hybridfree/eevblog-posts huggingface dataset:
Lithium battery protection from overvoltage at load side - Page 1
Forum section: electronics / projects

author: Krotow
author_rank: Regular Contributor
timestamp: November 28, 2022, 11:28:11 pm
content: Have an idea to convert some home appliance from dead non-standard form-factor 15.2V NiMH pack to 4S 18650 Li-Ion battery. Charger and BMS are ready (thanks, Ali). The real issue is 19V at load side when device is in charging mode. I have no wish to mess with appliance circuit which I don't have. But have no idea how to cut off battery from load in simple enough way and preferably use components which I already have in shelf and even better if it would be done with MOSFET-s and without fancy ICs which I don't have. Breadboard spaghetti from 4-6 components will be fine. Any ideas?Device itself is not very power hungry. Consume 1.2A on switching on and up to 800 mA during work. So 5A diode like SS54 between battery and load works too in inefficient room heater modeI wanted something a little more efficient.

author: TheMG
author_rank: Frequent Contributor
timestamp: November 29, 2022, 12:02:15 am
content: Does the device disconnect the load when charging the existing battery? If not, then I wouldn't even worry about it. The charging voltage for that NiMH pack is going to be around 20V anyways, so not much difference.Can you tell us a little bit more about what this mystery "appliance" is?

author: Peabody
author_rank: Super Contributor
timestamp: November 29, 2022, 03:44:36 pm
content: I'm not sure I understand where the 19V comes from. Is that what's coming in when connected to mains? If so, a standard "load sharing" circuit might work. It consists of a P-channel mosfet, a schottky diode and a resistor. You would be in room heater mode when plugged into mains, but not when the battery takes over. The circuit below shows load sharing for a 1S circuit. Note the orientation of the mosfet appears to be the reverse of normal, but has the body diode oriented to prevent high voltage from coming back in to the battery. A load sharing circuit has the additional advantage of letting you operate the device and charge the batteries at the same time without confusing the charging circuit.

author: Krotow
author_rank: Regular Contributor
timestamp: January 18, 2023, 02:08:06 pm
content: You both are right. Particular device (cheap robot vacuum) disconnect during battery charging. And with reverse current protection between my battery and main board this doesn't matter anymore. Also I discovered that reverse current protection modules without noticeable voltage dropare already availablein ready to use form (so called "ideal diode" modules). Charger module was also easy to obtain for cheap. So main task was battery assembling and planning the wiring. I made conversion description with upgrade circuit and part list in Instructables. See under link below.https://www.instructables.com/Dirt-Devil-M607-Spider-Vacuum-Li-Ion-Battery-Conve/
lithium battery protection ic questions - Page 1
Forum section: electronics / projects

author: [steven]
author_rank: Contributor
timestamp: June 13, 2020, 11:43:19 pm
content: I'm working on a design that uses a protection IC for a single lithium cell. When looking at some cheap chinese protection IC's I came across the app circuit in the datasheet for the fs312f-g:Something immediately stuck out to me: the current sense pin (cs) is connected with a 1K resistor to BATT-. This doesn't make sense to me, from my understanding a current sense pin should measure the voltage across a shunt resistor wired in series between the negative terminal of the battery and the source of M1. This would also make more sense if you look at pin CS in the functional diagram of the chip.Another weird thing is that if the charger voltage across BATT+ and BATT- is above around 4.3v the mosfet pair will isolate the battery from the charger since there is an overvoltage situation. Normally the IC will monitor the charger voltage until it has dropped to the release voltage. But how is the chip supposed to measure this if it doesn't have a reference of BATT- anymore since the mosfet pair isolated this pin from the chip? (via CS somehow?).Apparently there are more protection IC's with similar app circuits:https://www.digikey.com/en/maker/blogs/lithium-ion-cell-protectionI have worked with an MM3722 protection chip from Mitsumi before which has the following app circuit:This makes a lot more sense to me: pin CS measures the voltage across shunt resistor Rsns and pin V- is used as a reference for the release voltage.Why does the fs312f-g not work like this?

author: [steven]
author_rank: Contributor
timestamp: June 14, 2020, 12:16:26 am
content: already found it, the drain source on-resistance is used as a shunt resistor

author: eblc1388
author_rank: Frequent Contributor
timestamp: June 14, 2020, 01:08:55 am
content: I'm glad you have found the answer to your first question.If you examine the circuit I have posted, actual load current passes through the two MOSFETs from the BATT- terminal back to the physical battery -Ve terminal(also GND). Due to the ohmic nature of the conducted MOSFETs M1 and M2, a voltage(Vx) will develop proportional to the current, between the GND and CS pin. The 1K resistor at the CS pin is connected to the input of a voltage comparater, which is high impedance and thus its value does not matter much. It is not a current measuring resistor.W.r.t. your second question, the IC actually monitors the physical battery voltage between VCC and GND and this voltage is available regardless of the On/Off of the MOSFETs.Hope these clarification helps.

author: [steven]
author_rank: Contributor
timestamp: June 14, 2020, 12:43:12 pm
content: Thanks for the explanation, it's all clear to me now.
Lithium Cell Charger / Discharger Half-Bridge PWM current control - Page 1
Forum section: electronics / projects

author: gnasirator
author_rank: Contributor
timestamp: October 28, 2018, 03:55:21 pm
content: Hi there,I am currently tinkering with an idea of mine: I would like to build a small pcb that allows MCU controller charge&discharge of a single lithium cell to do capacity and impedance testing.And I am currently looking into the powerstage design. Requirements are 10A charge and 10A regenerative discharge back into the main power rail. My approach is as follows:SourceI want to use a current-mode PWM controller and feed a setpoint voltage into the current limit pin to have freely adjustable constant-current charge/discharge mode. I haven't found a controller IC to do that yet, I might have to build that part from discrete components.The topology in the end would be something along those lines (half bridge to allow buck charge / boost discharge operation):The voltage control loop for CV operation would run on the MCU and control the current setpoint voltage.As you can see, this is still in very early draft stage. I first want to get the basic topology right. Of course the shown circuits don't fully work yet ... but I think the principle should be usable.A first rough test circuit already seems to work:So the task now is to get a PWM controller IC that gives me the current control parts (opamps + flipflop) in silicon and allows bidirectional control of the half bridge. Can anybody recommend a PWM IC that can do this? Or would I really have to build this discretely?Maybe hijacking a Buck/Boost PWM controller IC's FB pin is possible, like here:http://www.ti.com/lit/an/snva829/snva829.pdfBut I haven't completely figured out how to do that for buck and boost mode and I don't want to reinvent the wheel. I'm sure there are plenty of chips out there doing this? I would assume e.g. they are also used in motor inverters? I simply don't know them yet.I hope this comes across understandablyThanks for your input!CheersValentin

author: jbb
author_rank: Super Contributor
timestamp: October 28, 2018, 07:41:59 pm
content: Maybe theADP1974would be helpful? It's designed for this role and includes precession V, I sense amplifiers, CC / CV control and a PWM block.While it's probably a bit more expensive than a pile of discrete components, remember that your time has value.

author: gnasirator
author_rank: Contributor
timestamp: October 29, 2018, 04:32:36 pm
content: Awesome! Exactly what I was hoping for.I will build the first sample following the typical application and once it's all up and running think about replacing the AD8451 with discrete components.Thanks heaps!
Lithium Charging destroyed inrush limiter and mosfets.  - Page 1
Forum section: electronics / projects

author: WayOverMyHead
author_rank: Newbie
timestamp: July 18, 2022, 07:42:14 pm
content: Hello, I am someone who is using an electric bike to commute back and forth to work currently (due to financial reasons mainly)My bike uses a 25A charger for the 100Ah battery and when I needed a charger for it, I turned to good ole aliexpress. ( I know I know)It’s rated at DC25a on 220v circuitAnd DC 13/14a on 110v circuit.I first tried it in a 110v circuit using provided adapter. No issues after 20 minutes. This adapter just connected the legs straight thru from the 220v plug to the 110v.I unplugged battery, unplugged charger. Switch to 220v circuit with 30 amp plug (dryer circuit) had them wire the matching plug I had (10-30p)It ran for around 5-10 minutes, I felt it at the 5 minute mark and it was room temp. Had a work call, came back to charger 5 minutes later and it was off. And the 220v breaker was popped.I checked everything, unplugged battery. Contacted seller, they said to see if charger still worked. As soon as I plugged charger into wall I heard a pop from inside.When I opened it, I found (see photos) the mf72 20d25 inrush current limiting transistor exploded. The seller told me to check mosfets and they were also damaged. (FDA 28n50)Nothing else appears damaged.Any input on what causes this? They told me they would refund me me the money but not offer a replacement as the issue was on my end they claim.On the 110V Adapter the wiring is as follows:Charger Blue goes to 110V NeutralCharger Brown goes to 110V HotCharger Yellow goes to 110V GroundOn the 220V Adapter the wiring is as follows:Charger Blue goes to 10-30 Dryer 220V Plug HotCharger Brown goes to 10-30 Dryer 220V Plug HotCharger Yellow goes to 10-30 Dryer 220V Plug NeutralThey Wired both adapters and charger.I am not proficient in circuit boards, how ever I could replace the mosfets and transistor (that’s as far as my skills go)I am just worried about what caused the fault. My smaller charger worked before and after this without any faults.The battery was within the chargers voltage range and is capable of 100 amps of charging so the 25a was not an issue and the battery management system had no faults.So can this be fixed? Should it be fixed? Can it fixed to not happen again.And does anyone offer this service? I would honestly be willing to donate or pay for some help with this. I really need to get my bike going to get back to work. If I cannot charge at work, I have to sit at a friends house and burrow his and he is getting tired of it.

author: WayOverMyHead
author_rank: Newbie
timestamp: July 18, 2022, 07:43:35 pm
content: Can mod move this to repair section, I thought I was in repair and made the mistake.
lithium ion battery self discharge - Page 1
Forum section: electronics / projects

author: m3vuv
author_rank: Super Contributor
timestamp: September 10, 2020, 01:12:16 pm
content: hi all,i have a 13s/6p battery pack made of 18650 cells,one row,ie bank keeps discharging,i assume one cell of the bank of 6 has some sort of internal short and drags the others down,is there a way to find out which one it is?

author: Daixiwen
author_rank: Frequent Contributor
timestamp: September 11, 2020, 06:39:06 am
content: Depending on how fast the self discharge is, you may find the defective cell with a thermal camera. If not you will need to disconnect the 6 cells and test them individually.(make sure they are balanced again at the same voltage before you put them back together in parallel!)
Lithium ion charger IC - Page 1
Forum section: electronics / projects

author: bastiaang
author_rank: Contributor
timestamp: October 08, 2018, 12:51:27 pm
content: Hello guys!New topic from me, I have a question about lithium ion charger IC. My first post here was about the LCR measurement device we are working on.Right now I have selected a microcontroller (ATxmega128A3U) but I am a bit stuck on the BMS.The battery that we will be using is a 18500 lithium ion (Samsung ICR18650-26).Therefor I have come up with some requirements:- Need for some kind of communication between the uC and the BMS (SPI, I2C, etc.)- Buildin output regulator, like a buck convertor or regulator (the system runs on 3,3 Volt)- 1 lithium cell controller- input will be 5 volt (USB)- output current will not be higher than 300mAIf it has some kind of LED interface, that would be great but it is not a must.I already have looked at Maxim and TI. But it is possible that I didn't searched well.So guys can you please help me the right battery management IC. Any tips are also welcome.

author: Zucca
author_rank: Unknown
timestamp: October 08, 2018, 01:28:09 pm
content: https://dlnmh9ip6v2uc.cloudfront.net/datasheets/Prototyping/TP4056.pdfnot sure if it helps... it's just a simple USB lion charger, with LEDs.BMS to me is a protection circuit for lion, not sure why you want to communicate to it with a µC.Confused.

author: bastiaang
author_rank: Contributor
timestamp: October 08, 2018, 01:41:50 pm
content: Quote from: zucca on October 08, 2018, 01:28:09 pmYou are right I want a battery charger with a regulated output of 3,3 Volt.The communication with the uC is to program different kinds of charge currents.I will charge via mini USB, and I want to do that with different kinds of wall adapters.Then you got two options, or you take a battery charger with USB interface, or you take a battery charger without but you get the current information of the uC.The battery charger you send isn't sufficient sadly. The output needs to be regulated outside this IC.

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 08, 2018, 02:31:45 pm
content: You should take a look at the so-called PMIC ICs, there are many on the market. Some have an integrated battery charger, and various voltage output options including buck, boost and LDOs.Examples:http://www.ti.com/power-management/battery-management/charger-ics/products.htmlhttp://www.analog.com/en/parametricsearch/11451

author: Koen
author_rank: Frequent Contributor
timestamp: October 08, 2018, 09:03:51 pm
content: Complete Linear Battery Charger with variable Integrated Buck Converter, 10 pins :http://www.analog.com/en/products/ltc4080.html

author: bastiaang
author_rank: Contributor
timestamp: October 18, 2018, 09:35:54 am
content: I have found this one LTC3556 . But will the switch frequency disturb the ADC of the microcontroller?Thanks for the replies so far guys!
Lithium-Ion power pack prototype - Page 1
Forum section: electronics / projects

author: laban93
author_rank: Contributor
timestamp: November 18, 2017, 03:41:50 pm
content: Hi!I'm trying to make a battery pack for a 5v screen with a peak current og 8A and a average powerconsumption of about 2-300mA. The system is also going to be powered from a 150W solar panel with 22V out max @ 8A.My plan was to use 8 18650 cells. 2 in parallel and 4 in series. the cells are unprotected.Does anyone have some good reccomendations to get started at this? I know they have to be over and under current and voltage protected. I guess also that they have to be balance charged.Do you know of any boards to use in this application? The form-factor has to be as small as possible, as the battery back is going to be mounted in a square tube, and the powersupply can be either inside the tube, or flat behind the screen. Is there a CE compliant multipurpose, Charging, MPPT regulator, buck conterter unit for this?Sorry for my rusty english spelling!-Simon

author: soubitos
author_rank: Frequent Contributor
timestamp: November 18, 2017, 04:57:59 pm
content: Charging current per specs is Standard charge: 1075mA Rapid charge : 2150mA. a 4S2P pack would require twice as much so in real life terms 2-4Amps MAX.You can find plenty of CC-CV modules around in step-down step-up or step-up/down configurations which you could use with the solar cell mentioned but it is quite a big one and perhaps you need to use a smaller one instead... or make a 4S4P pack instead or even larger... (I recommend a module based on LTC3780 step-up/down 10a max for under 10$)Then you need a suitable BMS which again, there are plenty around....

author: ocset
author_rank: Super Contributor
timestamp: November 18, 2017, 10:04:43 pm
content: I would just shove a voltage sense on each cell.....soon as any cell goes overvoltage...stop charging them.When you stop charging them, have switches (or fets) to disconnect them from each other so one cells leakage doesnt overcharge another cell.

author: nctnico
author_rank: Super Contributor
timestamp: November 18, 2017, 11:22:52 pm
content: You need a BMS circuit to charge Li-ion cells safely. TI has chips for this purpose and (AFAIK) some are complete solutions which don't need an additional microcontroller. Still I think you will be much better of with a readily made pack which also adheres to the UN38.3 battery safety regulations. Without the UN38.3 certification you won't be allowed to transport your battery pack. Li-ion cells (especially the unprotected ones) are not something to toy with. They can easely push out hundreds of Ampere and cause a fire instantly. I have dealt with Li-ion pack design quite a lot in the past and the approval agency banished battery testing to cheap temporary buildings because testing is too unsafe to do in the main building.
Lithium OVP - Page 1
Forum section: electronics / projects

author: robotix3
author_rank: Regular Contributor
timestamp: November 18, 2016, 04:07:10 pm
content: I am designing a 2-cell lithium polymer battery protection/charge management board. It is a software-defined board so I wanted to have some secondary over-voltage protection on each cell (with a circuit that I didn't design, to make sure I don't have any fires). I found the TI bq2945xxes chips chips(datasheet)and it seems exactly what I need. When the IC detects an over-voltage condition, it triggers a FET to blow a fuse.Annoyingly, the datasheet doesn't say anything about this mystery fuse, it just says it blows one and shows a schematic with a three pin fuse with a heater. After reading a forum post at TIforumsit seems that getting one of these fuses is a big pain, since they only seem to be available in high volumes. I just don't get why the IC is so openly available when the main aspect to the circuit is impossible to get a hold of, even the EVAL board doesn't come with the fuse...So, is there an easy way of getting one of these fuses? Or is there a reliable equivalent circuit for this? (needs to be able to handle ~20 Amps)

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 18, 2016, 04:39:15 pm
content: NC relay with a SCR to activate it until the external voltage is removed?

author: robotix3
author_rank: Regular Contributor
timestamp: November 18, 2016, 04:43:33 pm
content: QuoteThat would work, but it would be too large and too expensive for my application.

author: robotix3
author_rank: Regular Contributor
timestamp: November 18, 2016, 04:59:43 pm
content: There has to be a device out there that behaves like one of these fuses. Maybe something like a spring loaded contact that is released by melting something that is holding it down (like when dave used the resistor to melt the fishing line holding down the mouse trap arm). Of course I could build this but it would be too large and expensive to be practical.

author: amyk
author_rank: Super Contributor
timestamp: November 19, 2016, 05:28:57 am
content: Have you tried looking on AliExpress?

author: robotix3
author_rank: Regular Contributor
timestamp: November 19, 2016, 11:07:19 pm
content: QuoteYes, and I have found some that claim to be the parts I need, but they look counterfeit.QuoteI didn't want to add any more FETs since this would be a single use emergency device. Also, my board already has the functionality of these off-the-shelf boards. I also need everything to be on one PCB.
Lithium Polymer Batterys - Air freight. - Page 1
Forum section: electronics / projects

author: mrpackethead
author_rank: Super Contributor
timestamp: June 16, 2016, 10:10:22 pm
content: Does anyone know if LiPo batterys get treated differently in terms of airfreight, from LiOn or Lithum Metal batterys?I'm workign on somethign that needs hundreds of tiny ( 30mAh ) batterys which will likely tbe airfreighted around.

author: trevwhite
author_rank: Frequent Contributor
timestamp: June 16, 2016, 10:12:12 pm
content: They have to be shipped in a cargo only aircraft. Special labels and all that.

author: Siwastaja
author_rank: Super Contributor
timestamp: June 17, 2016, 07:12:04 am
content: Things called "LiPo" or "LiOn" do not exist.There is only lithium ion (li-ion) (rechargeable), which is sometimes also called "lithium polymer" as an industry inside joke. Polymer refers to the plastic vacuum pack enclosure. They actually tried to design a polymer-based electrolyte in late 90's, it never worked out but marketing wanted to still use the cool name! See how funny it is?What you describe is all the same, and only being one single thing, has one set of lithium ion regulation, regardless of whatever the marketing people is calling it this year.Then there is lithium metal (non-rechargeable), which is different, has completely different danger mechanisms, and may (or may not) have somewhat different regulations.
Lithium replacement for lead-acid batteries in golf cart? - Page 1
Forum section: electronics / projects

author: calzap
author_rank: Frequent Contributor
timestamp: August 26, 2025, 09:27:08 pm
content: We have an industrial, battery-powered golf cart, configured as van, on our ranch. It has six 6-volt lead-acid batteries in series for power. Looks like they need replacing yet again and cost about US$100 each. And I’m getting tired of servicing them and dealing with the corrosion. I’m thinking of getting a 36-volt lithium battery as a replacement. A 100-Ah, 36-volt lithium is about US$600. Is this adequate? The vehicle is driven only a few hundred meters away from utility power and only a few trips per day. And can the built-in charger, used for lead acid batteries, be used for charging a lithium battery with a built-in BMS? Any suggestions on good and bad brands?Mike

author: thm_w
author_rank: Super Contributor
timestamp: August 27, 2025, 12:52:14 am
content: The BMS has to handle the average and peak current draw of the cart, so depends on the motor, but 200A BMS is common.Usually built in lead-acid charger will work OK, check the max float voltage specified.I'm sure will and some others have good info:https://www.youtube.com/@WillProwse/search?query=golf%20cart

author: SteveThackery
author_rank: Super Contributor
timestamp: August 27, 2025, 06:56:52 am
content: So I assume we are talking about a LiFePO4 (lithium iron phosphide) battery? You can charge them from a lead acid battery charger. I don't think that is true for other lithium chemistries.

author: Phil1977
author_rank: Frequent Contributor
timestamp: August 27, 2025, 11:23:58 am
content: There are LiFePo-batteries that are designed for this purpose, e.g. like this:https://amzn.eu/d/70K8ekkThey usually work together with pre-existing chargers, though they sometimes show errors when the charge is complete.The only thing I would avoid is to use more than one LFP-battery-pack in series because it´s better to have one unified BMS for all the cells. So do not use 3 times 12V or 6 times 6V, get one battery pack that is designed for 36V nominal voltage.
Lithum-ion charging and protection circuit - Page 1
Forum section: electronics / projects

author: Emil
author_rank: Regular Contributor
timestamp: October 21, 2017, 03:00:28 pm
content: Hi,I'm making my first lithium-ion charging/protection circuit and I'm hoping for a few extra pairs of eyeballs to spot any mistakes I may have made..The charging controller is an MCP73812 and the protection IC is an AP9101CAK-ABTRG1. Q1 and Q2 are IRLML6344TRPBF logic level N-channel mosfets. It's for a single 18650 cell. Maximum discharge current ~500mA.Attached schematic.
Little 1/28 autonomous race car - Page 1
Forum section: electronics / projects

author: Prototyx
author_rank: Newbie
timestamp: January 01, 2024, 07:17:57 pm
content: Hello,I would like to share with you my project of creating a mini autonomous car from scratch.I have chosen 1/28 scale because frames, motors and batteries are not so expensive with this scale.I design myself the PCBs and assemble it also myself.I divided my project in several parts :Basic control (throttling, braking, turning):Part 1 : Make my own ESC on an Atmega328P (same as Arduino Uno) -->DonePart 2 : Integrate my ESC on and a receiver on an Uno board -->DonePart 3 : Testing the car as e regular RC car to check all basic functions are OK -->DoneMake it Automatic :Part 4 : Make a fast line follower -->DoneMake it Autonomous :Part 5 : Integrate a Raspberry pi 4 (CM4) and make a custom stereo camera to be able to avoid obstacles and detect turns. -->OngoingHere are some pictures of the project :Development of the ESC:The car assembled in basic configuration:The car in line follower configuration :I have a lot of raw videos and pictures of the project but I need time to have a correct result.Here is the video of part 1 :I will update with new content the first message if people are interested.Have a nice day.
little help with current transformer  - Page 1
Forum section: electronics / projects

author: Remy007
author_rank: Newbie
timestamp: July 22, 2018, 10:11:43 pm
content: Hey,I'm working on building a 3 phase AC current meter.So that I can view the ampere.Its a distrubution box ,,32A CEE 380VIN to6x 16A 230VOUTquestion 1I mounted the current transformers almost against each other, can they disturb on each other?question 2I have used silicone to hold the wire in place, gives this any affect the accuracy or functioning?

author: David Hess
author_rank: Super Contributor
timestamp: July 23, 2018, 01:14:26 am
content: Quote from: Remy007 on July 22, 2018, 10:11:43 pmToroids are self shielding so this should not be a problem. I have never seen it matter with toroidal current transformers.QuoteThe adhesive will not have any effect unless of course it fails but that is not an electronics problem.

author: floobydust
author_rank: Super Contributor
timestamp: July 23, 2018, 01:41:44 am
content: I had troubles with CT's with such a large window. If the conductor is in the center or the side, or passes through at a diagonal, the readings were all over the place. The CT's also picked up flux nearby. The steel screws seem like a bad idea.Not sure whyENT.30CT has such a large window for only 30A?I'm a bit uneasy about the enclosure and electrical codes.Make sure you have a high-current ground connection to the metal enclosure (frame).The box might heat up if it's good for 22kW, with wood and no ventilation slots.This distribution box is for indoor use only? It better not rain on stage.I would not have used wood.

author: Remy007
author_rank: Newbie
timestamp: July 23, 2018, 10:44:17 am
content: when the silicone is dry, i wil remove the screws.Yes for indoor only !I used this for more then a year, not any problem with heat building up inside.I just wanted to see the ampere and voltages, so put in the measurement device.

author: Janne
author_rank: Contributor
timestamp: July 23, 2018, 10:54:48 am
content: Wire position with those current transformers does not have any mentionable effect, from my experience in working with kWh metering. Also the metal screws are not a problem, if they were they would not be shipped with every CT

author: ArthurDent
author_rank: Super Contributor
timestamp: July 23, 2018, 12:01:15 pm
content: The shape of the window in the CT (current transformer) with the steps are to accommodate various size copper bus bars and the screw with the rubber bumper is to lock the CT onto the bar so it won't vibrate when high current flows through the bus bar. If you are using a wire for the primary the screw isn't needed.Make very sure that you always have the recommended load (burden) on the secondary of the CT because there is a real possibility of developing high voltages on the secondary. A lot of CTs have a shorting link to prevent this from happening when you are working on a CT in a live circuit.Here's a picture of the screw being used on a large copper bar.
Little Kickstarter Project - Page 1
Forum section: electronics / projects

author: Atton
author_rank: Newbie
timestamp: February 03, 2015, 04:58:57 am
content: I've been working on this little project. I have no clue if it will actually reach its goal but I think it still better than the solar road ways project. If you got ideas or suggestions that would be great.https://www.kickstarter.com/projects/223870491/simple-and-independent-solar-energy-system-sises/description
little screw as positive AA cell battery contact? - Page 1
Forum section: electronics / projects

author: Zeyneb
author_rank: Regular Contributor
timestamp: August 28, 2015, 04:21:02 pm
content: Hi there,Do you think a little screw would do for a reliable positive AA-cell battery contact? My idea is to have the positive battery terminal touching the head of an countersunk head screw of about the same diameter.I've read nicked plating is commonly used for that. So going for a nickel plated screw there?Also do you think the flat side of the countersunk head is the best for a reliable electrical connection? Otherwise I can do the pan head version.For the negative side I'm going for a regular spring:http://www.digikey.nl/product-detail/en/211/36-211-ND/315701Shall I design for 3 mm compression on this 7.37mm length during relaxation. Would that be a good amount?Thanks in advance for some suggestions around this.Zeyneb

author: Redcat
author_rank: Regular Contributor
timestamp: August 28, 2015, 05:09:08 pm
content: Of course you can use a screw as a battery contact. Doesn't look that nice and might come loose but it will work.We have an aluminium ball ( from chocolate) in the battery holder as a contact for one of our wireless Mac keybords at work...I didn't do that...Don't choose a too big head. You could make contact with the battery case with a big screw head and shorten the thing out. Try different head shapes on how tight your battery sits in the holder.A more rounded head might be better to not damage the battery during insertion.You might need something which holds your battery in place or it might fall out.Go for it if you really want.Good luck ^^ , Tom
Live wire powered RF wall switch. How? - Page 1
Forum section: electronics / projects

author: HSPalm
author_rank: Regular Contributor
timestamp: January 28, 2014, 12:30:33 pm
content: Hi,I'm trying to figure out how this device is poweredhttp://www.nexa.se/WMR-252.htmAs you can read from the english PDF manualhttp://www.nexa.se/res/pdf/Manualer/WMR-252-EN.pdfthe switch input is only connected to a physical light switch free from any voltage potential.So then it must be powered by the L and output connection, so it's in series with the load. I can see two possible options. One is that it's battery powered, and a small current transformer charges the battery each time the load is switched on. Or it might never switch fully off, it keeps a high impedance load in series just enough the power the RF receiver from the voltage drop. The current will of course be too low to get visible light in any light bulbs.I've seen quite a few transformer-less power supplies, but all use both live and neutral wire. This one I don't get.Thanks.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 28, 2014, 12:36:13 pm
content: Quote from: HSPalm on January 28, 2014, 12:30:33 pmQuite common in automatic light switches & touchdimmers - when off it passes a small current (can cause flashing in CFLs), and when on, it doesn't turn on for quite all of the mains cycle.

author: HSPalm
author_rank: Regular Contributor
timestamp: January 28, 2014, 12:49:26 pm
content: Thanks mikeselectricstuff. Do you know if this technique has name or anything? I haven't found one schematic that does this. I understand it's most probably triac based, but I wonder how the low current switching part can be done safely, at first.
LK-99 is back - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: January 06, 2024, 07:43:27 am
content: https://thequantuminsider.com/2024/01/04/its-back-researchers-say-theyve-replicated-lk-99-room-temperature-superconductor-experiment/can it be?

author: coromonadalix
author_rank: Super Contributor
timestamp: January 06, 2024, 01:32:20 pm
content: no need to brag theses news here.

author: coppercone2
author_rank: Super Contributor
timestamp: January 06, 2024, 09:31:18 pm
content: it would be the biggest discovery in electronics for the last 70 years, not to mention there would be something more to the sci fi of electronics then quantum computer BS
LLC converter overview/reference/book? - Page 1
Forum section: electronics / projects

author: Martinn
author_rank: Frequent Contributor
timestamp: September 22, 2023, 07:53:53 am
content: Hi all,I am not a power supply designer, but would like to try out some LLC designs (more in the direction of low noise/low power than high power it is normally used for).Is there a somewhat comprehensive, not too theory-laden (I love math, but only where it belongs and not artificially cluttering things) reference? Like AoE for LLC converters?As far as I have searched so far this does not exist. Best I have found (searching for "LLC converter tutorial") are various application notes and youtube videos (my favorite:).This somehow reminds me of FOC (field oriented control): Some time ago I did a BLDC motor control project and first really struggled with the apparent complexity - space vector modulation theory and such. After I had understood the overall principle, it was really quite straightforward and handled in maybe ten lines of C code (if you use P/C and PI control as subroutines). But to my knowledge no good overall reference material exists.Thanks - Martin

author: TimNJ
author_rank: Super Contributor
timestamp: September 22, 2023, 03:38:46 pm
content: This one is a little "mathy", but hits a lot of the questions I had:https://www.youtube.com/watch?v=7rMuAnFG_UA&pp=ygUWbGxjIHJlc29uYW50IGNvbnZlcnRlcg%3D%3DThere is Sam Ben Yaakov who shares a lot of practical approaches:https://www.youtube.com/@sambenyaakovThese days, getting an LLC up and running is pretty easy (IMO). Back 10-15 years ago, the controller options were limited and fiddly. These days, they are much more refined and more tolerant to issues with your design. (e.g. you can probably get a suboptimal LLC design at least "working" without the thing blowing up the first 10 times.)I'd suggest TEA19161T from NXP. It's probably the most widely used on the market, for good reason. There are newer iterations TEA2016 and TEA2017, which I have not used, but are I2C programmable which let's you tune a lot of the IC's parameters. How useful that is, I can't say.My point being: You may learn a lot more by getting your hands dirty prototyping...sooner, rather than later.

author: Martinn
author_rank: Frequent Contributor
timestamp: September 25, 2023, 06:51:46 pm
content: Quote from: TimNJ on September 22, 2023, 03:38:46 pmThanks, quite interesting!I also found that most of the content of the video I linked above is from this book:https://www.amazon.com/Switching-Supply-Design-Optimization-Second/dp/0071798145I bought the kindle version (half the price on amazon.de!), but I am not sure what to make of it. It certainly is hands-on, but feels a bit shallow at times (something you would never think of reading AoE). Also the illustrations are miserable quality - low contrast, low resolution b/w blurred pictures, often hard to decipher.

author: temperance
author_rank: Super Contributor
timestamp: October 07, 2023, 01:03:16 am
content: https://vtechworks.lib.vt.edu/handle/10919/28982
LLC secondary leakage inductance / Layout - Page 1
Forum section: electronics / projects

author: iliya31
author_rank: Newbie
timestamp: February 26, 2024, 06:42:30 am
content: Hello, probably most of the people that have designed LLC converter had faced the problem I will describe.When the LLC converter is designed with center tapped transformer and integrated inductance things come critical.First of all both leakage inductance ( shorted secondary windings ) must be equal as possible. Otherwise large current disbalance will occur on secondary switches.Another critical part is the parasitic secondary inductance that is coming from the layout. That parasitic inductance could create large current disbalance on secondary switches.So the question is related with the layout. Drain track layout is perfectly matched on both transistors, but how do you match and should you, source track layout.Here I have to mention first revision layout I didn't have matched drain paths and one of the switches raised its temperature with 30 degrees more than the other ( current disbalance ), With the second revision I populated one PCB and it works fine, but than I populated one more and it seems there is disbalance cause one of the switches temperature is larger than the other.

author: TimNJ
author_rank: Super Contributor
timestamp: February 26, 2024, 06:49:39 pm
content: Have you measured the leakage inductances of the transformers? Are they consistent between different samples? Have you tried to swapping the transformers? Put the transformer from the PCB which "works fine" into the board which is not working as well. Does the behavior reverse?It's good practice to match the distance of the PCB paths as much as possible, but I think the contribution of PCB trace mismatch is probably small in relation to the leakage inductances looking into the secondary windings. Depends on the transformer. If you measure 100's of nH looking into the secondary winding, then a few 10's of nH mismatch due to PCB is probably not a huge deal.

author: iliya31
author_rank: Newbie
timestamp: February 27, 2024, 06:32:32 am
content: I measured the leakage difference before solder it. difference was 3% ( 33uH and 34uH ). About the secondary leakage yes if it is only 10nH the reflected one will be n^2*Ln which is 2560nH and that adds huge difference.So I am wondering if I have to to take considerations on the layout source - capacitor path.

author: temperance
author_rank: Super Contributor
timestamp: February 27, 2024, 10:24:29 pm
content: Did you measure the current in both synchronous rectifiers?
LLC400W With LCS708 - Page 1
Forum section: electronics / projects

author: mirbagheri1122
author_rank: Contributor
timestamp: June 11, 2015, 09:24:35 am
content: HiI have builded a llc400w with lcs708.my primary current waveform is pure sinosuid in full load in advance but after 10 seccond my waveformconfront with distortion.THANKS

author: mirbagheri1122
author_rank: Contributor
timestamp: June 11, 2015, 09:29:12 am
content: Because of my low leakage transformer i had added a 20 uH self to my trans as Lleakage and ifound this distortion is because of overheating of my self core and decreasing permiability in hot temperatureand i added a fan and my problem of distortion is solved.my self is wounded based on pixls.please guide me in selecting a core with low core loss.in my circuit that i explained my switching frequency is 250khz,my bac is 144 mtand my wire is litz but my circuit had problem of transformer heathening and thus increasing frequency,my core was pq40/40 pc40 from chineese tydz.i changed my core with 47mm mpp toroid with no problem of heating but frequency increased againfrom 250 to 350 and suddenly my ic blowed.maybe reason of ic blowing is power train invertion,i cantunderstand.THANKS
lm-723 opamp addon - Page 1
Forum section: electronics / projects

author: p.larner
author_rank: Frequent Contributor
timestamp: March 20, 2024, 11:45:58 am
content: has anyone a link to a 723 bassed lab psu opamp addon schematic, for better cc mode operation?.

author: Terry Bites
author_rank: Super Contributor
timestamp: March 20, 2024, 02:28:45 pm
content: The Vbe based limit isnt so great. I'd be thinking along the lines of the attached.Current sense amps are cheap. eg INAx180You don't have to use the 723's ref for the comparator. This may be set with an external source like a pwm GPIO.

author: Zero999
author_rank: Super Contributor
timestamp: March 20, 2024, 10:35:02 pm
content: The 723's current limit is very rough. Another amplifier is required.Here's the circuit discussed in theother thread, with a separate current limit amplifier added. The U2 limits the voltage across R10 to V3*R8/R7. R9 = R7 and R10 = R8. R11 is just a test load for the purpose of the simulation. I've kept the original current limit, which is much faster than U2.This is just a DC simulation. Capacitors will need to be added for stability. Refer to the 723 data sheet.
LM1084 - help how to test - Page 1
Forum section: electronics / projects

author: Nexxen
author_rank: Regular Contributor
timestamp: March 09, 2024, 04:53:57 pm
content: Hello people!!I have a HB1084 5C,Vin is +5VVout is 0.27VAdj is 0.11VBeing a very simple circuit it looks to me that it is malfunctioning. After some research I found it is a LM1084.Looking at the LM1084 typical application,https://www.ti.com/lit/ds/symlink/lm1084.pdfthe circuit on the motherboard it is soldered to is exactly that.I think it's the ADJustable variant.If everything is correct, are these the same as the ADJ variant,- LM1084IT-ADJ- LM1084-ADJMaybe it's just a nomnclature thing but I prefer to have an expert opinon on this.To test the old one, can I attach a +5V battery and make it loop, soldering a diode to Vout? (no, I'm just guessing how to and probably wrong)Thanks a lot in advance!!

author: moffy
author_rank: Super Contributor
timestamp: March 09, 2024, 05:21:48 pm
content: Quote from: Nexxen on March 09, 2024, 04:53:57 pmThe LM1084IT-ADJ provides ordering info about the package the 'T' refers to the TO-220 package and I think the 'I' refers to industrial temperature range and the 'ADJ' means adjustable.see 'Adendum Page 1' of:https://www.ti.com/lit/ds/symlink/lm1084.pdffor the ordering alternatives and meanings.

author: Nexxen
author_rank: Regular Contributor
timestamp: March 09, 2024, 05:26:25 pm
content: Didn't venture that far. First problem is solved.
LM135/235/335 temperature range - Page 1
Forum section: electronics / projects

author: MikeK
author_rank: Super Contributor
timestamp: October 08, 2022, 02:08:59 am
content: According to the datasheet, the LM135 has continuous use to 150C, the LM235 to 125C and the LM335 to 100C. But they all are available in a TO-92 packet, which has a storage temp good to 150C. So...What happens to the LM335 above 100C? It just won't produce an accurate output? Or damage occurs? Why does the LM335 only allow intermittent use to 125C, but can be stored at 150C?

author: moffy
author_rank: Super Contributor
timestamp: October 08, 2022, 04:02:52 am
content: Ah, that goes back to the days when National Semi was still around and you had mil spec devices. As National acknowledged, the chips going into the 1/2/3 ranges were all the same the only difference might have been the level of testing. Pretty sure the 150C rated devices for use would have needed the metal case, milspec which is what the 1 series was about didn't like plastic cases much in the 80's because of temp and possible outgassing at high altitudes. It was all ceramic or metal casings for semis. The 1 was for military, 2 for industrial and 3 for comercial but you probably already knew that.

author: MikeK
author_rank: Super Contributor
timestamp: October 08, 2022, 12:17:24 pm
content: Thanks.
LM136 adjustment - Page 1
Forum section: electronics / projects

author: con-f-use
author_rank: Unknown
timestamp: August 08, 2014, 12:04:27 pm
content: So I'm a bit confused by the data sheet of the lm136 2.5V voltage reference. Never used that before. You can trim the lm136 for low temperature coefficient (picture 1 with the two diodes) or precise breakdown voltage (picture 2).For low tempco it says to trim to 2.490V.1.) I'm assuming the 2.490V are between ground and the node right at R_s, right? But than it's not a 2.5V reference anymore, rather a 2.49V one. Did I get something wrong?2.) Can I adjust both the tempco and the breakdown voltage somehow? I imagine not.

author: void_error
author_rank: Frequent Contributor
timestamp: August 08, 2014, 12:55:26 pm
content: Quote from: con-f-use on August 08, 2014, 12:04:27 pm1. As far as I understand the pot is only for calibration. The nominal voltage is 2.49V as sstated under Electrical Characteristics.http://www.ti.com/lit/ds/symlink/lm136-2.5-n.pdf2. You are correct. Temperature coefficient adjustment relies on the diode's -2mV/C temperature coefficient.
LM13700 outputs DC only With an AC input - Page 1
Forum section: electronics / projects

author: Scr1bbl3
author_rank: Contributor
timestamp: April 27, 2021, 01:40:32 am
content: Hello all,I built the circuit below (crude and not to scale as Dave says) from some reclaimed LM13700s but wanted to test the ICs. My AC input is 2VPP at 1KHz. The divider brings the signal down to about 60mVpp. I can vary Iabc from 0mA to 1mA (now set to 500uA) Idiode is 1mA. Power is correctly measured on pin 6 and 11. Problem is, all I get is a varying DC output, up to 10V, can't recall the negative value - and no amplified AC signal. Anyways, someone see a problem?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 27, 2021, 07:14:15 am
content: Circuit seems alright... tried the other side? Any others work?Can also probe it in parts, i.e. diode-check the diodes, Iabc to V- should also look like a diode, can measure the output current directly (DMM on current range), can disconnect the buffer (it is literally just the Darlington emitter follower it shows) and diode-check that, or test it with a separate signal and whatever.No idea what likely damage is, if ESD or overvoltage say, it might have any number of shorted or burned up transistorbits inside that cause partial or complete malfunction. Check supply current as well, it should be very low and essentially proportional to Iabc plus buffer pulldown current.Tim

author: Scr1bbl3
author_rank: Contributor
timestamp: April 27, 2021, 08:37:35 pm
content: Hi, Yep, tried the other side and both sides of another chip. Gremlins!!!!I haven't tried checking the diode. I'll do that next. Thanks for the feedback,

author: Andy Watson
author_rank: Super Contributor
timestamp: April 27, 2021, 08:57:15 pm
content: You have a diode bias current of 1mA . This current must go somewhere! I suspect that it is going into the two 10k resistors to ground on your input and swamping the real signal. So what you are seeing is a differential amplifier that is saturated and the output current is simply a function of Ibias. Try disconnecting the diode bias - it's only there to improve linearity.Also, be careful with the Ibias pin. The current into this pin is mirrored through the whole chip - any excursion, no matter how brief, beyond the limit specified in the datasheet, will destroy the chip (don't ask how I know this)