hybridfree/eevblog-posts huggingface dataset:
Any reason I can't substitute a polarised electrolytic with a non-polarised one? - Page 1
Forum section: electronics / projects

author: setq
author_rank: Frequent Contributor
timestamp: August 24, 2016, 11:06:24 am
content: I've only got a suitably valued non-polarised ones on hand. Is there any technical reason (leakage/noise etc) why I shouldn't sub a polarised one with a non-polarised one?These are for inter-stage coupling between two class A's and in a relatively low frequency amplifier (~1KHz) and supply decoupling and nothing else.

author: Zero999
author_rank: Super Contributor
timestamp: August 24, 2016, 11:20:48 am
content: The fact that the capacitor is non-polarised will not make any difference.What value is the capacitor and what's the dielectric?The only potential problem is if the replacement capacitor has a crappy dielectric, as is the case with ceramic capacitors with a Z5U or Y5V dielectric, which can cause the capacitance to be much lower than specified, with increasing voltage. The reduction in capacitance means the capacitor will have a higher then expected AC impedance and can cause distortion, especially if the AC voltage across the capacitor is significant, compared to the capacitors rating.If the replacement capacitor is film, paper or aluminium electrolytic, then it shouldn't be a problem.

author: setq
author_rank: Frequent Contributor
timestamp: August 24, 2016, 11:35:04 am
content: 1uF. Rated 35v but signal p-p is only 200mV and the supply is 8v. Cheap ass no brand aluminium electrolytic unknown dielectricThanks for the info. I'll sub them and see what happens.

author: timb
author_rank: Super Contributor
timestamp: August 24, 2016, 11:41:37 am
content: Quote from: setq on August 24, 2016, 11:35:04 amAluminum Electrolytic *is* the dielectric.

author: setq
author_rank: Frequent Contributor
timestamp: August 24, 2016, 11:47:48 am
content: Good point.

author: wraper
author_rank: Unknown
timestamp: August 24, 2016, 11:50:44 am
content: Quote from: timb on August 24, 2016, 11:41:37 amActually dielectric is an aluminum oxide layer.
Any recommendations for Qi transmitter ICs - Page 1
Forum section: electronics / projects

author: dmc0162
author_rank: Newbie
timestamp: October 09, 2017, 05:33:32 pm
content: Hello all,I have been lurking for a long time, but this is my first post.I am looking into making a Qi transmitter circuit, and I am searching through some of the chips available from TI and the like. Does anybody have any recommendations for transmitter control ICs? I was looking at the BQ500212A from TI, but almost all of their products in the category are listed as NRND (Not recommended for new designs). Is this because these were designed around the WPC Qi 1.1 standard, and we are now on 1.2?http://www.ti.com/product/BQ500212A/descriptionThanks in advance!

author: trevwhite
author_rank: Frequent Contributor
timestamp: October 09, 2017, 05:35:29 pm
content: IDT do cheap ICs along with cheap dev kits for them. TI I believe are withdrawing from the market and were not the cheapest anywaySent from my SM-G950F using Tapatalk

author: dmc0162
author_rank: Newbie
timestamp: October 09, 2017, 05:40:56 pm
content: Ah, that would make sense. Their offerings do seem outdated. Thanks for the suggestion, I will check it out.
Any reference for these power plugs ? - Page 1
Forum section: electronics / projects

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: March 24, 2015, 07:58:24 am
content: Does anybody knows any source for these power plugs that come fromsome 1980's equipment ?ThanksEdit: i am searching for the female plug of the power chord.

author: Lunasix
author_rank: Regular Contributor
timestamp: March 24, 2015, 09:38:17 am
content: I've seen many of these plugs on test equipments, produced between 80 et 90. But I don't remember the brand an I'm unable to get one.

author: dom0
author_rank: Super Contributor
timestamp: March 24, 2015, 01:13:31 pm
content: Looks like theres some writing on the base of the connector. What does it say?Any stamped symbols anywhere?

author: Neilm
author_rank: Super Contributor
timestamp: March 24, 2015, 07:51:35 pm
content: There are a lot of those high current plugs around - I know Tycho, Bulgin maybe Hirose make similar. My first thought looking at the thumbnail was they were D38999 or similar style that Amphonol makes, but I don't think they are.
Any schlumberger experts that can help? - Page 1
Forum section: electronics / projects

author: RAPo
author_rank: Super Contributor
timestamp: June 18, 2023, 03:10:22 pm
content: I've got two Schlumberger f30s signal generators.The oldest one works, but the lowest output frequency is 38kHz, not 10kHz as stated in the documentation.The newest one is intermittent. If I engage the MHz oscillator, the output is very chaotic, and no stable triggering is possible.Any pointers on how to resolve this?

author: coppercone2
author_rank: Super Contributor
timestamp: June 18, 2023, 06:37:00 pm
content: did you have a look inside to look for obvious failures?Regardless of what older equipment it is, you definitely want to check if there are leaks burns and broken solder joints and bad crimps. There is a good chance your problem will be mitigated or go away..

author: RAPo
author_rank: Super Contributor
timestamp: June 19, 2023, 06:49:15 am
content: No, as soon as the generators came in, I did a kitchen table test.These things are large and heavy. I need to make room on the bench before I can take them apart.

author: coppercone2
author_rank: Super Contributor
timestamp: June 20, 2023, 12:30:38 am
content: I think its a long shot to expect someone will know the answer to random damage for a esoteric function generator. I am waiting for the forum to impress me.My recommendation for those is a ~3x3 foot table you can sit under but also walk around 360 degrees, a parts tray and a meter on a nearby shelf. Or some kind of rotating platter if you have the the bench space to have it open on your bench.I like the stand alone table because you know that is gonna sit open for like a month before you fix it and DOS your bench. Big equipment repair for lab bench = mandatory holiday when you open it up and find out you need to order parts with 3 weeks shipping. Its like having a fucking pizza box.You really got yourself a logistics challenge there IMO.

author: RAPo
author_rank: Super Contributor
timestamp: June 20, 2023, 06:44:56 am
content: True words. I do have a logistic problem. Thank you for the heads-up.
Any serial analysis fixtures available for HP166x logic analyzers? - Page 1
Forum section: electronics / projects

author: bit_slicer
author_rank: Newbie
timestamp: September 11, 2014, 03:29:33 pm
content: I'm going cross-eyed reading my serial streams bit-by-bit on my LA. Does anyone know if there exists some sort of test add-on for these old LA's that can parallel-ize serial data streams? (or any other such test fixtures for that matter!) Ideally I'm looking for something that has:* A real PHY for the most popular serial standards (RS-232/422/485, USB?, etc.)* Multi-channel s2p ports* Plug the 40-pin connectors directly into the test fixture without having to use flying leads* Configurable for start / stop / flow control* Needs to show a near real-time capture along with other LA signals (an off-LA system might work if it had a trigger input)It might be possible to set up a trigger sequence in the LA to capture data, but I'd rather have the option of saving the trigger sequence for other events.Does any such thing exist?
Any servo experts here? - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: November 13, 2024, 05:39:22 pm
content: I'm planning to add CNC capability to the cross-slide of a lathe. I want to maintain the ability to use the cross-slide manually. From past experience using a stepper is not a good idea because even with the stepper disabled, the magnetic poles in a stepper don't allow it to turn smoothly. I have some ac servo motors and when disabled they spin freely.I have never used a dc servo, not sure if they are free-wheeling like an ac servo or stepper like when disabled?When rotated manually I would imagine a back emf will be generated, however any manual rotation will be quite slow because it will be done by hand. Do I need to be concerned with that back emf effecting the servo drive?

author: jpanhalt
author_rank: Super Contributor
timestamp: November 13, 2024, 08:32:02 pm
content: Coreless hobby servos are easily moved when not powered. I also have an integrated servo from Stepperonline (iSV57T(S)). It moves freely when not powered with just a little cogging feel. Clough42 used a similar servo for his ELS YT series. I don't know about other industrial servos.Edit: As for generated voltage, I suspect any DC motor will do that. A DPDT switch will solve the problem. Shorting the terminals will make it into a brake, but at slow speed, that probably won't cause much resistance..

author: H.O
author_rank: Frequent Contributor
timestamp: November 14, 2024, 08:19:35 pm
content: Yes, spinning the motor shaft will generate voltage.On a standard, cheap DC motor you will feel cogging but an actual PMDC servo motor has very little cogging and is smooth and easy to spin by hand.The output stage of the servo drive is, most of the time, an H-bridge built with MOSFETs. These MOSFETs contains diodes which basicallly forms a bridge rectifier with the motor at its AC terminals and the servo drives power supply at the DC terminal.This bascially means that the voltage generated by the motor gets rectified and placed across the drives power supply. If you spin the motor fast enough it'spossiblethat voltage generated is high enough to actually power up the drive (if the drives logic supply is derived from the motor supply).Easiest way is propably to have the drive powered up but with the output stage disabled (if the drive has an enable input). That way the DC terminals on that "bridge rectifies" sits at whatever voltage the power supply delivers and there's likely no way you can spin the motor fast enough to get any current flow. Basically the motor terminals are "open".
Any Silk Screen for the 20MHZ MAX038 Function Generator ? - Page 1
Forum section: electronics / projects

author: Timo
author_rank: Newbie
timestamp: October 20, 2011, 07:00:22 pm
content: Hello everyone,I am interested in building a Max038 function generator (based on project by D. Jones). I have details of the circuit and two copper side PCB layouts but no silk screen to help components' placement. This project was originally published (not sure on what date) on Electronics.alternatezone.com.I would be grateful for any help with this.Kind regardsTal
Any SoC with a gyro ? and Bluetooth ? - Page 1
Forum section: electronics / projects

author: Zog
author_rank: Regular Contributor
timestamp: June 07, 2021, 08:14:40 am
content: I see the tile and it's equivalents use these chips.DA14580Nordic Semiconductor nRF51822CSR1010A05(taken from a 2016 article)Does anyone know of any SoC chips that have a gyro built in ... and bluetooth ?Are there any sites I could go to to see the latest advances in this field ?Cheers

author: Benta
author_rank: Super Contributor
timestamp: June 07, 2021, 08:49:44 am
content: Try STM.

author: RES
author_rank: Regular Contributor
timestamp: June 07, 2021, 09:15:18 am
content: https://www.nordicsemi.com/News/2020/09/Sensry-Kallisto-employs-nRF52832-for-sensorbased-applications?

author: Zog
author_rank: Regular Contributor
timestamp: June 09, 2021, 03:00:30 am
content: Oh... nice. Thanks for the heads up.So many to wade though it's insane.

author: DrG
author_rank: Super Contributor
timestamp: June 09, 2021, 03:27:23 am
content: Arduino Nano 33 IoThttps://store.arduino.cc/usa/nano-33-iot-with-headersublox wifi/ble and an LSM6DS3 IMUhttps://content.arduino.cc/assets/st_imu_lsm6ds3_datasheet.pdf
Any Standard for min R between person and High Voltage? - Page 1
Forum section: electronics / projects

author: max_torque
author_rank: Super Contributor
timestamp: April 25, 2016, 09:49:26 pm
content: Most literature suggests that an average person can feel something like 1mA or more current flowing, which for say 1kV would mean an min series resistance of 1Meg if you wanted to be able to safely touch it. But is there any standard for this?

author: Zero999
author_rank: Super Contributor
timestamp: April 25, 2016, 10:24:37 pm
content: I'm not sure what you're asking.Are you talking about using a resistor to bridge an isolation between the mains and SELV (Separated Extra low voltage), exposed metal parts or protective earth?If so, then it isn't just the resistance which matters, the maximum voltage rating is important too. Look up Y-rated capacitors. The maximum permitted current through the resistor, withstand voltage and flammability of the resistor will need to be the same or better than a Y-rated capacitor used in the same situation.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 25, 2016, 11:03:57 pm
content: Maximum ground leakage current is a similar spec. Usually a few mA, depending on which standard you're working to.I forget if I've seen what's required between SELV and mains. 2.5kV is a typical peak voltage requirement. Not sure about current (aside from not jumping a spark).Tim
Any ideas on how to time or otherwise restrict firmware to allow evaluation? - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: September 03, 2024, 08:45:59 pm
content: Hi,I have made some PCBs with and written some related firmware for a client. They have been running late with a payment but being a new client and also having paid all other invoices on time and being easy to work with, I don't want to make a big deal out of it. But, at the same time, I want to make sure they clear the invoice asap.So would like to send them downloadable code (not the source code) via email so they can check it works exactly as per new agreed specs (just in case that is the reason why they might have delayed the payment) but also so that it works only for a limited time. Then I can send them the fully unlocked code when the invoice is cleared.I am using an STM32 (on custom PCB I designed for them). Any suggestions on the simplest way to do that without wasting much time writing a lot of code? Perhaps there are some freeware libraries I can use?Thank you

author: globoy
author_rank: Frequent Contributor
timestamp: September 03, 2024, 08:58:58 pm
content: Been there, done thatDo you have a loop anywhere (e.g. a main evaluation loop)? If so just get the HAL ticks somewhere in it and when they cross some limit (your timeout) go into an infinite loop (maybe tickling the WDT if you have it enabled). They have to power cycle to run it again. You could get fancier (if you wanted) and store some a count incremented each time the device came out of reset to a persistent storage (or some kind of non-volatile memory) and immediately enter an infinite loop if that count was higher than a number of times you wanted them to be able to use try the device out.I had a client who always paid late (but he eventually paid). We got to a point in the project where we had to make a bunch of units for testing and demo purposes. I could actually see him trying to sell them and running with the prototype code so I plastered things like "Engineering Prototype", "Not for resale" all over the GUI. It was a successful gambit :-)
any suggestions/improvement for this power supply circuit - Page 1
Forum section: electronics / projects

author: meisstupid
author_rank: Newbie
timestamp: June 29, 2023, 07:45:09 am
content: I want to power my laptop with a 3s li -ions battery and also want an electromagnet to turn on when I send 433mhz rf signals.This is a simplified circuit(attached blw) and I want to have suggestions or any possible improvements.I am using 2 converters as a bust-boost one is NA in my area.the step-up is rated for 150w while the step-down is rated for 300w. my laptop needs 19.5V at 3.34A = 65w.the electromagnet is used to create a magnetic field that can be detected by my laptop's hall sensor and into sleep.ThanksPS> I am new to the field of electronics.

author: mariush
author_rank: Super Contributor
timestamp: June 29, 2023, 08:52:29 am
content: Your laptop doesn't need 3.34A constantly, it will take only as much as needed, for example if you lower the lcd screen brightness and the laptop only consumes 25 watts, then the internal power supply will take only around 26w / 19.5v = ~ 1.33A (it's a bit more due to conversion efficiency)The dc-dc converter inside the laptop is not 100% efficient, so assuming 95% efficiency you'd be looking at a small waste.The laptop also needs 19.5v simply because that voltage has to be higher than the internal battery - if the laptop uses a 4 cell battery, then the input voltage must be above 4 x 4.2v = 16.8v (nominal voltage would be 4 x 3.7v = ~ 15v ) - the laptop would then take this voltage and use buck converters to produce 5v and 3.3v and other voltages for the laptop.So, the input voltage isn't really that critical, it could probably be 18.5v ... 20v and still be fine.My advice would be use 4 or 5 lithium batteries in series to get a voltage higher than 19.5v and then use a dc-dc converter to produce 18.5-19.5v - it will be easier and safer.You can buy ready made 5S lithium chargers to recharge the batteries when you need to.Alternatively, you could go with 2 12v lead acid batteries in series, each battery can be discharged down to around 10.8v without damaging it and you can trickle charge them back up by giving them around 13.5v per battery or around 26-27v for a pack of 2 (any 24v power supply will allow you to tweak output voltage up a bit)
Any technique for PCB routing with laser machine on copper plates? - Page 1
Forum section: electronics / projects

author: XxMandragoraxX
author_rank: Contributor
timestamp: January 29, 2025, 07:10:14 am
content: I have a laser machine with a 5.5W laser head, the laser pointer has a size of 445nm. It is capable of cutting 5mm thick balsa wood without any problem, but when it comes to putting it on a copper plate, the laser reflects and does not cut. Does anyone have any idea what to do? since I want to do mass production

author: kripton2035
author_rank: Super Contributor
timestamp: January 29, 2025, 07:18:43 am
content: you need a 20-30W pulse fiber laser to do this (a 50-60W would be faster too...)there are videos on youtube explaining it.https://www.youtube.com/shorts/HKAkQaw4o64https://www.youtube.com/shorts/pjSCnAbmJWw

author: Ian.M
author_rank: Super Contributor
timestamp: January 29, 2025, 09:49:20 am
content: https://hackaday.com/2017/08/22/laser-etching-pcbs/TLDR: Coat bare PCB with acrylic spray paint to use as etch resist, use laser engraver to blast it off where you don't want copper, then chemically etch.

author: twospoons
author_rank: Frequent Contributor
timestamp: January 29, 2025, 09:49:36 pm
content: ^this^Fiber lasers are not cheap. Laser cutting of copper is not simple because it is both reflective and thermally conductive - so you need a pulsed laser with a very high peak power.Laser ablated paint + chemical etching is way easier. I've used this technique with a 40W CW CO2 laser.

author: kripton2035
author_rank: Super Contributor
timestamp: January 29, 2025, 10:06:48 pm
content: the ComMarker B4 20W used in a video above starts around $2000.https://commarker.com/fr/product/b4-laser-engraver/$8000 for the 100W versionit is not cheap but still in a hobby range. and it is way faster than the chemical etching process.it seems to me interesting for someone that has a lot of pcb prototypes to makeand it is way cheaper than a lpkf engraving machine.

author: XxMandragoraxX
author_rank: Contributor
timestamp: January 30, 2025, 07:12:46 am
content: I understand, yes it is true that they are very expensive. My laser head is 5.5W and diode with 445nm laser pointer.I wanted to see if I could etch the copper directly with some technique, but I guess I will have to do the paint spray and chemical development technique. It's not bad at all but I would have liked to avoid that step hehehe

author: kripton2035
author_rank: Super Contributor
timestamp: January 31, 2025, 07:39:22 am
content: another video explaining the process
Any thoughts on glass bead rectifiers vs epoxy rectifiers for DC power supply? - Page 1
Forum section: electronics / projects

author: Hgspine
author_rank: Contributor
timestamp: September 14, 2019, 08:24:27 pm
content: Any thoughts on glass bead rectifiers vs epoxy rectifiers for DC power supply?Thank you.

author: Gyro
author_rank: Super Contributor
timestamp: September 14, 2019, 09:55:23 pm
content: I've always suspected that they must behigher quality, presumably they are hermetic and must be more expensive to package.I have absolutely no evidence that they are any more reliable than the epoxy packaged equivalents in practice though.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 15, 2019, 12:33:34 am
content: Well, they meet the specs in the datasheet. Is that what your application needs?Both are typically "glass passivated", which means the die itself has some kind of glass coating (probably SiO2). Obviously, the sinterglass type goes on to have a full glass body, of whatever type of glass has a fairly low melting point (probably not a silica-based glass, because the alkali content would contaminate the die; may be phosphate based or something like that).Don't think I ever looked up the cost difference. Sinterglass types seem to be more of an anachronism, I see them so rarely (if ever).Tim

author: amyk
author_rank: Super Contributor
timestamp: September 15, 2019, 04:02:26 am
content: I believe the ceramic package has slightly higher power dissipation capability and temperature range.
Any thoughts on TK (Toshin Kogyo) capacitors? - Page 1
Forum section: electronics / projects

author: lpc32
author_rank: Frequent Contributor
timestamp: December 13, 2016, 01:05:04 am
content: I encountered on an Asus motherboard a whole bunch of capacitors labeled "TK". Initially I assumed they are random cheap ones, but apparently it's aJapanese company. Any idea how's their quality?
Any uses for an Inductor outside of PSUs or RF/Tank Oscillator circuits? - Page 1
Forum section: electronics / projects

author: DANNYSEBAHAR
author_rank: Newbie
timestamp: September 26, 2018, 11:39:39 pm
content: I want to use an inductor in some interesting way. All I can think of is Power Supplies, Filters/Frequency dependent circuits (that I have no interest in making), and Tank Oscillators.Anyone have any fun projects that utilize the curly copper?

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: September 27, 2018, 12:08:05 am
content: You've certainly ruled out the most common uses. If it's a heavy one, you could use it as a doorstop. If you have a lot of them, maybe for better traction if you put them in the trunk. Now, if you have just the right type of inductor, you can build a parametric amplifier by saturating it. Not very common these days, but entire books have been written on the design of the things. If you have an unshielded inductor, you can use it as a magnetic field sensor.

author: Cerebus
author_rank: Super Contributor
timestamp: September 27, 2018, 01:18:59 am
content: Isolation transformers. Used in ethernet, telephone lines, microphone transformers and probably a dozen other common signal transmission situations where you want a galvanic barrier for either safety isolation or reduction of common mode noise.Also solenoids for making mechanical things lock, pop, spring or jump.Buzzers, loudspeakers, voice coil servos on disk drives...Induction furnaces.Motors of every electrical flavour.Metal detectors.

author: David Hess
author_rank: Super Contributor
timestamp: September 27, 2018, 02:55:31 am
content: Any circuit which commonly uses a capacitor can conceivably use an inductor instead like an integrator or sample and hold. A switched inductor filter would be an interesting alternative to a switched capacitor filter.Core memory uses inductors as storage elements.Inductors can be used in low frequency but long delay lumped element delay lines which would be infeasible with transmission line; check out the Tektronix 545 oscilloscope for an example. This is still done in some high power applications for pulse shaping.

author: Bud
author_rank: Super Contributor
timestamp: September 28, 2018, 08:03:24 pm
content: Tesla coil
Any video experts here? - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: April 07, 2019, 09:47:00 pm
content: Anyone ever use a Sony MEU-WX2?Apparently it's a professional video converter, composite video to DVI out. Or so I think.Can these be used with any old DVI or HDMI monitor these days?I snagged one for cheap on eBay and while it powers up smoke-free, there's no video output on the DVI when I hook it up to my monitor.The Sony manual gives some specific studio (DC powered) monitor models it works with.Is this a case of Sony once again implementing their own standard?

author: The Soulman
author_rank: Super Contributor
timestamp: April 07, 2019, 09:53:14 pm
content: I'm not an expert nor do I know anything about this specific device, howeverit should work IF your monitor supports the video format from your converter.Edit: from reading the manual it appears to be a dedicated device to work with specific monitors..

author: tsman
author_rank: Frequent Contributor
timestamp: April 07, 2019, 10:35:20 pm
content: The MEU-WX2 manual is vague and says it only use it with suitable monitors. However, if you look at the manual for a LMD-152 which is one listed then you'll find it just has a regular DVI-D input on it. The refresh rate is normal as well. There is a DC output for a monitor but it isn't required as they say to only use the display cable for one of the monitors.If the MENU button doesn't bring up anything then it is probably dead as it has a configuration menu OSD.Code:DISPLAY INDVI-D × 1Signal formatDot clock frequency/horizontal frequency/vertical frequency:25.175 MHz/31.469 kHz/59.941 Hz (VGA)68.250 MHz/47.396 kHz/59.995 Hz (WXGA) (LMD-172W/232W/322W)65.000 MHz/48.363 kHz/60.004 Hz (XGA) (LMD-152/212)

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: April 07, 2019, 10:55:44 pm
content: Yeah, just another 17$ wasted I guess.I made a bet about the connector and the specs when I bought the thing...Yeah it did say "For parts. Does not turn on. Unknown issue" in the item.But when I got it it powered up, but no video.So now I finally decided to probe the DVI connector and there are no signals on any of the TMDS pairs, but there's some 5V on the DDC signals. Maybe there's a dead DVI driver in there.The problem is the thing is built like a tank, and it's 75% power supply boards. The logic is buried in a metal cage.Ho well. Thanks for the comments. Too much work for now.Unless someone knows the pinout and protocol of the service port?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: April 08, 2019, 11:47:16 pm
content: Duh, I guess the unit checks the monitor through the DDC thing and then powers down the drivers if it doesn't see one of the Sony monitors.

author: Bratster
author_rank: Frequent Contributor
timestamp: April 08, 2019, 11:52:58 pm
content: finding what DDC/edid information the unit is looking for would be the tricky part, but actually spoofing that information is pretty simple afaik.Sent from my Nexus 9 using Tapatalk
Any Viterbi decoding pros out there? - Page 1
Forum section: electronics / projects

author: aalbri
author_rank: Contributor
timestamp: November 10, 2013, 11:51:43 pm
content: I'm working on a school project which simulates a wireless channel with this model: -> [8PSK Modulation] -> [Rayleigh fading] ->  ->  -> My simulator works perfect without the convolutional decoding and I know the encoder works after a lot of testing. So the problem is with the decoder. My power efficiency graph looks like the attached. Is there a Viterbi pro that might know why I get such a shitty graph?I can show you my code but it's probly unreadable to most people lol.
any warnings/suggestions before i invole myself into making this smps at home - Page 1
Forum section: electronics / projects

author: meisstupid
author_rank: Newbie
timestamp: July 10, 2023, 02:45:59 pm
content: this one-its a 24v 30a and i need it to run my flyback speaker.Will be doing this on a home-made pcb.All details in the zip attached

author: langwadt
author_rank: Super Contributor
timestamp: July 10, 2023, 04:41:19 pm
content: but why? if you need a powersupply of that size, just buy one

author: coromonadalix
author_rank: Super Contributor
timestamp: July 10, 2023, 04:43:08 pm
content: ok ill ask before others, what is the gain doing it yourself, why not buy an already made one ? soome of them have pfc correction cc cv limitters, or even thermally controlled fan ?cost of all the needed parts vs a fully assembled unit ?

author: floobydust
author_rank: Super Contributor
timestamp: July 10, 2023, 05:08:31 pm
content: All that work to build it... and it uses 555, LM358 for 720WI haven't seen the full schematic but PC power supplies are easier to modify and have protection for overcurrent etc.Why build someone's glamour project?
How are rodhe & schwaz using low value input capacitors in there PSUs? - Page 1
Forum section: electronics / projects

author: Farrow
author_rank: Contributor
timestamp: December 24, 2020, 04:04:40 am
content: I've been looking at many old hp e36XX series schematics and many other lab grade PSU teardowns on the eevblog. They all have very large input filter capacitors (12000uf) even at low output voltages. Recently in one of dave's teardown, he looked at Rohde & Schwarz power supplies which use 2200uf capacitors. Why is that?PS I'm talking about linear PSUs

author: Messtechniker
author_rank: Frequent Contributor
timestamp: December 24, 2020, 06:31:46 am
content: My rule of the thumb for the input capacitor oflinear power supplies in standard applications:1000 uF per A.Others may have a different approach.

author: exe
author_rank: Unknown
timestamp: December 24, 2020, 09:16:44 am
content: Do you mean capacitors immediately after bridge rectifier? Then 2200uF sounds about right to me. I use 2-3mF per A. Too little capacitance means higher ripple and less voltage headroom. Also smaller caps have smaller average current rating. Too high capacitance means huge inrush current, bad power factor and increased losses in transformer.I recommend play with bridge rectifier and capacitors in a simulator. I was surprised to see inrush currents of more than 40A in some of my designs.

author: Farrow
author_rank: Contributor
timestamp: December 24, 2020, 02:38:04 pm
content: So why do most power PSU manufacturers use high-value caps? Like for example the e3610a has a 30w output rating but has a 10000uf input filter cap. I'm confused, so they just throw in the largest value cap and call it job done without calculation?.Both of your answers make sense, they follow the general capacitance calculation as well.

author: exe
author_rank: Unknown
timestamp: December 24, 2020, 08:38:57 pm
content: I see it outputs up to 3A, that is ~3300uF per amp, which sound right to me.
Any way to do an interlock with a latching relay? - Page 1
Forum section: electronics / projects

author: julian1
author_rank: Frequent Contributor
timestamp: November 04, 2022, 07:03:54 pm
content: The simplest way I can think of to do an interlock, is to break the coil circuit of a normally-open relay. The end-user must complete the circuit by making a connection to enable output.The issue, with latching relay, is that it behaves like a flip/flop and can assume any state at power on.But latching relays are attractive since they only consume current when switching, and there is less potential for magnetic and electrostatic issues.

author: Kleinstein
author_rank: Super Contributor
timestamp: November 04, 2022, 08:47:00 pm
content: If the circuit is build right, one can make it in a way, that the relay state does not change at power on. So interlocks handled in software between latching relays should persist even after a power cycle.In some cases one can read back the current state of the latching relays.

author: julian1
author_rank: Frequent Contributor
timestamp: November 04, 2022, 09:26:42 pm
content: One strategy might be -- place a diode in series with the latching coil - with polarity such that any signal power/glitch/surge can only turn the relay off.- apply power with a timer at startup. To cover a change in relay state after last power-off, due to knocks/transport etc- to enable the interlock, and allow digital signals to control the relay - just short the diode.Edit . scratch that. As Kleinstein suggests, I think sensing the current relay state, using a pole of a double-pole Form-C, is a better starting point for working out the required transitions.

author: julian1
author_rank: Frequent Contributor
timestamp: November 05, 2022, 06:37:25 am
content: I think the following gets closer.Using a nor flip-flop to represent a latching relay. The current relay state is sensed (as Q ) which would correspond to a spare DT pole.- If interlock-sense is not enabled (pullup R1 is left hi), and relay is sensed on, then turn off.- If interlock-sense is enabled (R1 shorted to gnd), then drive relay according to ctrl signal and current relay state- As additional measure, interlock has 2 extra pins to short diode D1. D1 prevents any glitch/failure from turning on the relay if interlock is not enabled.It's a bit fiddly, maybe there is a simpler way?.
Any weekend-project idea to include a tiny 30mAh Li-Ion recheargeable? - Page 1
Forum section: electronics / projects

author: RoGeorge
author_rank: Super Contributor
timestamp: April 23, 2023, 12:00:12 am
content: The cell is very small (about the size of a through holes 16 pins IC), rechargeable, Li-Ion or Li-Po, 0.1Wh or 30mAh at 3.7V, has a battery protection board.Any project ideas to make a good use for it?

author: inse
author_rank: Super Contributor
timestamp: April 23, 2023, 06:09:22 am
content: Time is running out…

author: RoGeorge
author_rank: Super Contributor
timestamp: April 23, 2023, 08:35:18 am
content: Quote from: inse on April 23, 2023, 06:09:22 amThat's probably one of the deepest and harshest remarks about anything in this world.Now I'm in the philosopher mode.

author: robert.rozee
author_rank: Frequent Contributor
timestamp: April 23, 2023, 08:51:24 am
content: you could pair it up with a tiny boost converter module and a couple of white LEDs to make a tiny pocket torch.cheers,rob :-)
Any working Python library to interface with Bus Pirate 3.6a? - Page 1
Forum section: electronics / projects

author: zapta
author_rank: Super Contributor
timestamp: December 08, 2023, 07:21:23 am
content: I got Sparkfun's Bus Pirate 3.6a from amazon but having difficulty finding a working python library to interface with it. Even the example on Sparksun's site doesn't work with Python 3.12 and the libraries I could find are at least 5 years old.Anybody knows of a working library? Preferably one that is already on pypi.org and can be installed with pip.
Anybody ever heard of this company that makes this neon sign transformer? - Page 1
Forum section: electronics / projects

author: Ben321
author_rank: Frequent Contributor
timestamp: August 30, 2021, 10:37:35 am
content: It's called Light Source L.L.C. and apparantly makes this 12V DC powered neon sign transformerhttps://www.amazing1.com/content/Graphics/neonxul.jpgwhich is being sold by the high voltage hobbyist website amazon1.com. However I've never heard of that company before, and no amount of searching I do has actually gotten me to any information on that neon sign transformer company. The only company I can find with that name is this onehttps://findyourlightsource.com/that offers psychology services, and has NOTHING to do with electronics.

author: Psi
author_rank: Super Contributor
timestamp: August 30, 2021, 11:34:05 am
content: If it smells like shit, it's shit.

author: amyk
author_rank: Super Contributor
timestamp: August 30, 2021, 01:35:05 pm
content: How do you get 2000V 10mA out of 12V 1A...?It's probably a rebrand of something you can find on Ali{baba,express}.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 30, 2021, 01:39:35 pm
content: It's AC, so the power factor can be less than 1. Most likely it's just a common CCFL inverter circuit inside, similar to the ones used in old LCD TV backlights.

author: Ben321
author_rank: Frequent Contributor
timestamp: August 30, 2021, 11:53:30 pm
content: Quote from: amyk on August 30, 2021, 01:35:05 pmThat's 10 mA short circuit current, and 2000V open circuit voltage. The actual impedance match current and voltage levels though will be something that when multiplied together do not exceed the maximum possible input power (the input power maximum being 12W). It's also possible with AC for the real power to be 12W but the apparent power to be more than 12VA, because the current and voltage waveforms are out of phase.
Anybody ever use a TSDSON-8 package? - Page 1
Forum section: electronics / projects

author: AcHmed99
author_rank: Contributor
timestamp: October 27, 2011, 10:33:11 pm
content: I'm

author: amspire
author_rank: Super Contributor
timestamp: October 27, 2011, 11:32:59 pm
content: The 60C/W is with the 6cm2copper on the drain on a 40mm x 40mm board.I didn't see any Junction to Ambient for the device on its own.It looks like the devices themselves are amazing - if you can cool the case down to 25 C, they can dissipate 60W!So for 300mW, you will probably need 2 - 3 cm2of copper on the drain, as long as the device is not right next to other hot parts.Richard

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 27, 2011, 11:49:49 pm
content: Quote from: amspire on October 27, 2011, 11:32:59 pmWhich you will of course never manage, except for very short periods.QuoteSounds about right.There isn't typically much difference in thermal resistance between devices in similar package sizes, so if you can find data on something similar that is better speccecd it won't be to far off.

author: amspire
author_rank: Super Contributor
timestamp: October 28, 2011, 12:36:50 am
content: I see it now. That 62C/W is a very odd spec. If it were true, then the 6cm2of copper is almost totally useless - which I do not believe. It does look like a typo.You really do not need much to get rid of 300mw. If you had as little as 1cm2of copper near the device, it would probably be fine, as the copper is not just radiating the heat, but is is also dumping the heat into the bulk of the PCB. I am pretty confident that 2 cm2would be very safe.Richard
Anybody have try vxworks (especialy ver 1.4)? - Page 1
Forum section: electronics / projects

author: han
author_rank: Frequent Contributor
timestamp: April 10, 2014, 12:56:36 pm
content: If there is an OS that drive me crazy, it's vxworks:1. the bootrom.sys file cannot be segmented2. there are BSD config that cannot work in other hardware3. Very difficult to (re)install4. RTOS mean Real Translation Of sucks5. Proprietary means no body knows how to troubleshoot it..and i'ts the source of my frustration todayI try re install vxworks OS ver 1.4 in some agilent instrument that:1. Have no usb boot support on BIOS2. Error FDD with bloody proprietary connection.3. CF card as HDD4. i install Tornado IDE v 1.6 only to know the VXSYS.com is ver 1.6And after try format CF card and write the MBR with vxsys.com and copy all the file, its doesn't bootany one have experience with VXwork?
Anybody know how to drive this (vishay oled)? - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: September 09, 2017, 07:14:28 pm
content: Hi,I've got:http://www.vishay.com/docs/37756/oled050h016alpp5n00000.pdfIt doesn't mention anything about an init cycle.If I am understanding page 6 properly, you can only do a "goto" setting the location of the data to be written.I've got this connected: VSS=ground, VDD=5V, rs=PC2, e=PC3, DB0-7=PORTDCode://PD0-7 OLED data//PC2OLED RS h=data, l=instruction//PC3OLED EDDRD=0xff;DDRC=_BV(2) | _BV(3);//set gxaPORTD=0b10001000;PORTC&=~_BV(2); //RS instrPORTC|=_BV(3); //E highasm("nop");asm("nop");asm("nop");asm("nop");PORTC&=~_BV(3); //E low//set gyaPORTD=0b01000001;PORTC&=~_BV(2); //RS instrPORTC|=_BV(3); //E highasm("nop");asm("nop");asm("nop");asm("nop");PORTC&=~_BV(3); //E lowPORTD=0xff;PORTC|=_BV(2); //RS datafor(;;){PORTC|=_BV(3); //E highasm("nop");asm("nop");asm("nop");asm("nop");PORTC&=~_BV(3); //E lowDelay_ms(1);}Very little power consumpiton (<5mA) and no screen response to anything I've tried.With such a little power consumption, could it be in a sleep or power down mode? I don't see anything in their datasheet about it...I connected up a LA and verified that the E, RS, and top couple of DB pins are working as expected.

author: Andy Watson
author_rank: Super Contributor
timestamp: September 09, 2017, 07:41:49 pm
content: There's usually some sort of initialisation to be done. The Vishay datasheet is a bit terse!This looks like it might be the underlying chip that is doing the control:https://cdn-shop.adafruit.com/datasheets/WS0010.pdf

author: alank2
author_rank: Super Contributor
timestamp: September 09, 2017, 08:02:04 pm
content: Thanks Andy - that got it working.
Anybody know of a cheap 4S charger IC?  Unobtanium? - Page 1
Forum section: electronics / projects

author: sleemanj
author_rank: Super Contributor
timestamp: June 09, 2019, 11:57:48 pm
content: So, for lithium-ion charging, for 1-cell we have the classic NanJing Top Power TP4056 and similar, for 2-cell we can again look to Top Power's TP5100, that's the most that Top Power does but for 3-cell there is the Silergy SY6912.For 4S though which is what I really want, I'm having a great deal of trouble finding anything.Even with "proper western brands" there's a bit of a dearth (and multiple dollars per unit).I've tried LCSC butthey don't list it (or anything)as a parameter so the best I could do was google datasheets hosted at LCSC and was not successful.Obviously, one can just use a CC/CV supply and protection for cell overvoltage and limited balancing, but that's significantly less than ideal than a charge management IC.Anybody seen one in their travels, got a lead on a manufacturer I could look at?

author: Psi
author_rank: Super Contributor
timestamp: June 10, 2019, 12:32:47 am
content: A lot of 4S chargers seem to have 4x 1 cell charge IC on them.
Anybody know the HX3589 CH5KOK.3 IC? - Page 1
Forum section: electronics / projects

author: t1d
author_rank: Super Contributor
timestamp: September 16, 2019, 10:15:32 pm
content: It has 8 pins. I saw it on YT in a DIY Battery Level Circuit. The part number is clearly visible. Googling it does no good. I would list the link, but the author is being vague about where to get it, so I do not want to drive viewers to him, in case it is a hoax. So...1) What is it?2) Who makes it?3) Where to buy it?4) If it is obsolete, what replaced it?Thanks!

author: amyk
author_rank: Super Contributor
timestamp: September 17, 2019, 12:40:45 am
content: Searching that part easily brings you to the guy's videos, where he only tells others asking about it to "please wait", and apparently it serves as both a charger, battery level indicator, and LED "light chaser"... an integrated powerbank IC is the only thing I can think of, and in his latest video he describes a "HX3786D" which I assume isan HT3786D, although it's grossly miswired.That and the sketchy nature of the work, along with previous experiences of the culture from which I am quite certain he is from, lead me to believe this might be a cheap attempt at getting video views for ad money by publishing very poor quality/misinformation --- if so, go ahead and downvote his videos. Hard to say whether it's truly a hoax, but I think it's pretty damn close.
Anybody knows the difference between IPC-2221B and IPC-2221C? - Page 1
Forum section: electronics / projects

author: Relaxe
author_rank: Regular Contributor
timestamp: June 05, 2024, 01:40:24 am
content: IPC seems to have released IPC-2221CWhen I see people talk about 2221B, it's mostly negative comments.Did they change a lot with revision C?I have found nothing about it online...I'm mostly interested in clearance and creepage for high-voltage in internal layers, as IPC2221B is the only place where guidance about that is provided, that I know of...
Anybody recognize these underwater circular connectors? - Page 1
Forum section: electronics / projects

author: klr5205
author_rank: Regular Contributor
timestamp: March 04, 2021, 03:45:47 pm
content: As the title says, do the connectors below look familiar to anybody?I can't find any markings besides a Hummel logo on the smaller connector's strain relief. These are used in an underwater ROV application. Because of the way our equipment is typically abused I can see myself having to reterminate some of the cabling, but in order to do that I need to know what parts to get! The MFR claims they are proprietary but since I highly doubt they are making their own connectors, I thought I would consult the hivemind.Thanks to anyone who can help!

author: mon2
author_rank: Frequent Contributor
timestamp: March 04, 2021, 03:58:22 pm
content: They are DIN connectors. See here:https://www.macartney.com/what-we-offer/systems-and-products/connectors/subconn/subconn-micro-circular-series/subconn-micro-circular-2-3-4-5-6-and-8-contacts-and-g2-2-3-and-4-contacts/Scroll down to review the face on views. The 6 pin version looks like a match.

author: klr5205
author_rank: Regular Contributor
timestamp: March 04, 2021, 06:39:31 pm
content: Quote from: mon2 on March 04, 2021, 03:58:22 pmI came across these on my own at one point. I think they're very similar, but the 6 pin version doesn't have the flat that mine has (I verified by downloading the .stp file), and they seemingly don't even have a 7 pin version in this family.

author: mon2
author_rank: Frequent Contributor
timestamp: March 04, 2021, 11:13:49 pm
content: I would shoot them your pictures and ask for their assistance:https://www.hummel.com/en/electric-components/products/circular-connectors/

author: bdunham7
author_rank: Super Contributor
timestamp: March 04, 2021, 11:45:48 pm
content: Quote from: klr5205 on March 04, 2021, 03:45:47 pmThey don't have to make them for them to be proprietary. It isn't hard to get a manufacturer to OEM them for you with an exclusive contract, especially when it is a simple derivative of one of their existing designs.

author: ChemTalk
author_rank: Newbie
timestamp: March 05, 2021, 04:55:40 am
content: I actually deal with cables like that quite frequently when working with my underwater equipment. They are sync cords, used to send an electronic signal to fire a flash on a strobe. You just need to verify the thread size. I'm not sure if there is a particular "standard" for the type of ROV you are using.ChemTalk

author: klr5205
author_rank: Regular Contributor
timestamp: March 05, 2021, 12:58:04 pm
content: Quote from: mon2 on March 04, 2021, 11:13:49 pmSound advice. I have a feeler out at TE as well since they own so many of the big names, including SeaConn. They actually replied to me within just a few hours asking for additional info which I was pleasantly surprised by.