hybridfree/eevblog-posts huggingface dataset:
PFC'd petrol  generator? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: March 05, 2024, 08:05:30 am
content: Hi,Supposing you have a petrol sinusoidal mains generator, the typical car "trailer" size.Supposing that the PFC stage input current (from the generator) has a fair amount of harmonics in it, not as bad as Rectifier/smoothingCap, but nota beautiful pure sinusoid current.Will this mean more stress on the rotor bearings of the generator, compared to if the current was a pretty pure sinusoid in phase with the voltage?And also what does the attached current, if drawn from a petrol generator, do to the bearings of the genny?

author: Zero999
author_rank: Super Contributor
timestamp: March 05, 2024, 09:09:18 am
content: What PFC stage? Are you talking about a generator supplying an ordinary capacitor & rectifier vs one with active power factor correction?

author: Andy Chee
author_rank: Super Contributor
timestamp: March 05, 2024, 09:17:55 am
content: Quote from: Faringdon on March 05, 2024, 08:05:30 amFrom the prime mover's point of view (i.e. the internal combustion engine), bad power factor is seen as extra horsepower and fuel required to overcome I2R losses along the length of extension cable to the appliance. Or if you turn the equation around, bad power factor means less power available from your generator.Either way, the losses will not be significant enough to physically damage anything mechanical.And just to be clear, electrical harmonics does not create mechanical knocking or mechanical imbalance harmonics (not large enough to wear out a bearing anyway).

author: Jeroen3
author_rank: Super Contributor
timestamp: March 05, 2024, 09:24:13 am
content: Harmonics are additional currents in the stator/rotor, causing more heat. Derating is required when using non linear loads.Sometimes, harmonics can induce current paths that goes through the bearings, this is very bad.

author: Circlotron
author_rank: Super Contributor
timestamp: March 05, 2024, 11:22:18 am
content: Absolute worst case it would cause some variation of torque absorbed by the alternator, but seeing it is probably a 2-pole 3000rpm machine, even with a sinewave load the absorbed torque would vary twice quite a bit as the machine rotated through 360 deg anyway. In any case, there is a single piston moving up and down like mad right next door, so if the alternator bearings can tolerate this, then any electrical load would be nothing by comparison I expect.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 05, 2024, 02:49:07 pm
content: A teardown of a BMW i3 generator unit shows they do 3 phase PFC when rectifying to DC, of course they're trying to get the best efficiency possible on a given budget.
How is Vicor Power doing for stock right now? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: February 25, 2024, 04:52:30 pm
content: Hi,We know due to their supreme quality, Vicor modules can always go nil stock, especially today....we may need a load of them for a high power pulse app.....is it safe to go Vicor?...will they go nil stock? They seem to be a few on digikey/mouser/findchips etc, but some modules are a bit low stocked.

author: coromonadalix
author_rank: Super Contributor
timestamp: February 25, 2024, 05:07:48 pm
content: well i would say and not doing bashing or any speculation yada yada ....Some companies take a very long time to revert back to pre-covid timesSome middle man are making huge profits, and some buy anything they can find, even before some distributors get their hands on them ...you may have to change designs as we did in some cases, even got fake parts, using Zynq fpga who got 10x times their normal pricing etc ... list goes on and on ...Some distributors like Digikey, Mouser, Electrosonic .... some have lost their ways if i may say, a mere rf connector at 5$ is now 25$ a piece
How to clean up shunt regulator reference voltage?  - Page 1
Forum section: electronics / general

author: Jim from Chicago
author_rank: Regular Contributor
timestamp: February 23, 2024, 11:16:10 pm
content: Hi, recently I've been working on using a TL431B shunt regulator reference to create a tight reference signal for an opamp, but my issue is that the reference signal is not very clean. Originally I had 0.1uF between cathode and anode, and it was oscillating like nobody's business. I tried removing that cap, and it got worse. So I increased >10uF and it cleaned up the large lower frequency oscillation, but there is still some higher frequency visible junk on there around ~670kHz, and it's getting on the 48V line which feeds a lot of stuff including RF.Summary of things I have tried with KA cap:Removing that cap entirely (awful result)100pF (huge oscillation)1000pF (huge oscillation)0.1uF (big oscillation)10uF (improved but still clear oscillation)22uF (more improvement but still noisy - see attached scope shot)47uF (similar result as 22uF)47uF with series 100ohm (large oscillation - resistor made things much worse)I seek wisdom. (using a different reference altogether is on the table by the way)Also, I made sure the opamp portion was not impacting by totally removing the opamp. I also made sure the 48V line was clean without the reference in there. So I know the culprit is the shunt reference. Please see attachments if you are intrigued, thank you.P.S. - I am a bit frustrated because I am finding the claims of the datasheet & app note to be false - my reference is quiteunstable with no KA cap, but they say it should be stable without any cap (quote"Unlike many linear regulators, TL43xx is internally compensated to be stable without an output capacitor between the cathode and anode.", and it's also unstable with low value caps less than 1/10th of the stability region low-end boundary per the app note. Anyway, maybe I'm missing something.

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: February 24, 2024, 09:48:53 am
content: Hi Jim,loose the 390 pF-cap.Good luck

author: Ian.M
author_rank: Super Contributor
timestamp: February 24, 2024, 10:39:55 am
content: Yes, that Ref to Gnd cap is increasing the lag in the feedback loop and thus reducing stability.
High Current Buck Regulator - Page 1
Forum section: electronics / general

author: antercreeper
author_rank: Contributor
timestamp: February 24, 2024, 02:16:40 am
content: Hi, i am new to here. By now have designed a regulator to power a low voltage halogen lamp.(6V 20W and 0.2ohms during home temperature, so cannot be powered directly from USB power)I haven't found some useful ic to do it.Looking for any advice :'(and the JK latch chip in the picture is hard to find

author: antercreeper
author_rank: Contributor
timestamp: February 24, 2024, 02:18:24 am
content: SW node and Load current
Anybody know Riello UPS systems, or power ups systems in general? Advise needed - Page 1
Forum section: electronics / general

author: V_King
author_rank: Regular Contributor
timestamp: February 23, 2024, 02:19:45 pm
content: Hi, I need a three phase double conversion UPS to smooth out some voltage issues in an old building - our machine servo drives keep on tripping due to one phase showing undervoltage for a short period of time (probably on phase in the building is overloaded, and when somebody pops a kettle or something, there is a short dip in voltage on one phase).There is an older Riello unit being decommioned locally, due to age - 10years old. Looks like new, panel shows 100% battery and status ok. I can not test it under load because it is a huge unit. Called Riello with a serial number and was told the units is pretty much a scrap because power power units, all capacitors and inverter card must be changed. When I asked why, I was told because it is 10years old. So I guess the tech from Riello had to stick to official narrative and not step out the line.In practice, would I still be ok to use this UPS as is if the status showing ok? Really looking for some independent advise.Please stick to the topic with advise. Fixing el system in a building is a no go etc.
Making a 50Hz power  sine source. - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: February 17, 2024, 06:14:12 pm
content: Hi,The attached (LTspice and PNG) shows two voltage sources. Between them they contain the full 50Hz sinusoid power waveform.One contains the positive going half sines.The other contains the negative going half sines.Can you think of a better way than the attached to amlgamate them to give the full sine?The attached is just Bi-Di switches going at 10ms period.The load power levels will be up to some 2kW.

author: tggzzz
author_rank: Super Contributor
timestamp: February 17, 2024, 07:23:03 pm
content: Quote from: Faringdon on February 17, 2024, 06:14:12 pmYou are the (self-professed) power supply professional who makes their living from this kind of thing.So, how much are you going to pay "us" to give you ideas that you can use for profit? Don't forget to include the IPR in that!

author: f4eru
author_rank: Super Contributor
timestamp: February 18, 2024, 08:17:12 am
content: How do you generate a FULL SINE WAVEFORM ?obviously by adding up two opposed half-sines....

author: Andy Chee
author_rank: Super Contributor
timestamp: February 18, 2024, 05:13:34 pm
content: Quote from: Faringdon on February 17, 2024, 06:14:12 pmConnect the load between a H-bridge.Connect the positive sine only to the H-bridge supply.Alternate the H-bridge switches every 10ms.The resulting waveform across the load will be a full sinewave.

author: jonpaul
author_rank: Super Contributor
timestamp: February 18, 2024, 07:06:33 pm
content: just another FTSS troll.Generator or inverterj

author: Faringdon
author_rank: Super Contributor
timestamp: February 19, 2024, 03:56:43 pm
content: QuoteThanks, very very expensive though...we have cheap way, needs bare minimal software, to get variable sine source using a couple of switch modes, working together.I guess you can imagine how we do it...all you basically need is a sinusoidal reference for feeding to the error amplifiers.We are looking at isolated variable sine source to 500W and all nice and cheap.

author: Zero999
author_rank: Super Contributor
timestamp: February 19, 2024, 08:22:28 pm
content: Why? If you don't have access to the mains, a small pure sinewave inverter is the only way.If mains is available, a variac and an isolation transformer will give you an isolated variable 50Hz voltage source, capable of 500VA, for a few hundred quid.

author: jonpaul
author_rank: Super Contributor
timestamp: February 20, 2024, 01:21:38 am
content: 240V main>>Varac>>1:1 240V ISO xformer
Solar Controller/Regulator configuration - Page 1
Forum section: electronics / general

author: Hobby73
author_rank: Regular Contributor
timestamp: February 16, 2024, 10:58:16 pm
content: Attached is a diagram of a simple layout for solar panels with a controller. The basic controllers like this one typically have outputs to charge a battery, and another output to directly feed a device (load).My question is, why do I commonly see the DC/AC inverter connected to the battery instead of to the device output which I would think is better regulated to provide a more stable 12VDC output than the battery which could fluctuate?

author: ConKbot
author_rank: Super Contributor
timestamp: February 17, 2024, 06:36:48 am
content: Few reasons1) The inverter is already meant to run on a fluctuating battery voltage, and will generally include a low voltage cutoff to not over drain the battery.2) most controllers I've seen don't do anything with the output besides switch ithe connection to the battery off when the voltage is low, so a simple LED light or similar load doesn't over discharge the battery. Some may regulate it, but that's not what I usually see.3)for those that do, now you need a 300W/500W/1KW+ boost converter to provide a stable voltage to an inverter that doesn't need it because it has regulation internally when it generates the HV rails.

author: Hobby73
author_rank: Regular Contributor
timestamp: February 17, 2024, 06:10:29 pm
content: In addition to the helpful points made above, I found this explanation on a solar website:It’s important to note that the inverter is connected and powered from the battery, not the controller’s load terminals as with the DC load. That’s because the inverter can have a high energy surge upon startup (typically with a motor), and this high current surge might be higher than the rated capacity of the controller, whereas the battery will be able to meet the high energy surge requirement.
Vertical bifacial solar panels efficiency - Page 1
Forum section: electronics / general

author: tszaboo
author_rank: Super Contributor
timestamp: February 08, 2024, 02:37:44 pm
content: Clickbait title aside, the claim is that dual sided panels vertically mounted would produce more energy than panels mounted south (or north if you live in the down under). I don't think this will change the roof mounted market, but probably it could be very beneficial for the following:Fences made from solar panelsAgriculture, like in the videoI think the test done by TNO is flawed, since they were comparing it to computer simulation. On the other hand even if this is ballpark the same output, even within 10-20% then there is lot of opportunity in this mounting method.Video by Undecided with Matt Ferell.

author: Gyro
author_rank: Super Contributor
timestamp: February 09, 2024, 11:08:55 am
content: Yes, even if the efficiency is a bit down, I think the reduction planning permission challenges (a major issue in the UK), and so increased availability of sites, would more than make up for it. The current tilted array farms are really only suitable for grazing sheep under. Retaining agricultural capability would make a big difference.

author: .RC.
author_rank: Frequent Contributor
timestamp: February 16, 2024, 12:12:58 am
content: Imagine the wind loading in a storm.

author: Someone
author_rank: Super Contributor
timestamp: February 16, 2024, 07:12:08 am
content: Down a bit? Depends where you are on the globe, how about a loss of 40%:https://www.eevblog.com/forum/renewable-energy/tilting-(at)-solar-panels/

author: Siwastaja
author_rank: Super Contributor
timestamp: February 16, 2024, 07:16:45 am
content: Vertical installation is interesting here in North because winter-time production is actually higher compared to what you get when you optimize the slope angle for annual maximum production, and during winter electricity is worth more. Additionally, snow does not accumulate on the top and cleaning is super easy. You of course lose significant amount of production during summer.
TVS or Zener for High side gate protection? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: February 11, 2024, 06:47:37 pm
content: Hi,TVS or zener for high side drive (gate) protection?TVS seems the more obvioUS choice, but why is everyone recomending zeners for this?18V zener: 1SMA5931Hhttps://services.ts.com.tw/storage/resources/datasheet/1SMA5926H%20SERIES_A2102.pdf18V TVS: SMAJ18https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/608/SMAJ5.0-SMAJ188CA.pdf..Its most common to see just a SOT23 18V zener here...and of course, you cant get TVS's in SOT23.

author: selcuk
author_rank: Frequent Contributor
timestamp: February 11, 2024, 07:08:15 pm
content: That diode is for limiting mosfet gate voltage to its maximum, which is probably 20V. Zener diode is used for this purpose to run for a long time. TVS diode is a much faster device and is for protection against transient voltages. If you use a 18V TVS in place of the zener, it will not limit the voltage to 18V. Please check out the clamping and conducting voltages of a TVS diode. It is a wide range so that you cannot simply choose a 18V TVS for this job.If you need a protection against ESD or burst transients, you will place an additional TVS immediately after the connector and ground it to the chassis. Zener is between gate and circuit ground.

author: Faringdon
author_rank: Super Contributor
timestamp: February 11, 2024, 09:32:55 pm
content: Thanks, we are seeing most FETs of 500-700V have max Vgs of +/-30V

author: jonpaul
author_rank: Super Contributor
timestamp: February 13, 2024, 11:42:44 am
content: ARGGH FTSS DO YOUR OWN WORKTVS = large die area Zener with high transient power and clamp V rating.Zener = ordinary voltage reg diode.See papers and arts at General Semiconductor in AZ, USA back to 1980s.j

author: Zero999
author_rank: Super Contributor
timestamp: February 13, 2024, 01:18:25 pm
content: The MOSFET is rated to VGSof 30V, whist the SMAJ18 could allow the voltage to reach 32.2V. Go for the SMAJ18A or SMAJ16 to limit the voltage to below 30V. Another option is the P6KE18.

author: David Hess
author_rank: Super Contributor
timestamp: February 14, 2024, 01:49:08 am
content: Either a zener or TVS will work fine for gate protection. They are the same thing except for size, characterization, and perhaps a processing difference.A TVS might be processed more like an avalanche rectifier where the junction is made more uniform so breakdown is more uniform and no hot spots will form, however this is irrelevant for protecting the gate of a MOSFET.
Any DALY BMS experiance? Can not wrap my head around battery beeing depleated. - Page 1
Forum section: electronics / general

author: Jan E L
author_rank: Contributor
timestamp: February 09, 2024, 10:46:17 am
content: Doing a LiFePo4 4S Zippy RC 8400mah battery on my MC Cafe racer project. With the new DALY K-type BMS.https://www.dalybms.com/daly-nmc-bms-lithium-ion-batteries-4s-8s-16s-12v-24v-48v-40a-60a-100a-smart-bms-product/Testing it on the bench but it kind of act funny...I charged the battery up to 3.6V/14.4V (bit off-balance from what was set in menu) and let it sitt connected to the BMS, but not PCU for a week. And when I came back to it it was 3.3v on each cell (average: 3.319v) and balanced...What is this I was thinking?After one more night it was still balanced and to 3.317v...Hmm...Charged it up to 3.6v but see that cell nr.2 is lagging behind at 3.48v. At this time it was just "micro"-charging and sporadic indicating that it balanced the cells.Disconnected PSU and let it sit over night. Now it was 3.54v on 1,3 and 4 and 3.52 on cell2...It looks like the BMS takes it power to operate from cell2.But it should go in to standby/hybernation when full?Now it looks like it keeps the BMS activeated, drains from cell 2 and at the same time balanses cell 1, 3 and 4 up against cell2 as it is depleted. Even tho the PSU is not connectedAnyone know what setting in the BMS menu that can cause this?I also know that you get more options with the USB/PC connection/setup. Is this a must to be able to sett it correct or do I have a flaw BMS maybe?The DALY brand has been a little strange on other BMS's where it only balance during charging according to some out there, and only 30mA from the highest cell(s). That is why many recomend reduse the "balance opening start volt" - I set it to 3.2V in menu. But do that also mean that if the BMS draw power from battery when not charging it will continue to balance down to what you put this toFor this new BMS k-series it looks like it might also balance when not charging...The last thing I've been testing is charge the battery to 3.6v lett it sitt disconnected from the BMS and after 24h it is still 3.6v. So do not look like there is a bad battery even tho it has been sitting on shelf at 50%SOC for almost 2 yearsNext I guess would be to charge it full to 3.6v balanced then set "balance opening start volt" up to 3.45v and see after one week what it shows. If you do not have any better suggestions to test first?
The Spherical Solar Cell, Robert Murray-Smith - Page 1
Forum section: electronics / general

author: Gyro
author_rank: Super Contributor
timestamp: January 28, 2024, 09:05:11 pm
content: 'Invention' sounds like the wrong term for this. The Campbell–Stokes sunshine recorder has been around for well over 150 years, working by burning holes in a card to record the times, duration, and strength of un-obscured sunlight in a day...https://en.wikipedia.org/wiki/Campbell%E2%80%93Stokes_recorderThe concentrated focused heat output seems to be exactly what you don't want on a small solar panel. The cost of the optics, necessary cooling, and tracking mechanism is going to be way in excess of the equivalent area of solar panel too. One for the Dodgy Technology section.

author: jbb
author_rank: Super Contributor
timestamp: February 04, 2024, 11:10:58 pm
content: Can’t speak to this incarnation, but people tried Concentrated Solar Power with mirrors and high efficiency solar cells pretty hard back in the 90s and 00s. Ultimately the pain of the mechanical steering lost out to the (then) rapidly falling basic panel costs.

author: Marco
author_rank: Super Contributor
timestamp: February 04, 2024, 11:29:35 pm
content: The only concentrating solar which makes some sense to me is using lenticular lenses with striped PV. That way you need no complex aiming, just rotate.
Gotion LiFePO4 Cell - Page 1
Forum section: electronics / general

author: mustafayilmaz
author_rank: Contributor
timestamp: January 26, 2024, 08:23:25 am
content: I purchased a 100Ah LiFePO4 cell from a local seller. The seller sent me Gotion brand.The price is quite affordable: Approximately 50usdI couldn't manage to read the QR code on it.Does anyone have information about this brand? Or is it a bad Chinese product?

author: ejeffrey
author_rank: Super Contributor
timestamp: January 27, 2024, 07:26:19 pm
content: What matters more than the brand is how the cell came to you. If it's genuine it's probably fine. If it's a factory reject or didn't pass testing to be used in an EV pack and was sold on the grey market it could be OK for stand alone use or it could be a poorly performing fire hazard.

author: mustafayilmaz
author_rank: Contributor
timestamp: February 03, 2024, 08:25:40 am
content: Quote from: ejeffrey on January 27, 2024, 07:26:19 pmHello, thank you for your answer.Cell weights are as stated (1.95kg).I managed to scan the QR code. The page says the code is correct.https://www.gobelpower.com/lifepo4_decoder.htmlThere is no physical damage to the cells. Is there still a danger of explosion?How do I comment on whether these cells are real?

author: RLP
author_rank: Contributor
timestamp: February 03, 2024, 09:48:20 am
content: Curious is the discrepancy between the manufacture date on the label (12th September 2023) and the one on the QR code readout (22nd August 2023), but they are at least similar - it seems at least plausible that that's normal. I would be more suspicious if there was a discrepancy of many months, or years.I've heard of this brand before because they're also sold in my country. I haven't got any experience with them myself, but like many of the other LiFePO4 suppliers, these are large companies that obviously make good business, probably primarily in supplying OEMs not consumers, which is why most of us may not have heard of them. Thus, I am inclined to believe that they sell products that meet their specifications.As ejeffrey says, your cell is either genuine, or the most likely alternative is that it is a factory reject of some sort - which is nonetheless still a real cell from the stated manufacturer. B-grade LiFePO4 cells, as they are often called, are not known for spontaneously combusting or exploding - it's much more likely for them simply to have substandard performance in some respect (capacity, self discharge, internal resistance...). That's not to say it's impossible for B-grade cells to be unsafe, for example fast charging a cell with high internal resistance or using unbalanced cells in a pack could still create hazards... but in my view it's not as serious as the more volatile lithium chemistries like NMC where it is very plausible for faulty cells to cause fires.
Energy logger for outlet a PHEV is connected to for calculating kWh each month? - Page 1
Forum section: electronics / general

author: dentaku
author_rank: Frequent Contributor
timestamp: January 25, 2024, 02:51:31 am
content: My brother has a KIA Niro PHEV and we don't know exactly how much energy it consumes per month to charge it every night.What's the easiest way to log this and get a number at the end of the month so we can compare it to the power bill and know what percentage of the total consumption of the entire house is due to charging the car?The car is the only thing plugged into the outdoor outlet so I'm assuming a device connected to the wire leading to this outlet is what I'm looking for. The basement is not finished so I have access to all the wires.This is an outdoor plug so I don't want something that plugs into the socket.

author: uer166
author_rank: Super Contributor
timestamp: January 25, 2024, 03:52:40 am
content: Some EVSEs have that built in, like a Chargepoint Flex or similar. The app sucks but the data should be there.

author: themadhippy
author_rank: Super Contributor
timestamp: January 25, 2024, 04:10:14 am
content: Quotewhat about wiring a temporary indoor socket on the ev circuit

author: ejeffrey
author_rank: Super Contributor
timestamp: January 25, 2024, 04:12:32 am
content: You can get power meters designed to be wired into a circuit. They are going to be more expensive than a plug in device like a kill-a-watt. Here is a random one I foundhttps://www.ekmmetering.com/products/universal-single-phase-kwh-meterYou might also check if the vehicle itself can track this. I would guess it does, and might track by location as well.

author: dentaku
author_rank: Frequent Contributor
timestamp: February 03, 2024, 02:20:04 am
content: The EKM seems quite high quality and a bit pricey in $CAN. It's clever how it pokes through the insulation of the wire to power the device and measure the voltage but it seems to be clumsy to have to run the wires through the body of the device.I've found another one that has a split core current transformer so it's much easier to clamp onto the wire than the way the EKM does it.It also has the ability to reset to accumulated kWh (unlike the EKM) so you can set it back to zero at the start of each month.https://www.amazon.ca/Current-Amperage-Voltmeter-Multimeter-Transformer/dp/B07JB9B2QL/?_encoding=UTF8&pd_rd_w=6SFga&content-id=amzn1.sym.2fd36d35-e0d1-4258-ba0c-e42eba5f6561%3Aamzn1.symc.e5c80209-769f-4ade-a325-2eaec14b8e0e&pf_rd_p=2fd36d35-e0d1-4258-ba0c-e42eba5f6561&pf_rd_r=ZD3VFCGXH9BEBVST5F6T&pd_rd_wg=oeSR6&pd_rd_r=83410c12-50ec-4cbe-9703-77d1b7c000be&ref_=pd_gw_ci_mcx_mr_hp_atf_m&th=1The outdoor GFCI outlet has two screws on each side so I could connect wires to the unused screws and run that out the back of the box and back into the basement to give 120V to the meter (I'm assuming this both powers the meter AND let's it know exactly what the voltage is ?) and clamp the handy split core current transformer to the original black (hot) wire that leads into the outlet.Quote from: ejeffrey on January 25, 2024, 04:12:32 am
Mean Well LRS-350-24 - Page 1
Forum section: electronics / general

author: eeguy
author_rank: Regular Contributor
timestamp: February 02, 2024, 12:08:47 am
content: Hello, I am looking for a 24V PSU to drive a NEMA 23 stepper motor and perhaps also use it as a power supply for other projects. I read some people are using this PSU with NEMA motor.Is there anything special about PSU from Mean Well?There are 9 output ports without cover. Also there is no ON/OFF switch nor socket to connect to a power cord. Is there a possible danger of health hazard if somebody accidentally touch some of the ports? I asked Mean Well several times but they avoid answering this question.

author: Someone
author_rank: Super Contributor
timestamp: February 02, 2024, 01:38:20 am
content: Quote from: eeguy on February 02, 2024, 12:08:47 amYes. You are looking at a power supply "component" that is for integration into a larger product.If you want a ready to use lab style supply (with power switch etc) then buy that to begin with.
Flyback stability by increasing upper divider resistor? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: January 22, 2024, 09:34:48 pm
content: Hi,If you are doing offline flyback with the lowest component count feedback loop, then you are doingit like in the attached with TL431.Output caps are 2 x 35ZLJ330's by Rubycon.These have tan delta = 0.12 at 120Hz. This would mean ESR of some 0.48 Ohms at 120Hz.From post #11 of thishttps://www.edaboard.com/threads/calculate-esr-of-electrolytic-capacitor-over-frequency-sweep.407674/Its pretty obvious that the actual ESR of the 35ZLJ330 at 120Hz is going to be around 0.18 Ohms or so.Nothing like as high as 0.48 Ohms.Now , low Capacitor ESR is the biggest threat to stability of the shown flyback. So a good way of calculating ESR is needed.However, this is not to be found.Instead we are left with simply having to increase the Ohmic value of the upper divider resistor in order to increase phase margin (and simultaneously increase lower divider resistorso output stays at 24V).So how many people (who use the attached schem) simply up the divider resistor in order to increase phase margin in the face of the onset of future electrolytic capswith ever decreasing ESR?Rubycon ZLJ 'lytic capshttps://www.mouser.co.uk/datasheet/2/977/e_ZLJ-1601167.pdf

author: jonpaul
author_rank: Super Contributor
timestamp: January 26, 2024, 11:08:22 am
content: FTSS: usual garbage, get a lifej

author: multipla
author_rank: Contributor
timestamp: January 31, 2024, 08:47:30 am
content: Quote from: Faringdon on January 22, 2024, 09:34:48 pmwrong.
Couple of questions about designing an NiMH battery charger - Page 1
Forum section: electronics / general

author: Marmotta
author_rank: Contributor
timestamp: January 26, 2024, 12:17:46 am
content: I have a Neo Geo Pocket that I wanted to modify with a USB-C port and NiMH battery charger using a TI BQ25172. It uses two AA batteries in series and I wanted to be able to charge it while using it at the same time, but this is the first time I've tried to make a NiMH charger, so have a few questions if anyone can help out? It would be great appreciated- I'm assuming first and foremost that it's suitable for the job - the datasheet mentions "when the system load is placed in parallelwith the battery, the charge current is shared between the system and the battery" so I'm assuming I can just connect my circuit to the AA batteries inside the console and it will work as desired? I don't really intend on playing it much while it's charging, but it would be nice to have.- What is VREF in the datasheet connected to? There's no mention about what value it's supposed to be other than it being shown in example circuits and that it's a pullup line. I'm assuming it's an input for a refence voltage from the system? The Neo Geo does have a 4V reference voltage which seems to be pretty much constantly spot on 4V during use which I could use?- I'm pretty unsure about the values of the capacitors I've used and most of them are based on semi-educated guesses. I have a 375 ohm resistor connected to ISET, as this defines the current charge value at the max 800mA, which I believe should be fine? (assuming two 2000mAh Eneloop batteries) I then have a 27K resistor connected to TMR, which would equal a safety charge time of 6 hours - I believe more than enough to charge the two batteries with 800mA, but would it affect anything if I increased the time? Finally, I've chosen a 27K resistor on VSET to select 2-cell + intermittent charge.I've attached an image of my schematic so far and a link to the BQ25172 datasheet below.https://www.ti.com/lit/ds/symlink/bq25172.pdf?ts=1706058046887&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ25172
Tesla bots in Ukraine? - Page 1
Forum section: electronics / general

author: snovotill
author_rank: Newbie
timestamp: January 24, 2024, 09:28:36 pm
content: Tesla FSD12 based on full end to end AI is out and this is a world first; All other self driving systems are based on heuristics. Maybe if the war lasts long enough then Tesla bot will fight in Ukraine; Can Putin use nuclear or biological weapons against swarms of needle-threading Tesla bots covered in solar panels? They could hide out and charge during the day but then wreak havoc at night. If a bot gets cornered then it could just short out its battery, thereby exploding in a ball of flames without having to carry any munitions.What would this look like and how could this technology be used to dismantle the Kremlin with surgical precision, without harming the Russian people? It could cross the border empty-handed and obtain everything it needs to accomplish its objectives directly from its environment.Didn't the Mars rovers last several years? The bots could be extremely careful not to be found, perhaps by hiding out in the forest and coming out once in a while to do their work.How about outfitting each bot with thermal vision, FMCW radar, sky facing radar, GPS, inertial navigation, an ultra-sensitive magnetometer and seizmometer, two-way frequency hopping SDR, satellite communications, OTA, ultrasonic phased array hearing and a gas spectrometer. This should all fit into a 2kg payload.

author: Andy Chee
author_rank: Super Contributor
timestamp: January 24, 2024, 10:53:33 pm
content: Quote from: snovotill on January 24, 2024, 09:28:36 pmMars rovers are not 100% autonomous. They most definitely have humans making the decisions as to what rocks and geological features are worth investigating. If by chance the Mars rover hits a patch of quicksand or has motor failure, humans are required to analyse the problem and devise a solution.

author: magic
author_rank: Super Contributor
timestamp: January 25, 2024, 07:39:26 am
content: I can easily see how autonomous taxis can (and will) be hired by terrorists to safely deliver "payloads" to their destination, effective robot warfare is still decades away, particularly on the ground, and the idea that Tesla is anywhere close to that right now is simply ridiculous.

author: Faringdon
author_rank: Super Contributor
timestamp: January 25, 2024, 08:01:03 am
content: Quote..In reality , i think they just smoke a lot, and rarely explode in flames.....maybe a little fire eventually, but not enough to totally destroy them.
Or-ing Power EMI - Page 1
Forum section: electronics / general

author: antercreeper
author_rank: Contributor
timestamp: January 20, 2024, 01:40:41 pm
content: I am designing a FPGA board and suffer from EMI issue. While plugging in second USB (as slave, the first acted as power source), buttons will be false triggered(some spikes injected), as the power source 1 and power source 2 comes from different adapter(2 pin without ground) and have about 60 volts between them.What do i need to add? I have seen some solutions, for example tvs, ferrite bead(some in vbus, others in gnd), common chokes on power lines...

author: selcuk
author_rank: Frequent Contributor
timestamp: January 20, 2024, 10:14:35 pm
content: Is the 5V ground potential difference 60V, or protective earth ground? Apart from that you may connect ground and shield of the USB connectors together and to the board ground. Remove C30 an L9 and make a short and low inductance ground connection. So that you will have a single ground net on the board.

author: antercreeper
author_rank: Contributor
timestamp: January 20, 2024, 11:39:37 pm
content: thanks for replying. sorry for my bad english.what my questions is... two dc inputs have two grounds(of course soon generate a loop from Y cap of one adapter(virtual earth) to the other adapter's really 0 volts earth ground)......so When hot plug, a surge confused my chip......maybe a common choke is ok?

author: antercreeper
author_rank: Contributor
timestamp: January 21, 2024, 02:07:13 am
content: For my design(no enclosure, so no earth ground)(haven't been tested yet.)The first DC input:the VINADA is to DC-DC buck regulator(1*22uF SP-CAP, 2*33uF aluminum, 1*1uF ceramic, all 25 volts max, act as regulator's input caps, maybe can handle surge from inductor?) and convert 19V to 5V, and then two PMOS gates.The second DC input from USB:

author: selcuk
author_rank: Frequent Contributor
timestamp: January 21, 2024, 02:12:19 pm
content: I agree. A surge current which equalizes the ground voltages may cause a voltage difference on your circuit ground. So I can suggest to decrease the ground inductance to lower that ground shift voltage. You may try shorting the ferrites separating the grounds, with 0 ohm resistors. Common mode chokes may block this current if it is not differential but I'm not sure.

author: antercreeper
author_rank: Contributor
timestamp: January 23, 2024, 06:41:26 am
content: Thanks.
Battery Powered v Mains Power Suppy - Page 1
Forum section: electronics / general

author: BillMC
author_rank: Newbie
timestamp: January 22, 2024, 09:26:29 pm
content: I have a certain device (portable CD/mp3 play) which like many other devices can be powered from either battery or mains power supply. When I first used it I used batteries. I then found a mains power supply and used that, because the batteries power ran out. The device continued to work without any problems. I later used a new set of batteries, but for some strange reason the device would not work, yet when I plug the power supply back in it still continued to work.Can anyone explain the reason why it no longer works with the batteries? BTW I tried a few different sets of batteries and I even tested them wil a meter and they all have a full charge.

author: tunk
author_rank: Super Contributor
timestamp: January 22, 2024, 09:34:23 pm
content: The power supply contact in the CD player most likely hasa switch that disconnects the battery when the power supplyis plugged in. It could be bad.

author: BillMC
author_rank: Newbie
timestamp: January 23, 2024, 12:34:58 am
content: So I take it then that this switch must have permently switched off the contact for the battery input?

author: coppercone2
author_rank: Super Contributor
timestamp: January 23, 2024, 12:39:50 am
content: trace the battery circuit to the circuit board piece by piece and see if there is a circuit when you are probing a battery because consumer device battery cavities are oftenuttertrash and the problem is compounded by small amounts of corrosion damage from burping cells etc. A dodgy switch is also a common problem.its methodical probing that will find this problem most likely.
24V isolated power supply @350mA from 24V SMPS - Page 1
Forum section: electronics / general

author: monis
author_rank: Newbie
timestamp: January 15, 2024, 11:52:35 am
content: Help needed in designing 24V isolated power supply capable of delivering 350mA from 24V SMPS source.

author: Faringdon
author_rank: Super Contributor
timestamp: January 21, 2024, 12:47:49 am
content: Sounds like its got mains input?Why not try Power Integrations website.They show you how to do it.They have the tinyswitch, and the Innoswitch.There are also offtheshelf modules which do it all for you.You could have an enclosed version, or an "open frame" one, a bit cheaper.
High Frequency Inverter inducing high frequency noise - Page 1
Forum section: electronics / general

author: elex_enthusiast
author_rank: Regular Contributor
timestamp: January 20, 2024, 05:58:47 am
content: I have 5KW hybrid Deye inverter on my solar set-up and it's inducing noise on both the grid and EPS ports thus messing up measurements on the workbench. All test instruments are connected to grid which is supplemented by the set-up. I am aware that high freq inverters are noisier than its counterparts but never anticipated that would affect much on the instruments until recently. What are your best practices to minimize its effects? Am thingking of having separate set-up using Low Frequency Inverter just for the lab or a good EMI filter with enough rating to handle the test gear I have. Your suggestion may help a lot. Thanks!Inverter connected to gridInverter disconnected from grid

author: jonpaul
author_rank: Super Contributor
timestamp: January 20, 2024, 03:28:58 pm
content: Bonjour:1/ How was the mains voltage probed, what probe, isolation trsf?2/ Set trigger of scope on LINE or MAINS, see if EMI burst is in sync to mains 50/60 or 100/120 Hz?3/ Cheap Chinese electronics usually omits compliance, safety or EMI to save money.The inverter topology, design, components are selected for LOWEST COST regardless of quality safety ofr compliance.4/ Any external EMI filter requires special inductors and capacitors designed for the voltage and current and safety eg VDE X, Y caps.Suggest to contact the vendor or manufacturer and get a refund.Never run sensitive electronics on a junk inverter.Chinese = CCP = liarsJon

author: Faringdon
author_rank: Super Contributor
timestamp: January 20, 2024, 08:36:49 pm
content: Is the inverter in a metal case, and does it have an earth wire connection?If not, then that might be part of the reason of the noisiness.You could try one of those Schurter mains filters at its front end.Or rig up a common mode choke and put that at the front end........put it in an earthed metal box, and have y caps up and downstream of it, which connect from line/neutral , to the earth.You say its messing up the measurements...but doesnt the measurement kit have enough input filtering in order to give itself immunity from the noisy inverter?...it should do
The Best Full bridge control IC - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: November 26, 2023, 05:28:08 pm
content: We need to do Full Bridge, 120W, Vin = 90VDC, 24Vout, FSW 100-200kHz we'll see.We need overload protection.Its best to just use a cheap, simple , 8pin, single output, current mode controller (one that has inbuilt overload protection) and add D Type, Buffers, Dual Analog switch and FET drivers…as attached..But nobody does this.There is no offTheShelf Full Bridge driver IC with inBuilt Overload protection….the extra components here are cheaper than having a Full Bridge control IC with the added components to do overload protection.So why is it not done? (I take many apart...nobody do this.)

author: analityk
author_rank: Regular Contributor
timestamp: November 26, 2023, 10:18:20 pm
content: It is quite weird configuration. Why not use halfbridge or HB-LLC?From the other side there are full bridge phase shift integrated controllers, it seems to be overdesigned but it will work.UCC28950, LTC1922-1, HIP4081AIBZ-ND

author: youngda9
author_rank: Regular Contributor
timestamp: January 17, 2024, 09:55:06 am
content: I've used the LTC3722-1 quite successfully on several designs.

author: jbb
author_rank: Super Contributor
timestamp: January 17, 2024, 09:12:36 pm
content: Well, the best I’ve used personally is the TMS320F28335 from Texas Instruments

author: pcprogrammer
author_rank: Super Contributor
timestamp: January 17, 2024, 09:20:09 pm
content: Quote from: jbb on January 17, 2024, 09:12:36 pmYes, that one is very good. No need for all these external components.

author: jonpaul
author_rank: Super Contributor
timestamp: January 20, 2024, 03:30:38 pm
content: FTTS: FW br is nuts for such low W.The simple engineers solution: Use a flyback or foward, ONE device, no floating drives.j
6V version of TLV431 is fine for current clamp - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: January 15, 2024, 07:27:52 pm
content: Hi,Our contractor tells us that the attached "current clamped voltage regulator" circuit needs to use the 18V version of TLV431.This, he says, due to "corner case operation".But we beleive it only needs the 6V version (6V max from Cathode to Anode).As you can see its just a bog standard current clamp, aswell as a bog standard linear regulator that can source or sink some current.The TLV431 cct must current clamp to approx 80mA.The output can have any size load resistor attached to it, and the TLV431 should never "see">6V from Cathode to anode.Also, the output, may sometimes erroneously have a 16V power supply attached to it which is current limited itself to sourcinganything up to 100mA output.Again, of course the TLV431 should never see >6V from Cathode to Anode...But we dont beliebve that it ever will.Would'st you kindly agree?The control voltage can be anywhere from 0V to 3V3. It sometimes pulses at T=5ms from 3v3 to 0V.(The application is strange, its just a special kind of mini resistive heater power supply. Its for the garment industry, (a special operation which needs a low power variable heater))LTspice and PNG attached

author: dobsonr741
author_rank: Frequent Contributor
timestamp: January 15, 2024, 08:39:08 pm
content: TL431 in that position would never see more than 3.2V across, given it’s getting the sum of the shunt voltage and the Vbe of the pass transistor.Not sure what the 18V version mean, either. TL431 is spec’d to work up to 36V.
Mains short circuit protection and switch out. - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: January 13, 2024, 05:49:46 pm
content: Hi,You are kindly requested to propher your fave short circuit switch-off for mains. ie, 230vac mains gets a short circuit, and you want to switch it off. (short circuit from line to neutral)Eg, back2back IGBTs in the neutral with a isolated supply feeding their gate drivers...and a comparator and sense resistor etc, to switch off the igbtS When sht cct occurs.orOvercurrent sensor and relay with relay snubber.orBack2back FETs in neutral.....and they are controlled for say 30A to 0A over some 2 seconds when sht cct occurs.Whatever it is, it cant just be back2back FETs in neutral, then turn them off simply when overcurrent occurs..since FETs will explode if not "nannied" off with such high current and voltage cct.

author: Gyro
author_rank: Super Contributor
timestamp: January 13, 2024, 10:28:36 pm
content: A BS1362 fuse.

author: themadhippy
author_rank: Super Contributor
timestamp: January 13, 2024, 10:50:51 pm
content: Depends on the trip characteristics im after,if it needs to deal with a large start up current then a 10mm bolt,if however it needs to be a fast acting device a bit of silver paper.

author: MF-jockey
author_rank: Regular Contributor
timestamp: January 14, 2024, 12:43:13 am
content: You should never install a fuse or circuit breaker in the neutral wire. The shutdown must always take place in the phase. Normally you take a circuit breaker with a rated current that matches the cable cross section.https://www.amazon.co.uk/Schneider-EZ9F16120-Miniature-Circuit-Breaker/dp/B00WRBRAGW/ref=sr_1_1

author: Gregg
author_rank: Super Contributor
timestamp: January 14, 2024, 12:58:35 am
content: Keep it simple --- use a fuse!Over complicating things seldom is necessary unless you are planning obsolescence!