hybridfree/eevblog-posts huggingface dataset:
SMPS circuit with oscillation in output current.....or is it? - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: March 11, 2020, 09:27:34 pm
content: Hello,The attached SMPS circuit is showing an oscillation in the output current. That is, the output current as seen at the output of an ACS722 current sensor, as in the attached.Vin = 30v, vout=48v, iout = 3.2A (Av)However, I suspect the problem is with the ACS722 current monitor itself.The ACS722 is setup for 20kHz bandwidth.I see no oscillation on Vout of the DCDC module.The oscillation (at the ACS722 Hall sensor output) is around 80kHz……and is about 0.8Apkpk.The oscillation at the signal output of the ACS722 Hall sensor gets twice the magnitude when I connect the Hall sensor for 80khz bandwidth, instead of 20khz.There is no oscillation when i disable the dcdc module and shove 3.2A through the Hall sensor with a lab power supply.ACS722 current monitor (10A, unidirectional)https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=2ahUKEwjk34LdrJPoAhWKYsAKHWONCYAQFjABegQIAxAB&url=https%3A%2F%2Fwww.allegromicro.com%2F~%2Fmedia%2FFiles%2FDatasheets%2FACS722-Datasheet.ashx&usg=AOvVaw3JPQuBETUeMAFE0wXfP4gr

author: ocset
author_rank: Super Contributor
timestamp: March 12, 2020, 08:25:50 pm
content: Ive a terrible feeling that since the ACS722 is a Hall sensor, it relies on having a precise magnetic field inside it…and very possibly, with the sensor being just 1cm away from a powerful DCDC module (as shown attached) , the magnetic field inside the ACS722 Hall sensor chip is getting disturbed….producing the oscillation. Would you agree?We wanted to use the Hall sensor because it is isolated…..and the control ground , where the current measurement will be used, is not the same ground as the output ground of the DCDC module….so an isolated Hall sensor seemed like the best choice…no I don’t believe it is.BTW the oscillation is 80kHz.Do you agree we will have to shield the Hall sensor from the DCDC module?..ie, with some metal strip
Input filter for Fast transient response SMPS can mess it up - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: February 29, 2020, 12:02:51 pm
content: HiI have deliberately designed an SMPS module test board with the wrong input filter, will it be OK?.....We are using the DCM36623T50M53C2T00 DCDC module from Vicor.Page 21 of its datasheet says that the downstream part of the input filter should be 20uF of ceramic capacitance....We agree that ceramic SMD capacitance is needed because otherwise there may be instability when the load has heavy transient behaviour. So the filter will need to comprise 20 pieces of 2.2uF ,1210,100V,X7R Flexiterm ceramic capcaitors. (since the Vin is 33 to 43v).However, in the first instance, we are just doing a test board, (as in the attached schem), and since the test board is likely to get bent and bashed about, we don’t want 1210 ceramic caps on it, which may break.Therefore, for the test board, we have used a parallel combination of 5 pieces of 1uF, 0805,100V,X7R capacitors, in parallel with 5 pieces of radial ceramic capacitors, in parallel with one 10uF,100V radial film capacitor……..this doesn’t quite add up to 20uF…..however, its cheaper than 20 Flexiterm caps, and more resilient to capacitor cracking………also, since the test board is simply to proove that our external error amplifier correctly clamps the output current to 6.5A, we believe this “alternative” input capacitor bank, will be satisfactory for use.Would you agree, that since our testing will not involve load transients, we will be ok not using the 20uF of SMD ceramic capacitance? (which the datasheet asks for on pg 21)The Vicor “DCM design guide”, on page 23, actually calls for the input ceramic capacitor bank to have an SRF higher than the DCDC module switching frequency (1MHz)……so we have violated this, but again, since our test will not involve load transients, can you confirm that our alternative input filter (as in the attached schem), will be fine?DCM36623T50M53C2T00 datasheet:http://www.vicorpower.com/documents/datasheets/DCM3623x50M53C2yzz_ds.pdf...................................*...............................................................*...............................................................*............................Basically i'd just like to confirm that, although this SMPS module is super fast with a 20kHz crossover frequency, and a 1MHz switching frequency, it won't see problems when on constant load? (ie, not a transient load).I mean , clearly, i have used an in-appropriate input filter....i did so for reasons of making a test-board more highly robust, and also for cost reasons.

author: Zero999
author_rank: Super Contributor
timestamp: March 02, 2020, 08:09:48 pm
content: Well don't complain, if it doesn't meet its specifications, if you've not followed the design guidelines on the data sheet.20µF does sound like an insane amount of capacitance. Beware that ceramic capacitors saturate, at higher voltages.
Solid State Batteries - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: February 15, 2020, 02:07:38 am
content: TLDR; Solid state batteries are at least 5-10 years away.

author: FreezeSSC
author_rank: Contributor
timestamp: March 02, 2020, 06:22:27 pm
content: I'm hoping it's more 5 then 10, Goodenoughs plan to not exclusively liscense means there will hopefully be multiple companies racing to get to manufacturing first.

author: MLXXXp
author_rank: Frequent Contributor
timestamp: March 02, 2020, 07:11:53 pm
content: Quote from: FreezeSSC on March 02, 2020, 06:22:27 pm5 then 10 would make it 15.
INVERTER via sine wave -> opamp or transformer?  - Page 1
Forum section: electronics / general

author: mikeinfodoc
author_rank: Regular Contributor
timestamp: February 29, 2020, 06:12:03 pm
content: I want to create a simple inverter circuit which will run small A/C appliances (such as A/C fan) from 12v or 24v batteriesHas anyone successfully engineered a near-sine wave inverter circuitwhich is driven by a small sine wave generator chip(something like this or similarhttp://www.ti.com/lit/wp/snoa839/snoa839.pdf)which goes into an opamp (or transformer) to step up to "mains" power levels?

author: james_s
author_rank: Super Contributor
timestamp: February 29, 2020, 06:58:51 pm
content: I have an AC power source that works like that, it's very inefficient though, drawing 2kW from the wall to supply 500VA to the load, with a noisy fan that blasts out hot air. It's essentially a sine wave oscillator driving a power amplifier that feeds a transformer.Sine wave inverters typically use high frequency PWM to create the waveform. Most cheaper inverters produce a "modified sine" wave which is essentially a square wave with dead time or in some cases a stepped wave that looks like a very pixelated sine wave.

author: ocset
author_rank: Super Contributor
timestamp: February 29, 2020, 07:32:54 pm
content: i assume you are in USA...You need to boost up your 24vdc to 200vdc...then feed this to an H bridge.....which its probz best to control with a sine wave inverter IC...which which will switch the h bridge transistors with a pwm that will give you your sine wave output.By the way, you need to make the 200v isolated from the 24v...so use eg a bridge type or forward type smps...or a flyback if lower power.(EDIT...oops, you are not doing grid tied, so actually you dont necessarily need the isolation)you are not asking for grid-tied operation, so it should be much easier for you.........and indeed, you therefore dont need to be exactly boosting up to mains peak or a little higher....you could be a little flexible.Good luck in finding a sine wave inverter IC that doesnt need you to program a micro...this one...http://www.ti.com/lit/an/slaa602a/slaa602a.pdf...needs you to program a micro.There are OTS sine wave inverter ICs that dont need you to do any programming, but i cant find one yet....i found ONE once...but cannot remember the website, Sorry.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 29, 2020, 08:17:48 pm
content: It's very easy to implement more or less all of the control logic in a microcontroller.

author: KaneTW
author_rank: Frequent Contributor
timestamp: February 29, 2020, 08:28:15 pm
content: Use subharmonic elimination PWM with a suitably high frequency so that the resultant LC filter is small enough and you're good.
Nomad Power System - Page 1
Forum section: electronics / general

author: margrove
author_rank: Newbie
timestamp: February 13, 2020, 12:11:03 am
content: Obviously a shameless moneymaking scam, but this guy has put a lot of effort into gleaning internetwide support giving apparent approval. Try finding an independent review!http://nomadpowerbook.com/The very brazenness deserves a scathing debunking.How about it, Dave?
Five OTS DCDC modules in parallel...best way to do it? - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: March 01, 2020, 02:58:16 pm
content: Hi,We wish to use five Vicor PRM* modules in parallel for an 800W power supply.Vout is 25V and Vin is 48V.The application has fierce no_load to full_load transients.Our contractor wishes to have one “master” PRM* module and 4 “slaves”. (all in parallel)He is worried that the MASTER will conduct too much current, since the PRM* datasheet states that output current can be anything from 8A to 12.5A…….we wish to limit current to 8A.Therefore, our contractor reasons that we can have an external current monitor feeding an error amplifier, which clamps the MASTERs current to 8A by pulling down the Master’s TRIM pin…….then , he reasons, the slaves will then also have their current output limited to 8A since they are connected to the masters SHARE pin.The thing is , for a start, page 30 of the PRM* datasheet states that the TRIM pin should not be used in an external feedback loop (albeit for unknown reasons).His method is certainly low on component count…though would we even need the current monitor/external error amplifier if the slaves are all guaranteed to mimick the masters current?PRM* module datasheet:http://www.vicorpower.com/documents/datasheets/PRM48AF480T400A00_ds.pdf

author: Zero999
author_rank: Super Contributor
timestamp: March 02, 2020, 08:15:21 pm
content: I agree, it does sound like a bad idea to use the TRIM pin in a feedback loop, because it could do just about anything.Quickly searching though the data sheet, it says up to five can be connected in parallel, in master slave, or ten in configuration. RTFDS and follow the guidelines it gives.

author: ocset
author_rank: Super Contributor
timestamp: March 04, 2020, 07:40:48 am
content: thanks, the Datasheet offers the two methods of paralleleing...one is by simply put in master/slave mode and hook their share pins together....the other involves having them in remote sense mode and having one external error amplifier and feeding it to all the PRMs control pins......we dont want to do these methods, since we want our PRMs to be individual units, not interconnected............for one thing, interconnection is problematic when common mode chokes are used...and when we later work towards greater numbers in parallel...having interconnections between PRMs becomes again an awkwardness........so we were thinking of hacking our own method...but yes , i think you are right trying to control a unit by the trim pin is not a good idea.........dont know why though....they do it with the "sister" DCM module and the TRIM pin appears to be just the same in DCM and PRM.

author: Zero999
author_rank: Super Contributor
timestamp: March 04, 2020, 10:38:33 am
content: Don't bother trying to hack it.Use ORing Schotky diodes or an ideal diode controller IC and MOSFETs, if volt drop is an issue. The LTC4357 is good because it has a built-in charge pump, so low on resistance N-channel devices can be used, but there are plenty of alternatives.http://www.farnell.com/datasheets/85443.pdf
12kW power supply using multiple Vicor modules (60 of them in series parallel!!) - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: February 11, 2020, 09:13:25 pm
content: Hi,We need 240Amps at 50V to feed to drone motors. (One overall power supply, we aren’t allowed a power supply for each drone motor)Do you believe the following method solves it with Vicor modules?....The power supply has 820VDCinLoad = 50V at 240Amps (12kW)There is a 320 Metre long cable between 820V source and load. (9.5 ohms go and return)We believe that there is a possible way that this can be done with Vicor modules….It involves one Vicor BCM4414xH0E5035yzz module feeding four paralleled Vicor DCM3623T50M53C2T00 modules……the output of the four than goes via a current monitor to the 240Amps bus…and 12 other lots of the above would also feed into the same bus.The schematic is as attached. (just shows one “group”, not all 12.)The current monitor output would be fed to an error amplifier, which would ensure that no group of four DCM modules fed more than 24 Amps of current into the common bus…….in this way we would get “droop” sharing, and no significant current hogging …the error amplifier would be fed, as in the schematic, to the TRIM pins of the DCM modulesWe think this overcomes any significant sharing problems.Can you see any Gremlins in this?DCM3623T50M53C2T00 datasheet:http://www.vicorpower.com/documents/datasheets/DCM3623x50M53C2yzz_ds.pdfBCM4414xH0E5035yzz datasheet:http://www.vicorpower.com/documents/datasheets/ds-BCM4414xH0E5035yzz-VICOR.pdf-----------------------------------------------------I must confess, I would really rather like to address this with eight paralleled, synchronous 1.5kW two transistor forward converters (Sic FETs throughout)….all being fed the output of a single external error amplifier, which would regulate the single Vout….but we are bound to Vicor, as its perceived to be quicker ,and more commonplace tech with a globally proven track record.
Using solar inverters to balance reactive power? - Page 1
Forum section: electronics / general

author: paulca
author_rank: Super Contributor
timestamp: February 11, 2020, 10:44:27 am
content: I don't think he is explaining it very well, but the technology seems to be legit... unsure.https://youtu.be/c_h05Mv3_x4?t=270

author: Styno
author_rank: Regular Contributor
timestamp: February 11, 2020, 02:06:39 pm
content: This is indeed established technology.SMA, the Solar inverter company from Germany, has it for many years:https://www.sma.de/en/partners/knowledgebase/sma-shifts-the-phase.htmlhttps://files.sma.de/dl/18858/Q-at-Night-TI-en-12.pdfAnd there are academic publications available as well:https://www.researchgate.net/publication/224233990_Analysis_and_control_of_PV_inverters_operating_in_VAR_mode_at_night(PDF)https://www.osti.gov/etdeweb/servlets/purl/21438149https://res.mdpi.com/d_attachment/energies/energies-10-00912/article_deploy/energies-10-00912.pdfetc.

author: ejeffrey
author_rank: Super Contributor
timestamp: February 11, 2020, 05:23:53 pm
content: I didn't watch the video but the claim is certainly reasonable.Balancing reactive power requires energy storage for a fraction of a cycle. Grid tied inverters already have those capacitors and all the necessary power electronics available for daytime use. There is no reason they can't be used at night for active power factor correction. 3 phase inverters should also be able to cross-feed between phases to provide phase imbalance correction.
Are modern solar panels affected by potential induced degradation? - Page 1
Forum section: electronics / general

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 18, 2020, 11:38:18 pm
content: https://en.wikipedia.org/wiki/Potential-induced_degradationAre modern solar panels affected by it or have manufacturers taken measures to mitigate it?Assuming they are, is the circuit to solve it as simple as biasing them to the opposite voltage at night? Also, it seems to be most pronounced in a large system operating at 1kV, would it even be significant in the system I'm designing that would have the negative side at about 200-300V below ground?

author: bdunham7
author_rank: Super Contributor
timestamp: February 08, 2020, 03:58:55 pm
content: As you haven't received replies from any experts more qualified than me, I'll give you my 2 cents...1) PID, from what I know, would be much worse at 1000 volts than at 200 volts. I can't give you any numbers or citations, just what I remember, although I'm not sure how carefully this has been studied, at least as far as cataloging the effects by panel model and potential.2) At least one manufacturer claims that their panels are "certified PID free"https://www.yourenergysolutions.com/solar/panels/solarworld/I have no practical experience because I avoided the whole issue by using microinverters.

author: nctnico
author_rank: Super Contributor
timestamp: February 10, 2020, 09:56:47 pm
content: I did some reading into this subject when looking into solar panels a couple of months ago. IIRC everything should be OK up to around 400 Volts. IMHO it is better to use multiple strings each with their own MPPT to get optimal performance anyway so the issue is kinda moot. Many cheap inverters on the market have multiple MPPTs.
Anti-solar PV panels that work at night - Page 1
Forum section: electronics / general

author: gmb42
author_rank: Frequent Contributor
timestamp: February 09, 2020, 02:51:14 pm
content: https://www.ucdavis.edu/news/anti-solar-cells-photovoltaic-cell-works-nightApparently just theoretical at the moment, although they say they are developing prototypes.

author: coppice
author_rank: Super Contributor
timestamp: February 09, 2020, 03:02:41 pm
content: The idea looks OK. Its just the misleading title that makes it sound stupid. The title includes the word "photo" but the article is talking about energy at thermal frequencies. All they are really talking about is generating at night, from energy stored during the heat of the day, by radiating that energy to the environment.

author: Styno
author_rank: Regular Contributor
timestamp: February 09, 2020, 05:37:49 pm
content: -deleted-
DIY zinc bromine batteries from scratch - Page 1
Forum section: electronics / general

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 13, 2020, 03:51:46 am
content: I'm not convinced it's a viable route to home energy storage yet, but maybe it just needs some development to make it practical.

author: george.b
author_rank: Frequent Contributor
timestamp: January 13, 2020, 04:45:17 am
content: I saw that on my YouTube feed last night. Quoth Wikipedia:QuoteI wonder what the implications are for his battery for purposes other than demonstration. Also, I don't know much about flow batteries, but shouldn't the electrolyte be pumped around for it to be useful?

author: JamesPatterson
author_rank: Newbie
timestamp: February 09, 2020, 01:51:41 pm
content: Something seems off, honestly.
Coin cell Battery Voltage dropping immediately - Page 1
Forum section: electronics / general

author: LakshmiN
author_rank: Contributor
timestamp: February 06, 2020, 09:13:54 am
content: Hello,In my project I use CR2477 Coin type lithium batteries (CR series).https://industrial.panasonic.com/ww/products/batteries/primary-batteries/lithium-batteries/coin-type-lithium-batteries-cr-series/CR2477Current consumption is around 100mA.(controller+GPS+sensor etc).when I power on the GPS (at which current consumption is around 100mA(continuous)) Battery Voltage drops instantly within 5-8 seconds it reaches 1.8V and shuts off.Power circuit:- Battery-Fuel Gauge-Buck-Boost regulator (TPS63806-3.3V)-controller(max of 5mA).I understand battery is not able to provide that much of current but CR2477 is 1000mAh,I do not know whether it's bad one or using coin cell for this application is bad idea?Thanks.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: February 06, 2020, 11:38:54 am
content: You're spot on: those cells aren't designed for high power output. The cheap no-name ones in particular have high internal resistance, so the voltage quickly falls, especially once they get hot from overload.Another problem is their voltage is too low to begin with, so you lose efficiency in the boost converter, which quickly becomes even less efficient as the input voltage collapses.Three alkaline AAAs are notmuchbigger but will work far better for a high-current application (Ikea's are good and cheap, ₹15 each... but the nearest Ikea is in Hyderabad). If you really need something tiny, consider an appropriately sized Li-ion. Either way you won't need to boost the voltage. If your load is peaky, add a 33 uF ceramic bulk decoupling cap in parallel with the battery.Also see if you can get the current consumption down. GPS will use about 50 mA but other sensors and the microcontroller should be far more efficient.

author: Ian.M
author_rank: Super Contributor
timestamp: February 06, 2020, 12:00:38 pm
content: At *best* you'll get about 25mA for 15 seconds with the voltage dropping to around 2.5V from a fresh CR2077. See this Murata datasheet that has pulsed discharge curves for their version of this cell:https://www.murata.com/en-eu/api/pdfdownloadapi?cate=cgsubMicroBatteries&partno=CR2477
What is this part? Meanwell LRS-150 - Page 1
Forum section: electronics / general

author: aramosfet
author_rank: Contributor
timestamp: March 12, 2020, 12:24:57 pm
content: HiI build a compact PC case powered by a Meanwell LRS-150-12 PSU. But I noticed arcs being generated when I plugin the PSU due to switch bounce on the AC power switch.The arcs are generated specifically from a part marked D1 next to the common mode choke. There are no arc when the supply is operating. Only when plugging in at times. Is this normal?https://photos.app.goo.gl/f94mr1KzTheTLeXZ6

author: TERRA Operative
author_rank: Super Contributor
timestamp: March 12, 2020, 03:27:47 pm
content: Judging by the suppression caps etc nearby, it looks to be maybe a glass encased transient spark gap.For example the SCD-181n spark gap protector.https://www.alldatasheet.com/datasheet-pdf/pdf/580687/SOCAY/SCD-181N.html

author: k8byp
author_rank: Newbie
timestamp: March 13, 2020, 05:05:49 pm
content: Its a DIODE. Did you not see "D1" printed on teh board?Please.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 13, 2020, 11:51:51 pm
content: It's a GDT, but I'm not sure why it would spark when plugging in the supply. Perhaps the high frequency from the high dV/dt triggers it like a xenon flashbulb?

author: aramosfet
author_rank: Contributor
timestamp: March 14, 2020, 06:32:01 am
content: here's a closer picture of the part. I was not able to find any marking on it. Its is connected directly across the line winding of the common mode choke. There also a PCB spark gap parallel to it.
Cut 12 Volts from inverter remotely or automatically  - Page 1
Forum section: electronics / general

author: davelectronic
author_rank: Frequent Contributor
timestamp: January 11, 2020, 02:56:18 am
content: Recently I've had to use an inverter to charge a mobility scooter from a large capacity leisure battery. It's going ok from a charge point of view, but the storage battery recharge regime is a bit trying at times.What I'm needing to do is remove of disconnect the 12 volt battery input to the inverter. If I can't get there to manually disconnect it, I've noticed it can drop the battery terminal voltage more than if disconnecting after charge cycle. The out put to the scooter charger is controlled with a simple plug in 13 amp mains timer. I get 3 hours charge time, which isn't fantastic but it's better than nothing at all.The inverter input has upwards of 72 Amp power leads and crocodile clips. Is there a way to interface such large cables with some kind of 12 volt timer ? All I'm looking to do is disconnect the battery from the inverter, and preserve battery terminal voltage if I can not get to the inverter to remove the leads manually.Thanks for reading, thoughts appreciated.

author: SeanB
author_rank: Super Contributor
timestamp: January 11, 2020, 09:43:04 am
content: You get battery disconnectors from RV dealerships, that are designed to disconnect the RV battery from the load if the battery voltage drops too low, saving the battery. they typically use a voltage comparator that will drive a coil that trips off the breaker that supplies power to the output, so you have a push to reset button to latch the output on, and it will trip when the battery goes low.Easy enough to connect inline, and then you leave it either as designed, to prevent the battery being damaged, or modify it with an extra timer to rip the internal coil.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 11, 2020, 02:05:21 pm
content: Open the inverter and wire to the switch, which only has to switch the logic power.

author: davelectronic
author_rank: Frequent Contributor
timestamp: January 12, 2020, 04:51:44 am
content: Thanks for the replys. I will look at both ideas, just for ease of use, breaking into the front panel power switch sounds the way I might go. I will be dead before worrying about any warranty lol.It's just to cut that idle power the inverter consumes, less than 1 Amp according to the user manual. I should measure it really. If I was AWOL from the inverter for upwards of a day (possible) Its might drop the battery terminal voltage to low. I know the inverter sounds an alarm and led for low voltage, but 10 Volts for a terminal voltage can't be much good for the battery.
Do high quality, high efficiency portable solar panels exist? - Page 1
Forum section: electronics / general

author: rthorntn
author_rank: Frequent Contributor
timestamp: January 08, 2020, 03:03:02 am
content: Hi,Do high quality, high efficiency portable (foldable) solar panels exist?There seems like a lot of junk out there.I would rather not pay the earth though considering you can get a great 325W roof panel for a $300 AUD for something portable with half the power I would be wanting to keep the cost under $400 AUD.Thanks.Richard

author: mikeinfodoc
author_rank: Regular Contributor
timestamp: January 12, 2020, 09:42:58 pm
content: I bought and used this one last year during my son's scout summer camphttps://www.amazon.com/dp/B0748FYFSK/ref=cm_sw_r_em_apa_i_HFj8CbY61GBBFit worked quite wellI basically created a pneumatic wheeled "wagon" upon which I mounted the included solar controllerand small mower battery, and then I found sunny placesand had batter powered lighting at nightand phone charging, etcit is a bit flimsy, but if you are careful with it, it will last
Flyback Quasi Resonant Switching Frequency & Transformer Behaviour - Page 1
Forum section: electronics / general

author: deeplutan
author_rank: Newbie
timestamp: February 07, 2020, 05:18:18 pm
content: Hi all,As I know, the major difference between normal flyback converter & flyback quasi resonant converter is for flyback quasi resonant converter, the switching frequency is variable. This means that the switching frequency is based on the output load. When the load decrease, the switching frequency will increase, and when the load is increase, the switching frequency will decrease.My question as below:1. Since the switching frequency is always changing, how do I select the switching frequency as my initial value to start the transformer design?2. Since the switching frequency is always changing, how do I know that my transformer is capable for that switching frequency range. Let say I choose a transformer A with value of 300uH @ 55kHz, and my switching frequency for quasi resonant converter is range from 35kHz to 130kHz. Will this transformer A is capable for that frequency range? As I know, as the frequency increase, the inductance will be smaller & as the frequency decrease, the inductance will be bigger. Is it means that at lower frequency, this transformer A (300uH,55kHz) will change its inductance value at lower frequency(suddenly will increase inductance) & high frequency(suddenly will decrease inductance)? Or this transformer A will have fix inductance value of 300uH at all frequency?Thanks
Full time power for Hess Truck display case. - Page 1
Forum section: electronics / general

author: Skylimit
author_rank: Newbie
timestamp: January 06, 2020, 12:44:06 pm
content: Hello I am looking for advice on how to have constant power to a battery powered Hess Truck. I was asked to make a display case for a collection of Hess Trucks and to provide power on a switch to turn the trucks on when desired in their display case. I have little to no experience with this type of electrical work and wonder if it is even possible. Thanks ahead of time for any advice you can give.
Solar panel powered car ? WTF ? Or am I just reading it wrong ? - Page 1
Forum section: electronics / general

author: Saskia
author_rank: Super Contributor
timestamp: December 31, 2019, 07:34:36 pm
content: https://www.heise.de/newsticker/meldung/E-Auto-mit-Solarmodulen-Sion-Sono-Motors-verfehlt-Crowdfunding-Ziel-4624993.htmlCrowdfunding for a solar panel car missed crowdfunding objective of 50 million euros ?Is this plain nuts or am I just reading it wrong ?

author: tautech
author_rank: Super Contributor
timestamp: January 02, 2020, 06:23:54 am
content: We had some discussion on the subject of PV’s on EV’s a few months back;https://www.eevblog.com/forum/renewable-energy/solar-pv-on-electric-cars

author: digsys
author_rank: Unknown
timestamp: January 02, 2020, 07:44:44 am
content: Yes, this subject has been beaten to death. Summary - If you check -https://www.worldsolarchallenge.org/event-information/teams... you will notice "we" have been building solar powered cars for over 30 yrs. The last 8+ years we introduced a "Cruiser class" = road-legal-capable... up until then, we had pushed technology as far as it could go (for the time) - with ~ 600Km on 6sq mtrs panel, and ~600Km on 5KWHr battery packIn the Darwin-Adelaide challenge, cars are to achieve ~ 1,000 - 1,200Km a day with a recharge. Achieved by dozens of teams over the years.So, it was not a road practical car (even though they had to pass crash / structure failure tests etc), is why we started on Cruiser class.Some of the entries are starting to look quite nice, and YES, we have a way to go, but IT'S A START. AT least someone is investing time + in the venture.A couple of teams have already released a production car (short run). eghttps://lightyear.oneYES, they only have realistically 10-25Km range, but IT'S A START ! Everything starts somewhere. Our current design in progress, we hope to get ~250Km solar and ~250Km on a 20KWHr battery. As panel technology improves, it will get better. AT least we have a base.

author: nctnico
author_rank: Super Contributor
timestamp: January 02, 2020, 10:56:15 am
content: Quote from: blueskull on January 02, 2020, 06:37:53 amThat is rather optimistic but still I agree that having a solar panel on a roof of a car (EV, fuelcell or hybrid) can have a positive ROI. And it could mean no charging is needed if the car is used occasionally or for very small distances. But in the latter case you should ask yourself if you aren't better off with an (electric) bicycle or motor bike.
Charging time of recharge-able battery (TR 18650 8000mAh 3.7V) - Page 1
Forum section: electronics / general

author: promach
author_rank: Frequent Contributor
timestamp: November 17, 2019, 12:59:59 pm
content: How many hours should I charge this recharge-able battery (TR 18650 8000mAh 3.7V) ?Too long: battery might overload.Too short: battery not fully chargedLet's say the charger converts 5V input source to 3.7V internally.Anyone have any idea how to calculate the charging time based on this specific battery below ?

author: wraper
author_rank: Unknown
timestamp: November 17, 2019, 01:19:28 pm
content: You cannot charge Li-ion like that, it's not nearly forgiving as NiMH or NiCd. Charge status must be controlled and current set accordingly, then completely cut off. Never try to charge lithium batteries with anything but specialized chargers. Also those batteries are fake junk. You will be lucky if they have even 800 mAh capacity. More likely to be something around 400 mAh. FYI 18650 batteries with capacity larger than 3500 mAh do not exist.

author: mariush
author_rank: Super Contributor
timestamp: November 17, 2019, 02:12:09 pm
content: You need to charge them with a battery charger IC.Here's an example, MCP73831-2 :https://www.digikey.com/product-detail/en/microchip-technology/MCP73831T-2ATI-OT/MCP73831T-2ATI-OTCT-ND/19798036-7$ evaluation boarda (everything ready to use, just connect battery to charge) :https://www.digikey.com/product-detail/en/adafruit-industries-llc/1904/1528-1833-ND/5054545https://www.digikey.com/product-detail/en/adafruit-industries-llc/1304/1528-1865-ND/6618716Stupid easy to use, requires only a resistor and a couple of ceramic capacitors. Optionally, you can add a led and a resistor to get some charge status.

author: m3vuv
author_rank: Super Contributor
timestamp: December 02, 2019, 03:35:09 am
content: think you wont find it an issue as id say %100 these are fake chinese more like 1.5mah!

author: Siwastaja
author_rank: Super Contributor
timestamp: December 21, 2019, 04:50:39 pm
content: Do not use such UltraFire cells at all. They are likely dangerous, and can be anything. Best case, it's a usable 2000-ish mAh cell. Worst case, it blows up. Middle case, it's filled with sand or flour and contains a very small battery of a few mAh.Unprotected 18650 cells are not supposed to be handled or used as consumer products. They are supposed to be bough by professional manufacturers and integrated into products with proper spot welding, and with proper circuitry.
Battery powered power supply for Audio application - Page 1
Forum section: electronics / general

author: XavierM
author_rank: Newbie
timestamp: December 23, 2019, 03:07:09 pm
content: Hello everyone !I'm new here and seeking for help cause I'm at a point with my project where I see many roads but don't know which one to pick !I'm working on a portable audio preamp and I want it to be powered with one or two 18560 batteries.I already tried having multiple switching regulators (MC34063) in parallel only to see how much noise it would generate. Finally, I managed with one MC34063 and a splitting rail to obtain decent +10V/-10V with a relatively small form factor (50V capacitor becomes huge at large capacity !). I also tried a SIM2 SIL7 2W DC converter which, with a bit of filtering, gives a +/-15V with only about 15mVpp of ripple.But now I'm stuck cause I need to have phantom power. What should I do ?-> add a switching regulator on the +15V rail ? but how to avoid crazy ripple noise ?-> Create a flyback with 3 outputs (-/+15V and 48V) : but can one easily make the coil for that ?What I am missing ?Thanks so much in advance for your help !

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 24, 2019, 03:42:31 am
content: Go with a more modern switching regulator, specifically the kind optimized for low noise. The MC34063 is a really primitive design.
Need to buy off-the-shelf power supply of certain spec. - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: November 02, 2019, 11:27:33 am
content: HelloWe need an offtheshelf offline PSU.The spec is as follows…--------------------------------200 to 400w output (anywhere in that range)VAC input = 100-265VACVout = either 12V or 15V or 24VNo FanMetal casing so it can be screwed to a metal enclosure for thermal management.Fully enclosed , but only to IP51 rating.Dimensions is open-----------------------------------------It is not possible to sort power supplies on this basis, either direct from manufacturers sites such as meanwell, or from digikey.Do you know how I can find such power supplies?We found the meanwell HEP-240 after much searching, but that is only one...we need to cost-compare manyhttps://www.meanwell.com/webapp/product/search.aspx?prod=HEP-240

author: beanflying
author_rank: Super Contributor
timestamp: November 02, 2019, 11:56:59 am
content: Seriously you need to stop USING the members here to run your 'business' and 'professional' needs. Pay acompetentperson some real money and stop sponging on the members for a handout because you have NFI or are to lazy to do the work

author: ahbushnell
author_rank: Frequent Contributor
timestamp: November 02, 2019, 09:18:23 pm
content: Quote from: treez on November 02, 2019, 11:27:33 amGood job. Try using the internet and search some more.

author: dmills
author_rank: Super Contributor
timestamp: November 02, 2019, 11:25:00 pm
content: Am I missing something or is that about the most jellybean switcher out there?

author: nctnico
author_rank: Super Contributor
timestamp: November 03, 2019, 02:26:40 am
content: Quote from: dmills on November 02, 2019, 11:25:00 pmAnd very easy to find. Maybe Treez' keyboard is rotated 180 degrees today.

author: Simon
author_rank: Unknown
timestamp: December 14, 2019, 11:00:29 pm
content: any distributors parametric search will allow you to find power supplies in a certain range of power outputs and many other characteristics including manufacturer.

author: fourtytwo42
author_rank: Super Contributor
timestamp: December 15, 2019, 06:10:31 pm
content: Quote from: beanflying on November 02, 2019, 11:56:59 amWhat makes me laugh is he thanks peeps who actively criticise his posts
Synchronous two transistor forward controller allows too high reverse current - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: December 15, 2019, 12:13:14 am
content: ..Thought this might actually be informative for others too..Hi,The attached is a picture of the inductor current in a synchronous two transistor forward converter just after going from full load to no load. (its an LTspice sim)As you can see the inductor current suddenly reverses to a badly high level due to the fact that the LT1681 has “malfunctioned”….the LT1681 holds the “catch” synchronous rectifier ON for far too long.If the Vout had been higher, then this inductor current reversal would have been even worse, if not catastrophic.The LT1681 is a $6 chip and for that price its amazing to see poor performance like this.Do you know of other synchronous rectifier control chips which don’t allow this behaviour?Attached is the LTspice schematic and the LTspice simulation of this part.If we were to use this part in real life, we would have to buffer the SG output of the LT1681, (and add other circuitry) then take the buffered SG output high if it went low for more than one switching period.LTC1698https://www.analog.com/media/en/technical-documentation/data-sheets/1698f.pdfLT1681https://www.analog.com/media/en/technical-documentation/data-sheets/1681f.pdf

author: MagicSmoker
author_rank: Super Contributor
timestamp: December 15, 2019, 02:22:36 pm
content: It looks like the LT1698 is to blame here, because the CG output on the LTC1698 seems to be following the SG output on the LT1681 up until charge needs to be sucked out of C5, at which point the SG output is low for several switching cycles while the CG output goes high.However, the Isns input on the LTC1698 isn't being used so that might be the problem right there.EDIT - if you think the price of the LT1681 is bad then don't look at the LTC1698... together you're talking $20 worth of chips right there...
Trailer breakaway battery charging - Page 1
Forum section: electronics / general

author: Grant
author_rank: Newbie
timestamp: December 11, 2019, 12:10:26 am
content: I have a trailer that has electronic brakes, the system uses a 12v Sla battery as a safety to activate the brakes if the trailer becomes detached from the car.The brake controller is a portable unit and is plugged into the 12v plug in the cab of the car and works quite well, the only issue is it does not charge the battery. the battery system has a charge controller.can i hook the tail lights/brake lights up to the charge controller using the magic of diodes to allow the trickle charger to maintain the battery while the trailer is being towed around?

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: December 11, 2019, 02:16:03 am
content: I have a similar setup. Except I have a big battery and have lights on the trailer so I can see at night too. What I did was connect the ignition wire up to a relay which sends current (without the use of diodes!) to the Anderson plug at the back of the ute. This battery line is protected by a self-resetting circuit breaker of 20A inside the engine bay.So when the ignition is on the battery in the trailer is being fed by the car battery and on the hour trips I usually run, the hour or so is usually enough.

author: Grant
author_rank: Newbie
timestamp: December 11, 2019, 04:14:01 am
content: The only issue i have with that is that the trailer is shared amongst employees, im trying to find a solution that requires no modification to a standard vehicle.i cannot trust people to plug in a charger or check to see if the battery is charged. it is a safety device so i want to make sure it is always charged and ready to go without relying on people.If it was only mine i would 100% go with the anderson set up.The idea i had was to just leech some power from the trailer lights to maintain the charge, the lights on the trailer are all LED so draw next to no current. and brake/taillights should be on enough to top up the battery from self discharge every day, maybe?

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: December 11, 2019, 05:04:45 am
content: Quote from: Grant on December 11, 2019, 04:14:01 amAs you must realise, the supply would be intermittent with which ever lights were on. Throw in the cable volt drop plus the volt drop on a diode, your going to be far lower than needed for battery float level voltage. But in theory, yes, a small current derived from the parkers could maintain the charge of a small SLA battery if left on long enough. But then, I don't like the idea of just connecting a battery without some sort of controller.If the trailer has provision for a charger, what about a solar panel on the trailer somewhere?What is the input voltage range of the charger input?

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: December 11, 2019, 05:29:02 am
content: Check the regs of what state you are towing it in.https://www.caravanersforum.com/viewtopic.php?t=10474
Nikola Motor claims doubling of li-ion battery performance - Page 1
Forum section: electronics / general

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 19, 2019, 05:37:31 pm
content: This press release is getting my bullshit-ometer twitching. Feels like they are ticking just too many boxes. At the very least it looks a fair way off if they are only now hiring a bunch ofPh.d'shttps://nikolamotor.com/press_releases/nikola-corporation-to-unveil-game-changing-battery-cell-technology-at-nikola-world-2020-67

author: ejeffrey
author_rank: Super Contributor
timestamp: November 19, 2019, 06:53:48 pm
content: Improving density to 500 Whr/kg would be a huge deal and isn't outside the realm of possibility AFAIU. The real question is where along the commercial readiness curve they are and what their specific invention is. Obviously the idea of reducing the weight of structural materials that don't contribute to capacity has occurred to anyone in the field. I don't know enough about the field to know what research demos are out there, but honestly this sounds like "someone made a slightly more manufacturable process for a technique that has only been practical in research labs, so we hired them." That *could* be the start of a legitimate revolution, or it could be another of dozens of ideas that go nowhere or are still waiting for another few key advances.

author: woodchips
author_rank: Frequent Contributor
timestamp: December 02, 2019, 11:16:25 am
content: Umm, 500 Wh/kg, so only needs a 22 times improvement to match diesel or petrol!This does make the idea of electric vehicles somewhat doubtful, a 44 tonne artic can carry up to 1000l of diesel, lots of batteries.

author: iMo
author_rank: Super Contributor
timestamp: December 02, 2019, 11:55:51 am
content: Interesting - fromhttps://ourrenewablefuture.org/chapter-1/

author: PA0PBZ
author_rank: Super Contributor
timestamp: December 02, 2019, 12:31:35 pm
content: Sure, but from that chart only the batteries can be re-used

author: tszaboo
author_rank: Super Contributor
timestamp: December 02, 2019, 02:19:42 pm
content: Quote from: woodchips on December 02, 2019, 11:16:25 amSure, battery recharged 2000 times, diesel used once, diesel only needs to be improved 90 times.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: December 02, 2019, 02:47:58 pm
content: If they had something to demo, wouldn't have to wait until "fall 2020".
BQ51050BYFPR:BQ51003YFPR_BQ25100YFP-Wireless Power Receiver__Not generate output - Page 1
Forum section: electronics / general

author: arul
author_rank: Regular Contributor
timestamp: November 27, 2019, 12:30:11 pm
content: We have two types of wireless power receiver circuit. One circuit is made using BQ51050BYFPR(Texas Instruments) and another one is made using of BQ51003YFPR (Texas Instruments) , BQ25100YFPR (Texas Instruments) . And also we are using the two types of coil. The coil manufacturer part numbers are AWCCA-18R18H10-C01-B(Abracon LLC) , 760308201(Würth Elektronik)The wireless power transmitter is VUSOLOBL-T (TYLT -https://www.amazon.in/Vu-Solo-Wireless-Charging-Enabled-Devices/dp/B00QJ8D7O8/ref=sr_1_25?keywords=tylt&qid=1574855890&sr=8-25). Input of transmitter is DC 5V, 1.8A and the output is 5W.We are tested the transmitter along with mobile phone, that is charging. But we are connecting our receiver circuit, that is not charging.I have attached the schematic, testing setup images.So please let me know, why our receiver circuit is not charging.Advance in thanks.

author: Gribo
author_rank: Frequent Contributor
timestamp: November 27, 2019, 04:41:29 pm
content: AD_EN should not be left floating. Also, flip your receiver coil. The winding should be between the charger and the ferrite.
Anyone feel like reverse engineering this patent app? - Page 1
Forum section: electronics / general

author: lawrence11
author_rank: Frequent Contributor
timestamp: November 27, 2019, 07:58:44 am
content: https://www.youtube.com/watch?time_continue=2&v=NTHxWpXI-WY

author: Simon
author_rank: Unknown
timestamp: November 27, 2019, 12:37:09 pm
content: Free energy is not possible. Anyone advocating free energy is a conspiracy theorist. We don't do conspiracy theories or junk "science".