 1
Forum section: electronics / projects

author: AussieBruce
author_rank: Regular Contributor
timestamp: September 20, 2022, 08:49:36 am
content: I’m designing a major upgrade of a PCB-resident device that I first created a very long time ago. It needed, and needs to be physically robust, including the PCB, and the original used a thicker than usual board substrate – can’t recall the specifics but it eyeballs at a bit under 2.5mm thick.The original device used almost totally discretes, and could be done on a single layer board, whereas the new one will use digital devices. I’ve managed to avoid anything smaller than 0.1” pin spacing, but trial runs with the PCB design tool have confirmed that 2 copper layers will be required. How thick a board can thru-plating (eg. vias) be implemented on reliably? This is a small run item, so a bit of extra cost is no problem. Thanks for any info.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 20, 2022, 09:02:58 am
content: Look at the options at ALLPCB and PCBWay to give an idea of what's possible without getting really expensive.I think the main thing to note is that the minimum hole size probably increases as thickness goes up due to the hole aspect ratio - don't expect to do 0.25mm holes in 3.2mm material, but I doubt you'll have issues with sort of hole sizes used for through-hole parts
THS4531A Fully Differential Amplifier - Single Ended to Differential Help - Page 1
Forum section: electronics / projects

author: Haeden
author_rank: Newbie
timestamp: June 10, 2025, 10:52:33 pm
content: My goal is to interface a 0.5-2.8V single ended/pseudo differential signal to a differential ADC (Specifically the ADC3908S025) which accepts a 1.9Vpp 1.25Vcm differential signal.It seems that using a fully differential amplifier is the correct way to achieve this result.Using a fully differential amplifier (THS4531A) I can produce a 2.3Vpp 1.25Vcm differential signal.However I am not sure of two things:1. How do I make the output differential signal 1.9Vpp instead of 2.3Vpp?2. I have limited experience with amplifiers so if someone could sanity check my schematic to make sure it wont explode in real life that would be appreciated.Top Plot: Signal Source OutputMiddle Plot: Amplifier InputsBottom Plot: Amplifier Outputs

author: Terry Bites
author_rank: Super Contributor
timestamp: June 28, 2025, 06:10:35 pm
content: Yes, this is exactly what the doctor ordered.I think this is a measurement issue not a circuit one. It aint 2.3V differential unless there's some crazy wiring error.The output is not referenced to ground but Vcm.The ADC sees the difference of the outputs centred around Vcm. Happy days.Use your scope to do the math for you. eg Ch1-Ch2. All dual channel scopes made since the stone age can do this with ease.I have simulated it here for you. It does exactly what you'd think. It removes the input common mode voltage, applies gain and adds an offset to centre the outputs it for the ADC input range.Easy.

author: moffy
author_rank: Super Contributor
timestamp: June 28, 2025, 08:55:57 pm
content: If you wish to reduce the output amplitude just reduce the values of R12 and R13 proportionally.

author: bson
author_rank: Unknown
timestamp: July 01, 2025, 09:01:25 pm
content: I don't get it. V2 is a differential signal. How do you imagine you're going to input a single-ended signal in its place?I'd suggest connecting the ground input to the negative input and the single-ended signal to the positive input. This way you get some common-mode rejection, even more so if you buffer them on the input end, but it will of course never be as good as with a differential input.
THT and SMD component holder - Page 1
Forum section: electronics / projects

author: mattko
author_rank: Contributor
timestamp: August 11, 2025, 08:12:01 am
content: Hi all,I got at work and older S-parameter network analyzer HP 8753ES 30kHz-6GHz with Agilent 85047A 300kHz-6GHz test set. I'm testing some component and filter impedance/attenuation for EMC issues and design. My issue is that I usually have to solder the components to a small PCB to make a good connection. I tested once the B-WIC and B-SMC test fixtures with the bode 100 and they work great. I don't think they are compatible directly to the network analyzer, I think some resistors would have to be take out. are there some good alternatives to the B-WIC and B-SMC test fixtures, especially lower cost, to make swapping SMD and THT components easier for testing? Ideally come gold plated spring contacts. Any ideas?https://www.omicron-lab.com/products/vector-network-analysis/accessories/impedance-test-fixtures-b-wic-b-smc