hybridfree/eevblog-posts huggingface dataset:
CyperPower CO1599PFCLCDa neutral v ground - Page 1
Forum section: electronics / general

author: Linwood
author_rank: Contributor
timestamp: February 19, 2023, 10:49:26 pm
content: This is a question about why...I have never paid much attention to home UPS'. I was responsible (prior to retiring) for many data center systems, but for home use I just considered them a fancy surge suppressor and something to ride out brief outages, and gave them little thought.I thought they were all cheap versions with nasty square waves, but realized my last purchase was a sinewave line interactive sort, and decided to look more closely (boredom was involved).I was expecting and did confirm that when on battery the ground maintains continuity back through the building power.I was pleasantly surprised to see a relatively clean sinewave, even under substantial load (though to be fair it was a resistive load since I was lazy at the time).What I was not expecting was to find was that it was sort of a split phase (probably not the right term), with neutral and load about 60v each (RMS) relative to ground and inverted phase for 120v between (RMS).I realize nothing bad should come of that, but I am curious about the approach (rather than using ground as a reference for neutral).Is that because of restrictions of bonding neutral and ground other than at the panel? (I would think it would not apply, being separately derived, but that is an area of the NEC that I know little about).Is it to reduce the voltage for some reason on each one relative to ground? (I guess in principle a short to ground thru a human might be less deadly, but the short to neutral remains the same).Is it because it is easier to make that way? (i.e. cheaper)Something I haven't considered?Apologies if this is a silly question, it was just a bit of a surprise.LinwoodPS. Attaching waveform if anyone is curious.

author: uer166
author_rank: Super Contributor
timestamp: February 20, 2023, 08:26:09 am
content: It is the easiest and cheapest way to do it if you need clean common mode output. 2 half bridges make for a natural split phase lower voltage output, this is how I'd do a battery inverter as well.Any other topology that allows neutral to be at zero would either be less efficient, more expensive, or have very large common mode noise output.

author: Linwood
author_rank: Contributor
timestamp: February 20, 2023, 09:23:22 pm
content: Quote from: uer166 on February 20, 2023, 08:26:09 amSo cheaper and better. Thanks.
UCC29002 Load  share controller suffers when grounds are different - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: February 04, 2023, 11:16:08 am
content: Hi,The UCC29002 load share controller makes multiple smps's share current when pllel'd.But if the local ground at each smps is different, then the sharing will be compromised.Why is there no chip which deals with this "different local grounds case".When many smps's are pallel'd, there is a hugh chance that local grounds will be different.Clearly a "digital share bus" is needed, even a PWM to analog converter, so that local gnd differences are cancelled out.?Attached is a mock up of UCC29002 in LTspiceUCC29002https://www.ti.com/product/UCC29002?utm_source=google&utm_medium=cpc&utm_campaign=app-null-null-GPN_EN-cpc-pf-google-eu&utm_content=UCC29002&ds_k=UCC29002&DCM=yes&gclid=Cj0KCQiAofieBhDXARIsAHTTldo3PiowaXl-Mu1llS0D-XXzsOV0pcdgHZlHHrO01wq6cEhATG8RVB4aAovBEALw_wcB&gclsrc=aw.ds
Unusual Plug Pack for Vaccuum - Page 1
Forum section: electronics / general

author: mbarszcz
author_rank: Contributor
timestamp: February 03, 2023, 07:02:19 pm
content: I got the new Lithium Ion version of the Bissell Pet Hair Eraser (the Purple One) and noticed it came with an charging adapter unlike the old one. The vacuum contains a 14.4V Lithium Ion pack. When charging, my kill-a-watt shows that it is charging at 5W. The unusual part is the output voltage listed on the back of the adapter is 5V-23V DC, 300mA. A variable output voltage plug pack with only two connections to the vacuumDoes anyone know why there is a variable output voltage on the adapter and how this might work? Perhaps more than just a simple DC supply and instead acts as a constant current source working in conjunction with some kind of internal battery charging circuit? That's fine for the beginning of the charge cycle (CC mode), but to complete the charging of a lipo, at some point it needs to switch to CV charging. How will that work with this arrangement?Open circuit the output of the charger measures 17.5V. When plugged in and charging, I measured 15.05V across the output.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 03, 2023, 08:23:43 pm
content: My guess without additional information is that your supposition is correct. USB-C fast and ultra fast chargers do something similar. Although not related specifically to your case, I find the DigiKey explanation one of the easiest to understand:https://www.digikey.com/en/articles/designing-in-usb-type-c-and-using-power-delivery-for-rapid-charging?
Battery solder/welding problem - Page 1
Forum section: electronics / general

author: naujoks
author_rank: Regular Contributor
timestamp: February 20, 2023, 09:53:52 am
content: I'm trying to equip an old laptop battery with new cells.As this is the only project I'm doing with batteries, I bought one of those cheap little Chinese spot welders off Amazon, hoping that it would be alright, but it isn't.It creates only a very weak spark und the strip doesn't adhere to the contact at all (it's set to maximum power; when trying to weld two pieces of strip together on a wooden surface I get a very big spark and it holds together very nicely).So I tried the soldering iron instead. I roughened up the surface with sandpaper and scratched it with a screwdriver, I used flux on it, 60/40 solder, tried different soldering iron tips... no joy. The solder just wouldn't stick to the surface, and the little bit that did stick to it I could easily remove with the nail of my thumb.Is there anything else I could try, other than try to find a person with a proper spot welder?

author: mzzj
author_rank: Super Contributor
timestamp: February 20, 2023, 04:36:41 pm
content: Battery case could be aluminium for the prismatic cells. (Datasheet also points to this direction)Aluminium is very tricky or impossible to spot weld, laser or ultrasonic is used normally.Same cell is also available with nickel strip pre-welded to case:https://www.tme.eu/fi/details/nca103450/akut/panasonic/This would be lot easier to weld with proper spot welder.

author: james_s
author_rank: Super Contributor
timestamp: February 20, 2023, 08:12:39 pm
content: I use a capacitive discharge spot welder I built, it works very nicely for this. I used roughtly 1F in a bank of capacitors and charge them up to 20V at max power.
Good affordable isolation transformer + variac or AC PSU? - Page 1
Forum section: electronics / general

author: nimish
author_rank: Regular Contributor
timestamp: January 22, 2023, 09:54:52 pm
content: See title. It's either $500 Staco/ISE stuff or sketchy $100 shenzhen special.Would like something that I can easily step down 115v with and also won't cause my lisn and other stuff to trip GFCI AND won't also kill me.

author: bdunham7
author_rank: Super Contributor
timestamp: January 22, 2023, 10:08:26 pm
content: How much power? The BK Precision 1655 shows up on eBay for $200-ish if you are patient. That's good for 3A and has a nice meter and leakage testing. The smaller 1653 is 2A and has less features. The 'A' models are newer and made in Taiwan, AFAIK they are functionally identical although they appear different.

author: jonpaul
author_rank: Super Contributor
timestamp: January 23, 2023, 02:18:48 am
content: Variac >>>1kva 120/240 1:1 isolation from Signal TransformersNo need for power synthesizerj

author: ledtester
author_rank: Super Contributor
timestamp: January 23, 2023, 03:00:19 am
content: Another item to keep a lookout for is the Heathkit IP-5220 - can do 3A on the isolated output.

author: edavid
author_rank: Super Contributor
timestamp: January 23, 2023, 04:40:48 am
content: Quote from: bdunham7 on January 22, 2023, 10:08:26 pmI get a lot of use out of my B+K 1655, but the metering does not work very well. I got tired of recalibrating the voltage range and added marks to the variac dial instead. If I had paid $200 for it instead of $30, I would have more trouble forgiving that.

author: bdunham7
author_rank: Super Contributor
timestamp: January 23, 2023, 05:17:26 am
content: Quote from: edavid on January 23, 2023, 04:40:48 amThere's a mark on mine for quick setting, but the meter is quite accurate and has been for the several years I've had it. I rely on it too. I've heard that the meter diodes can go bad (they may even be Ge), but I haven't had the issue. As for $200 vs $30, that's the way things are these days. The days of cheap deals are gone and the knobs on yours are probably would go for $30.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 24, 2023, 03:45:25 am
content: Could also consider running an inverter from a surplus server PSU, especially if you also have some other use for the inverter.
Sine wave purity of solar generators - Page 1
Forum section: electronics / general

author: Hogwild
author_rank: Regular Contributor
timestamp: January 18, 2023, 07:27:01 pm
content: Hi everyone:As I research solar generators, I'm wondering about the sine wave quality of their output.I haven't found any testing of the sine wave quality yet, except for this very quick test done on a multimer with a scope function.https://thetechnologyman.com/ecoflow-delta-2-detailed-review-best-all-round-portable-power-station/Has anyone done/seen any more extensive tests done on a regular scope?From the research I've done so far, Ecoflow supposedly has the best inverters (for efficiency and wave quality output as well). Does that sound about right?

author: jonpaul
author_rank: Super Contributor
timestamp: January 18, 2023, 11:58:15 pm
content: Fluke, Yokogawa, other instruments firms make power Analyzers that read I, V, W VARS, PF and harmonics.The better the sine wave the more complex and costly the inverters.Most solar inverters are cheaply designed and made in China, so just enough power quality to get by.The waveform will vary depending on the load kW, load PF.impossible to comment on a particular brand as the OEM sources, Resale, rebranding always vary.Finally the bulk inverters are completely different from so called microinverters.For the cost if the mentioned inverters, $3,500, one can buy a fine naturel gas/ propane generator.way better than solar for emergencys and use in Winter or high latitudes.JonJust the ramblings of an old retired EEJon

author: trobbins
author_rank: Frequent Contributor
timestamp: January 20, 2023, 03:19:35 am
content: Perhaps try and identify some forums that report on user experience, as the generated AC voltage has many ways it could damage or negatively impact with powered equipment (ie. not just voltage or current harmonics). You take on the risk if the generator equipment has no rigorous performance specification, or if hundreds of users have not reported back on ok use.If the equipment contains Li-Ion batteries then I would advise you get the best quality from a reputed seller, as a way to mitigate the risk of poor electronics design related to the LiIon system causing collateral damage way beyond what you had foreseen.

author: Hogwild
author_rank: Regular Contributor
timestamp: January 22, 2023, 05:50:07 pm
content: I don't own anything yet, so no need to worry about battery replacement. I know I could test gear myself, but I don't have the time.Please let me know if anyone finds any, even basic test results.This was all I found so far on the Ecoflow Delta Prohttps://thetechnologyman.com/ecoflow-delta-2-detailed-review-best-all-round-portable-power-station/And also this video (at ~ 13:35)No mention was made of scale/time increment in either video.though I admit I haven't spent that much time searching so far.
Smart systems are stupid sometimes... - Page 1
Forum section: electronics / general

author: bdunham7
author_rank: Super Contributor
timestamp: January 20, 2023, 02:34:04 am
content: https://www.nbcnews.com/news/us-news/lights-massachusetts-school-year-no-one-can-turn-rcna65611

author: bidrohini
author_rank: Regular Contributor
timestamp: January 21, 2023, 07:39:47 am
content: What a waste of power!

author: MadScientist
author_rank: Frequent Contributor
timestamp: January 21, 2023, 12:15:23 pm
content: Some countries and communities are just too dumb to have any technology. s my friends used to joke when he was in wordstar support. “Please send back the disks as you’re too dumb to use technology “
How to mess up a cascaded boost converter? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: January 11, 2023, 09:32:42 pm
content: Hi,Can anyone show this cascaded boost LTspice sim, going faulty such that the mid_level voltage goes above 80V?(Ie adjust the sim, or put in some conditions in the sim which bring that about)

author: Faringdon
author_rank: Super Contributor
timestamp: January 12, 2023, 07:15:31 am
content: In the attached cascaded booster ltspice sim i managed to "hack" it so the mid rail goes up to 68vpk....normal is 58v...but cant get it any higher than 68v.....you just cant break the thing......why is a research paper even needed for it?...its just literally 2 boosters "joined at the hip">

author: pardo-bsso
author_rank: Frequent Contributor
timestamp: January 12, 2023, 07:45:43 pm
content: Why do you subject yourself to that kind of technical pain?AYK that's no good for short and long term mental health.

author: jpanhalt
author_rank: Super Contributor
timestamp: January 12, 2023, 08:32:54 pm
content: Quote from: pardo-bsso on January 12, 2023, 07:45:43 pmIsn't that like telling a 40-pack-year man dying of lung cancer to stop smoking?

author: pardo-bsso
author_rank: Frequent Contributor
timestamp: January 13, 2023, 03:01:46 pm
content: Quote from: jpanhalt on January 12, 2023, 08:32:54 pmQuite certainly.But sometimes I like to fiddle with him trying to extract some sort of sense from his words.

author: jonpaul
author_rank: Super Contributor
timestamp: January 15, 2023, 03:01:57 am
content: just more usual FTSS Farrington Treez Time Sinklife is to shortj
Can a rotary single to three phase converter fault to too high an output voltage - Page 1
Forum section: electronics / general

author: Chris Wilson
author_rank: Super Contributor
timestamp: January 13, 2023, 07:26:56 pm
content: I have used a commercial single phase to three phase rotary converter here for some 18 to 20 years without issues. It runs, one at a time, a Harrison 11 inch swing lathe, a Bridgeport universal milling machine, a hydraulic surface grinder, or a two post two ton vehicle lift.Today I ran the Bridgeport to accurately drill some holes and it seemed to turning bloody fast and i think I smelt a hot electrics odour. I turned it off pronto and tried the lathe. That too seemed to be over speeding. Having had a plethora of bad luck issues in the workshop I locked the doors and called it a night, and opened a beer.Before I actually measure the output voltage can any of the gurus here say if a rotary phase converter can suddenly start playing up outputting too high a three phase voltage? If so what might cause this? There's a gizmo on one of the house power sockets that reads mains voltage, current, Wattage and phase. The mains, as expected, is still in specThanks.

author: themadhippy
author_rank: Super Contributor
timestamp: January 13, 2023, 07:51:25 pm
content: As well as the voltage double check the frequency is correct

author: jpanhalt
author_rank: Super Contributor
timestamp: January 13, 2023, 07:57:08 pm
content: I don't think too high a voltage has much effect on 3-phase induction motor speed. It could cause overheating. How did the converter sound? Perhaps you lost a phase, which can cause overheating, but not increased speed

author: Chris Wilson
author_rank: Super Contributor
timestamp: January 13, 2023, 08:06:03 pm
content: It did, in hindsight, perhaps sound a bit "growly". I will check voltage and frequency tomorrow, thanks for the info chaps!
How to parallel  three  75W Flybacks? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: January 03, 2023, 08:46:07 pm
content: Do you agree the attached is THE modus operandi for paralleling multiple flybacks with cheap circuitry and still ensuring pretty equal load sharing (LTspice and PDF)They are each 75W flybacks

author: tggzzz
author_rank: Super Contributor
timestamp: January 03, 2023, 09:01:03 pm
content: Before replying, people might like to note the number of very different threads the faringdon/treez/ocset has started in the past few days. A quick look shows 5 since Christmas, or about one every two days.It is also worth noting various peoples' reaction to his statements in the posts.I'll ask why he uses this rather odd phrasing...Quote from: Faringdon on January 03, 2023, 08:46:07 pm... since the answer to such questions is almost always "no".

author: Faringdon
author_rank: Super Contributor
timestamp: January 04, 2023, 06:24:27 pm
content: Thanks..Its funny how one can draw out a schem for a "great idea"........and you realise its just trash.....the schem of the top post is trash, wouldnt you agree?This is a job for a UCC29002 Load share controller...more expensive than the schem of the top post, but oh so needed.UCC29002https://www.ti.com/product/UCC29002Just a matter of comparing the old UC3907 , to see if thats any better than UCC29002UC3907https://www.ti.com/product/UC3907The only difference between UC3907 and UCC29002 seems to be that the voltage error amp is inside UC3907 , but not in UCC29002.The UCC29002 seems to have no 50mV offset, and this offset is needed in the '3907 in order to stop the master from adjusting its own reference...so ucc29002 must have some other trick up its sleeve for this function.

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: January 07, 2023, 05:26:33 am
content: if you're needing to parallel multiple power supplies to do a job, you can afford to do it properly with load-sharing capable PSUs.

author: jonpaul
author_rank: Super Contributor
timestamp: January 09, 2023, 01:43:02 pm
content: FTTS, just use ONE properly rated 300W psu, no need to complicate with many smaller PSU, that increase cost and reduced reliabilityj

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 09, 2023, 02:09:44 pm
content: One wonders if one is missing out on the proliferation by not reading themperhaps there is something theresomewhere surelymust pay more attention
Inductive kickback from driving LED far from source. - Page 1
Forum section: electronics / general

author: Wize93
author_rank: Newbie
timestamp: January 05, 2023, 06:42:33 pm
content: So I'm working on a project that requires driving an LED load far from its power supply by about 30m. I am aware of possible loss in voltage due to the length of the wire, but I read about possible inductive kickback when I turn it off. Will this be a concern for my application? I'm planning to use 18 awg copper and use 24V

author: Siwastaja
author_rank: Super Contributor
timestamp: January 06, 2023, 08:06:54 am
content: Two options, or combination thereof,1) add freewheeling diode (and nearby capacitor to close the loop). Diode goes right next to the switching transistor, like you would driving any inductive load (e.g. relay coil, motor winding, inductor of a buck converter...)2) slow down switching, increasing switching loss of course, but this does not matter for on/off switching. For PWM, switching loss might be a problem.Simplest way to slow down switching is to introduce gate series resistor to the MOSFET. With very small MOSFETs with tiny gate capacitance, you might want to add an explicit capacitor (like 1nF) in parallel with G-S.
RT8070ZQW voltage regultaor not working - Page 1
Forum section: electronics / general

author: sumofforces
author_rank: Newbie
timestamp: January 03, 2023, 09:50:58 pm
content: Hello all,I have followed the design requirements found on the datasheet provided for Richtek P/N: RT8070ZQWHowever, my LED indicating 3v3 output is not turning on. I am getting 0.8V output. My input voltage (using a noisy power supply) is 5.17V.I have reached out to the manufacturer of this part.

author: mon2
author_rank: Frequent Contributor
timestamp: January 03, 2023, 11:53:05 pm
content: 1) You are missing a recommended Cin bulk cap @ 10 uf.2) Double check the wiring and be sure the metal ground tab is properly connected.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 04, 2023, 10:17:01 am
content: Input capacitor is arguably THE most critical component in a buck converter, and it's just 0.1uF, clearly orders of magnitude too small. There is no way for a buck converter to work without input capacitor, because the loop inductance now includes the whole battery and input wiring.Also show the PCB layout.

author: sumofforces
author_rank: Newbie
timestamp: January 04, 2023, 05:08:36 pm
content: Thank you,I changed the bypass cap to 10uF this morning. It got the correct output!
Pre-charged Active snubber for 300W Full Bridge SMPS? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: December 27, 2022, 03:07:43 pm
content: Hi,The attached LTspice sim and PDF schem, is a 300W Full Bridge with Current Doubler output.Vout = 32V, Pout = 300W, Vin = 10-36Vdc, F(sw) = 125kHz (ie, each full bridge diagonal FET pair switches at 125kHz).The transformer turns ratio needs to be Ns/Np = 9:1.As such, when Vin is at 36V, the V(reflected) to the secondary is 324V, and on top of that, AYK, the output diodes suffer the leakage inductance voltage spike.The Vds ringing due to the leakage inductance, and high voltage on the sec diodes, means that this SMPS dissipates too much in the secondary diode snubbers, and indeed overvoltages the 600V secondary diodes….however, with an Active Capacitor Snubber (as shown), its possible to damp the Vds ringing (to less than 400V) and indeed , allow paralleled 600V SiC diodes to be used. SiC’s share current so no trouble there either.The trouble is the amount of auxiliary circuitry that’s necessitated (as shown)….And, the Active Capacitor Snubber means that huge 200A spike currents are seen in the primary FETs at start up…therefore, the Active Capacitor has to be pre-charged with a dual cascaded boost converter (as shown). Also, the Active Capacitor Snubber needs the shown flyback converter to constantly switch the energy building up in the Active Capacitor to the output of the Full Bridge.The problem is the Dual cascaded boost, …..ie, we really need a controller with two overcurrent sense inputs for it, but a long search shows there are none.Do you know of any?

author: jonpaul
author_rank: Super Contributor
timestamp: December 27, 2022, 03:36:18 pm
content: no need, we use a double fwd, perfect clamp, no snubber or wasted energy, just 2 diodes and 2 FET/BJT.Made many at 750W.j

author: Faringdon
author_rank: Super Contributor
timestamp: December 27, 2022, 05:45:52 pm
content: Thanks, yes, in the primary side yes, but , AYK, secondary diodes just as stressed as the full bridge, in fact, more so, as it is limited in duty to 0.5......even if duty isnt limited (and AYK, there are ways round this,), it still suffers as does the full bridge in terms of Secondary side leakage inductance effects.The only way round it AYK, is to use some kind of resonant converter, but the wide vin range points away from this.I beleive that the "active snubber with precharge" (as in the top post) looks like being the best way?
EV Chargers - "They don't work in the Cold..."  But Tesla's Superchargers do.  - Page 1
Forum section: electronics / general

author: DougSpindler
author_rank: Super Contributor
timestamp: December 27, 2022, 04:56:13 pm
content: The new Electrify America chargers they co-developed with BTC don't work in cold temperatures.Charges say they are they charging, then they fault.

author: bidrohini
author_rank: Regular Contributor
timestamp: January 10, 2023, 12:38:56 pm
content: Tesla is always different

author: f4eru
author_rank: Super Contributor
timestamp: January 10, 2023, 09:14:03 pm
content: A charger that works in the cold.... WOW. Tesla is so innovating.......
Interfacing Fronius Symo Gen24 10 3 phase inverter with PVOutput - Page 1
Forum section: electronics / general

author: darksplat
author_rank: Newbie
timestamp: March 16, 2022, 04:13:05 am
content: Hi TeamI was wondering if you guys can help me with interfacing my Fronius Symo Gen24 10 3 phase inverter with PVOutput the specs are in the below link. I want to use the following GitHub script but have no idea how too.https://github.com/ngardiner/Fronius_PVOutput_Uploaderhttps://www.fronius.com/en-au/australia/solar-energy/installers-partners/technical-data/all-products/inverters/fronius-symo-gen24-plus/fronius-symo-gen24-10-0-plusI have my own website and hosting on crazydomains darksplat.com if I need to have that.I plan to have home assistant setup as well in the next few weeksI have a PVOutput account and have enabled the keyI just need a step by step guide for dummies to get it working. Can anyone help?CheersJeremy

author: darksplat
author_rank: Newbie
timestamp: May 09, 2022, 05:47:24 am
content: Just giving this a bump. Can anyone help?

author: darksplat
author_rank: Newbie
timestamp: December 31, 2022, 12:50:30 am
content: Just giving this a bump. Can anyone help?
Why does synchronous rectifier datasheet avoid the best advice? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: December 21, 2022, 06:51:53 am
content: Hi,The LTC3901 iss an excellent synchronous rectifier controller.The best way to use it is to NOT use the current sense inputs of it...but just to let it freely switch, and then when the load goes no_load, it just swings the output inductor current back and forth.As in the attached LTspice sim.So why does the LTC3901 datasheet not recomend this operation?LTC3901https://www.analog.com/en/products/ltc3901.html

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 21, 2022, 07:01:07 am
content: So it keeps magnetizing current flowing? Sounds wasteful.Tim

author: Faringdon
author_rank: Super Contributor
timestamp: December 21, 2022, 07:41:13 am
content: Thanks, if you let the fets get switched off when current is reversing in them, in pushpull+split coil output...then AYK, you get broken inductive current (output inductor), and huge overvoltage spikes on the synch fets.
LED tube that fits in place of fluorescent -- What's in it? - Page 1
Forum section: electronics / general

author: mcovington
author_rank: Regular Contributor
timestamp: December 19, 2022, 02:45:38 am
content: I have a whole room that used to be lit with F32T8 fluorescent tubes, and now is lit with the LED tubes that go in place of a fluorescent tube (with no alteration to the light fixture).What is inside these? Given that the lamp ballast is a current limiter, how much of its functionality can they use vs. having to limit current further, or do voltage conversion or something, internally?I know there's another kind of LED tube that fits in place of a fluorescent with the ballast removed, and contains its own mains power supply for the LEDs. I'm wondering how similar this is to that. I am using Philips "retrofit" tubes,https://www.lighting.philips.com/main/prof/led-lamps-and-tubes/led-tubes/master-ledtube-t8-ultra-efficientor similar.(That link is for a 240-volt product; I am using a 120-volt one.)

author: mcovington
author_rank: Regular Contributor
timestamp: December 19, 2022, 02:49:34 am
content: I see that Big Clive has taken this on.https://youtu.be/kOAaTMXiDCYNot quite the same, though, because his requires a special starter, but mine works with a rapid-start ballast (conventional or electronic).
free energy time! - Page 1
Forum section: electronics / general

author: ivi_yak
author_rank: Regular Contributor
timestamp: April 29, 2020, 11:18:16 pm
content: What do you think about this one perpetuum mobile ?https://youtu.be/zNLELxVZtW4https://support.wiliot.com/hc/en-us/categories/360001475734-Wiliot-Product-and-Technology

author: nuclearcat
author_rank: Unknown
timestamp: April 30, 2020, 03:35:38 am
content: On some pics they have quite large antenna and claiming energy harvesting module inside.It might work, no magic seems.

author: f4eru
author_rank: Super Contributor
timestamp: May 01, 2020, 03:36:34 pm
content: They claim their energy harvesting rectifier is "efficient" at -30dBm.I Built that kind of thing, and I don't believe that.

author: ivi_yak
author_rank: Regular Contributor
timestamp: December 04, 2022, 06:57:05 pm
content: Does anyone know an energy harvesting ICs?
Wrong use of Y capacitors on a Boost converter PCB? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: December 03, 2022, 12:20:46 pm
content: Hi,The attached shows the bottom layer of a Boost converter, 5vin, 24vout, 3A75 out, 350kHz.Customer has asked us to “make it work”. Customer is at “end of tether” with this PCB, and is even hard to get hold of to ask questions.This PCB sits on a metal plate. (you can see the 4 screw holes). The “Y” capacitors C25, C26, C17, C18 are 100nF 2220 1000V X7R capacitors. They are all connected from circuit ground to chassis ground.This PCB has no common mode chokes on it.Would you agree that the use of 100nF , 2220 capacitors makes no sense for common mode filtration? A 100nF, 2220 capacitor will have too much internal inductance (ESL) to be of good use in common mode filtration? Alternatively we should use around 1nF , 0603 capacitors for this purpose? (due to their lower ESL).Also, would you agree, that without the use of common mode chokes, the actual use of Y capacitors is almost a waste of time here?…..they are better than nothing, but really need to be used with common mode chokes?Also, these capacitors are of X7R dielectric. Would you agree, it is officially known that X7R is of no use for Y capacitor dielectric? X7R cannot “heal” after an overvoltage transient. Only Z5U or Y5U dielectrics can heal in this way?Also, these “Y” capacitors are rated 1000V. This is presumably due to an isolation requirement between chassis (metal base) and circuit nets. However, the clearance distance from circuit ground to chassis copper pour is just 0.25mm in places. (and that’s on the top layer). So do you agree, that 0.25mm would not meet any currently existent isolation safety requirement for creepage and clearance distance?

author: tggzzz
author_rank: Super Contributor
timestamp: December 03, 2022, 12:28:53 pm
content: Quote from: Faringdon on December 03, 2022, 12:20:46 pmIf you can't deal with the customer ----- don't.If you haven't the skill to sort out the board ----- don't try.Don't ask random strangers toremotelydo your work for you, based oninevitablyincomplete information. You never know, some might adopt the old usenet technique used for students that tried to get people to do their homework for them: feed them subtly wrong answers so that their tutors could see they didn't understand
Looking for a smart powerstrip with monitoring over ethernet - Page 1
Forum section: electronics / general

author: timg
author_rank: Newbie
timestamp: November 29, 2022, 05:06:41 am
content: I was wondering if anyone knows of a powerstrip/powerboard that has Australian GPOs, that comes preflashed with something like Tasmota? Bonus points if it has an Ethernet cable for data!At the moment I have a KP115, but it seems to disconnect from the wifi pretty often, even though the Wifi router is probably 100cm away with a clear line of sight. Drives me insane!I could get a bunch of the Athom 16A AU Power Monitoring Plugs (https://templates.blakadder.com/athom_PG05V2-AU16A-TAS) but I am scared that it would still not play nicely with the wifi network.Been thinking about maybe a managed PDU, but they all seem relatively expensive ($500+).Would be awesome if there was a power-board that had 10 general purpose outlets, or a mixture of outlets with GPO/IEC C13 that could be used to plug in computer power-supplies & monitors directly. A bunch of USB outlets for charging devices would be nice, but not necessary.(two monitors, two computers could be then plugged in directly with IEC 13 cables, and everything else, wall warts etc could be plugged in using their supplied cables).
Hard to grasp info on capacities of Lithium battery packs - Page 1
Forum section: electronics / general

author: abdulbadii
author_rank: Frequent Contributor
timestamp: November 28, 2022, 12:40:18 am
content: These are many different capacities of Lithium battery packs as PS to most, if not all, of cordless equipment/devices todayBut while they have a voltage value info also they have few confusing, hard to grasp info on:48Vf, 88Vf, 98Vf and 268VfSo what's actually the Vf all about ?Please whom I thank sincerely help clarify its true meaning

author: ataradov
author_rank: Super Contributor
timestamp: November 28, 2022, 01:05:10 am
content: The confusion is the goal. It means absolutely nothing, just a made up number for marketing reasons. You can safely ignore it and look at the actual stated battery capacity and voltage.This is like PMPO Watts for speakers.
Power to the People! (Freedom for Tooting) - Page 1
Forum section: electronics / general

author: PerranOak
author_rank: Frequent Contributor
timestamp: November 23, 2022, 04:33:43 pm
content: With the looming possibility of power cuts in the UK, I am wanting to run my router and FTTP wall thingy from a car battery.Is it simply a case of connecting them both to the battery and their internal regulators will take care of everything else?Great idea, yes?

author: rteodor
author_rank: Frequent Contributor
timestamp: November 23, 2022, 05:37:59 pm
content: 12V, 9V and even 7.5V switches and routers I encountered so far and tried worked fine directly from VLRA battery with solar charger. That is up to 15V when charging.But to have peace of mind I put some Pololu modules and a Meanwell DCDC converter RSD-60G-12 (60W Reliable Railway DC-DC Converter, 9-36Vdc input 12V output). Runs well this way for a few years already.

author: 2N2222A
author_rank: Regular Contributor
timestamp: November 25, 2022, 11:52:31 pm
content: Has anyone considered modifying a 12V regulated power adapter up to 13.3V, and then connecting a lead acid battery across that to provide back up power and changing at the same time? A diode and (resistor + PTC) in parallel would connect to the battery to prevent excessive charge current.

author: vk6zgo
author_rank: Super Contributor
timestamp: November 26, 2022, 01:07:27 am
content: I was delighted when I discovered that it was only 13 miles between Tooting & Barking!I'm sure that would work on a quiet night with an optimally aurally sensitive canine!

author: rteodor
author_rank: Frequent Contributor
timestamp: November 26, 2022, 06:00:06 am
content: Quote from: 2N2222AThere already are adjustable PSU's. I use Meanwell LRS-50-12 (two of them but not for charging). With a pot for tuning output voltage 10.2-13.8 V the PSU can be set to float charge forever and have the charger, battery and load(s) all in parallel. Still you_SHOULD_take care somehow of the battery. The biggest enemy of any rechargeable battery is over and undercharging. I knew this and still ruined half a dozen VLRA's by draining them out because I was not there to disconnect them when they were empty.If you charge from the power network there are battery protection circuits. Many solar chargers already have this protection built in.
Most reasonable current drawn from 20-21V brushed motor - Page 1
Forum section: electronics / general

author: abdulbadii
author_rank: Frequent Contributor
timestamp: November 23, 2022, 06:55:55 pm
content: What is the typical or the most reasonable current drawn, between medium to max load, from 20-21V brushed DC motor of cordless grinder ?Had it given a quite correct watt, would please elaborate the argumentative answer ?

author: Gyro
author_rank: Super Contributor
timestamp: November 23, 2022, 07:10:08 pm
content: I wish you wouldn't post these one or two line badly worded / unanswerable / incomprehensible questions.Argumentative enough?

author: Siwastaja
author_rank: Super Contributor
timestamp: November 25, 2022, 01:55:54 pm
content: For the motor itself? When applied a voltage, infinite current. The more the better. Motor current is actively controlled by the controller, to whatever current value required. In a realistic motor, resistance limits maximum possible current, sacrificing efficiency.Exactly the same story for driving LEDs or charging batteries.
Clarification on how is the cordless electric powered machine sourcing  - Page 1
Forum section: electronics / general

author: abdulbadii
author_rank: Frequent Contributor
timestamp: December 10, 2022, 03:27:56 am
content: How's actually the working mechanism of the cordless electric powered impact wrench or other cordless of kinds such nowadays? Why can't they bypass directly to source the mains 110/220V AC either with or without adapter ?as sellers say 'it can't', so confusing

author: Gyro
author_rank: Super Contributor
timestamp: December 10, 2022, 01:29:10 pm
content: Another incomprehensible question.Why don't you just buy a mains one.
Electrical generator compound transformer voltage control questions please. - Page 1
Forum section: electronics / general

author: Chris Wilson
author_rank: Super Contributor
timestamp: November 18, 2022, 08:02:20 pm
content: I am looking at either power take off (PTO) tractor driven single phase generators, or stand alone diesel powered ones of about 20kVA. I am in the UK, so it would need to be 230 volts and 50Hz. It appears to be a bit of a minefield to the uninitiated!My questions are, what is compound transformer based voltage regulation? I understand AVR control, (in it's most basic form), but how does compound transformer control work and what are its advantages and disadvantages? I think I have seen advertised generators that use a combination of compound transformer as well as AVR control?Can either compound transformer or AVR control work on both two and four pole alternators?Can a compound transformer regulated alternator be retrospectively changed to AVR board control if it's superior?Can all 12 wire alternators, two and four pole, be reconfigured to give either single or three phase outputs? (In future the ability to reconfigure the alternator to give 3 phase may be useful to me, albeit I realise the control circuits and meter box would need reconfiguring / modifying, too).Sorry for all the questions, but the more I probe the more the questions that pop up... Most people you talk to in generator sales are just salesmen, few seem to any in depth technical knowledge, and with the demand for generators right now they seem to be able to sell all they can make, regardless.Thanks.

author: jonpaul
author_rank: Super Contributor
timestamp: November 20, 2022, 04:51:05 pm
content: In 55 years as EE, never hear term " compound transformer"You meant autotransformer, step Down, variable?Jon

author: Chris Wilson
author_rank: Super Contributor
timestamp: November 20, 2022, 07:23:42 pm
content: No, it appears they are a multi tapped transformer with a variable air gap, used to control the output voltage of the alternator against changes in load and RPM. I attach a screenshot of some info from the manual for a Leroy Somer alternator, others seem to be similar. No manuals seems to give info as to the pros and cons of this method though. Thanks for the reply, it may be that some manufacturers or even countries use different terms for these things!The full manual is at:https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwi21eXhu737AhVFkFwKHU-jAIQQFnoECBEQAQ&url=https%3A%2F%2Fwww.leroy-somer.com%2Fdocumentation_pdf%2F3651_en.pdf&usg=AOvVaw2aQN6POLr0vdw-MqiEZ4mI
SMPS with LT1431 based "opamp integrator"  feedback - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: November 17, 2022, 07:56:25 pm
content: Hi,Can you see any pronbelms with the attached Buck feedback? The LT1431 is like an opamp with internal 2.5V reference.But wouldnt it be better with an RC between COMP and COLL aswell?LT1431https://www.analog.com/media/en/technical-documentation/data-sheets/1431fe.pdfLTspice and jpeg attached

author: jonpaul
author_rank: Super Contributor
timestamp: November 18, 2022, 03:27:20 pm
content: TL431 cheaper

author: Faringdon
author_rank: Super Contributor
timestamp: November 19, 2022, 12:00:22 pm
content: Thanks, i suppose you are right...but i wish someone would design a cheap TL431 alternative that didnt use its Vcc pin for the control current aswell.
Thermal reliefs not wanted for SMD inductor?....(dissipating 3.5W) - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: November 19, 2022, 11:43:26 am
content: Hi,Please confirm this footprint for an inductor is a joke?....We have a pushpull SMPS, 24VIN, 32VOUT, 225Khz, split secOutput inductor is IHLP8787 inductor 6.8uHhttps://www.vishay.com/docs/34350/ihlp8787mz5a.pdfIrms = 9.5A, therefore DC conduction loss is 0.27WVishay core loss calculator says we have 3.5w of total loss and 2.7w of core losshttps://www.vishay.com/en/inductors/calculator/calculator/do you think its too much?......there is no fan air...its in enclosed metal (Al) box....the footprint is as attached...its 4 layer PCB, screwed to the metal bottom of the enclosure.....no thermal vias in the inductor pads, and ridiculously thin thermal reliefs as shown.........surely that footprint and 3.5W is asking for trouble?Max external ambient 50degcHaving "no thermal reliefs" is allowed here?
Whats wrong with SMD FETs on PCB lying on top of metal plate/heatsink? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: November 26, 2022, 07:19:52 pm
content: What's wrong with heatsinking SMPS SMD FETs by having them on a PCB, with thermal vias going through to bottom copper pour...then 0.05mm thin thermal/insulator pad....then that PCB screwed to a metal heatsink/plate?...Why instead, do people put the SMD FETs on the bottom side of the PCB, then gouge out a divet in the metal plate for the said FETs, then gap-pad the SMD FET tops to the metal plate?

author: jpanhalt
author_rank: Super Contributor
timestamp: November 26, 2022, 08:27:15 pm
content: It's a trade secret. Publishing it here might get me deposed by my customer's, customer's, customer.
EcoFlow price - Page 1
Forum section: electronics / general

author: Bloch
author_rank: Unknown
timestamp: October 05, 2022, 08:26:38 pm
content: This mostly me ventingWhy is EcoFlow the only battery on the market ?? I mean there is no youtuber that dont "brag" about there new wonderful batterywonder how they all got one.I wonder if that the reason that they are so expensive for us non youtuberssome get the 4000 euro model others get the 2300 euros. And some get more than one unit.And for that reason alone i will not buy fromEcoFlow

author: f4eru
author_rank: Super Contributor
timestamp: October 06, 2022, 08:28:19 pm
content: Get an old school used UPS for 200Euros, change the batteries to lithium.

author: mikerj
author_rank: Super Contributor
timestamp: October 10, 2022, 08:23:56 pm
content: I agree the Ecoflow models seem pricey on the face of it, but if you compare with the other big name, Bluetti, they are pretty similar in price. I suspect both companies are doing well off the back of the scare stories regarding winter power outages in Europe

author: mikerj
author_rank: Super Contributor
timestamp: October 10, 2022, 08:28:50 pm
content: Quote from: f4eru on October 06, 2022, 08:28:19 pmNot quite that simple. To start with the charging circuitry and battery management will be for lead acid, not lithium, so that will need to be completely redesigned/replaced. There's no built in MPT solar charging, so that's another extra if you want to use solar charging.

author: Bloch
author_rank: Unknown
timestamp: November 12, 2022, 09:12:37 pm
content: www.youtube.com/watch?v=bXd-aP06lug?t=96Two more for a "free"

author: Haenk
author_rank: Super Contributor
timestamp: November 16, 2022, 11:37:36 am
content: These are simply advertising expenses - and likely well spent, as the viewer is a potential or likely buyer of the product.Compare this to advertising/sales costs on e.g. Amazon - those could be ranging from 10% to 30%.Giving away a free one to a YouTube-channel with 10k or more viewers as advertisement will certainly pay off.
Current sensing in a 500W Full Bridge SMPS - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: November 13, 2022, 12:37:04 pm
content: Hi,Do you agree, in the attached 500W Full Bridge (28Vout, FSW=250kHz), Position 2 is a better place for the overcurrent sense than Position 1?(LTspice and jpeg attached)(But of course, as we all know, that a Full wave rectified current sense would have been better, in Position 1.....but we are being told, the way its done uses one rectifier diode instead of 4)

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 13, 2022, 09:12:01 pm
content: Neither..?!Tim

author: Faringdon
author_rank: Super Contributor
timestamp: November 13, 2022, 10:28:57 pm
content: Thanks, so you prefer bipolar CST with full bridge diodes output in position 1?That would be my argument, but i am being told its three more diodes.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 14, 2022, 12:16:03 am
content: I'd do it on the primary side (CT into FWB), or secondary with a DC shunt with control circuit secondary referred. Perhaps both. Possibly with a GDT ala ye olde TL494 circuit.But doing an LLC is more feasible than ever these days, and current limit is somewhat free there.Tim

author: jonpaul
author_rank: Super Contributor
timestamp: November 15, 2022, 02:47:00 pm
content: at 500 W a double Foward is much simpler, full bridge unnecessaryJ