hybridfree/eevblog-posts huggingface dataset:
Web sharing of pinouts - Page 1
Forum section: electronics / projects

author: farsi
author_rank: Regular Contributor
timestamp: October 21, 2014, 08:45:43 am
content: Hi,I am exploring a small idea to share pinouts of devices online. For this, I am mainly looking into Arduino boards, and have built a first prototype:* Arduino Uno:http://pinboardjs.divshot.io/arduino_uno* Arduino Micro:http://pinboardjs.divshot.io/arduino_microI am thinking this might be interesting for beginners to find pins, but also to easily share and debug a setup online.What do you think? Do you work with web browsers when tinkering with a board? What other information might be interesting to have from a browser except the pins locations?Thanks!

author: Dave
author_rank: Super Contributor
timestamp: October 21, 2014, 12:27:11 pm
content: Quite honestly, I don't see the value of it.Prototyping boards like arduino usually have the names of pins written next to them.You have datasheets for individual components.

author: farsi
author_rank: Regular Contributor
timestamp: October 21, 2014, 02:10:44 pm
content: thanks. background is that I found myself googling "pinout arduino" (micro/nano/uno/tessel) all the time, but I have not found easy things in the browser except mostly pictures .are you having a web browser open to track a project setup? what bookmarks do you use? I thought a nicer way might help some.any case thanks for your thoughts!

author: graynomad
author_rank: Regular Contributor
timestamp: October 22, 2014, 04:08:35 am
content: I think you have missed the boat, have a look at this lothttps://www.google.com.au/search?q=arduino+pinout+diagrams&client=firefox-a&hs=jf9&rls=org.mozilla:en-GB:official&channel=sb&biw=1760&bih=856&tbm=isch&tbo=u&source=univ&sa=X&ei=1ixHVNCwMYWi8AWppYGoDQ&ved=0CB8QsAQMostly done by Arduino forum member pighixxx.______Rob
Website for Lochmaster 4 Designs? - Page 1
Forum section: electronics / projects

author: Chris56000
author_rank: Frequent Contributor
timestamp: April 19, 2023, 03:14:46 pm
content: Hi!Can anyone point me in the direction of a website with Abacom "Lochmaster" 4 Designs for download please?My friend has quite a number of circuits he wants me to make for him that don't warrant PCBs making, as we couldn't sell the other four left over from each JLC order, so I'm looking for a website with native Lochmaster layouts I can use and adapt, ideally larger and more complex boards!Chris Williams

author: Doctorandus_P
author_rank: Super Contributor
timestamp: April 19, 2023, 03:53:30 pm
content: https://duckduckgo.com/?q=abacom+lochmaster&t=h_&iax=images&ia=imagesQuite a bunch of years ago I had a look at that software, but It was quite short, as I decided it did not have enough functionality for me, and I decided to go with a full PCB program, because I also want to design PCB's, creater gerbers and order PCB's.But for one-offs and simple things I also use vero / matrix board.Although I don't do it much, I don't see any reason why a regular PCB design program can't be used in the same manner as lochmaster. You just have to limit yourself to a 2.54mm grid, and use only horizontal tracks on one of the copper layers. One of the advantages of doing it in software first, is that you can shift things around in the planning stage. When I was a kid (30+ years ago) I often got into trouble because I put all the parts too close together on veroboard, and even adding wiring was dificult.From what I remember, there is also no schematic drawing in Lochmaster, and thus also no real netlist and DRC check between a schematic and the "PCB". This is a real hindrance. Once you've had your PC keep track of all connections between a (human readable) schematic, and the chaos on a PCB / breadboard / vero board etc, then you do not want to go back.
Webster Chicago 180-1 Wire Recorder Restoration - Page 1
Forum section: electronics / projects

author: jcrubin
author_rank: Frequent Contributor
timestamp: August 14, 2022, 03:07:48 pm
content: I picked this up recently in good cosmetic condition. The owner said there was no spools with it but i did find a complete roll on the take-up. A mystery for later. Dividing the project into Electronic and Mechanical. I worked mechanical first which was more of a complete disassembly, cleaning and oiling than anything else, only minor repairs.Mechanicals rebuilt tested and adjustedThe electronics would need more work than the mechanicals. Id thought a tube overheated [convection not electrically] the output transformer, but tested in specWhen i tested the tubes, the 6x5 was completely shorted I knew the power transformer ate it. I really knew it when testing the motor and the unit was pulling 200W without a rectifier.The center tap on HV was internal, non fuseable,a crappy designIve pulled enough windings to do the maths and evaluate the values, waiting for the new wire order to arrive.

author: jcrubin
author_rank: Frequent Contributor
timestamp: August 16, 2022, 02:40:10 am
content: The heater is a 28 turn center tapped coil. at 6.3v its .225v/turn. The rest is not yet apartSecondary shows about 484 give or take a turn or two. Hard to compute given the operational range of the unit is between 110/120v484 turns against 28 turns to produce 6.3vac is around 109mains voltage, 117V would be 520turns, 123v would be 547 turns.HT is 1559 turns to center tap. given 547 turns for 123v to produce 6.3v at 28 turns, the HT would be almost exactly 350vac off Each lead to ground. I believe this is my answer.

author: jcrubin
author_rank: Frequent Contributor
timestamp: August 16, 2022, 02:45:01 am
content: L3 Heater 6.3v ~28T ~3.64m 16awgL2 Mains 123v ~547T ~66m 26awgL1 HV 350v ~3118T ~406m 34awgBobbin 26x35mm EI-76mm

author: jcrubin
author_rank: Frequent Contributor
timestamp: September 06, 2022, 03:07:19 am
content: HV 350-0-350 wound and varnishedTaped, mains startedMains wound for 110 117 123v taps

author: jcrubin
author_rank: Frequent Contributor
timestamp: September 30, 2022, 03:12:47 am
content: Final coil with heater windings added.
Wedding Announcement Trinket - Page 1
Forum section: electronics / projects

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: June 04, 2016, 01:21:59 am
content: Here is a simple project I just finished rushing out, an RGB LED trinket for my wedding invitationhttp://imgur.com/a/XAUcq

author: xrunner
author_rank: Super Contributor
timestamp: June 04, 2016, 01:23:50 am
content: Ha - very cool!

author: ataradov
author_rank: Super Contributor
timestamp: June 04, 2016, 03:00:49 am
content: What language is the Cyrillic writing? It looks like Russian, but then there is a typo.

author: joeqsmith
author_rank: Super Contributor
timestamp: June 04, 2016, 03:11:26 am
content: Congratulations

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: June 04, 2016, 03:38:09 am
content: Quote from: ataradov on June 04, 2016, 03:00:49 amIts Russian, and yup both our parents pointed that out as well...

author: zapta
author_rank: Super Contributor
timestamp: June 04, 2016, 03:13:07 pm
content: Quote from: ANTALIFE on June 04, 2016, 03:38:09 amYou don't have the same parents, right?;-)

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: June 05, 2016, 01:13:30 pm
content: Quote from: zapta on June 04, 2016, 03:13:07 pmI hope not ;^) but both are Russian
Weekend project - Chinese kaleidoscope light - Page 1
Forum section: electronics / projects

author: Bud
author_rank: Super Contributor
timestamp: January 22, 2020, 05:40:53 am
content: Back to Christmas time a month ago I bought a pack of two chinese Christmas kaleidoscope lights. They have a small slow rotation motor with a bubbled clear plastic wheel on the shaft and an aluminum PCB behind it with 3 high power LEDs (RGB) shooting through the wheel. Then the light go through the clear faceted spherical cover and creates a moving RGB pattern on the surface you project it to.The Red LED on both lights soon failed. One right after I unpacked the light and turned it on, the second one failed in 3 nights. This was a quick weekend evening project to fix them.The lights have a small constant current driver board inside with a 5W LED driver chip CL1221. The circuit is very simple and the load current is set by the resistor on pin 1:The resistor value can be calculated from the formulas in the datasheet. The datasheet is in Chinese but I at some point found the English version but did not keep the link. Anyways, you basically just need the reference schematic and the formulas. The chip has two 4.7 Ohm resistors connected in parallel and connected to pin 1. That sets approximately 275mA load current (I figured the Np/Ns ratio of the transformer windings is ~5.2). The green and blue LEDs work OK with this current but the red LEDs failed.The 3 LEDs are mounted on an aluminum board. To get access to the board I removed the wheel and a retaining washer that held it to the motor shaft. It was the LED1 that failed, I unsoldered it.I ordered a more beefy red LED from Digikey (350mA max current)It is a bit larger than the failed one but fits the PCB pads just fine.Soldered on the PCB, watching the proper polarity. The three LEDs are all connected in series. I also put a bit of thermal paste on the LED bottom.That did the trick and the lights are now ready for the next Christmas season.

author: floobydust
author_rank: Super Contributor
timestamp: January 22, 2020, 10:17:32 pm
content: Those 1W and 3W bead LED's need the thermal-pad soldered to the MCORE pc board, for heatsinking.I notice originally there was no paste, the factory just hand-soldered the leads down but no solder for the thermal pad? I would expect them to overheat and have a short life.I find it takes a ton of hot air to heat up MCORE enough to solder/desolder these LEDs.

author: Bud
author_rank: Super Contributor
timestamp: January 23, 2020, 12:39:20 am
content: The bottom pad on the original LEDs was not soldered to the board but there was some sort of thin plasticy gasket between the board and the LED which i replaced with thermal paste. The failure mode however seemed to have something with overcurrent i believe, as one of the lights quit right when i brought itfrom the store and swithed on for the first time. The other one was outside in winter, i guess cold weather naturally helped with cooling. Likely the red LEDs were 200mA or 250mA ones andthe driver was pushing 275mA. Will find out next Christmas
Weekend Project: converter from RS-232 to fibre optics  - Page 1
Forum section: electronics / projects

author: 128er
author_rank: Regular Contributor
timestamp: December 14, 2014, 11:36:37 pm
content: Hey EEVBloggers,thought I could present my little weekend project. Often at my job a converter from RS-232 to fibre optics would have been very useful . Primarily to readout/configure power devices or test gear.Some examples:http://www.advanced-energy.com/en/THYRO_P.htmlhttps://www.gossenmetrawatt.com/english/produkte/mavowatt40.htmWhy DIY? Because they seem to be not that cheap and of course for the fun and education.In particular I wanted the thing to be small. So it should fit in some sort of DB-9 enclosure. Found out that a Siemens Profibus-DP Connector provides enough space for all parts. Some parts of the enclosure had to be milled off. Then I etched a PCB and soldered all parts on. And dont ask why, but I don't remember myself why the hell I ordered a MAX3311 in µMAX package. It was a PITA to solder the damn thing.It is powered from USB with 5V. I could have done a few improvements. Like LED's to indicate power or data transfer action. And one little thing. If I had swapped the positions of the optics transmitter and receiver, the arrows on the enclosure would correlate to the data direction of the fibres. Also I'm not that happy about the board layout. Because of limitations from the single sided construction. But I think the whole thing is not realy critical in terms of signal integrity. The converter actually works very well. Maybe I will do a revision in the futureNo rocket science, but a usefull tool for me.Not to forget . . . pictures and schematic!

author: tautech
author_rank: Super Contributor
timestamp: December 15, 2014, 12:10:36 am
content: Revision 2 with LED's?Pwr, Tx, Rx ?

author: macboy
author_rank: Super Contributor
timestamp: December 15, 2014, 12:38:04 am
content: I would think this would be trivial to do with a pair of TOSLINK (digital audio) modules on each end. They are cheap, have logic level inputs/outputs, and can handle at least 6 Mbps.

author: 128er
author_rank: Regular Contributor
timestamp: December 15, 2014, 01:13:32 am
content: Quote from: tautech on December 15, 2014, 12:10:36 amAs I mentioned in my first post. Didn't thought of that, doh. Maybe I will do a rev. 2Quote from: macboy on December 15, 2014, 12:38:04 amDon't understand exactly how your arrangement should look like. But these VL connectors are widely used in the industrial field (fieldbus over fibre, etc, . . .). No need for TOSLINK. And the TX/RX modules that I use are rated up to 10MBaud and CMOS/TTL compatible.

author: timb
author_rank: Super Contributor
timestamp: December 15, 2014, 01:39:08 am
content: What parts did you use for fiber connectors?Sent from my Tablet

author: 128er
author_rank: Regular Contributor
timestamp: December 15, 2014, 01:54:52 am
content: TX module: AVAGO HFBR-1528ZRX module: AVAGO HFBR-2528ZBought them on Ebay. The fibre cabel and plugs are from Siemens. I had them lying around at work. Normaly used with Siemens OBT's, for Profibus over fibre.
Weekly Timer - Page 1
Forum section: electronics / projects

author: gevv
author_rank: Contributor
timestamp: September 22, 2022, 04:29:48 pm
content: Hello,1 and 7 channels have available software source codes. Multi-language support. flower watering, garden watering, light-on, motor control, etc. Can be used in many projects.https://youtu.be/p5ZEiKV24qs07:00 Detailed information about the circuit04:09 Information about settings09:49 Test for 7 channels11:36 Multi-channel test12:49 Circuit diagram, PCB drawing13:05 Language change from softwareSource:http://picsource.com.br/archives/7414

author: rstofer
author_rank: Super Contributor
timestamp: September 22, 2022, 08:03:38 pm
content: A commercial unit that does all kinds of sprinkler related stuff including networking so I can control the unit from my iPad all via wifi. It's very handy. I thought to build one but for $100, I can't build up any enthusiasm.https://www.amazon.com/Orbit-57950-12-Station-Controller-Compatible/dp/B01D15HOTU

author: gevv
author_rank: Contributor
timestamp: September 25, 2022, 08:58:58 pm
content: Quote from: rstofer on September 22, 2022, 08:03:38 pmHello @rstofer,Very good controller thanks. $100 big money (my country ) here is the cheapest DIYupdate Orbit 57950 B-hyve Smart 12-Zone Indoor/Outdoor Sprinkler Controller price $115.54

author: SiliconWizard
author_rank: Super Contributor
timestamp: September 25, 2022, 10:16:10 pm
content: The OP's device, beyond being DIY, has the benefit of not being "connected".

author: quadtech
author_rank: Regular Contributor
timestamp: September 26, 2022, 08:35:24 am
content: Nice project - for those who prefer the Arduino ecosystem, similar projects below -https://www.instructables.com/Timed-Based-Relay-Controlled/https://www.instructables.com/Arduino-Timer-With-OnOff-Set-Point/

author: gevv
author_rank: Contributor
timestamp: September 27, 2022, 09:07:36 pm
content: Quote from: SiliconWizard on September 25, 2022, 10:16:10 pmOps..still source code can be improved
Weighing system / dosing system project ideas - Page 1
Forum section: electronics / projects

author: Blaffetuur
author_rank: Regular Contributor
timestamp: April 19, 2016, 07:55:33 pm
content: Hi all,I'm currently looking for a company to do my master's thesis and it looks like I'm gonna be doing it in a company that's specializing in weighing systems and dosing systems for powders and granulates.Now here's my question: Do you guy's know some cool projects that involve load cells/dosing systems/algorithms to become the best wheight out of a combination of multiple parts/.... anything !That I can build as a home project so I can take something with me on my first interview ?

author: hendorog
author_rank: Super Contributor
timestamp: April 19, 2016, 08:47:52 pm
content: I wouldn't recommend that approach. Instead focus on finding out what that companies challenges are right now.Find out why they want someone with your abilities.That is what they are thinking about, and so that is what you need to try to learn about.Then you can still build the project - with the confidence you are on target.If you go the other way you will end up creating something they don't need - which will just sidetrack you and won't gain you any traction with the company.

author: Blaffetuur
author_rank: Regular Contributor
timestamp: April 20, 2016, 06:23:15 am
content: Quote from: hendorog on April 19, 2016, 08:47:52 pmGood point, but I thought that since my thesis will be focused on industrial automation and not elecectronics. I still wanted to show off my interests in electronics by taking a project with me.

author: hendorog
author_rank: Super Contributor
timestamp: April 20, 2016, 07:28:56 am
content: Yeah I understand.I'd suggest just taking in something you have done that is interesting and fits in your pocket/bag/folder.So if they ask you what you can do/or have done, you can bring it out and show them.
Weird beheaviour in some of the opamps - Page 1
Forum section: electronics / projects

author: opa627bm
author_rank: Regular Contributor
timestamp: March 20, 2014, 09:59:23 pm
content: Hello Everyone, I just noticed that when I ground the + input of some opamps in non-inverting configuration, the output went all the way to the positive rail. For example, when I use opa277, it outputs fine from 1.3V (GND+1.5) to 18.5(Vs-1.5). However, when I switch the opamp to LT1152, it outputs 10.8(when pot is ground ) and 18.5 (when pot is maxed).I am now confused......

author: Lunasix
author_rank: Regular Contributor
timestamp: March 20, 2014, 10:29:34 pm
content: Working area is specified by datasheet. Outside operating area, it will vary. Some OPA are output rail to rail but NOT input rail to rail.

author: w2aew
author_rank: Super Contributor
timestamp: March 20, 2014, 10:32:08 pm
content: Quote from: opa627bm on March 20, 2014, 09:59:23 pmYou have to pay careful attention to the input voltage range allowable on the various op amps. When you take the inputs beyond their rated common mode range, odd things can and will happen, including phase reversal. Some op amps will guarantee that no phase reversal will happen (which helps to keep feedback loops from latching up), but most do not specify what will happen.In other words - don't violate the input common mode range.

author: opa627bm
author_rank: Regular Contributor
timestamp: March 21, 2014, 07:41:04 am
content: I am building this circuit, if the op amp is OPA277, it works extremely fine but if I switch it to LT1028 it began to oscillate at 347Khz....

author: w2aew
author_rank: Super Contributor
timestamp: March 21, 2014, 01:24:07 pm
content: Quote from: opa627bm on March 21, 2014, 07:41:04 amThe LT1028 is a much faster op amp than the OPA277, and thus can have stability issues unless properly compensated. See the datasheet on the LT1028 regarding compensation (page 15).

author: opa627bm
author_rank: Regular Contributor
timestamp: March 21, 2014, 07:53:34 pm
content: Quote from: w2aew on March 21, 2014, 01:24:07 pmThank you!, Is it possible that because I use it in the single supply mode that it begins oscillate ?

author: w2aew
author_rank: Super Contributor
timestamp: March 21, 2014, 08:25:20 pm
content: Quote from: opa627bm on March 21, 2014, 07:53:34 pmNo, it's just that it is so much faster that it runs out of phase margin with the feedback you're using. So, either compensate it (there is a compensation pin, or apply it externally), or use a slower op amp.

author: Richard Head
author_rank: Frequent Contributor
timestamp: March 24, 2014, 11:10:50 am
content: Hello Everyone, I just noticed that when I ground the + input of some opamps in non-inverting configuration, the output went all the way to the positive rail.That's because the input offset voltage is being amplified by the open loop gain. Welcome to op-amps.The solution is to either reduce the gain or trim out the input offset. Or maybe AC couple if thats ok.Dick
Weird Buzzing From TV Backlight Tubes - Page 1
Forum section: electronics / projects

author: paul_g_787
author_rank: Frequent Contributor
timestamp: July 05, 2022, 09:04:51 pm
content: Hey guys. I was playing online this evening and was wondering about something that I have never found an explanation for before.My TV, a Sony KDL-40W5500 from 2009, sometimes randomly starts buzzing. The buzzing sounds like 50Hz mains buzzing but I it appears to be from the backlight fluorescent tube driver and if I turn off the backlight in the settings then back on it goes away. But comes back another time.The weird thing is the buzzing happens only occasionally, sometimes happening in small more frequent occurences and then not happening for ages and ages.The buzzing starts quiet then over a few minutes gets very loud and eventually stops suddenlyIt has done this on this TV since it was brand new and also our old KDL-37W5500 had the same issue before we upgraded it to a larger one.Now the TV is working fine but I am just wondering what on earth the buzzing could be as I have never encountered it on another TV before or since.Just something that I find interesting and would like to understand why.Can anyone suggest any reason for this?

author: moffy
author_rank: Super Contributor
timestamp: July 06, 2022, 11:46:21 am
content: Sounds wierd.I have a similar problem with some ceiling fans but I am pretty sure it is due to the switching tones that the electricity supplier puts on the lines to turn controlled loads on or off. They only appear at certain times of the day, but can continue for a few minutes before disappearing.

author: paul_g_787
author_rank: Frequent Contributor
timestamp: July 07, 2022, 01:30:51 pm
content: Quote from: moffy on July 06, 2022, 11:46:21 amThat is interesting! I never even knew such a thing existed! Very clever.Now you mention it, it does appear to occur at the same time of day on select days of the week.
Weird circuit in a datasheet - Page 1
Forum section: electronics / projects

author: rea5245
author_rank: Frequent Contributor
timestamp: September 19, 2020, 12:06:33 am
content: Hi,I'm looking at a potentiometer with a built-in switch. Here's the datasheet:https://www.ttelectronics.com/TTElectronics/media/ProductFiles/Potentiometers/Datasheets/P170.pdfThere's a drawing in the datasheet on page 7 that I don't understand. It's the pot's circuit diagram. What the heck does it mean?Thank you,Bob

author: andy3055
author_rank: Super Contributor
timestamp: September 19, 2020, 12:18:56 am
content: If you are referring to the horizontal line, it shows that the switch and the pot sections are operated by the same common shaft.

author: rea5245
author_rank: Frequent Contributor
timestamp: September 19, 2020, 12:29:56 am
content: Quote from: andy3055 on September 19, 2020, 12:18:56 amThank you. Thatwasone of the things confusing me.The OFF and ON lines also bother me. I mean, I'm reasonably confident that the two "SW" terminals (shown in the drawing of the pot) get connected, but the circuit diagram sure isn't drawn the way I'd expect a switch to be drawn.- Bob

author: andy3055
author_rank: Super Contributor
timestamp: September 19, 2020, 03:01:54 am
content: True, not the best representation.
Weird fuse arrangement - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: April 19, 2025, 03:23:16 am
content: I have this Commodore 128 power supply I need to deep clean so I took it apart. It works fine, it's just filthy.It has a user accessible fuse holder, you can see it on the bottom of the supply. But it's not what it seems.First time I see an arrangement like this.Did someone change their mind too late in the design, or is this some weird regulatory thing maybe?It's made in Japan during the late '80s.

author: UnijunctionTransistor
author_rank: Frequent Contributor
timestamp: April 19, 2025, 03:33:15 am
content: In the background, on the photo where the bodged fuse appears, there is this ironic message of: “for continued protection replace only with the same type fuse”.

author: macboy
author_rank: Super Contributor
timestamp: April 19, 2025, 01:05:54 pm
content: I can only guess but perhaps this unit was sold in a market where user replaceable fuses are not allowed for safety/other reasons.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: April 19, 2025, 05:04:31 pm
content: The Commodore 1541 drive has a user-accessible fuse on the mains side.This power supply fuse is on the 9VAC secondary. There's another fuse on the board on the other secondary that feeds the 5V switcher.The 9VAC line is quite lightly loaded on the 128. Why put that fuse accessible but not the other one? I don't know what the logic is here. Just funny. At least it's cleaner now.
weird issue with ESP32 server - Page 1
Forum section: electronics / projects

author: hussamaldean
author_rank: Unknown
timestamp: February 10, 2019, 11:21:51 am
content: Hi allI built a mobile robot which is controlled using web browser over wifi. however, the webpage does appear on my macOS with safari and iPhone's safari but once I switch to other browser it is no longer working at allfor example chrome on macOS doesn't work firefox IE etcis there any solution ?I am using arduino IDE with this projectregards
Weird LDO behaviour - Page 1
Forum section: electronics / projects

author: escapekit
author_rank: Contributor
timestamp: August 17, 2020, 11:11:29 am
content: I am designing a PCB and I have a problem with the LDO, the voltage mesured in the output should be 5v but it is over 7v.I have several PCB's i got assembled from JLC and all of them have the same problem, one is outputting 7,02v, another 7,26v and the rest are somwhere in between.This is the schematic for the power supply part of the PCBI used anAO4407A(P-channel Mosfet) to protect from reverse polarity, and anAMS1117-5.0to lower the 12v VCC into 5v to power an ATmega 2560, optoisolators, mosfets, a couple of ULN2003A, a YX5200 mp3 player IC, an oled display and a couple more little things.I don't know if I did something wrong or the LDOs are defective.This is the pcb layout:Any help would be really appreciated.

author: mzzj
author_rank: Super Contributor
timestamp: August 17, 2020, 11:25:43 am
content: From datasheet: minimum load 10mA. Did you happen to test the boards without load on the 5v supply?

author: escapekit
author_rank: Contributor
timestamp: August 17, 2020, 11:40:03 am
content: Yes, that must be it, I tried plugging in the OLED display and it works fine.

author: mzzj
author_rank: Super Contributor
timestamp: August 17, 2020, 07:36:52 pm
content: This is a really common trap with low dropout regulators and negative 79xx type regulators.

author: perieanuo
author_rank: Frequent Contributor
timestamp: August 18, 2020, 11:13:05 am
content: that should be made sticky for every beginner in electronics.most of us saw the same thing at one time

author: uer166
author_rank: Super Contributor
timestamp: August 20, 2020, 04:26:48 am
content: Is there a decent modern jellybean regulator similar to the 1117 types that does not have a minimum load, stable with ceramics, 0.5A+ and such? I'm not sure why, but the most available LDOs/linear regulators seem to be relics with weird requirements like minimum load.

author: iteratee
author_rank: Contributor
timestamp: August 20, 2020, 06:53:46 am
content: Zero load floating linear reg? Isn't that like trying to charge a cap to 5V with a series 5V zener? If zener leakage > cap leakage it's hopeless.
[SOLVED] Weird LED multiplexing (works on magic?) - Page 1
Forum section: electronics / projects

author: Manx
author_rank: Contributor
timestamp: September 30, 2020, 12:56:25 am
content: I want to make a big DIY LED clock using a cheap LED bedside clock and 12 V RGB LED strips, with optocouplers and transistors in-between.Analyzing the original LED PCB I wondered how in the hell this could work, and, lo and behold, when I copied the design using optocouplers in place of original segment LEDs, it does not work.The board has the following layout:and the multiplexing can be simplified as below:There are three such sections, with 4, 7 and 3 led pairs. Each section consists of LED pairs sharing an anode. One LED of each pair, in all sections, is connected to one common cathode. However, the other LEDs of each pair are connected together in a given section, and are not connected externally, forming some kind of blind common cathodes.Could anyone explain how this would work and why wouldn't my copy of this circuit work?

author: Doctorandus_P
author_rank: Super Contributor
timestamp: September 30, 2020, 01:08:24 am
content: You probably drew the wrong conclusions while reverse engineering the PCB.Some of the "LED" locations have 2 wires, while others seem to have 3, but those are probably some kind of wire bridges.Clocks like that also often have weird connections. The display is not necessarily connected as a "normal" multiplexed display.To properly reverse engineer the LED's, use a DMM in diode mode that has enough voltage to light up the LED's, or some battery with a series resistor.A battery witn a voltage of 3 to 5 volts would be fine, Such as a Li-ion or 2 or 3 AA's in series. For series resistor, asume a voltage drop of 2V for the LED's and a LED current of a few mA, which will give a series resistor of around 500Ohm to 2k, but it's not critical.Have you already thought about taking up programming?With a small microcontroller you can control your own LED's in any order you like.

author: Manx
author_rank: Contributor
timestamp: September 30, 2020, 01:37:08 am
content: Oh damnI completely ignored the three footprints I think you're talking about. I thought they were some unpopulated LEDs. But only now I've noticed they are different shape. I guess they indeed were wire bridges! (I haven't noticed them since I removed LED wires with my fingers while removing diffusor cover). I haven't tested it yet but I guess it solves the problem(I could make a clock from ground up but I thought it will just be simpler, faster and cheaper to do it the way I did it, given it doesn't matter how it's done for the purpose I do it).
Weird Load Switch Problem AP22802 with Bluetooth HC-05 Module - Page 1
Forum section: electronics / projects

author: yagizhanugur
author_rank: Newbie
timestamp: October 06, 2019, 10:18:18 am
content: Hello everyone,I am having issues with AP22802 load switch with HC-05 Bluetooth ModuleI soldered 5 boards and only 1 is having weird problem and i cannot sure about the problem is general or individual...My board working well begining ... after couple turn on and turn off process AP22802 is getting hot staying always on(bluetooth module turning on) until AP22802 getting hot and burn. I checked short circuit for OUT for AP22802 and signal levels, but everytings looks perfect.Do i miss something about it ? Any help is very apperciated ..I attached schmatic used.Note : EN signal voltage level is 5V. Same as VCCThank you.

author: jhpadjustable
author_rank: Frequent Contributor
timestamp: October 06, 2019, 11:06:12 am
content: When you say turn-off and turn-on processes, do you mean the entire board, or just the switch and HC-05 module? Is there any big difference in power/signal lead length when you test the broken board?According to the datasheet, it's well protected against over-current and over-temperature. The power switch also has a discharge function on the output, which has always seemed like asking for problems to me. Perhaps that HC-05 has much larger input capacitors than the others. You can try adding a diode to pass current from output to input, to suppress any inductive current spikes or large capacitive charges from anything on the HC-05 side.

author: yagizhanugur
author_rank: Newbie
timestamp: October 06, 2019, 12:05:37 pm
content: Quote from: jhpadjustable on October 06, 2019, 11:06:12 amI mean turn off HC-05 power. I measured 49uF capacitor on OUT pin of AP22802. I think it is not too much.I tried thermal shutdown feature .(Shorted OUT and GND) Chip survived for 5 min with having any problem.I measured resistance between AP22802 pins on board. All looks same.Chip burns if it stays open. Maybe you are right there is an inductive effect on PCB. I soldered new one it is working good. I will put a shotcky diode between OUT and GND and will try broken.Also i wonder why are you curios about discharge function. If you share your ideas it will be very helpfull.
weird transformers thread - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: September 24, 2018, 10:29:32 pm
content: So alot of people say transformer winding is a art and skill. There is the popular isolation transformer thread up now.What kind of weird transformers have you seen? And how do they deviate from what the novice would design?Maybe keep it under 50 amps so we don;t get a ton of power transmission equipment.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 25, 2018, 09:50:05 am
content: https://www.seventransistorlabs.com/Monitor/Images/PSU2_Map.jpgSee the little ferrite blocky thing on the right (under the blue line, hrm, I didn't happen to take a closeup picture of it, for shame)?Sony was quite fond of these sorts of things. It's a saturable-reactor-controlled self-excited resonant switching supply. Here's a diagram:Resonant transformers themselves are probably worth a mention, having explicit leakage inductance. This includes ferroresonant transformers (used for AC regulation, assuming line frequency remains constant).Tim

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 25, 2018, 11:26:25 am
content: I posted this one 4 years ago:Full thread:https://www.eevblog.com/forum/reviews/interesting-smps-design/
welded contactor test - Page 1
Forum section: electronics / projects

author: classified
author_rank: Contributor
timestamp: July 20, 2022, 07:40:30 pm
content: hi there now for me safty is #1 so for a battery i am building i will have 2 contactors a side (mostly for safty incase one or more weld closed) but to test if there closed i can not see how this couldgo wrong its simple raily useing a optoisolater going from usaly open side of the contactor to the opasit pole useing a resistor to avoid blowing up and leds so dose this seem like a good way to do it and if there better ways i am open to ideasF.Y.I i know in the picture it shows relays but i couldent find a contactor sch item but a contactor is just a realy after all

author: inse
author_rank: Super Contributor
timestamp: July 20, 2022, 07:58:23 pm
content: Well, I think you could do it this way, although for me this is close to paranoia.There is also a special type of relay, Dold calls them Safety relays with forcibly guided contacts, which could spare you the additional circuit.As far as those type of relay are suitable for your application demands.Is there a specific reason why you use the NC contact on the negative side?

author: classified
author_rank: Contributor
timestamp: July 20, 2022, 08:03:50 pm
content: as i stated i used what i could find to do a quick schematic of what i was thinking the relays will be replaced with contactors that are NO when i build it

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: July 21, 2022, 01:31:11 am
content: If u1 welds, but u2 doesn't how will you know? I don't see a current path for the LED in U5 when the contactors are deenergized with U1 welded. I'm assuming they all turn off at the same time. I think you would need to turn the contactors on and off sequentially while monitoring the optos for faults.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 21, 2022, 01:34:29 am
content: Use a "shunt trip" circuit breaker as the backup disconnect. That way, a fault that the main contactor is not able to break would require a manual reset.

author: Terry Bites
author_rank: Super Contributor
timestamp: July 21, 2022, 04:29:02 pm
content: If one arc welds shut so might the other, it will have to try and disconnect the same load current.RC snubbers are essential. The capcitor slows the di/dt and the resistor limits the peak current in the cap.see section 4-2 ofhttps://sound-au.com/articles/relays2.htm.You might want to consider using IGBT(s) or MOSFET(s) to make a solid state contactor. SiC MOSFETS would be my first choice.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 21, 2022, 04:40:41 pm
content: Model sailplane flyers who use a 12V DC winch to get the planes to altitude will often use two solenoid switches in series for safety. It does happen that a single switch will weld in the on position. That creates a problem.The solution we used was just an LED with suitable resistor across the contacts for each switch. Both LED's on = OK; otherwise, not safe.
Welder Teardown and Horror Show - Page 1
Forum section: electronics / projects

author: calzap
author_rank: Frequent Contributor
timestamp: February 08, 2016, 02:49:48 am
content: I need to do some welding and am out of practice, so decided to do a little reading and watch some videos. Discovered this one on the Everlast SuperUltra 205. The videographer let them off easy. Fortunately, my welder is a different brand.Quote from Everlast website:"We manufacture our product in modern, off-shore facilities using name brand, off-the-shelf electronic components such as Infineon, Siemens, Texas Instruments, IXYS, Intersys, International Rectifier, Toshiba, Sharp, Panasonic and others. This results in a lower purchase price for you, the customer. However, we feel it doesn't affect our ability to provide reliable products ..."Mike in California

author: Paul Moir
author_rank: Frequent Contributor
timestamp: February 08, 2016, 03:45:53 am
content: I own one, and it does have it's build quality issues. But it is supported locally and warrantied for three years (+) which makes a huge difference.These cost something of the order of 1/4 the cost of a name brand unit. I don't know exactly what you expect for that price?
Well shielded DC Cable - Page 1
Forum section: electronics / projects

author: ezalys
author_rank: Frequent Contributor
timestamp: February 21, 2020, 12:41:55 am
content: Hey all,We're building some lab equipment and I want to pick some kind of cable to carry power (5,12,15 V, with 5 being high current at 5 amps) from our linear DC supplies (mostly acopian boxes) to our custom instruments. I'm looking for some off-the-shelf connector that I can use to carry 3 voltages (so 4 pins + shield) to an instrument, where high quality cables are also cheaply available. At first glance, XLR seems perfect. High current capacity, cheap cables, well shielded, nearly ideal. I just want something with more pins. Any suggestions?E

author: ejeffrey
author_rank: Super Contributor
timestamp: February 21, 2020, 02:55:23 am
content: I wouldn't recommend using the shield alone for return. Shields are usually foil that isn't meant to carry high current. Look for a 4 pin cable plus shield and connect shield to the chassis ground at both ends unless proven otherwise.There should be some M8 / M12 and DIN style connectors that will work.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: February 21, 2020, 09:00:12 am
content: What about 5 pin XLR? Commonly used for DMX lighting control.Although, off-the-shelf DMX cables probably won't have the appropriate wire gauge for your DC power application.

author: Zero999
author_rank: Super Contributor
timestamp: February 21, 2020, 09:09:42 am
content: Quote from: ejeffrey on February 21, 2020, 02:55:23 amYou've misread the original post. He has no intention of using the shield as a current return path and is looking for a 4 pin + shield connector.Quote from: ezalys on February 21, 2020, 12:41:55 amYes, XLR sounds like a good idea. How many pins do you need? You said three voltages, plus return and a shield, so a 5 way XLR seems perfect. The usual distributors such asRS ComponentsandDigi-Keysell them.
Weller RT1 solder tip voltage - Page 1
Forum section: electronics / projects

author: BertVK
author_rank: Newbie
timestamp: December 14, 2015, 09:14:09 pm
content: Hi all,I want to build a soldering station using an Atmega328 and a Weller RT1 soldering tip. The design is based on this one :http://www.martin-kumm.de/wiki/doku.php?id=Projects:SMD_SolderstationI am looking for the maximum voltage on the temperature measurement connection of the tip. This voltage is mentioned in the Dutch July August number of Elektor but I can't find my copy anywhere.Anybody can help me get this data? Google is not my friend this time.Bert

author: kwass
author_rank: Frequent Contributor
timestamp: December 15, 2015, 04:15:27 am
content: How about this thread:http://dangerousprototypes.com/forum/viewtopic.php?f=19&t=3583I have a Weller WSM 1C that uses the RT tips, I suppose I could make some measurements if you need them. BTW I love this iron!

author: nanofrog
author_rank: Super Contributor
timestamp: December 15, 2015, 04:30:51 am
content: Supply Voltage for RT series tips = 12VAC
WeMacro focus rails serial command description - Page 1
Forum section: electronics / projects

author: davorin
author_rank: Unknown
timestamp: April 08, 2022, 08:20:19 am
content: Good morningHas someone seen any protocol description for the WeMacro focus rails for doing an own control software in Python as they offer only macOS/Windows control software?Would like to use it with a horizontal setup to make close up pictures of assembled PCBs.thanks in advance
Western Electric WE-175 restoration - Page 1
Forum section: electronics / projects

author: jcrubin
author_rank: Frequent Contributor
timestamp: October 09, 2016, 12:41:54 pm
content: This thread documents the restoration of the WE-175

author: TimFox
author_rank: Super Contributor
timestamp: January 24, 2017, 10:16:42 pm
content: I assume this is "Westinghouse", not "Western Electric"?
Western Pacific Rim PCB 'Gunk'? - Page 1
Forum section: electronics / projects

author: CaptnYellowShirt
author_rank: Frequent Contributor
timestamp: March 29, 2014, 06:02:17 pm
content: So I've ordered several electronic related things from areas surrounding the western pacific rim over the last two years (Hong Kong, Thailand, Singapore, Taiwan, et al). Most of these things I'm getting from eBay, so the items have a cross section of being both new and used (e.g. some have been manufactured there, some have been imported, used, and then resold). However, something I've noticed about just all of them is a salt-like 'gunk' on various areas of the PCBs.Maybe 'stain' would be a better word for it because it won't come off, but it has the appearance of dried salt water. Its nothing I've seen on new or used equipment from the north america or europe.Has anyone else seen this? Any clue what it is?

author: fcb
author_rank: Super Contributor
timestamp: March 29, 2014, 06:18:20 pm
content: Flux residue from wave soldering probably, and/or cleaning the PCB with contaminated water (leaving flux residue on the boards).

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 29, 2014, 08:51:30 pm
content: Like the flux residue in the most recent EEVblog video?That stuff, it looked like they hand soldered the last parts, then splashed it with some solvent and let it dry. No soaking, no scrubbing, no rinsing. Needless to say, the flux doesn't go anywhere, except smeared out a little (and changing the deposit from shiny to hazy or crusty, so it looks even worse).I've seen poorly washed boards, which weren't crusty (except in few spots), but had, essentially, white water stains all over. More of the same -- incomplete, hasty processing, just not as bad....By the way... what...does it taste like?...dare I ask..?! If it's actually salty, its resemblance would be more than appearance alone!! Warning, don't actually do this, it's probably not worth the risk.Tim

author: CaptnYellowShirt
author_rank: Frequent Contributor
timestamp: March 30, 2014, 12:13:54 am
content: I haven't had a chance to see Dave in his latest exploits. But if that camera is the caliber of items I've purchased.
weatherproofing board to board connector - Page 1
Forum section: electronics / projects

author: maarten42
author_rank: Newbie
timestamp: July 20, 2022, 11:51:26 am
content: I have this idea to make a device with a (cheap!) ip20 or ip65 enclosure protecting the pcba from direct weather influences so the pcba will not be wet, but it can be damp.The pcba will be protected using conformal coating, but there will be a small 10pin board to board connector for an optional small io board.My problem is the board to board connector: how can i protect that from oxidation in the long run?I looked at dielectric grease but i do not have any experience with that. Would that work in the long run?Also, what b2b connector is suitable for protecting with dielectric grease (i assume small pin-holes are not suitable) ? Any suggestions?thanks

author: nctnico
author_rank: Super Contributor
timestamp: July 20, 2022, 08:32:18 pm
content: I'd use good quality brand gold plated connectors. If both boards are in the same enclosure, this should do the trick.

author: Benta
author_rank: Super Contributor
timestamp: July 20, 2022, 08:35:47 pm
content: ^^ ThisQuality gold plating is the way to go.

author: maarten42
author_rank: Newbie
timestamp: July 21, 2022, 11:46:43 am
content: I would not have thought that would do the trick, but kind of logical.Thanks.FYI: i looked further in using dielectric grease: that is indeed not advisable for using ON contacts because it can reduce contact conduction.