hybridfree/eevblog-posts huggingface dataset:
Heating issues with solar charging circuit - Page 1
Forum section: electronics / projects

author: aakash dey
author_rank: Contributor
timestamp: February 07, 2019, 02:01:56 pm
content: I am using the above circuit to charge a 7.4V Li-ion Battery.With input MPPT voltage set at 12V, I have applied 13V input voltage to the circuit. The battery is charging at 1.4A. (according to the calculation it should be 2A). But, the input diode D1, Input capacitor C1, MOSFET Q1, diodes D3 and D4, Inductor L1 are heating too much during charging. What could be the reason of heating ? Any design problem or other?

author: nsrmagazin
author_rank: Regular Contributor
timestamp: February 08, 2019, 02:44:01 am
content: D4 should not be heating, your output has a very low resistance and D4 drains a lot of current to ground, maybe around "0.4..0.6ADC". Whats the frequency at which your driver IC controls the MOSFet, it seems as if the MOSFet is on for too long.

author: aakash dey
author_rank: Contributor
timestamp: February 08, 2019, 05:47:20 am
content: As per as datasheet the switching frequency of DRV pin of cn3722 is 300KHz. And I am using AO3401 MosFET. Is the MosFET has some issue in this frequency?

author: nsrmagazin
author_rank: Regular Contributor
timestamp: February 10, 2019, 02:17:41 pm
content: Can be I have to check the datasheet and I don't have time at the moment. Check the datasheet and measure with an osciloscope if possible? Also check with a multimeter or osciloscope the voltage after the MOS.

author: Kasper
author_rank: Frequent Contributor
timestamp: February 10, 2019, 05:32:26 pm
content: Have a close look at PCB layout considerations in the datasheet. Specially the parts about grounding. It can be challenging to satisfy all the considerations but if you look at some dev kits, you might get some good ideas.Try measuring voltage between battery ground and input ground with a scope, that might highlight one of the problems, too much resistance between bat ground and input ground.Per figure 4 kelvin sensing of charge current: R14 layout could be improved by making it more similar to the image. You want to measure voltage across resistor, not across resistor + a bit of track.
Heatshink standard guide, compendium, vademecum... or similar - Page 1
Forum section: electronics / projects

author: ElektroQuark
author_rank: Unknown
timestamp: September 25, 2014, 07:10:14 am
content: Do anyone know a guide about standard heatshink models?I have a bunch, most of them salvaged, and I would like to find thermal characteristics for future use.Some are of this common type:I suppose I can find them one by one but some type of guide could help.

author: MK
author_rank: Regular Contributor
timestamp: September 25, 2014, 10:55:13 am
content: Heatsinks come in many shapes and sizes, you will need the original manufacturers catalogues that show the typical rating for any given length of the profile that matches, eg try Aavid and see the full range they do, there are many other manufacturers to each with their own profiles on offer.

author: free_electron
author_rank: Super Contributor
timestamp: September 25, 2014, 01:08:16 pm
content: Looks like fischer to meFischerAavidOhmite

author: ElektroQuark
author_rank: Unknown
timestamp: September 25, 2014, 01:31:12 pm
content: Now I know the principal manufactures.Thank you.

author: SeanB
author_rank: Super Contributor
timestamp: September 25, 2014, 06:19:54 pm
content: That style is typically going to be rated 20C/W, or only use if you have to dissipate under 5W. Taller ones ( double height) are typically 15C/W, or will do 8W, and wider ones are going in the 10C/W range, so will do 10W.Not exact, but will do for most TO220 packages and will keep them under 125C die temperature with the dissipation. You will need to have them though mounted vertically fins vertical with airflow around then to get this rating. If you use a fan to actively cool then you can double the power dissipation without problems, though you probably would use a fixed speed fan blowing directly on the heatsink with the air allowed to exit the case directly after the device and air inlets that are not too restrictive.
Heatsink extrusion specs per inch - Page 1
Forum section: electronics / projects

author: reyntjensm
author_rank: Regular Contributor
timestamp: January 01, 2021, 10:26:15 pm
content: I'm using an aluminum heatsink profile and the specs are given per inch of profile.I don't understand what will happen when i use 2 inch ( or more) of the same profile? Will the thermal resistance be divided by the length unit?

author: Ian.M
author_rank: Super Contributor
timestamp: January 01, 2021, 10:36:35 pm
content: Yes and no! If your heat sources are reasonably evenly distributed over the length of the heatsink and approximately equal power that's a valid assumption If not you need to consider the thermal resistance of the heatsink itself down its length which appears in series with the thermal resistance to ambient of each 'slice'. This is unlikely to be a significant issue if the length is not several times greater than the width

author: reyntjensm
author_rank: Regular Contributor
timestamp: January 01, 2021, 10:56:49 pm
content: Quote from: Ian.M on January 01, 2021, 10:36:35 pmThank you for the feedback. I have no idea on how i should do this. I'm planning to use 4 inch of profile and the heat source would be placed in the middle. So can i assume the thermal resistance of the profile would be 4 times smaller as in the datasheet?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 01, 2021, 11:11:18 pm
content: I would think the factor is smaller than 4. If it were, that would assume four times as much surface area on the ends as well, which clearly isn't the case. It assumes the air column isn't saturating with heat, which may not be the case. I wouldn't think it would be as bad as 2, though, and you could run more air flow (or better ducting) to keep the temp rise down.You can also compare with similar shapes and lengths in manufactuers' catalogs, and see if the Rth is adequate.Tim

author: trobbins
author_rank: Frequent Contributor
timestamp: January 02, 2021, 01:19:06 am
content: How limiting is the heatsink thermal resistance to what you have planned? It sounds like you are just going to use natural convection too - in which case the heatsink orientation would be a concern, and placing the heat source in the 'middle' would not be optimum for vertical heatsink stance.

author: Harm314
author_rank: Newbie
timestamp: January 02, 2021, 10:01:55 am
content: For an increasing length the cooling efficiency becomes relatively worse. See for examplehttps://www.fischerelektronik.de/web_fischer/en_GB/heatsinks/A01/Standard%20extruded%20heatsinks/$catalogue/fischerData/PG/SK519/search.xhtml, where the thermal resistance is plotted against the length.
Heatsink for Charging Devices  ? - Page 1
Forum section: electronics / projects

author: Petdevils
author_rank: Newbie
timestamp: January 15, 2024, 06:44:07 pm
content: HelloTangentially related to my other thread about slow charging devices...I have always wondered about getting some kind of Ribbed Heatsink tray to put phones/tablets etc on when charging (to dissipate some excess heat to protect the battery). You know, kind of like the big hunk of metal on your GPU?Something like this...https://www.google.com/search?q=heatsink&sca_esv=598624957&tbm=isch&sxsrf=ACQVn0_wXAPdQJJ4Xkl-xQEhTaP3PJMEUA:1705343408928&source=lnms&sa=X&ved=2ahUKEwjMwu-gg-CDAxUucfUHHZlABtYQ_AUoAnoECAMQBA&biw=1707&bih=791&dpr=1.5#imgrc=ZoYBJ4xXIw_J-MIn a perfect world, it would be made to have a soft surface level, so that it won't mark/damage the phone/tablet when you put it down/pick it up, also non-slip to prevent it from accidentally slipping/getting knocked off?But that might be a tall order.Could you just put a layer of non-slip rubber/latex (with the holes in it), or same thing but solid - over a heatsink or would that totally mess it up?@Andy Chee mentioned some of the things I was already thinking about - the peltier idea is fun, but probably a little too finicky/risky for me. Same with an enclosed cold box. I just want to keep it low tech and unpowered. Unless you've got a really simple, powered idea that has zero risk.I think something like a big ribbed aluminum heatsink or something similar might be good?What do you think? What types of things, and any specific items, would you recommend?I suppose it could be something vastly different, not for purpose originally...Maybe a brick of ballistics gel?https://www.google.com/search?q=ballistics+gel&sca_esv=598624957&tbm=isch&sxsrf=ACQVn0_Ftd25J5vaG-3K2yCNE_m9xVlQ6w:1705344189172&source=lnms&sa=X&ved=2ahUKEwjy7fWUhuCDAxUTU_UHHQy2DNoQ_AUoAnoECAIQBA&biw=1707&bih=791&dpr=1.5If you actually made the ballistics gel yourself, you could actually mold your phone to fit exactly and suck up some more heat?After all, the problem is, that most phones already have a damn phone case trapping a lot of heat, so maybe a flat solid surface like ballistics gel might work well?I'd prefer something affordable and something that's not too difficult to get my hands on, where I won't need to spend ages making it (unless it's really fun).See my other thread to see what items I need to cool when charging.Whoa your Horses... I want Slow Charging, here's my idea...https://www.eevblog.com/forum/projects/whoa-your-horses-i-want-slow-charging-heres-my-idea/msg5280184/#msg5280184Thank you for your help

author: coromonadalix
author_rank: Super Contributor
timestamp: January 15, 2024, 06:58:10 pm
content: mmmmmmmmmm do you love starting some useless threads ? seriously, you have to use web search and find your solutions outside eevblog ?

author: David Hess
author_rank: Super Contributor
timestamp: January 16, 2024, 03:43:55 pm
content: Get a phone cradle that has a fan blowing on the back. Even a tiny amount of airflow will make a huge difference.
Heatsink for multiple devices, floating, grounded or connected? - Page 1
Forum section: electronics / projects

author: Miyuki
author_rank: Frequent Contributor
timestamp: September 04, 2021, 06:55:14 am
content: Hi folks.I want to ask your opinion and best practices.Everything will be in a grounded metal case.I have that long heatsinks for multiple devices, so all are either in FullPak or have an insulating pad.Some Thyristors (so slow switching) and some SiC Mosfets (so high speed)The question is does it matter if the heatsink is then connected to some internal voltage, grounded or floating?

author: mariush
author_rank: Super Contributor
timestamp: September 04, 2021, 09:19:01 am
content: I would say consider various scenarios like what happens if the case falls or gets bent and touches heatsinks ... I'd rather have heatsinks grounded.What if random user opens the thing and touches the heatsinks? May make sense to have it grounded.The only concern I see is if the mica insulators/pads break and that component has voltage on the pad, then it's gonna cause short. It happened to Corsair with some power supplies, they had a bad batch of insulators and mosfets shorted against heatsink.

author: Zero999
author_rank: Super Contributor
timestamp: September 04, 2021, 04:38:14 pm
content: It depends on whether the heat sink can be easily touched by the user, or come into electrical contact with exposed metalwork?If the heatsink is safely tucked away inside a plastic enclosure, there's no need to earth it, otherwise, it definitely must be earthed.

author: bob91343
author_rank: Super Contributor
timestamp: September 04, 2021, 11:14:45 pm
content: Consider the stray capacitance between the devices and the heat sink. That can cause oscillation in some cases. Safest is probably to ground the sink, perhaps even in several places.
heatsink microholes technology name? and other weird heatsink things - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: December 05, 2018, 05:04:00 pm
content: https://www.eevblog.com/forum/projects/the-performance-of-a-heatsink-with-a-black-surface/Someone here mentions of microholes in heat sinks that are 7 times deeper then wide. What is this kind of patterning called and what diameters are used?Quote

author: coppercone2
author_rank: Super Contributor
timestamp: December 05, 2018, 10:17:41 pm
content: thread broadened to incorporate discussion about other odd heatsink coatings textures and seldom seen effects.Could this effect described by the thread title be one of the reasons why ceramic porous heatsinks might actually perform better then anticipated (they were prior regarded as kind of a joke or marketing gimmick when previously discussed on this forum).https://uk.farnell.com/amec-thermasol/mpc303025t/heat-sink-ceramic-30-30-2-5-std/dp/1892476

author: nctnico
author_rank: Super Contributor
timestamp: December 05, 2018, 10:42:27 pm
content: IMHO the biggest advantage of the ceramic heatsinks is that they don't conduct. I have used these to increase the cooling on an existing circuit board. They give some measureable improvement.

author: filssavi
author_rank: Frequent Contributor
timestamp: December 05, 2018, 11:41:03 pm
content: For power electronics I would love having a ceramic (even just a coating) heatsink/cold plate, unfortunately the matherials that have a high enough thermal conductivity is either horrendously toxic (berilium oxide) stupidly expensive (boron nitride) or a mix of the above

author: coppercone2
author_rank: Super Contributor
timestamp: December 06, 2018, 12:05:41 am
content: hard to justify over a spacer, unless its R F , but I am really curious about the effect of those holes as described by the other thread.on the bright side with how hard boron nitride is to produce, at least I don't feel like im being completely screwed over...

author: Ian.M
author_rank: Super Contributor
timestamp: December 06, 2018, 12:19:24 am
content: Last year's ceramic heatsink threads:https://www.eevblog.com/forum/projects/micro-porous-heatsinks/https://www.eevblog.com/forum/projects/micro-porous-ceramic-heatsinks-for-raspberry-pi-et-al/TLDR: Porous ceramic heatsinks suck! Any random chunk of metal of comparable dimensions will do as well or better.

author: coppercone2
author_rank: Super Contributor
timestamp: December 06, 2018, 12:30:36 am
content: are you sure convection is a dominant force with the pore size it has?

author: Ian.M
author_rank: Super Contributor
timestamp: December 06, 2018, 05:08:37 am
content: In air, with the heatsink exposed to the thermal IR radiation from ambient surfaces above 0 deg C? Conduction and convection will certainly dominate.
Heavy Duty Connector Power + Signal - Page 1
Forum section: electronics / projects

author: luky315
author_rank: Regular Contributor
timestamp: January 07, 2014, 04:01:59 pm
content: Does anyone know a connector system for automotive use / light trucks ("12V") with at least IP68 and vibration resistant interlock? I need power (5-10A) and a differential CAN signal (100/120Ohm). Is there a system which combines power and signals or is it bether to use separate conectors and cables for signal and power?

author: Frost
author_rank: Regular Contributor
timestamp: January 07, 2014, 04:43:24 pm
content: Quote from: luky315 on January 07, 2014, 04:01:59 pmMaybe the Superseal Series from AMP, the Standard-Buccaneer Series from Bulginor very rugged the M Series from Lemo?With two seperate connectors you can combine the Buccaneer 400 with their Mini Series.

author: Unknown
author_rank: Unknown
timestamp: January 07, 2014, 05:39:15 pm
content: https://b2b.harting.com/ebusiness/app/displayApp/%28xcm=ebusiness_espel32&layout=7.0-12_131_125_139_129&uiarea=1&carea=0000100450&cpgnum=1%29/.doI use loads of Harting industrial connectors. Just making some looms and connectors up currently to replace some that have been in a very heavy industrial application since the 70's and are only being replaced as part of scheduled maintenance.

author: ConKbot
author_rank: Super Contributor
timestamp: January 07, 2014, 06:35:54 pm
content: The J1939 connector comes to mind. Already carries a few amps of power and CAN bus signalling for the J1939 bus. Its kind of big, but should be available.

author: luky315
author_rank: Regular Contributor
timestamp: January 08, 2014, 01:19:55 pm
content: Thanks. J1939 semms nice. A bit bulky and hard to obtain, but robust.The Buccaneer-Series is also worth a try because there are PCB and panel mounting connectors available.Thanks again!
HEF CMOS IC is NLA--what to use? - Page 1
Forum section: electronics / projects

author: iXod
author_rank: Frequent Contributor
timestamp: March 10, 2020, 03:25:23 am
content: A 25-year-old relay switching circuit (6 inputs driving 6 relays) includes a HEF4023BP: triple, 3-input AND gates. Now kaput, it needs to be replaced.This IC has not been available for some time. I can find no supplies (other than eBay which for obvious reasons I'd like to avoid).What CMOS family can provide this modest performance? The circuit is neither fast (switching relays a few times a minute) nor quick (fast relay activation is not a requirement).I don't know what makes HEF CMOS unique, so I don't know for what feature the designers chose this CMOS family. (Trying to educate myself, Google wouldn't return any useable search results for the HEF family.)Replacement suggestions welcome. And a clue to what HEF is all about.Thanks.

author: oPossum
author_rank: Super Contributor
timestamp: March 10, 2020, 03:31:29 am
content: CD4023 should work in place of the HEF4023. They are readily available.https://www.findchips.com/search/cd4023

author: Ian.M
author_rank: Super Contributor
timestamp: March 10, 2020, 03:41:29 am
content: HEF is just Philips (now NXP)'s prefix for 4000 series CMOS logic. Simply substitute any other brand of 4000 series 4023 still available from major distributors.@oPossum: You beat me to it!

author: oPossum
author_rank: Super Contributor
timestamp: March 10, 2020, 03:44:55 am
content: Looks like the On Semi (Motorola) is also still available.https://www.findchips.com/search/mc14023

author: Gyro
author_rank: Super Contributor
timestamp: March 10, 2020, 12:37:44 pm
content: HEF tended to be faster than the other 4000 series manufacturers (used to be handy if your address decode logic didn'tquitemake it), but I doubt that would be an issue for a relay switching unit.

author: jfiresto
author_rank: Frequent Contributor
timestamp: March 10, 2020, 01:17:07 pm
content: The CD4023BE from TI may be the last PDIP part still in production. It is rated for a higher, 18V maximum operating voltage.If nothing but a Philips part will do, the Silicon Ark currently hasfive NOS partsin stock.
Height above ground plane in 4-layer SMPS? - Page 1
Forum section: electronics / projects

author: incf
author_rank: Frequent Contributor
timestamp: January 24, 2025, 12:21:31 am
content: I'm laying out a 4-layer PCB for a SMPS. Due to component density the layers in a particular area area are as follows:Layer 1: High power traces switched at ~100kHz + Components and heavily filtered DC signals[~0.2mm FR4]Layer 2: Ground[~1.2mm FR4]Layer 3: High power traces switched at ~100kHz[~0.2mm FR4]Layer 4: Components and heavily filtered DC signalsI've got a question about the height of a PCB trace above a ground plane.I've got high power traces switched at 100kHz on layers 1 and 3. While I've got a ground plane on layer 2.The distance of layer 1 to the ground plane on layer 2 is 0.2mm.The distance of layer 3 to the ground plane on layer 2 is 1.2mm.Does this difference in height make for a large difference in radiated EMI? Magnetic / capacitive coupling to nearby traces? etc.Thanks!

author: CosteC
author_rank: Regular Contributor
timestamp: January 24, 2025, 07:33:16 am
content: The thinner insulator the higher capacitance. This helps with shielding but also increases common mode currents.Opposite is also true.Personally, I would prefer to have lower capacitance from switching nodes to GND in most of places, to avoid parasitic capacitances. This however is layout thing - those nodes shall be geometrically small for many reasons and layerstack may be of secondary importance.In many practical designs there are holes in GND planes around some nodes to reduce parasitic capacitances.There is also matter of safety if, it is mains powered SMPS - too thin layer of PCBA insulator may be not sufficient.

author: mtwieg
author_rank: Frequent Contributor
timestamp: January 24, 2025, 01:31:22 pm
content: I would check whether trace capacitance actually contributes significantly to overall capacitance. For the switching node of a power supply I would usually expect the capacitance of semiconductors to dominate.And also consider that if you are relying on your PCB and power planes to cool the power components, thicker dielectric will make that worse.
Help finding cheap flip dots panels - Page 1
Forum section: electronics / projects

author: Unknown
author_rank: Unknown
timestamp: October 28, 2014, 10:24:47 am
content: Does someone know where i can find dirty cheap flip dots panels?For an art installation i have to make a 1m x 0.5 m display and i am on a tight budget. I only need the dots or panels, no controller.

author: mark03
author_rank: Frequent Contributor
timestamp: October 28, 2014, 03:48:01 pm
content: If you find a good source, let me know. There is an outfit in Poland which sells them new, but they don't come cheap. The last time I saw some on Ebay they were small panels, as I recall about 0.1 square meter. Tried to talk the seller down to $100/ea and he wouldn't budge!The strange thing is that there is a steady flow of these from my local transit agency (bus signs), but in typical American fashion the govt agencies have outsourced their surplus auctions to private auction houses. The buses get sold intact, and where the parts go from there is anyone's guess. For all I know the signs are sitting in a dumpster someplace.
help! homemade oscilloscope project - Page 1
Forum section: electronics / projects

author: ali6x944
author_rank: Frequent Contributor
timestamp: January 27, 2016, 07:29:08 pm
content: hello everybody,I was recently working in this homemade oscilloscope project using a CRT module I salvaged out of some old equipment i found in a scrap yard, it works reasonably will -at low frequencies-.and by spinning the yoke 90 degrees to the left i was able to actually use it as an oscilloscope, but it is not that great; due to the fact that I'm not using the module controls, rather i used to drive it with a TIP31C and a fly-back diode between the two terminals of the yoke.at first, i thought that my signal should first go into a single transistor amp to buffer it so it dose not get distorted that much, but that didn't work.so I'm trying to amplify the signal properly with this LF347N -quad op amp- by Motorola, but am having a heck of a hard time doing it ;because i would need to power it with split rail supply , another problem rose when I want it to trigger it on the input signal and these things..so please help me in this if you can, here is some pics of the thing and some datasheets i found:

author: ali6x944
author_rank: Frequent Contributor
timestamp: January 27, 2016, 07:34:49 pm
content: this is op amp datasheet:

author: ali6x944
author_rank: Frequent Contributor
timestamp: January 27, 2016, 08:52:59 pm
content: the module:https://drive.google.com/file/d/0B5vW-k7HbsL4bERFUnNRc2pCVEE/view?usp=sharing

author: Kleinstein
author_rank: Super Contributor
timestamp: January 27, 2016, 09:14:54 pm
content: A CRT with magnetic deflection will not give a useful analog scope. It is just way to slow and need ever increasing voltages as the speed goes up. At best this is a crude demonstration at low frequency (e.g. line frequency and maybe up to 5 kHz).

author: ali6x944
author_rank: Frequent Contributor
timestamp: January 28, 2016, 03:32:28 am
content: OK, that disappointing, but do you know a way for me to display at lest characters?or display images like the canon CRT viewfinder?because i happen to have an NEC7220AD HGDC or "high-preformans graphics display controller" so could i do anything useful at low frequenciesand for the yoke capability it is more in the current side rather than the voltage, so it is beam being deflected by the beam the farthest the higherthe current flow. so i could drive it with a voltage controlled current source and i would be just fine, but this is not useful that much because then when mesaring square waves i have to deal with very high voltage spicks.

author: ali6x944
author_rank: Frequent Contributor
timestamp: January 30, 2016, 05:24:30 pm
content: please any help?
Help - Page 1
Forum section: electronics / projects

author: Swaroop 21
author_rank: Regular Contributor
timestamp: September 03, 2021, 05:06:03 pm
content: Can anyone help me choose a ferrite core required for my inverter project which will be of 6KW but I will divide them into 12 sections of 500W each but I dont know which ferrite core can handle 500W maybe a EE35 or EE55?? Can anyone help?

author: Vovk_Z
author_rank: Super Contributor
timestamp: September 03, 2021, 06:53:38 pm
content: Can you edit a topic name to something like "How to choose a ferrite core"?

author: Doctorandus_P
author_rank: Super Contributor
timestamp: September 04, 2021, 07:43:24 pm
content: I did not read your post, but you can start by making a decent title.

author: Benta
author_rank: Super Contributor
timestamp: September 04, 2021, 08:12:43 pm
content: On every other forum I visit, this thread would be closed/deleted due to:"Meaningless Topic Title".1: Activate brain.2: Post question.
Help about adc board  - Page 1
Forum section: electronics / projects

author: Dzoro
author_rank: Contributor
timestamp: January 10, 2023, 03:31:51 pm
content: Hi everyone i want to make a board like the ads1115 (there is a picture for those who don't know what it is)these boards can be bought from aliexpres but i don't want to wait 3 months to arrive at my country so i wanted to buy an adc chip to make one myselfBut in my country suppliers i cant find the ads1115 chip so the best one i could get is the mpc3208So my question is how to configure this chip to have the same outputs as the board bellow but i don't understand the adc chip to make a useful schematic so please help

author: RogerThat
author_rank: Regular Contributor
timestamp: January 10, 2023, 10:00:51 pm
content: What is it that you don't understand? It looks very straight forward...look at the pinout and go one by one. If you get stuck with one pin, google and search until you understand that pin.Note that the MPC3208 is 12bit with SPI interface while the ADS1115 is 16bit with I2C.

author: bidrohini
author_rank: Regular Contributor
timestamp: January 11, 2023, 01:53:45 am
content: You can follow these videos:

author: Dzoro
author_rank: Contributor
timestamp: January 12, 2023, 12:32:07 pm
content: yes but my question is how to make this chip to have i2c interface because the whole project is i2c basedi found a DAC in my country that has i2c interface, but i cant find ADC with i2c interfacethat is my problem

author: jpanhalt
author_rank: Super Contributor
timestamp: January 12, 2023, 12:43:19 pm
content: I2C and SPI cannot be directly connected to each other and work. The I2C is a send/acknowledge system. The SPI is a system in which bits are exchanged in sequence.You could use an MCU as an interface between the two, and there are probably several examples of freely available code to do that.

author: RogerThat
author_rank: Regular Contributor
timestamp: January 12, 2023, 08:57:48 pm
content: Using an MCU to do i2c SPI conversion, while possible, is not very efficient use of parts. Can't you just get an MCU with 12bit ADC? Microchips AVR DA series perhaps? It also have a 10bit DAC.
help about How to stop the car pump with a connection from phone vibrator curent - Page 1
Forum section: electronics / projects

author: zwawitotti10
author_rank: Newbie
timestamp: August 29, 2021, 01:19:40 am
content: Need helpI have an old phone and I want to connect it with Relay 12v so that I can control a pump that is always workingWhen I call her, the pump turns offI brought a Relay ,old phone, a transistor BC547 , a reset button, and a MOSFET IRF540N in order to maintain the state even after the excitement applied to it had stopped.I designed the schema and tried the project on the Proteus software, it works normally, but when I delete the ground and rempalce it by connect it alone to the negative, the project does not work

author: SL4P
author_rank: Super Contributor
timestamp: August 29, 2021, 07:20:49 am
content: Where’s your flyback diode?

author: zwawitotti10
author_rank: Newbie
timestamp: August 29, 2021, 11:32:22 am
content: Quote from: SL4P on August 29, 2021, 07:20:49 amWhat I want is only a schema to control the relay with a transistor, but until I remove the exciter on the transistor, the relay remains in its state until I come to it and press the restart button after that change the state

author: Renate
author_rank: Super Contributor
timestamp: August 29, 2021, 11:40:42 am
content: You don't have anything in your circuit to function as a latch.You could use an SCR (if a normally closed reset pushbutton is acceptable).You could use extra contacts or rearrange the circuit to use the relay to latch (with a NC reset button).You could make a two transistor latch.
Help about sidac component in circuit - Page 1
Forum section: electronics / projects

author: Dzoro
author_rank: Contributor
timestamp: March 09, 2023, 03:13:36 pm
content: Hello guys i want to build this circuit it is a jammer that can block some thing but it has one component in it that i can not find and also in my experience in electronics i have not seen it anywhereFrom what i have read on the internet it is similar to diac but i don't understand itThe component is mkp3v240 you can see it in the schematic downMy question is where can i find it or can i put something else instead of it

author: Terry Bites
author_rank: Super Contributor
timestamp: March 09, 2023, 04:00:49 pm
content: Jamming explicity prohibited by International Agreements.I hope you get caught!

author: Dzoro
author_rank: Contributor
timestamp: March 09, 2023, 04:01:59 pm
content: I am not going to jam other people staff i wanto to joke around with my equipment

author: themadhippy
author_rank: Super Contributor
timestamp: March 09, 2023, 04:06:18 pm
content: QuoteBut what if your jammin in the name of the lord?

author: Dzoro
author_rank: Contributor
timestamp: March 09, 2023, 04:07:10 pm
content: 😂😂😂😂
Help calcculating an power source for Paralel Led Circuit - Page 1
Forum section: electronics / projects

author: FTVlog
author_rank: Newbie
timestamp: August 25, 2015, 11:44:54 am
content: hi,I searching on web ways to calculate the amperage needed for a power source to a line of LEDs connected in parallel.I found something talking about resistor but only talk about resistance nothing about amperage.maybe this is a super newbie quest.from my calculations i got an ridiculous amount of amperesthanks

author: alexanderbrevig
author_rank: Frequent Contributor
timestamp: August 25, 2015, 11:48:59 am
content: You can try this which helps you design the circuit:http://led.linear1.org/led.wiz

author: FTVlog
author_rank: Newbie
timestamp: August 25, 2015, 12:10:50 pm
content: Thanks alexanderbrevigi try you link i still have a lot of power for an 5V source!by the wizard calculation i need 750W of powerdo you have any idea how can I use a more commercial source to light the LEDs?

author: Zero999
author_rank: Super Contributor
timestamp: August 25, 2015, 12:19:05 pm
content: Connecting LEDs in parallel is generally a bad idea.You could connect them in series and use a higher voltage.Power is power. You could run them at a lower current but they will be dimmer.

author: FTVlog
author_rank: Newbie
timestamp: August 25, 2015, 09:18:41 pm
content: hi Hero999,Thanks for reply,i understand the reason but, i want understand the concept.I'm having playing with some circuit simulators and my values are different from the simulator.(Please see the Attachment image)On the left circuit only have one LED connected do we have 5V 17,82mA 89,08mWSo if i want have 1000 LEDs in parallel it will be:(17,82mA * 1000LEDs) = 1782mA = 17.82Aand (17.82A * 5volt) = 89.1wattRight??but on left circuit, have 1000 LEDs connected (exactly equals) but the values we got are differentwe have 4.99V 14,15A 70.76WI don't understand why?thanks
Help choosing a "low frequency" (under 1GHz) resistor - Page 1
Forum section: electronics / projects

author: Pat Pending
author_rank: Regular Contributor
timestamp: January 25, 2020, 10:05:48 am
content: A termination resistor for a (DC-300MHz) differential signal shows a 120R 1% 1206 resistor rated for 0.5W.The differential voltage across the resistor is ~0.4V and there is no direct DC path that would create the conditions for a large thermal dissipation.Much of the literature online indicates that thin film resistors in much smaller package sizes are useful out to 1GHz before the effect of parasitics significantly kick in.And other online discussions on DIY VNA calibration standards that extend the useful frequency range to several gigahertz.I am tempted to replace it with a 0603 package to simplify layout but my question is why specify such a large package size and large thermal rating when the signal of interest is low power and band-limited to under 300MHz?

author: Leo Bodnar
author_rank: Frequent Contributor
timestamp: January 25, 2020, 11:55:05 am
content: Is it a field bus termination and has exposed green terminal connectors?Then expect an electrician to stick 12V or 24V down it from time to time.Leo

author: Kalin
author_rank: Regular Contributor
timestamp: January 25, 2020, 04:28:17 pm
content: Quote from: Leo Bodnar on January 25, 2020, 11:55:05 amAs an electrician I feel personally attacked. Usually we stick 120V down it! No messing about with that extra low voltage rubbish.

author: ConKbot
author_rank: Super Contributor
timestamp: January 27, 2020, 02:08:58 pm
content: Quote from: Kalin on January 25, 2020, 04:28:17 pmI've done an optoisolated digital input into a DAQ before, put a current source to drive the LED that could take up to 340V forwards, and a similar reverse diode. This paid off within a week of putting it to use when it got hooked to a packaged system with multiple pieces of equipment in a pelican case powered via a 240V single phase generator (EU grounded neutral and 240V phase style, not US split phase style) and a ground wire broke, putting 120V with more than a couple mA of current behind it from power supply emi cap leakage on all the 'grounds'. If you can allow for it, expect mains everywhereBut yeah, using an oversized resistor on user accessible terminals is insurance against dumb end users to to a degree.

author: tkamiya
author_rank: Super Contributor
timestamp: January 30, 2020, 12:04:22 am
content: Quote from: Kalin on January 25, 2020, 04:28:17 pmAs yet another electrician, I AGREE! How about 3 phase 480V?
Help choosing a remote power delivery module - Page 1
Forum section: electronics / projects

author: RuufusJ
author_rank: Newbie
timestamp: October 14, 2025, 01:44:39 pm
content: I’ve been looking for a way to remotely and safely distribute power to a few high-current monitoring systems in the field, stuff like outdoor or vehicle setups (robotics, defence, off-road applications).Basically i want to turn things on/off remotely and still have proper fuse protection and current feedback to easily diagnose issues.I found this thing:https://krakul.eu/fuseboard/it seems to suit my needs (8 channels, RS485, robust and remotely controllable). Reminds me a bit of an industrial pdu mixed with an automotive fusebox.I checked out some similar modules like:phoenix contact cbm e8-24dc-05-10a:https://www.phoenixcontact.com/en-pc/products/electronic-circuit-breaker-cbm-e8-24dc-05-10a-no-r-2905744puls pisa-b:https://products.pulspower.com/en/pisa-b-electronic-circuit-breakersBoth are nice, but more for cabinet installs and not really something i could throw into a field box with remote control and feedback. Are there other products like this that combine efuse protection + monitoring + remote control (ethernet/modbus/can)?I’m mainly interested in powering remote DC systems safely and keeping everything monitored.Any recommendations or ideas?

author: David Hess
author_rank: Super Contributor
timestamp: October 14, 2025, 09:38:53 pm
content: I was thinking power-over-ethernet, but your links seems more suitable for your application.It might be the kind of thing I designed into a product. I never looked into a separate product, but I know modular industrial stuff has similar things.I wonder if there is an Arduino or Pi shield that implements what you want.
Help classify a weird part... - Page 1
Forum section: electronics / projects

author: ivaylo
author_rank: Frequent Contributor
timestamp: December 02, 2014, 11:40:43 pm
content: Not a great fan of these "tell me what this part is" threads, but this one stumped me (and the thing looks sufficiently interesting to ask here). Came from me harvesting parts from a 90s (?) Japanese VCR. Could swear it's a power transistor or a chip, but when googling for the part identificators on the can didn't turn anything out I cut it open. I see two sections of some sort of microstrip or something, one measures infinity resistance the other 38 Ohms or so (not sure I didn't short this one out while "cleaning it").Appreciate your insights...

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 02, 2014, 11:59:56 pm
content: Comb filter?

author: edavid
author_rank: Super Contributor
timestamp: December 03, 2014, 12:01:48 am
content: It's a SAW filter.

author: ivaylo
author_rank: Frequent Contributor
timestamp: December 03, 2014, 12:20:27 am
content: Thank you!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 03, 2014, 03:51:54 am
content: Beautiful! Never seen one magnified before.Surprised there's so many lines in the thing, I wonder how sharp it is.In a VCR, that should be due to the, if I remember the modulation correctly, the luminance is pushed to a frequency band above chroma (which remains more or less normal), and very sharp filters are needed to separate them without crosstalk.You'll also see TVs advertized with comb filters, for the same purpose: sharp filtering of the video spectrum.Tim

author: Falcon69
author_rank: Super Contributor
timestamp: December 03, 2014, 07:49:56 am
content: What's a "VCR" ?J/kPretty cool. I like threads like this when you can see the inner workings of components.

author: atferrari
author_rank: Frequent Contributor
timestamp: December 03, 2014, 11:14:11 am
content: How do they etch such a fine grid?

author: CM800
author_rank: Frequent Contributor
timestamp: December 03, 2014, 03:01:23 pm
content: Well, Its a heck of a lot easier then doing it on semiconductors, so for a professional industry, I would imagine it would be fairly easy

author: atferrari
author_rank: Frequent Contributor
timestamp: December 05, 2014, 10:21:54 am
content: Quote from: evb149 on December 04, 2014, 11:00:14 pmShort and to the point. Gracias.
Help: identify component creating mysterious I2C address - Page 1
Forum section: electronics / projects

author: unturned3
author_rank: Contributor
timestamp: September 23, 2022, 04:45:22 am
content: Hello!I bought a "rasperry pi compatible" Sony IMX290 image sensor module and I'm testing it out on a custom (non-RPi) Linux development board (unfortunately I don't have a RPi on hand). When I ran i2cdetect, 2 addresses are shown: 0x1a and 0x36.The first address, 0x1a, is expected: as per the datasheet, this is the slave address of IMX290. I was not expecting the 2nd address of 0x36. After checking theschematicsof the official Raspberry Pi Cam v2 module, there seems to be an additionalcrypto ICthat's connected to the same I2C bus, apparently for preventing the production of unauthorized clones.In the datasheet of the crypto IC, I did not find any info of a slave address (it only says the slave address is stored in the Configuration zone; could this mean that the address is not fixed?) On my IMX290 module I didn't find the same crypto IC, but an unknown 6-pin IC that seems to be connected to the I2C bus, with markings "24N", followed by what seems to be a "17" rotated 90 degrees anticlockwise (please see attached image). I would greatly appreciate any pointers on what this chip could be and whether could it be the source of the mysterious 0x36 address.Thank you.
Help converting a dimmable LED floor to a wall dimmable LED lamp. - Page 1
Forum section: electronics / projects

author: thisisnotdave
author_rank: Newbie
timestamp: October 20, 2018, 12:18:41 pm
content: Hey folks,Been a long time watcher of the EEVblog, but I've never really messed with anything electronics related aside from the most basic stuff around the house. I'd like to get some help with a project. I'm in the process of installed Lutron Caseta switches and dimmers and I'd like to convert a dimmable LED lamp to be dimmable from the wall instead of the foot slider it came with.This should be eyerollingly easy for most of you, and I think I have the right idea but I'd like to ask a couple of questions to make sure I don't burn down my house, and/or burn out my expensive dimmable lamp.The lamp has a 24v wall adapter which feeds into a dimming slider that reads 5-20v 1400mah constant current. So I know that I need to find a wall dimmable LED driver that follows those specs - easy enough. My question is how much, if any, play is there in these numbers? If I find a 5-24v at the current, will I risk overvolting the LED's and killing them? I can trim the dimmer to some extent and watch the output with a meter but basically I'd like to get some input what I should be looking for. Also since I don't really know where to look, if someone can recommend a site where I can buy this I'd be greatly appreciative!Thanks in advance!
Help converting server PSU into ATX PSU - Page 1
Forum section: electronics / projects

author: WhiteFireDragon
author_rank: Regular Contributor
timestamp: January 16, 2014, 07:19:29 am
content: I want to convert a DeltaDPS-2000BBserver PSU into one I can use for my desktop PC, which needs to be ATX specifications. I'm proficient with soldering, but I just don't exactly know how to get the 5v or the 3.3v needed for a desktop computer, or where to solder in wires. I found a useful pin layout, so figuring out how to turn on the PSU won't be a problem:http://www.rcgroups.com/forums/showpost.php?p=18117345&postcount=611Can anyone point me to some general resources or guides on how to convert server PSUs to ATX specs? Or some brief explanations would be greatly appreciated.

author: mariush
author_rank: Super Contributor
timestamp: January 16, 2014, 01:00:53 pm
content: That power supply only produces 12v and just a tiny bit of 5v, probably barely enough to be classified as 5v standby, so you should ignore it.You can't make it produce 5v or 3.3v like a computer needs because it's missing the electronics inside to do it. You would need to add the 3.3v and 5v dc-dc converters and then put the wires in the atx connector and the molex connectors and so on.It's probably a job that's too difficult for you, because computers still require about 6-10 amps on 5v and about 5 amps on 3.3v and you can't achieve these with cheap ebay dc-dc converters.
Help Converting Sine to Square Wave (Sine/Quadrature Encoder) - Page 1
Forum section: electronics / projects

author: 691175002
author_rank: Regular Contributor
timestamp: January 14, 2015, 08:38:48 pm
content: I recently purchased some used linear servos and need some help with the encoders. I'm just a hobbiest/programmer so I'm new to this kind of thing.Currently they use a 40um analog encoder (RGH40) that is interpolated down to 20nm quadrature steps using an REE2000 interpolator. Here are some datasheet snippets:(The output is open collector. The servo drive is compatible with open collector or 5V TTL.)Essentially the current system converts a 1v sine wave to a 5v square wave with 2000 pulses for every period of the sine wave.While nanometer level resolution is pretty damn cool, it severely limits axis speeds because the servo drives max out at 10MHz encoder input. I also have no need for such high resolution and would rather not have any interpolation at all.I want to directly convert the sine wave into a square wave. If the differential sine signal is greater than 0v, output 5v. If it is lower than 0v, output 0v. Is there an easy circuit that will perform this task at 50KHz? Can I just throw something together on a perfboard or do I need to be more careful?Ideally I want a drop-in replacement for the REE. All of the reference/alarm/setup/limit switch pins can be ignored.Thanks for any help you can provide. Let me know if you would like any more information.PS. Anyone know where I can buy a similar enclosure to the one pictured above?

author: 691175002
author_rank: Regular Contributor
timestamp: January 14, 2015, 11:19:40 pm
content: I've been doing some googling and it looks like I can just connect a comparator to a differential line driver. Does this make sense?http://datasheets.maximintegrated.com/en/ds/MAX941-MAX944.pdfhttp://www.ti.com/lit/ds/symlink/ua9638.pdf

author: dannyf
author_rank: Super Contributor
timestamp: January 14, 2015, 11:28:33 pm
content: QuoteIf the output is OC, it couldn't have been below 0v. Actually I would be surprised if it goes below 10mv.There are countless ways of doing this. You have to figure out if you want the threshold to be precisely 0v or not.

author: 691175002
author_rank: Regular Contributor
timestamp: January 14, 2015, 11:34:30 pm
content: Quote from: dannyf on January 14, 2015, 11:28:33 pmThe signal is differential. By below 0v I meant that the difference between the sin+ and sin- signal is negative.Forgive my mistake, I'm not familiar with the usual terminology.

author: moffy
author_rank: Super Contributor
timestamp: January 15, 2015, 01:52:58 am
content: Doing something similar ( sine to square) but I am using the LM319 comparator. You need to be careful to keep the input voltages into the comparator within its common mode input range, for the MAX941 that is between 0v and V+. Also a little bit of hysteresis around the comparator will help avoid spurious edges.