hybridfree/eevblog-posts huggingface dataset:
Battery protection circuit with comparator (recovery voltage) - Page 1
Forum section: electronics / beginners

author: rks96
author_rank: Contributor
timestamp: December 20, 2020, 09:03:31 pm
content: I have comparator ic's (lm393) and it is easy to create a low voltage cutoff using Zener diode, a potentiometer and mosfet/transistor for switch or over/under voltage protection using a window comparator circuit!My question is how to handle voltage recovery of battery when using it to power for example router? When the battery is discharged, because of battery voltage recovery, router would turn on/off ect. I could use Arduino/attiny85 for logic, but I want to keep it simple! In other words, how to make comparator switch off and on at different voltages? Maybe there exists such a circuit, but I just don't know what to look for. Or suggest an example that uses comparators (not op-amps) for low battery protection and handles recovery voltage too. Maybe that isn't possible?Thanks in advance for any help you are able to provide!PS I also know there is specific ic chips and pcb modules online for this purpouse! I just want to know if it is possible to handle voltage recovery after the battery is discharged with comparators?

author: mikerj
author_rank: Super Contributor
timestamp: December 20, 2020, 09:25:01 pm
content: Add hysteresis to raise the "on" threshold when the comparator switches your circuit of.

author: fourtytwo42
author_rank: Super Contributor
timestamp: December 20, 2020, 09:27:22 pm
content: I think you are talking about adding hysteresis to your comparator. This is normally done by adding a small amount of positive feedback so the switching point depends upon the current state of the output. Typically that means you add a small resistance in series with the existing signal to the + input and a much larger resistance between the + input and comparator output.
Battery protection IC TI BQ29703DSET - Page 1
Forum section: electronics / beginners

author: m_maursund
author_rank: Newbie
timestamp: January 15, 2015, 06:58:12 am
content: Hi,I've tried to make a battery protection pcb with an Texas Instrument BQ29703DSET IC.It can barely power a led, the voltage slowly rises to battery voltage.If I use a power supply as "battery" and turns the voltage to 5.5V and back down to normal lipo voltage it can deliver enough current.Anyone that can tell what I am doing wrong?Schematic:http://postimg.org/image/j2r45hgdx/BQ29703DSET datasheet,http://www.farnell.com/datasheets/1838960.pdfFarnell did not have the TI Mosfet so I ordered the one below, it was suggested as a replacement.INTERNATIONAL RECTIFIER IRFH5255TR2PBF MOSFET, N CH, 25V, 51A,http://www.irf.com/product-info/datasheets/data/irfh5255pbf.pdf

author: wraper
author_rank: Unknown
timestamp: January 15, 2015, 11:07:50 pm
content: Probably because of this:QuoteYour MOSFETS do not meet this criteria. According to curve in the datasheet they meet this criteria only at Vgs = 4.5V

author: m_maursund
author_rank: Newbie
timestamp: January 17, 2015, 12:11:01 pm
content: Thanks Wraper.Found IRLH7134TR2PBF on Farnell after a lot of searching. Looks like it Rds on is correct for this.Does everything else look OK?Maximum discharge of the circuit is 1.5A.Is there a simpler lithium-ion protection circuit?I use a Lithium charger from 220v. Just need to protect against over and undercharge.When I search on Google for a circuit, the only results are ready made pcb's and multiple cell protections.Bought a protection pcb from batteryspace.com, nut I'm not able to reverse engineer it to make one for myself.http://www.batteryspace.com/PCB-for-3.7V-of-Li-Ion-Battery-2.0A-limit.aspxDatasheet:http://www.irf.com/product-info/datasheets/data/irlh7134pbf.pdf
Battery tester - Page 1
Forum section: electronics / beginners

author: Jane
author_rank: Frequent Contributor
timestamp: January 29, 2019, 08:30:46 pm
content: Can anyone recommend a good battery tester for testing batteries in mobile phones and tablets and probably also in laptops?Are any any rules for setting charging and discharging current?Thanks

author: FrankE
author_rank: Regular Contributor
timestamp: February 02, 2019, 07:40:57 pm
content: In what sort of environment and for how frequent usage?For storefront? Home use?

author: soldar
author_rank: Super Contributor
timestamp: February 02, 2019, 08:10:02 pm
content: Quote from: Jane on January 29, 2019, 08:30:46 pmI guess it would make sense to discharge at the rate at which it is used in whatever device. If it is a phone and it uses on average 250 mA then it would make sense to discharge at that rate and see how long it lasts. And the same with charging.
Battery Voltage Drop - Page 1
Forum section: electronics / beginners

author: corrado33
author_rank: Frequent Contributor
timestamp: June 16, 2015, 05:35:18 pm
content: Voltage drop across a resistor is simple. V=IRMy question is this. Why does the battery voltage drop when you draw a current from it? Is it because of the internal resistance of the battery?If it isn't, how would you calculate it? The voltage drops much more in a "dead" battery than it does in a "good" battery.Why does a dead AA battery drop to ~.8 volts when I apply a ~6.5 Ohm load to it?

author: Gyro
author_rank: Super Contributor
timestamp: June 16, 2015, 05:56:21 pm
content: The answer to your first question is yes...sort of. Ignoring the discharge effects, the short term voltage drop is due to internal resistance.In traditional zinc carbon batteries and probably alkaline too there is a polarization effect which limits the absolute current that can be sustained and is responsible for the slow (rather than the instant that would result from pure internal resistance) recovery of voltage after the load is removed.As batteries discharge, their internal resistance increases, leading to greater drop for a given load.As for how you calculate it - difficult as it will vary between battery brands and types. Mallory (Duracell) used to produce a useful databook which showed discharge voltage curves (voltage against time) for various resistive loads. If you look on the web at battery manufacturers sites you will hopefully find similar curves. Obviously this will only work for major brand batteries rather than no-name.Hope this helps.

author: Gyro
author_rank: Super Contributor
timestamp: June 16, 2015, 06:03:38 pm
content: In fact they do....http://ww2.duracell.com/en-US/Global-Technical-Content-Library.jspx?utm_source=TechOEM&utm_medium=Cross-link&utm_term=D1100&utm_campaign=UtilityNav_techLib

author: fubar.gr
author_rank: Unknown
timestamp: June 16, 2015, 06:09:07 pm
content: You can calculate the internal resistance using the voltage divider formulaFirst, measure the battery voltage without load. This will be the V1. R2 is the load resistance and V2 is the voltage with the load connected to the battery.Solve for R1, that's the internal resistance.This figure however is only valid for that specific battery type, load and charge level.
baud and bit rate in case of RS-232 - Page 1
Forum section: electronics / beginners

author: m4rtin
author_rank: Regular Contributor
timestamp: November 19, 2013, 10:48:02 pm
content: If I connect to a network device over a console port, I usually choose the speed "9600" in my terminal program(I tend to useminicom). Some equipment support for example "115200" speed. However, is it bit rate or baud rate? I guess in case of RS-232 the bit rate is always the same as baud rate?

author: Hideki
author_rank: Frequent Contributor
timestamp: November 19, 2013, 11:11:33 pm
content: For RS-232, one bit is one symbol, so you are absolutely right.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 19, 2013, 11:17:40 pm
content: Depends how you interpret it...baudrate determines the time between bits.However as every byte has a start and a stop bit, the maximum throughput of actual data bits transmitted is 0.8 x the baudrate

author: Hideki
author_rank: Frequent Contributor
timestamp: November 20, 2013, 12:03:57 am
content: The start and stop bits are overhead on top of the useful data, but the baud- or bit-rate isn't concerned with that.Baud rate is how many times the signal actually changes per second.Bit rate can be higher (like QAM256), the same (like UART signals, including RS-232 voltage levels) or lower (like 10/100 Mbit Ethernet), depending on the type of modulation.

author: digsys
author_rank: Unknown
timestamp: November 20, 2013, 12:23:12 am
content: Addition: The bit-rate / baud-rate is the "frequency" of the stream, the "Byte" size may vary from a min of 10 to 15+UARTS can have 2 stop bits, some include address-line decoding option and at least one I've used allowed for 12 data bits !Then there are the IrDA variants, so a 9600 baud line may have max 960 Bytes down to ~620 or less. Check the UART specs

author: IanB
author_rank: Super Contributor
timestamp: November 21, 2013, 02:18:14 am
content: Quote from: Hideki on November 19, 2013, 11:11:33 pmSeconded. For RS-232 interfaces the bit rate is the same as the baud rate. Hence 9600 baud is 9600 bits per second. But as has been mentioned, not every bit is necessarily a data bit. There are start bits, stop bits and parity bits to consider. As a rule of thumb divide by 10 to get bytes per second, so that 9600 baud is ~960 bytes per second.
BCC = XOR of values hatched - Page 1
Forum section: electronics / beginners

author: Samset
author_rank: Newbie
timestamp: April 19, 2018, 04:20:49 pm
content: Hello,[OK I fund the solution, it was dumb] now I cannot delete the post!I was trying to communicate with a distance finder via RS485 (CD22M-35-485). The bytes must conform to the datagram. I would like to know what is meant by "BCC = XOR of values hatched" at the end. I know what XOR mean but not values hatched!?For exemple:02h^52h^40h^06h^03h= gave me15hnot0x14from the documentation exemple, what's wrong?http://www.optex-ramco.com/index.php?route=module/product_downloads/get&did=375Thank youSam

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: April 19, 2018, 04:33:00 pm
content: My guess is that they leave out the "STX" (1st) and "ETX" (last before BCC) values for the XORing and only use command and data.0x52 ^ 0x40 ^ 0x06 = 0x140x57 ^ 0x00 ^ 0x04 = 0x53

author: Samset
author_rank: Newbie
timestamp: April 19, 2018, 04:35:51 pm
content: Yes thank you, I realized right after sending this post. I thought "BCC = XOR of values hatched" was a bytes maniplation ...
BD679 & BD680 transistors - Page 1
Forum section: electronics / beginners

author: IvoS
author_rank: Frequent Contributor
timestamp: June 08, 2017, 03:52:17 pm
content: I am looking for fully insulated package for these transistors but I don't see any info in the datasheet about the marking. Is the BD679ASfully insulated package? I am not sure.

author: fourtytwo42
author_rank: Super Contributor
timestamp: June 08, 2017, 04:21:46 pm
content: Thats a TO126 device and it has an area of metal behind the package (in contact with the heatsink) connected to the collector so you need an insulating tab BUT the package incorporates the insulation around the screw so you dont need that part.

author: IvoS
author_rank: Frequent Contributor
timestamp: June 08, 2017, 05:08:58 pm
content: I am looking for a part without exposed metal. I am pretty sure they make them. If not BD679 then BD139 or similar small power transistors fully encapsulated.

author: tooki
author_rank: Super Contributor
timestamp: June 08, 2017, 06:26:37 pm
content: The BD139/140 are also TO-126 (AKA SOT-32), which by definition uses the metal back. It's there for cooling.Why must it be fully encapsulated? (I'm curious as to what use case wouldn't be solved easily by just using the silicone insulators.)I know there are variants of TO-220 that are all-plastic, like the TO-220F ("fully encapsulated"), so maybe you could look for a transistor in that package. Just know that it will have appreciably worse thermal performance than the regular exposed-metal TO-220.There does seem to exist a fully encapsulated TO-126F package, and aliexpress has a handful of components in that package, but whether they meet your needs is another matter.

author: tooki
author_rank: Super Contributor
timestamp: June 08, 2017, 06:37:28 pm
content: P.S. You realize the metal tab is connected to the center pin, right? I mean, the pins have to be exposed, so I'm not sure what you gain by insulating the tab.
Beaglebone Black (BBB) - Internet over USB is not working - Page 1
Forum section: electronics / beginners

author: elektronika
author_rank: Newbie
timestamp: March 23, 2021, 06:18:22 pm
content: Long story short - I can't run internet over USB in BBB in Windows 10. This tutorial WORKS always in Win7 and works NEVER in Windows 10:I've tried many times in different ways to set the system in Win10, writing in /etc/network/interfaces and another tricks, found in the web, but nothing helped me. Some links related to this issue here:https://groups.google.com/g/beagleboard/c/9PWK96YLkzA?pli=1https://beagleboard.narkive.com/jHKjwkhR/cannot-ping-google-in-bbb-even-after-sharing-internethttps://unix.stackexchange.com/questions/137827/static-ip-on-bbb-wont-change-with-network-interfaces-filehttps://www.element14.com/community/thread/75000/l/bbb-can-not-access-internet-via-usb-to-win-10As a NOOB, I politely ask you for advice if anyone has overcome this problem. I was forced to buy a router extender to provide an Ethernet connection to the BBB when working on Win10. This works flawlessly, but that was not my goal, but to have only one USB cable between the BBB and the computer, as it is when I use Win7.Many thanks in advance!
Beating my brain trying to find the datasheet for this IC (C9650 tuner IC) - Page 1
Forum section: electronics / beginners

author: Wanderling
author_rank: Newbie
timestamp: February 06, 2023, 06:36:55 pm
content: I get exactly one hit on the Googs for a 403 forbidden link that appearently was searchable years before. If anyone has the PDF I really need it. I want to tie into the SDL SCA lines to see if this chip puts out currently selected frequency information. Thanks!

author: wasedadoc
author_rank: Super Contributor
timestamp: February 06, 2023, 06:43:09 pm
content: You need to learn about Google's cache.https://webcache.googleusercontent.com/search?q=cache:-L4H10bh0_AJ:https://v1.cecdn.yun300.cn/100001_2012315689/C9650_Datasheet_EN_REV_1.3.pdf&cd=5&hl=en&ct=clnk&gl=ukInside that is cachip.com.cn which can lead tohttp://www.cachip.com.cn/list_details/979419117295919104.htmlandhttps://omo-oss-file.thefastfile.com/portal-saas/new2021121109332978230/cms/file/18e42b69-991e-447b-ac2d-5fd3b1159f9d.pdfwhich does contain fairly complete details in English.

author: Andy Watson
author_rank: Super Contributor
timestamp: February 06, 2023, 06:58:25 pm
content: Or use DuckDuckGo - first hit:https://v1.cecdn.yun300.cn/100001_2012315689/C9650_Datasheet_EN_REV_1.3.pdf

author: wasedadoc
author_rank: Super Contributor
timestamp: February 06, 2023, 07:08:23 pm
content: Quote from: Andy Watson on February 06, 2023, 06:58:25 pmStrange. That is the same URL that Google initially gave me but clicking on it at that time returned the 403 that the OP reported. But just now it does open the pdf.

author: Wanderling
author_rank: Newbie
timestamp: February 06, 2023, 07:09:50 pm
content: @wasedadoc Thank you for that. That's just what I needed. Google use to have a cached link on each link but they move or removed that feature and I haven't taken the time to learn where they moved it to. I appreciate you taking the time to drop these links.D
Becoming a qualified electrician in the UK - Page 1
Forum section: electronics / beginners

author: mianchen
author_rank: Regular Contributor
timestamp: November 04, 2013, 02:02:58 pm
content: Is this the right forum to talk about it?Since I started visiting the EEVBlog and watching videos of electronic related stuff, Mr. Google keeps showing me a lot of ads related to electrician training and examinations in the UK. I had a quick look at relevant stuff, it seems that the cost is not that high. It got me interested in taking some courses and trained as an electrician.Don't get me wrong, my main purpose of doing the training is not to get into the trade. I'm in a completely unrelated profession, which I like and it treats me well. I dunno, maybe just want to be qualified and be able to DIY here and there at home or helping family and friends. I don't mind the odd paid job here and there, if I have time.So what is the minimum requirement to be able to work in a domestic environment? Is 17th Edition Courses enough?

author: Bored@Work
author_rank: Super Contributor
timestamp: November 04, 2013, 07:00:00 pm
content: Your government has thishttps://nationalcareersservice.direct.gov.uk/advice/planning/jobprofiles/pages/electrician.aspxto say about it. Scroll down for the "Entry requirements" section and following sections.

author: djsb
author_rank: Super Contributor
timestamp: November 04, 2013, 08:30:02 pm
content: It's not easy to get training as a "mature student" at local colleges as the funding is only available for under 19 year olds. However if you have the money and live in the south east of England you could try this placehttp://www.ableskills.co.uk/The full course is several thousand pounds.There may be other options available I've not thought of.David.

author: Alex
author_rank: Regular Contributor
timestamp: November 04, 2013, 08:33:15 pm
content: You could consider speaking with someone/some organisation already in this trade. Choose carefully.A

author: Monkeh
author_rank: Super Contributor
timestamp: November 04, 2013, 08:34:51 pm
content: You can do DIY electrical work without having to get qualifications.

author: Neilm
author_rank: Super Contributor
timestamp: November 05, 2013, 06:53:05 pm
content: Quote from: Monkeh on November 04, 2013, 08:34:51 pmThis is true if all you are doing is replacing an existing fitting that is not in a wet area (bathroom, kitchen). If you are adding sockets where there aren't any then the work needs to be approved by a "competent person". If it isn't then there will be issues when the house is sold.

author: Monkeh
author_rank: Super Contributor
timestamp: November 05, 2013, 06:55:01 pm
content: Quote from: Neilm on November 05, 2013, 06:53:05 pm'competent person' is not strictly defined. If you perform the appropriate tests, fill in the appropriate paperwork, and get it signed off by LABC, you're fine.Also, a kitchen is not a special area.
Becoming an engineer - Page 1
Forum section: electronics / beginners

author: coolguy841
author_rank: Newbie
timestamp: April 19, 2011, 07:27:31 am
content: Hey guys I am just wondering whats the best way to go to be an electrical engineer once i leave High School? Should I go to University? Thanks in advance

author: GeoffS
author_rank: Unknown
timestamp: April 19, 2011, 07:46:43 am
content: Depends on your location's education system, but yes, university or college will be required to get an engineering degree.

author: EEVblog
author_rank: Unknown
timestamp: April 19, 2011, 07:46:59 am
content: There are many ways to get into engineering (that can vary by country), university is just one of them, albeit the most traditional, regnognised and most guaranteed route. It is also the hardest, one of the longest, and IMO one of the more boring ways.So yes, university is the standard answer to that question.Dave.

author: coolguy841
author_rank: Newbie
timestamp: April 19, 2011, 08:02:10 am
content: Great thanks! i guess ill go to university after i leave school. Im Australian. What is albeit?

author: Zap
author_rank: Newbie
timestamp: April 19, 2011, 11:47:54 am
content: I would recommend uni in Australia, i did not complete a degree and rather worked through the ranks learning on the job ( with a tafe diploma) and don't get me wrong it was fantastic. I learn't heaps and i felt it made me a better engineer however when i applied for new roles they always held it against me.( not having a degree)If i had my time again i would get the paperwork (degree) out of the way young and then start really learning on the job, and as such i would not focus on the wage for your early years but rather a good job where you will learn and enjoy your time and place yourself in a good position for the years to follow.I have since obtained my degree as a mature age student and although i don't think i am much better than prior, its removed the "snob - no degree attitude" some HR people have.Enjoy your time, because the 4 years will fly

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 19, 2011, 04:24:48 pm
content: Quote from: coolguy841 on April 19, 2011, 08:02:10 amafaik, albeit =all be it

author: McPete
author_rank: Regular Contributor
timestamp: April 23, 2011, 08:50:28 am
content: Quote from: Zap on April 19, 2011, 11:47:54 amThis is the road I'm going too. I've also done a trade (instrumentation and control), currently doing my Adv. Diploma, and the goal is the degree.I will agree, a lot of HR and headhunter people seem to barely acknowledge the existence anything less than a Bachelor's degree (And trumpet the fact they have such a qualification...). If you ever encounter someone with this attitude, remind them of this; The smart employer hires the person capable of doing the work.Enjoy your Uni, but try to get yourself some practical time on holidays with a local employer. If you can whack on your CV that you've worked (even voluntarily) in engineering more than the other graduates of your year, or even an associated field, that'll put you streets ahead of the pack.Best of luck, and maybe I'll see you out there!Peter
been a while. hello all. soldering iron is being dusted off. - Page 1
Forum section: electronics / beginners

author: lupinehorror
author_rank: Contributor
timestamp: May 01, 2018, 11:54:04 am
content: hey.for various reasons the few projects i had on the go were put to one side for a good while. now, though, i can feel some enthusiasm returning.half way through a component tester kit. the resistors have been staring at me across the room for 6 months or so.there's an LED audio analyser thing to start also.just got a TS100 iron which looks good (and firmware upgradable!). bought a 15V-24V laptop charger to power it...hope that's right.though i'd say hello and have a look around...been a while.cheers.

author: lupinehorror
author_rank: Contributor
timestamp: May 01, 2018, 12:06:16 pm
content: thishttps://www.ebay.co.uk/itm/15V-24V-Laptop-AC-Adapter-Power-Supply-Universal-Charger-10-tips-UK-Lead-Cord/301727795674?epid=1741908785&hash=item464060c9da:g:VgUAAOSwmCVY-Cjnis the supply i got...i do hope it is ok to post linksthat'll do i think.

author: Brumby
author_rank: Unknown
timestamp: May 02, 2018, 03:11:23 am
content: Welcome back. We all have our stories about irritating influences (like the job, paying bills and such) interfering with our electronic endeavours - so you're in good company.I won't offer any comment on the TS100. I've never had the pleasure and there are enough opinions on this forum as it is. Just try using the search button and plug in 'TS100'.Including links is not a problem, neither is inserting inline images - but it is considered good manners to not do this with huge images or a series of large images (several MB), since there are some members here who do not have access to high speed internet connections. Reduced size images with links to full size versions are preferred if you have something that really needs the large file size. Often, though, photos can be compressed down to 100kB or so and still retain more than enough detail for their purpose.

author: Gyro
author_rank: Super Contributor
timestamp: May 02, 2018, 08:59:04 am
content: Regarding the TS100, this is probably the most current helpful thread for you...https://www.eevblog.com/forum/reviews/ts100-doesn_t-function-properly-when-earthed/I've not seen anyone comment on the power supply that you linked, so your feedback on it will be helpful and interesting!The switchable output voltage would be useful though. The key issue is whether the output is grounded or floating (grounded is what you need). It does appear to have a 3 pin mains input but that isn't a guarantee these days.The other viable alternative is a second hand genuine laptop PSU - you can pick up 20V 65/90W Lenovo one for less than £10. HP, Dell etc are also options.Whatever you use, you will benefit from adding a decent piece of flexible burn-proof silicone cord and decent plug, purely from the physical handling perspective. You don't want a bunch of adapters hanging off the back.
Been offered some work with a small local business..... - Page 1
Forum section: electronics / beginners

author: zero_budget_tech
author_rank: Newbie
timestamp: January 22, 2016, 01:13:00 am
content: Hello.I have been offered some work doing repairs for a small but seemingly fairly profitable local business. Changing fuses, fitting bulbs, maybe replacing the occasional blown cap, but mostly mechanical. All easy stuff.I have very little idea about the business side of it. It's probably not going to be enough work to be worth starting my own company for, and the owner of the business seems happy to take me on as a part time employee. Parts would be paid for by the business, an hourly rate negotiated for my time, but what about money I need for tools? Should I be looking for a high enough wage to cover my equipment, or would it be in with the cost of parts? If it is in with the parts cost, what about wear and tear on the equipment I already own?

author: AlxDroidDev
author_rank: Frequent Contributor
timestamp: January 22, 2016, 01:28:37 am
content: I don't know what the local legislation is in your country, but around here, if you are an employee that needs tools to do work-related job, then the boss/company is obligated to provide the proper tools + equipment required for it, including safety equipament (like isolated gloves and shoes).You can suggest that he buys the tools and equipment, and you use as long as you're working for him. If your contract with him is terminated, the tools and equipament are returned to his company.

author: zero_budget_tech
author_rank: Newbie
timestamp: January 22, 2016, 01:59:05 am
content: "I don't know what the local legislation is in your country, but around here, if you are an employee that needs tools to do work-related job, then the boss/company is obligated to provide the proper tools + equipment required for it, including safety equipament (like isolated gloves and shoes)."Yes, I believe that is the case here too, but the small amount of work I would be doing, would not cover the cost of buying a workshop full of tools. I think you helped me get the answer in a round about about sort of way though. I will buy my own tools, and only take the job if they pay enough to make it worth doing.
Before & after the inductor, how does it look? - Page 1
Forum section: electronics / beginners

author: Rick Law
author_rank: Super Contributor
timestamp: April 24, 2013, 09:51:11 pm
content: Folks, I need your experience and help again. (Here is where I wish I have a scope).(1)With the LM2577 (or similar), Vcc is connected to 2577's Vin and via an inductor connected to 2577's SwitchOut. That line continues to a diode then capacitor and Vout.How would the signal look like at at the SwitchOut pin? A more-or-less square wave at LM2577's internal 52kHz?(attached schematic from app notes)(2)The LM2577 pin 1 is Compensation, what is it intended to compensate?Thanks!Rick

author: c4757p
author_rank: Super Contributor
timestamp: April 24, 2013, 10:05:30 pm
content: Quote from: Rick Law on April 24, 2013, 09:51:11 pmMore or less, but expect it to be very messy.QuoteThe feedback loop, which can sometimes become unstable without compensation, especially in current mode switchers like the LM2577.

author: c4757p
author_rank: Super Contributor
timestamp: April 24, 2013, 10:08:08 pm
content: Page 19 of the datasheet explains a bit more, as well as giving a method for choosing them.

author: Rick Law
author_rank: Super Contributor
timestamp: April 24, 2013, 10:20:45 pm
content: Quote from: c4757p on April 24, 2013, 10:08:08 pmThanks! (again)I was using National Semiconductors datasheet and it is only 6 pages total with no info on compensation.I just downloaded TI's datasheet and on page 19 - there it is all about compensation! Even an inductor selection guide. Something to read tonight. Thanks again.(Reminds me of a famous saying, "you don't know what you don't know...")Rick

author: c4757p
author_rank: Super Contributor
timestamp: April 24, 2013, 10:55:39 pm
content: Quote from: Rick Law on April 24, 2013, 10:20:45 pm"The datasheet"... I forgot National was recently borged by TI and used to have shitty datasheets. I should have been more specific.
Beginner - Page 1
Forum section: electronics / beginners

author: rizike
author_rank: Newbie
timestamp: April 02, 2025, 10:16:59 am
content: Hello.I bought a LONGWEI PDS 3010G power supply.I noticed that there is a red LED inside that is constantly on. Is this normal or is there a problem? Thanks in advance for your answers.

author: ataradov
author_rank: Super Contributor
timestamp: April 02, 2025, 01:56:21 pm
content: It is fine. Devices often have basic diagnostic LED. They are useful when you need to do a spot check on the PCB alone.
Beginner about to use a heat gun and Kopton/Kapton question? - Page 1
Forum section: electronics / beginners

author: FearTec
author_rank: Regular Contributor
timestamp: September 19, 2020, 06:34:29 am
content: HelloI orderd 1x Kapton roll from flea Bay and it arrived as "Kopton" not "Kaptoon" even though the listing said it was Kapton.eBay Llsting Desc: "Heat Resistant High Temperature Kapton Tape Polyimide For Mendel 3D Printer AU"I asked the seller "Hello, this arrived and it's not Kapton tape but Kopton, it's fake. You listed this as "Kapton"?"The seller replied with "This is the supplier telling us it's 'Kapton'. We have checked the quality of the product and there is no problem"I replied with "I did a reverse image search for your listed images and they belong to Xiamen Aerchs Adhesive Solution Co., Ltd.not Kapton (not Dupont). Kapton is a registered trademark of "E. I. du Pont de Nemours and Company."Is this ok to use with a Heat Gun to do SMD reflow repair or is it Junk?I suppose I can test it and see if it is ok?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 19, 2020, 06:42:06 am
content: If it's still proper polyimide film and the adhesive (if applicable?) is fine, yeah, it doesn't matter. You did pay for a trademarked item however, and you are technically in the right to complain. Probably if you report it you can get it for free (they aren't going to care about returning it). Give or take the calculus of +/- reviews, I don't know what eBay is like these days.Tim
Beginner analyzing UART using a scope - Page 1
Forum section: electronics / beginners

author: kiler129
author_rank: Newbie
timestamp: July 31, 2024, 01:48:03 pm
content: Howdy!I spent years in the software world with only occasional dabbles in hardware. Recently I've got, recommended widely, Siglent SDS804X HD. It is my first scope after owning an analog HP years ago. With new found capabilities, I started playing with various measurements to get to know the equipment. I stumble upon bus analysis which is a great option. However, I'm yet to find two things on the scope:Automatic UART/CAN/etc baudrate calculation- while it's quite easy to do a single capture on raising edge, measure the width of the shortest positive pulse, use confuser to do 1/(width*10^-6), and then set the scope to the proper baud.... it is quite cumbersome. Is there some easier/automatic way of doing that, or is such option simply missing from my scope?Linking channels settings- while playing with the scope I noticed I often measure similar signals with multiple probes. The interface has an option to copy settings from one channel to the other. However, is a notion of "binding" channels together so that changing vertical scaling of one changes all ever a thing?I checkedthe user manualfor my oscilloscope, but I don't see neither of these options.I would be glad to get some help-- Greg

author: Jeroen3
author_rank: Super Contributor
timestamp: July 31, 2024, 02:03:14 pm
content: Rohde and Schwarz has a copy feature for channel settings iirc. But linked channels I have not seen yet on scopes. only function gens.Could be a nice feature.Automatic baud rate is fairly typical for decoders, doesn't it have that?Most of the time you know beforehand the baud rate, and if it's not 9600 or 115200 something is probably off.

author: tggzzz
author_rank: Super Contributor
timestamp: July 31, 2024, 03:53:27 pm
content: Consider using a scope to ensure analogue signal integrity. i.e. voltages, timings, transition time/monotonicity/overshoot, noise. Once you have determined all those are within limits, you will be sure the analogue waveform will be correctlyinterpretedby the receiver as a digital signal.At that point flip out of the analogue domain (i.e. a scope) and into the digital domain, i.e. a logic analyser for bits/words or protocol analyser for messages.Very capable LAs and PAs are very cheap, and remarkably effective. Examples: the many 8-bit 24MS/s "LAs", or a BusPirate 5. The latter will allow you to output UART/SPI/etc messages as well.
Beginner: any idea why R43 would have disintegrated? - Page 1
Forum section: electronics / beginners

author: rthorntn
author_rank: Frequent Contributor
timestamp: September 09, 2024, 12:17:48 am
content: Hi,I have a subwoofer that powers on but doesn't work.I've dismantled it and the amp (a rebadged Dayton SPA250) has the legs of a resistor at R43 but no body?I found a diagram that's has it as a 10K connected between earth and the soft-limit circuit, I'm assuming a mains power surge but want to be sure before I replace it, I'm guessing it was a 1/6W or less as the body "gap" is tiny?ThanksRichard

author: bostonman
author_rank: Super Contributor
timestamp: September 09, 2024, 12:50:09 am
content: I may be wrong, but that looks like a thermistor since it has an oval circle around it.

author: rthorntn
author_rank: Frequent Contributor
timestamp: September 09, 2024, 12:55:31 am
content: Thanks, does a thermistor make sense, do they just explode then, would it cause the symptom I'm seeing, power on, no sound?

author: bostonman
author_rank: Super Contributor
timestamp: September 09, 2024, 01:18:27 am
content: I'm not exactly sure how the circuit works, but point A is connected to the left side near the J1 connector.The circuit marked point A is also connected to standby and a temp node, so it's possible the circuit thinks the system is too hot and not turning on.

author: rthorntn
author_rank: Frequent Contributor
timestamp: September 09, 2024, 01:20:18 am
content: Thanks, I'm reading up on it now, they can explode and they do act as a sort of surge protection, I just had a good look at the soft-limit PCB and I don't see anything obviously wrong. Probably just get a 10k thermistor and solder it in?

author: bostonman
author_rank: Super Contributor
timestamp: September 09, 2024, 01:26:08 am
content: Looking at the thermistor chart, it's 10k at 77 degrees F and the resistance decreases as temp increases.Maybe stick a 10k resistor in the spot and see if it turns on.
Beginner DSO - Page 1
Forum section: electronics / beginners

author: mlapaglia
author_rank: Newbie
timestamp: August 17, 2014, 01:36:09 am
content: I've always wanted to get a scope for personal use. I do hobby rc quadcopters and I love tearing things apart when they don't work to figure out what's wrong. Big fan of eevblog's youtube I could watch the channel for hours.I want to learn how to become proficient with a modern day scope, and am looking into studying up with one from online resources. The purchase of a scope has been on my back burner for some time but a (i think) awesome opportunity has come up.Recently a Agilent MSO-X 2012A appeared in my area. It's only been used once and comes with a water proof case for carrying/storage. He is asking $750 for it. I see it retails for over 1k and think this is a pretty nice price considering it's practically brand new.For a beginner user like myself this seems like a nice scope to learn on. I watched through #143, the review of the 2024a and am wondering if anyone had advice on if this scope would be good for my case.Thanks!

author: TimNJ
author_rank: Super Contributor
timestamp: August 17, 2014, 04:28:24 am
content: MSO-2012A??If he's asking $750 for a fully functioning MSO-2012A, that is a steal. That thing retails close to $2,500. And they don't drop in market value too much if they are used, so hell...you could probably even resell it if you had a reason to.

author: mlapaglia
author_rank: Newbie
timestamp: August 17, 2014, 06:21:24 am
content: That's what I was thinking... Maybe it is stolen lol.. That's prey darn cheap.. I'll have him turn it on and test the probes with the test signals but it even comes with a nice water proof case.. He is moving though maybe he just needs some cash..
Beginner EEVBlog Show Suggestion - Page 1
Forum section: electronics / beginners

author: JacobEdward
author_rank: Regular Contributor
timestamp: March 22, 2015, 03:38:15 am
content: I am learning about Op Amps and I thought it would be sorta amazing if Dave would do a show on the internals of an Op Amp (I've attached a picture of a schematic of a LM741 I found from TI to this post). I think I basically understand the idea of an op amp, but feel like I would more fully understand if it was deconstructed to its basic building blocks. :-) I mean I understand the idea behind all of the different parts that are in that schematic, but just how they combine and interact with each other still seems ridiculous to me lolhttp://www.ti.com/lit/ds/symlink/lm741.pdf

author: Stupid Beard
author_rank: Regular Contributor
timestamp: March 22, 2015, 03:55:06 am
content: Alan did a good video along those lines here:

author: zapta
author_rank: Super Contributor
timestamp: March 27, 2015, 04:00:07 pm
content: Quote from: JacobEdward on March 22, 2015, 03:38:15 amEpisode #741 is behind the corner.
Beginner electronics help with wiring PLC's - Page 1
Forum section: electronics / beginners

author: rthorntn
author_rank: Frequent Contributor
timestamp: May 07, 2018, 12:51:20 am
content: Hi All,Apologies if this is a little bit off-topic, everyone is just so darn helpful here (many thanks for all that helpfulness)!Please keep it relatively simple, all this is an occasional hobby for me, thanks!I just purchased a PFXLM4301TADAC it's a Pro-Face HMI/PLC combo, I would like to learn a bit about PLC (including security) without blowing an expensive bit of kit up.So the integrated I/O specs:DIO (Source Type)12 Points Standard Input (including 2 Points for Fast Input)6 Points Standard Output, 2 Points for Fast OutputAIO2ch analog inputs (13-bit) and 2ch analog inputs (16-bit) for Thermocouple2ch analog outputs (12-bit)My first issue is what's the best way to provide 24v DC to it, I have a MW S-201-24 (24v, 8.5A) that I ripped out of cheap CNC controller, should I use that or get something less "dangerous" from Jaycar?My second issue is I can't really comprehend the differences in the way I would wire sink vs source and whether I need to look for a certain characteristic of a sensor/actuator that would make it compatible/incompatible with my source-type (for output the load is on the negative?) digital I/O?I would like to get a temperature input to the PLC, what do I buy or can I just use something I have already from my electronics gear, I have a few DMM temperature probes, would they be OK, if so, how would I wire it (in the manual I can see pin C8-11 & D8-11 are temperature inputs with the signal names MS0+/EX0+/MS1+/EX1+ and MS0-/EX0-/MS1-/EX1- I've no idea what it means)?Also is there an output accessory I can add to switch 240v AC, can I use the PowerSwitch Tail PSTK-240 I have here, it can be configured for 24v control, if so, how would I wire the control to the PLC?Do I need to ground and/or fuse things, sorry this is a basic question?Feel free to suggest I go read a section of some book or look at a certain video, I just purchased... Electronics from the Ground Up, The Art of Electronics, Practical Electronics for Inventors & Grob's Basic Electronics.Thanks (again)Richard
Beginner exploring electronics, next steps?  - Page 1
Forum section: electronics / beginners

author: ajr1991
author_rank: Newbie
timestamp: December 30, 2017, 03:57:43 am
content: Hi! I'm a software programmer who is exploring the world of electronics. I have a good understanding of basic circuits somewhat of diagrams, and just want to go further with learning and maybe designing my own circuits.So far I'm learning to solder. For Xmas, I got a soldering station (X-tronics #3020 XTS) which had some pretty good online reviews (although I understand it's not a renown brand; maybe that will bite me later), bit of soldering wire (63/37), and some project kits to solder together. I've already done some cheap moving bug kits (ones with two motors and light sensors to move towards light) and am going to do two others (MintyBoost charger and some electronic clock/temperature thingy that looks daunting). I also recently got a Klein MM600 multimeter for $65. Seems to be similar to the MM1000 it (and the higher end MM700) replaced but without a few things like TrueRMS, low impedance, and moving bar that I don't plan on using soon. Seems pretty solid.I've already ordered more tips for my soldering iron since heating up some of those giant copper pads was a chore if I didn't have enough surface touching with the conical tip. Also have a desk fan on the way to blow the fumes away from me. An aside, some people seem to love the fume smell; I heavily dislike it.Few things:1) Where should I get some stuff like desoldering wicks and soldering wire? Is there a particular brand to look for or is it all mostly the same? Can't seem to find brick and mortar stores with this stuff so probably just get it online.2) What should I focus on learning/doing next? I'm wanting to learn more about understanding and designing a circuit but don't exactly know where to go next.3) Are there any other equipment I may need? Oscilloscope may be next for me but for now I'm just wetting my toes and don't want to spend too much in case I lose interest for whatever reason.Thanks much!

author: rstofer
author_rank: Super Contributor
timestamp: December 30, 2017, 05:05:36 am
content: There's another thread running related to this topic:https://www.eevblog.com/forum/beginners/complete-noob-here-any-tips-on-how-to-get-started/

author: danadak
author_rank: Super Contributor
timestamp: December 30, 2017, 12:12:40 pm
content: You can start with a PC sound card based scope for free. Will give you basicallyaudio range scope, spectrum analyzer, and function generator all using yourPC sound card.https://www.zeitnitz.eu/scope_enhttp://www.zelscope.com/http://www.ledametrix.com/oscope/http://www.virtins.com/downloads.shtmlBut first build a simple circuit to protect sound card inputs so you do notruin from transients, overvoltage. Google "protect sound card input".For examplehttp://makezine.com/projects/sound-card-oscilloscope/Regards, Dana.

author: danadak
author_rank: Super Contributor
timestamp: December 30, 2017, 12:26:10 pm
content: Sound card impedance bridge -http://www.marucchi.it/ZRLC_web/ZRLC/Steber_An_LMS_Impedance_Bridge.pdfhttp://www.sillanumsoft.org/ZRLC.htmRegards, Dana.
Beginner looking for cheep ossilliscope - Page 1
Forum section: electronics / beginners

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: October 26, 2013, 09:22:32 pm
content: I am a beginner looking for a cheep ossilliscope, it can be any make or model and I don't care whether its digital or analog. If you respond with an offer I would like a list of pros and cons to help me make a choice in the event of multiple offers.

author: Maturola
author_rank: Contributor
timestamp: October 26, 2013, 09:31:28 pm
content: What's "cheap" to you? For some a $1000 scope is a cheap one.Also, please share your requirements, what do you think you will be doing? what type of circuits, systems? What protocols? what voltages?The better we understand your usage, the better we can recommend something.A quick search on the forums and you will find most people here like the Rigol 1052E (or the 1103E), that's around $350ish, if you have some more budget the DS2072 (hacked) is the best bet for about $800ish

author: rexxar
author_rank: Frequent Contributor
timestamp: October 26, 2013, 10:14:55 pm
content: What country do you live in, what's your budget, and what kind of electronics will you be working on?Like Maturola said, the DS1052e is a great low-end scope, but if you can afford it, the DS2072 is so much better.Or, if you're just looking for something to poke around with, there's a ton of cheap analog scopes on ebay and the like. A good 20MHz dual channel scope is a great option for beginners, as they can be had for around $50.

author: deth502
author_rank: Frequent Contributor
timestamp: October 27, 2013, 02:23:57 am
content: judging by the wording, i dont think hes looking for advice, i think he is soliciting a sale. this should be in the buy/sell/wanted section.

author: KJDS
author_rank: Super Contributor
timestamp: October 27, 2013, 09:06:35 am
content: I'd recommend the Canary brand for the best cheeps

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 27, 2013, 10:16:55 am
content: Quote from: KJDS on October 27, 2013, 09:06:35 am*Begins to clap slowly*

author: rolycat
author_rank: Super Contributor
timestamp: October 27, 2013, 12:28:19 pm
content: This is getting silli.

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: October 28, 2013, 04:25:22 pm
content: well I'm on the budget of a 16 yo ski coach, so as cheep as possible would be good. as for what I would be doing with it, it would be my first oscilloscope so I would mostly be learning about how to use them. for those wondering about country I live in Alberta, Canada.

author: Chrisalat
author_rank: Newbie
timestamp: October 28, 2013, 07:44:03 pm
content: Why don't you start with one of those sound card oscilloscopes?Works for the audio range and you can get a feeling for what you may need later.

author: deth502
author_rank: Frequent Contributor
timestamp: October 28, 2013, 09:47:31 pm
content: you can watch eebay for some cheep ossillisscopes.