hybridfree/eevblog-posts huggingface dataset:
Noisy class-D amp with boost converter - Page 1
Forum section: electronics / projects

author: elektrinis
author_rank: Regular Contributor
timestamp: November 30, 2020, 08:48:08 am
content: Was looking for a single board stereo amplifier for my car, but slightly more powerful than you could get from 12V. Ended up finding this one (see 1st attachment).It's based on class-D chip TPA3116 (which is quite good and works well). And it has dual 5-amp boost converter XL6019.The problem I am having is this thing is quite noise on high frequency audio range.I understand the routing is pretty poor, as analog audio traces go right under the boost inverter... However are there any ways to mitigate this?Bonus question. The inverter is made of two identical inverters running in parallel. There is two of everything drawn below.Each inverter has two more diodes than it would typically need. First there is a beefy diode in series to 12V input. What is this for? To keep the amp running when I crank the engine? Anything else?And then there is an extra diode in series to output of the inverter, before the capacitors. (see 2nd attachment)Does it have something to do with two inverters in parallel? There seems to be no capacitance before this diode.

author: trobbins
author_rank: Frequent Contributor
timestamp: November 30, 2020, 10:53:26 am
content: Your noise may be be related to ground loops for input signal and power - sketch out your arrangement and identify where the power is being sourced from, and look for a ground loop.Have you confirmed the speakers are floating, with no ground connections?The input diode is a form or reverse polarity protection, to reduce warranty returns based on 'it doesn't work'.

author: elektrinis
author_rank: Regular Contributor
timestamp: November 30, 2020, 10:57:03 am
content: The noise is there when nothing is connected, only speaker. The noise is strongest when potentiometer is set at 50% and it lowers when set to 100% or 0%.For the input diode, I guess I can simply short it to get rid of some heat.The output diode, however, has a strange configuration, with capacitors behind it.

author: mikerj
author_rank: Super Contributor
timestamp: November 30, 2020, 12:45:48 pm
content: I suspect the output diodes are to prevent the regulators control loops fighting each other since their output voltages won't be exactly equal. I am surprised there is no cap prior to the output diode though, I'd have though that would potential cause problems with regulation. It's all a pretty nasty bodge IMO.

author: trobbins
author_rank: Frequent Contributor
timestamp: November 30, 2020, 11:37:14 pm
content: Quote from: elektrinis on November 30, 2020, 10:57:03 amYou have got power connected ?Have you shorted the signal input socket?How long is your speaker wiring, and is it a pair (ie. twisted, or joined)?You have got 2 speakers connected?
Noisy sound system automatic power-off. - Page 1
Forum section: electronics / projects

author: ghorizo
author_rank: Contributor
timestamp: May 06, 2021, 09:46:07 am
content: Hello, please help me with this little problem of mine.I find myself with a rather noisy surround system producing a hum particularly noticeable when no music is playing.I was wondering if it would be possible to insert a relay after the main switch that turns on when power is detected on the line-in or would that mean lots of isolation circuitry? Can't seem to find anything of the sort.Otherwise I thought of having the computer control the relay whenever something is playing with a usb relay board.What do you think?

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 07, 2021, 12:46:04 pm
content: Try using a digital input on the amplifier if there is one?

author: ghorizo
author_rank: Contributor
timestamp: May 07, 2021, 03:44:14 pm
content: Sadly no digital input, it's quite a cheap little 5.1 surround. The cables aren't even detachable from the unit. At least the subwoofer features connectors.Probably not worth dealing with for many but it sort of works, and since I have some relays around, I hoped it would not be too difficult but I don't know much.

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 08, 2021, 01:27:58 am
content: Turn the volume on the PC all the way up (or slightly less if it starts clipping) and turn down the volume on the amplifier.

author: ghorizo
author_rank: Contributor
timestamp: May 12, 2021, 07:52:15 pm
content: Had tried that at the beginning but even if I turn the ampifier way down to zero the sound from the speakers remains always constant.

author: themadhippy
author_rank: Super Contributor
timestamp: May 12, 2021, 08:05:36 pm
content: sound/vox operated switches were a fairly common project in magazines several moons ago,and google search for "sound operated switch turns up plenty of circuits" .Do be aware youll miss the first bit of the audio and you need to have the hold on delay time long enough so its not turning off during any silent passages

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 12, 2021, 10:19:57 pm
content: Quote from: ghorizo on May 12, 2021, 07:52:15 pmThat means the amplifier itself is junk, you could replace it with a better one - try your local Goodwill or similar if you want something cheap, specifically look for ones that have S/PDIF but no HDMI or those that have HDMI but no 4K passthrough for some nice deals. Or you can try connecting power resistors in series with the speakers to increase the usable SNR, experiment with lower powered resistors with nothing playing to find out what minimum value gets the noise to tolerable levels.The more advanced hackers can start reverse engineering the amplifier and try to redesign it for better SNR. If you can provide pictures of the boards inside, we might be able to suggest reasonably simple mods.
Nokia 6500S project (STM32) - beginner, feedback welcome! - Page 1
Forum section: electronics / projects

author: stevenhoneyman
author_rank: Regular Contributor
timestamp: September 15, 2015, 07:08:41 pm
content: I wanted to make sure this actually worked and I hadn't completely screwed up before posting, and it doesThis is just a hobby/personal project, (obviously!) not for mass production or sale of any kind so some of the compromises I had to make have been done for a reason and I'm aware they would have serious consequences if this was a commercial design... e.g. vias in pads, only a 2 layer board, the many USB 'best practices' I've violated, that kind of thing. I was curious so got a quote for 4/4mil, 4-layer board of the same size - $140 for 10(over ten times the cost of these)I've kind-of detailed (as in not step-by-step instructional, but info and pics along the way) both my first board and second revision that has just arrived and been quickly tested, available to see here:http://www.stevenhoneyman.co.uk/2015/08/learning-by-doing-pcb-design.htmlhttp://www.stevenhoneyman.co.uk/2015/09/more-pcbs-6500-rev-b.htmlI've only just put this together a couple of days ago so there could be some horrible mistake yet to be discovered! The I2S remains untested as I haven't yet learnt how that protocol (or the partially documented codec) works. Any low power/standby stuff is also not yet tested. Other than what I've already mentioned, I'll gladly take any feedback or constructive criticism about my layout. I seem to be running out of board space due to the positioning of the connectors and the fact I can't put components on most of the back because of the battery. I'd like to go BGA and add SDRAM so when I get hold of some of the new 'F446 it could run a very cut-down Linux build, but that's too costly to be risking screwing up at the moment.And to give a preview without having to click my links, here's my rev A and B boards:(the Eagle screenshot was too big to attach)
Nokia 8800e Arte broken micro USB fix - Page 1
Forum section: electronics / projects

author: wraper
author_rank: Unknown
timestamp: August 15, 2013, 12:47:34 pm
content: Was watching my old pictures, when ran across how I fixed micro USB connector on Nokia 8800e Arte which was broken off together with two top layers of PCB. So I decided to share them. This model is charged via this connector so it needed to be rugged enough fix. When I came up with idea that I need to take a pictures of this porn, already scratched PCB up to the third layer, desoldered vibra and soldered connector back to it's place on the internal ground layer Slodering vibra back was the last tough part because wires unsoldered from the heat nearby on the first try and I had to do half of the work again. This is my friend's phone and it still works without problems after 1 year and 4 months.
Nokia phone Arduino Shield - Page 1
Forum section: electronics / projects

author: charlespax
author_rank: Regular Contributor
timestamp: May 21, 2015, 03:10:35 am
content: I am making an Arduino shield to interface with old Nokia phones. I'd like to keep the price around $20 for the shield, cables, and phone. If I can get some software help from the community, this will be great for interfacing projects with the internet.For photos, code, and a detailed writeup please check out my post athttp://paxinstruments.com/nokia-phone-arduino-shield/Should the shield be for a specific Arduino board or be configurable? The AltSoftwareSerial library uses specific pins for different Arduino boards.Is it fine to have the phone and serial-to-USB chip both connected to the Arduino RX/TX lines?Do we need the level shifters?Is there a better Nokia cable that also provides power?The Nokia 3100 needs a battery to run even with the power cable inserted. Is there a way around this?Is there a better target phone?Thought you might be interested. Thanks :-)
Non addressable SPI devices with Addressable SPI devices. (AD5290, MC23s17) - Page 1
Forum section: electronics / projects

author: iampoor
author_rank: Frequent Contributor
timestamp: December 06, 2013, 09:10:40 pm
content: HiI am building a little demo board with a few shift registers, an MC23s17, and a couple Analog Devices AD5290 to learn about digital signal interfacing, and all that jazz. O0Since the MCP device has settable "address" pins, and the ad5290 just shifts in data, would this be an appropriate hookup method? Im using a Pic micro controller. And yes I am aware of the tiny errors like the upground pins.It was the only screenshot I have right now.Also, would it be possible to enable independant addressing using the cs line tied to a micro controller pin?Im just trying to not make this a software nightmare.

author: AndreasF
author_rank: Frequent Contributor
timestamp: December 07, 2013, 09:35:56 am
content: The address pins on the MCP are only relevant for I2C communication. In SPI addressing of individual slave devices is done via their CS pins.

author: jancumps
author_rank: Unknown
timestamp: December 07, 2013, 10:01:24 am
content: The TI TMS570 family supports addressable SPI. They call it 'encoded chip select' where you can combine CS pins to form an address - the slave listens for a particular CS combination to react. Is that outside the SPI standard?
Non ATX SMPS Question - Page 1
Forum section: electronics / projects

author: Tinkerer
author_rank: Frequent Contributor
timestamp: October 22, 2013, 01:12:07 am
content: Hi, I figured this would be a good place to come to ask a question like this.Long story short, I delved into computer power supplies recently and have learned quite a bit, with that said, I will get straight to the point:http://320volt.com/en/dell-sa145-3436-uc3842-lm358-145w/I have a practically identical power supply as the one in the link.(for all intents and purposes)My question here is what would I look at if I wanted to adjust the output voltage?As it currently stands, this particular SMPS requires a load across the 5v and 12v in order to run.(otherwise it of course simply cuts off)This also does not have a soft start, the switch is a direct on or off switch, not really any standby.Now, I am not sure if I am right, but I believe the LM358 is involved in over voltage protection.(partially at least)If there isnt anyone who easily knows the answer, just being pointed in the right direction would be great too.(if anyone was curious, I got this PS out of a 1996 Gateway 2000; was somewhat suprised by a lack of electrolytic caps, 3 total, ignoring the 4 5/12v output filter caps and the 2 rect. mains caps, just means I would have less to replace)Offtopic question, I have wondered, just how long would it take caps like the rect. mains caps(200v 470u) to dry out anyway? I would assume quite a bit longer compared to the smaller ones.

author: c4757p
author_rank: Super Contributor
timestamp: October 22, 2013, 01:33:40 am
content: The LM358 isn't involved in OVP, it is the regulator. IC6 (TL431) provides a 2.5V reference, and IC5B (LM358) compares this to a feedback voltage derived from both the +12V and +5V rails. You'd have to recompute the entire feedback network R39/R40/R41/R42/R43/R44, which is all interdependent.IC5A just controls the power-good output.As for OVP, you have SCR2 (TYN112) tripped by either of the two Zener diodes Z4 and Z5. The OVP is set very tightly - if you increase the voltage even a bit, change these or it will trip.As far as I can see, it does have a crude soft-start: TH1 is a negative temperature coefficient thermistor, which will limit the input current until it heats up.Quote from: Tinkerer on October 22, 2013, 01:12:07 amA very, very long time if they are good ones, sometime tomorrow if they're not.

author: Tinkerer
author_rank: Frequent Contributor
timestamp: October 22, 2013, 04:55:29 am
content: Thanks for your response. That helps a bit. I had an inkling about the feedback network resistors you mention but was hoping it would be simpler, not that basic resistor/voltage calculations are that terrible.(I had already replaced R41-44 with a pot and yes, the output is tightly controlled)QuoteI did not realize you could consider that a soft-start but I otherwise knew the purpose.QuoteAs suspected, but never could find a solid answer on it.
Non-constant Torque issue in FOC algorithm (Simulink) - Page 1
Forum section: electronics / projects

author: cadena
author_rank: Contributor
timestamp: April 16, 2020, 11:04:35 pm
content: Hi everyone,I am trying to develop an FOC algorithm in Simulink (see image attached) but I am having extrange results in my simulation. My torque is not constant, when it should, but varying periodically (see image attached), when it should be constant at 2 Nm. Also the scope for my q-axis current my probe is giving me a strange graph (see image attached) I can't even make sense of. Please if anyone could help me I would really appreciate it since I have no clue what is going on. I don't know if it could be the values of my PI regulator but I have already tried all sorts of values and have no idea what else I can do. Please could someone help me out ?P.S. Simulink file can be downloaded from my OneDrive:https://1drv.ms/u/s!AokIrMv_d8kz3BMaImhVY_guP_N-?e=3H9HRJ

author: cadena
author_rank: Contributor
timestamp: April 20, 2020, 10:25:58 am
content: Does anyone know why my model isn't working ?

author: cadena
author_rank: Contributor
timestamp: April 21, 2020, 06:50:36 pm
content: Hi does anyone know what is wrong ? Is there something I need to further clarify ? I have beent trying to tune PI values but nothing has improved. I have tried playing around with the motor and nothing either. I thought it would simple to implement since it's basically linking blocks together. I hope you are just not answering because they genuily don't know the answer but if there is another reason nobody is replying please let me know because I really need to do what I am doing wrong. Thanks.

author: max_torque
author_rank: Super Contributor
timestamp: April 21, 2020, 07:25:47 pm
content: I would suggest that you run "open loop" and disable the PI controllers, just run with a fixed output to the SVM. Then scope the motor's back emf, and the average output voltage of the SVM blockset. You will only get a "constant" phase current (which leads to a constant torque) if the forward voltage (produced by the SVM) accurately tracks the motor's actual backemf.
Non contact non line of sight proximity sensing and secure data transfer - Page 1
Forum section: electronics / projects

author: whiskeyjack
author_rank: Contributor
timestamp: November 22, 2015, 06:07:29 pm
content: I am looking for a sensor which would allow non contact and non line-of-sight identification of an entity. Here is an example usage:1) I attach the sensor module to my PC and I keep another node in my pocket. As soon as I come within one meter range of my PC, it unlocks. When I get out of one meter range, it locks back again. I also want the pocket node to send some identification information. The node that goes into my pocket can have a micro-controller and a small battery (CR2032) if at all that becomes a necessity. However I should be able to get a decent battery backup (at least a month)2) Consider a room equipped with this sensor and various people carrying differently programmed nodes walk in. Sensor will sense the exact person and send out a greeting message. Also, the room sensor will know how many (and who exactly) are present in that room. It should also be able to know when someone leaves the room. This suggests a ping mechanism after every 5-10 seconds or so.After some search, I found that bluetooth can be used for range measurement but I am not sure whether it will work in such a close range. Small range is a requirement. If I have flexibility to adjust range sensitivity in the range 1-5 meter, that'd be another benefit.Second option is RFID/active RFID. Passive doesn't seem to be a good option because a tag/card is required to be brought close to the sensor. Active RFID might work but it's transmitted data can be sniffed easily and can be a security concern. Besides this, the module is quite bulky and it doesn't seem to be a suitable fit for example 1.Is there any other option for implementing such a feature? I am not asking just for ready made solutions. If someone can suggest some ideas that I can start with, that also would be great.

author: tomy983
author_rank: Contributor
timestamp: November 22, 2015, 08:58:10 pm
content: I have no clue on the technology used, but you can open some cars with the keys in your pocket...

author: janoc
author_rank: Super Contributor
timestamp: November 22, 2015, 09:30:44 pm
content: Quote from: whiskeyjack on November 22, 2015, 06:07:29 pmThe range of the passive RFID pretty much depends on the shape and the size of the reading antenna and the radiated power from it. That most require close contact doesn't mean it is necessary - I have seen a project where a yagi antenna was attached to a gun-like device and used to read RFID-enabled passports and credit cards from many meters away.There are also large RFID readers meant to be used with vehicle and asset tracking - those work up to a few meters as well.
Non-contact proximity sensor for transparent film - Page 1
Forum section: electronics / projects

author: azhang100
author_rank: Newbie
timestamp: November 23, 2022, 12:43:18 am
content: I'm looking for a non-contact proximity (~1mm precision) sensor for 100um thick PDMS (silicone) film.Can be binary or continuous (i.e. I'd use a limit switch if non-contact wasn't a concern). Rangefinder would be fine, but I can't find one precise enough. I can get as close to the film as I need to.I went down the list of auto-levelers for 3D printers, but it seems unlikely any of them will work.Ultrasonic would probably work, but it's not as precise as I'd like it to beThe transparent nature of the silicone rules out most optic solutionsI tried a capacitive sensor (used to auto-levelling on 3D printers), but it didn't pick up even if I use the upper range of voltage (probably because of how thin the material was), even if it touches the film. Obviously inductive is a no-go.Any suggestions? Only thing I can think of is a computer vision solution, which I'm trying to avoid because of the overhead of setting up a processor capable of running CV algorithms.

author: SmallCog
author_rank: Frequent Contributor
timestamp: November 23, 2022, 01:50:01 am
content: Is radar an option? I've never pointed one at silicon film to know if they can "see" it or notYour material may not be transparent at certain wavelengths allowing you to use an optical sensor of a certain wavelength

author: Marco
author_rank: Super Contributor
timestamp: November 23, 2022, 06:13:30 pm
content: Confocal sensors can probably do it off the shelf for a price ... an unattractive price.Just picking the first ultrasonic sensor I found with a google search, the U300.D50-DPMJ.72N ... why isn't it precise enough?

author: artag
author_rank: Super Contributor
timestamp: November 23, 2022, 07:54:04 pm
content: Industrial machines would often use a jet of air.Monitor the pressure in the supply line and it will be affected before the film actually touches the nozzle.
Non-contact real-time heart rate monitoring system using Raspberry Pi 3 Model B  - Page 1
Forum section: electronics / projects

author: salvazero
author_rank: Newbie
timestamp: February 03, 2018, 08:27:02 pm
content: Hello,Is anyone working on the use of the Raspberry Pi Camera module as a heart rate sensor?I am new to using Raspberry Pi. I want to build a non-contact real-time heart rate monitoring system using Raspberry Pi 3 Model B and Pi NoIR camera.I found two related projects which are:https://github.com/prouast/heartbeathttps://github.com/thearn/webcam-pulse-detectorIs it possible to build this system using Raspberry Pi? Also, Is it possible to calculate FFTs and FFTs on the Raspberry Pi?Thanks for your time and consideration.Ramy

author: cdev
author_rank: Super Contributor
timestamp: February 05, 2018, 06:48:04 pm
content: Is this meant to monitor peoples heart rates without them knowing its being monitored?
Non-conventional use of Surface Mount Components - Page 1
Forum section: electronics / projects

author: jonovid
author_rank: Super Contributor
timestamp: January 10, 2018, 04:01:28 am
content: liquid crystal nightlight thermometer clock mod. this basic project got documented on video.so this may be of interest to someone that likes adding modifications to cheap chinese gadgets.to make a nightlight, this liquid crystal display modification has some added surface mount 0.5 watt warm white light emitting diodes run at less then 50% with two 500 ohm resistors. optics plastic diffuser plates lightbox ,reflective polarizers a reflector to guide otherwise wasted light back toward the LCD panel.the indoor thermometer is only up by one degree after 24 hrs. so the brightness setting's are about right?update-just one example of non-conventional use of surface mount LED's in a confined space.if you have better examples do post.my discovery was that the liquid crystal display's reflective silver adhesive back is removable.will peel off without leaving any residue or damaging the liquid crystal glass. the trick is to find a start point.then peel off in a spiral. pulling back not up , like peeling an orange. with the reflective adhesive back removedI then can add my own plastic diffuser plates & lightboxnote that many of my more complex projects are un-documented as lot of backtracking. re-testing. no time for setting up video shot's.what you see what you get.
Non-destructively evaluating the quality of a switch? - Page 1
Forum section: electronics / projects

author: e100
author_rank: Frequent Contributor
timestamp: November 20, 2019, 08:23:31 am
content: Is it possible to distinguish good vs poor quality switches based on their contact bounce characteristics?In other words, is there a typical fingerprint indicative of a poor or well constructed switch?Also, can you judge the age of a switch based on the way the bounce signature has changed (assuming that it does change) since it was new?

author: tggzzz
author_rank: Super Contributor
timestamp: November 20, 2019, 10:14:25 am
content: Quote from: e100 on November 20, 2019, 08:23:31 amFirst you define what "good" and "poor" meanin your application. (For example, there might just be a different answer for a 5V switch and a 400kV switch, or a keyboard switch and a 25A switch!)Only after that can youbeginto answer your question.In order to determine the age of your switch, you would have to have measured changes over that particular type of switches' lifetime.

author: dom0
author_rank: Super Contributor
timestamp: November 20, 2019, 03:33:51 pm
content: Quote from: e100 on November 20, 2019, 08:23:31 amMaybe. Just looking at the contacts would be far easier though.
Non EE question...screwing plastic parts - Page 1
Forum section: electronics / projects

author: Gibson486
author_rank: Frequent Contributor
timestamp: February 16, 2021, 05:02:16 pm
content: Is there a pre tapped bushing you can buy so I do not have to tap plastic for use with screws? if so, what are they called?

author: Andy Watson
author_rank: Super Contributor
timestamp: February 16, 2021, 05:09:53 pm
content: Search your favorite providers for "plastic inserts".

author: penfold
author_rank: Frequent Contributor
timestamp: February 16, 2021, 05:13:56 pm
content: Threaded bushes or threaded inserts normally gets you some results, cold press, barbed and heat settable varieties exists depending on your need,For hobby purposes you can get descent results with "thread repair inserts" and "NUTSERTS" and a bit of creativity

author: Gibson486
author_rank: Frequent Contributor
timestamp: February 16, 2021, 05:44:06 pm
content: Thank You! I just googled plastic inserts at first....did not occur to me to add "threaded"!

author: TimFox
author_rank: Super Contributor
timestamp: February 16, 2021, 05:54:30 pm
content: McMaster Carr has a wide range of threaded inserts designed for plastic:https://www.mcmaster.com/threaded-inserts/for-use-in~plastic/There are also clip-on nuts that might be suitable, depending on your application:https://www.mcmaster.com/clip-on-nuts

author: ConKbot
author_rank: Super Contributor
timestamp: February 16, 2021, 09:13:37 pm
content: There is also self tapping plastic screws, if you don't need something as durable as an insert. McMaster has them under "plastite screws" they are self tapping, and have a rounded triangular cross section that is less likely to back out, they work well in my experience. Just make sure to stick with inserts and machine screws for battery doors
Non intentional FCC certification for Signal Generator? - Page 1
Forum section: electronics / projects

author: Bandit-Technical
author_rank: Contributor
timestamp: September 03, 2015, 01:45:38 pm
content: Let's say for a product like Signal Generator, which has of course all types of mixed-signal electronics inside and an SMA output jack for freq. out, am I correct that in terms of FCC the only required certification is unintentional radiator?Here is a thing, if during a test, they turn it on and SMA out there is just as is... of course it will radiate maybe some and violate conditions of unintentional radiator, but on another side, user supposed to attach shielded coax cable there.That's basically was a reson I wanted to make sure that unintentional radiator is only type of certification needed for that product.

author: qno
author_rank: Frequent Contributor
timestamp: September 15, 2015, 08:48:22 pm
content: I do not know what the max output voltage is of the generator but you need quite some voltage levels to detect unwanted levels at 3 meter distance.

author: marshallh
author_rank: Unknown
timestamp: September 15, 2015, 08:55:07 pm
content: FCC has an exemption for test equipment, check that out.

author: nctnico
author_rank: Super Contributor
timestamp: September 15, 2015, 08:57:18 pm
content: Just to make sure you can connect a terminator to the output. Still if the generator is designed well the most likely source of emissions is any cable connected to it (like a power cable, USB cable, RS232, etc).

author: forrestc
author_rank: Unknown
timestamp: September 16, 2015, 01:47:42 am
content: Quote from: Bandit-Technical on September 03, 2015, 01:45:38 pmAs marshallh said, I don't think you need a FCC cert for this:QuoteI'd recommend reading that section, along with the note on (i).
non-isolated AC/DC buck converter with no transformer for microcontroller - Page 1
Forum section: electronics / projects

author: srinivas
author_rank: Newbie
timestamp: December 31, 2013, 01:35:01 pm
content: Recently While breaking into a Industrial controller i came across Microcontroller board that was 230 vac input and had No-Transformer or inductor which was quiet new to me. The AC input was filtered, rectified and then through a D-PAK pakage (some kind of requlator ??) and then through several diodes and resistor which then powers the microcontoller.How does it work???Is it an efficient Design (especially for industrial use)to be used with microcontroller circuits.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 31, 2013, 01:41:07 pm
content: There are several ways to do it. Power integrations do a number of chips (LNK30x series).Are you sure there was no inductor?For very low currents it could even be a linear regulator.It would be feasible to have a microcontroller that stops running when the line voltage is high to reduce dissipation.Another approach is to have a high voltage switch that turns off when the voltage in each cycle exceeds a certain level.

author: tszaboo
author_rank: Super Contributor
timestamp: December 31, 2013, 02:26:21 pm
content: If you know that the used current will be low, you can make a very crude supply voltage with a 5V zener diode with capacitive coupling/dividing. Teacher of my at university was suggesting this. It is not efficient, nor nice, nor safe so finally I did not used the design.They discuss it here:http://electronics.stackexchange.com/questions/41938/230v-ac-to-5v-dc-converter-lossless

author: mariush
author_rank: Super Contributor
timestamp: December 31, 2013, 02:33:28 pm
content: Maybe it was a simple capacitive dropper power supply (use a capacitor and resistor to go down to about 10-30v then use a linear regulator? )See this appnote :http://ww1.microchip.com/downloads/en/appnotes/00954A.pdf

author: LukeW
author_rank: Frequent Contributor
timestamp: January 01, 2014, 10:31:18 am
content: There are a couple of different options.If you only want a very small amount of current (like say <50mA) you can use the classic transformerless capacitive dropper approach with a large polymer capacitor, zener diode, rectifier diode etc.Or if you need a little bit more power (say 3-5W) you can use chips such as the NXP TEA1721 or Power Integrations LNK30x which are basically just buck converters with a very high voltage DC input, and some basic rectification and filtering of the mains to yield 340V DC or so (less if you have 110VAC) going in to the chip. These sorts of chips will give you a little bit more power that is just not practical with a RC "dropper" in a transformerless circuit, and they'll be much smaller and more efficient and won't dissipate heat, as well as working with universal 90-260VAC input.In this thread I discuss a basic example circuit which uses a LNK304 for exactly this sort of job.https://www.eevblog.com/forum/projects/lnk304-smps-design/
Non-isolated offline LED driver with LED MCPCB screwed to earthed heatsink. - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: September 02, 2017, 01:17:33 pm
content: Hello,We have an 230VAC offline, non-isolated LED driver with a 300V LED bank.The LEDs are on MCPCB, which is screwed down to an earthed heatsink.Can you confirm that this is illegal?, since if the earth wire that connects to the heatsink was (for whatever reason) not secured, then the heatsink would be insufficiently insulated from live mains.So….we are using the same sort of setup as on Figure 3 on page 4 of the following App Note on LED MCPCB’s..http://www.lumileds.com/uploads/539/AB06-pdf

author: dmills
author_rank: Super Contributor
timestamp: September 02, 2017, 03:11:05 pm
content: The devil is in the detail, but it could well be acceptable.Providing the isolation and creepage are ok, you have on the face of it two faults required to give a dangerous situation (Missing earth and failure of the MCPCB), so that could well comply for a class I device, but you will want to check what standard it was designed to and then check the requirements from there.60950 might be a good place to start, but I bet there is a product specific standard that overrides that.Regards, Dan.
Non-Isolated power supply- around 100mW - Page 1
Forum section: electronics / projects

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: February 18, 2014, 07:13:07 am
content: HiJust fishing for ideas, feedback or ... ideally the complete solution wrapped up in a box.I want to drive a MCP3901 on the mains side power monitoring device.http://ww1.microchip.com/downloads/en/DeviceDoc/22192c.pdfBut I need to power it.It's power requirements would be minimal, 60mW maximum, including the optocouplers.Power is important so I would like to minimise consumption when in use,Also I would like to minimise consumption by switching it off when not in use. I would have an isolated digital signal to control this. Si864x I think.There seems to be a few options on the supply.http://www.digikey.com.au/product-detail/en/LNK302DG-TL/596-1236-1-ND/1975498anyone used these before?The other main option is a capacitive supply such as described in an994http://ww1.microchip.com/downloads/en/AppNotes/00994b.pdfThis one seems heavily dependant on the incoming voltage and tolerances of the components to be efficient though. I put it in the simulator and it seems quite power hungry, I was hoping to do better. Maybe with careful part selection this would be good. It is obviously a very inexpensive solution.The lack of feedback seems to force a compromise between having heavily restricted operational parameters Pout, Vin vs efficiency.In both of these cases I would like to put in a switch to turn the psu off. Any suggestions here?Which would be the best method do you think?Cost is not a huge issue as I am not making 1000s.Any other solutions or suitable chips?
non isolated power supply breaking buck converter. - Page 1
Forum section: electronics / projects

author: Jnation
author_rank: Newbie
timestamp: June 15, 2016, 08:12:26 pm
content: Hello all, I am having an interesting problem, and cant seem to figure out whats going on. I am designing a circuit (arduino clone that powers a small or large dc motor, schematic attached) that uses a dc/dc buck converter (digikey part# BP5277-50-ND). When I'm powering the device with my bench top power supply, or an isolated power supply I have no problem. However once I use a Mean Well GS160A24-R7B power supply (24V 6.67A 160W Max) it destroys the buck converter! The only thing I have noticed is that when I use my fluke to check polarity, the ground output of the Mean Well power supply is connected to mains ground which tells me its not a isolated power supply. I'm going to switch to a isolated power supply, but I would still like to learn why this would break the buck converter.Any help would be greatly appreciated!-Jim

author: uncle_bob
author_rank: Unknown
timestamp: June 15, 2016, 11:23:52 pm
content: HiAll wall wart style supplies that are not "medical" have a common ground. That's just the way they do it. The ground is not your problem unless there is a sneak path. Best guess, you are not holding off the startup of your converter long enough or you do not have big enough input capacitors on the converter.Bob

author: Jnation
author_rank: Newbie
timestamp: June 17, 2016, 04:56:48 pm
content: Thanks so much! I attached a 47uF and a 1uf ceramic capacitor to the input voltage of the converter, works perfectly now.Thanks again,-JimEDIT* I was using a micro symbol, however they posted as ? so i replaced them with a u.

author: uncle_bob
author_rank: Unknown
timestamp: June 17, 2016, 05:05:57 pm
content: Quote from: Jnation on June 17, 2016, 04:56:48 pmHiThe *input* capacitor requirements for switching supplies are something that messes up a *lot* of people. First time through, nobody ever expects it to be an issue.Bob
Non-Local Closed Loop OpAmp Gain? - Page 1
Forum section: electronics / projects

author: CaptnYellowShirt
author_rank: Frequent Contributor
timestamp: May 12, 2014, 10:47:30 pm
content: I'm in the process of designing a high voltage constant-current supply for a project I'm working on.For this project, I'm going to need currents in the range of 0.1 - 10 mA supplied at around 225 V.Rather than designing the supply from scratch I'm opting to combine a Burleigh High Voltage OpAmp (typically used for controlling precision piezo devices) with a current sensing opamp setup. The Burleigh will supply the current at the high voltages, while a low-side shunt resistor will provide voltage feedback to some type of local precision opamp that ultimately feeds its output into the Burleigh box.The Burleigh box is basically a non-inverting amplifier with an adjustable gain from 0 - 100. The precision sensing opamp will be something like an LT1100/1150 with a wirewound shut resistor and LM399 as a Vref.My question here is on local feedback for the precision opamp. I'm concerned that, even though the Burleigh opamp closes the loop for the sensing opamp, without local feedback (e.g. << 1m of hook-up cables) the sensing opamp will find itself in some type of instability. That is to say, its open-loop behavior will dominate for some part of the spectrum.I'm fairly week on my practical opamp Fu, so I was hoping someone might be able to set my intiution straight here before I build a test circuit.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 12, 2014, 11:21:12 pm
content: The voltage amp* inside a loop to regulate current?*I don't suppose they make a current mode (Gm?) amp. Which is basically any normal amp, but without the compensation and low impedance follower inside. A voltage amp is normally made by intentionally slowing down a fast amp. The excuse is, the dominant pole compensation is easy to use?It follows, to have good current accuracy you need stupid high gain outside the volt amp (if you're talking LM399, it better be a damned fine amp and current sensor!). Which means that amp has to be at least as slow as the volt amp, plus some headroom (expect maybe 1/3rd bandwidth overall).The volt amp is dominant pole, but the pole moves up by the gain reduction. So at a gain of 10, it's GBW/10, etc... This makes it relatively easy to calculate the outer compensation too (if you were so inclined).Tim

author: CaptnYellowShirt
author_rank: Frequent Contributor
timestamp: May 13, 2014, 12:50:54 am
content: I had a few LM399's laying around.
Non-plated hole on an SMD Pad in Eagle Autodesk? - Page 1
Forum section: electronics / projects

author: gmanda
author_rank: Newbie
timestamp: July 21, 2019, 11:50:18 pm
content: Hi,I'm trying to make a footprint on Eagle for the following component (https://www.digikey.com/product-detail/en/LAMA2-14-QY/298-10109-ND/317639/?itemSeq=298643028) and I'm thinking of doing an SMD pad with a through hole in it. However, I'm not sure how to do a through hole in an SMD pad. Anyone have any suggestions on how I can achieve this?Thanks.

author: wraper
author_rank: Unknown
timestamp: July 21, 2019, 11:56:55 pm
content: If there is a hole, it's not SMD pad. I don't use Eagle but in general I would make rectangular/custom shape TH pad or make opening in solder mask around regular TH pad.

author: wraper
author_rank: Unknown
timestamp: July 21, 2019, 11:58:48 pm
content: 5 seconds of googling.

author: gmanda
author_rank: Newbie
timestamp: July 22, 2019, 12:08:57 am
content: Thanks man... I think I might have been googling it bad.. thanks again! appreciate your help

author: wraper
author_rank: Unknown
timestamp: July 22, 2019, 12:12:19 am
content: I misread your question a bit in regards of non-plated. But first of all there is no reason making non plated hole in pad for this. Secondly, if you will will make a hole in pad without any gap between hole and copper, PCB fab will make plated hole anyway.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 22, 2019, 12:14:44 am
content: In earlier versions of Eagle (e.g., 7.7), you can put a via on a pad. Just adjust the size to be what you need. Some board houses may flag it, but an e-mail to my board house solved the problem, and the boards were made as designed.Hard to imagine that feature being disabled. There are several reasons to do it.
Non PLC industial logic - Page 1
Forum section: electronics / projects

author: qwaarjet
author_rank: Regular Contributor
timestamp: July 27, 2015, 01:54:27 am
content: I'm looking for discrete logic fit for industrial application (high heat and vibration 28V logic). For variety of reasons I want to avoid the use of a PLC and the number of inputs I would like ~70 is inconvenient for din mount relays. I was think making PCB with some 74 series logic but would prefer a COTS solution.
nonconverging ngspice sim - Page 1
Forum section: electronics / projects

author: vectorotter
author_rank: Contributor
timestamp: June 24, 2024, 08:59:05 pm
content: Hi there,I've attached my qucs-s schematic, the netlist and the sim output after much tweaking and trying things out, for example adding initial conditions to C's, adding small value resistors to ideal L, big shut R from L node to GND.Each part of the circuit and by that I mean the gate driver and the power stage both work in isolation with no issue as expected. In the case of the power stage I attach a PWL source to the gate to drive it.No matter what I seem to try including swapping the transistor model for the built-in IRF540Z model I get roughly the same result which is nonconvergence after after about 1ms of 20ms sim time.Any ideas or pointers appreciated.

author: moffy
author_rank: Super Contributor
timestamp: June 24, 2024, 11:09:07 pm
content: You could try converting your AC voltage source to a Norton equivalent, an AC current source with a load resistor across it to give the same voltage, sometimes that helps with discontinuities and non convergence, had to do it previously, it was a diode thing.
noob needs help (A) (about SA ppe2400) digital controlled analog EQ - Page 1
Forum section: electronics / projects

author: milanhofman
author_rank: Newbie
timestamp: April 21, 2014, 03:47:27 pm
content: hi fallow EEVblog fans/usersi have a broken PPE2400, i think its un repairable,. (bought it broken, and found all kinds of attempts to fix it)is there anybody who want's to help me?im planning to use a raspberry pi and connect the interface and buttons to it, and than use a external sound card to alter the sound (any suggestions are welcome)this is the unit,http://www.bse-pro.nl/cfsystem/userData/Productplaatjes/originals/stage_accompany_ppe_2400.jpggreetings,milan hofman
Noob upgrades a Garmin GPS battery. - Page 1
Forum section: electronics / projects

author: rebelrider.mike
author_rank: Contributor
timestamp: April 22, 2017, 03:37:50 pm
content: Hi folks,I'm a noob here, and a noob to electronics. I though I'd share a very simple upgrade I did for my Garmin.So back in 2009 I bought my first GPS, a Garmin Nuvi 255. I immediately discovered that I love having a GPS! In 2013 though, it up and died. I tried a new battery, but the unit was just dead. So I replaced it with a Nuvi 40.Well, the Nuvi 40 had some nice advancements. General performance was improved, except for battery life. The 255 would last around 4 hours on a single charge, but the 40 only lasts about half that. To make matters worse, a few months ago, the battery started losing half its charge just by sitting off for a few days. So I decided to compare the batteries of the old and new units before I sprang for a replacement. Here is what I found:Voltage and plug are exactly the same, but the new model takes a smaller battery with fewer mAh. Shame on you Garmin! Of course I want the larger battery in the in the Nuvi 40, but the cavity in the plastic housing was made for the smaller battery.Only took a few minutes with a razor knife to make the cavity just a little larger.Passed the "smoke test"!Not only did it work, but that 8 year old battery, after sitting on a shelf for 4 years, still had 3/4 charge! I don't know if it was even fully charged when it was removed. I've let the GPS run for two or three hours to let the battery run down, and have started charging it. Hard to tell when the battery is full. The Nuvi doesn't give a charging indicator, nor does it tell you when its charged. It only indicates that its on external power. So I'll let it be on external for a while and then see how long it will go for until it has to shut itself off. So far though, it seems to be taking a charge fine, and looks like I will have a 4 hour GPS again!
Nook Simple Touch: Sound card, headphone and microphone jack - Page 1
Forum section: electronics / projects

author: idoit
author_rank: Contributor
timestamp: October 31, 2013, 03:50:19 pm
content: Hi Dave and everyone,I want to add sound capability to my Nook Simple Touch (NST). I know there are external USB sound adapters (likehttp://www.ebay.ca/itm/Sabrent-Virtual-7-1-USB-2-0-External-Sound-Card-Adapter-USB-SBCV-/161133438682?pt=US_Sound_Card_External&hash=item25844d26da&_uhb=1) that I can use and one can enable USB host mode in NST. This way sound works fine. But what I want is to integrate it inside the NST case.This is what has been done for adding sound to NST:External Sound adapter + MicroUSB to USB converter + USB Host modeWhat do you think? let me know.

author: xchip
author_rank: Regular Contributor
timestamp: November 01, 2013, 04:15:02 pm
content: let's do it!

author: lapm
author_rank: Frequent Contributor
timestamp: November 01, 2013, 05:37:36 pm
content: Should be doable is there is room for it inside the case. Don't forget to remove bulky USB connectors where necessary.

author: idoit
author_rank: Contributor
timestamp: May 01, 2014, 05:03:20 am
content: Thanks for your replies and sorry for my really late post after almost 4 months. Well, it seemed doable, but soon after posting this, I lost my interest in NST with Glowlight as it was really prone to get its screen broken (personal experience), so I didn't go any further and got back to my really solid Kindle Keyboard which I dearly love.But you know, I'll buy hardware modding equipments soon.