hybridfree/eevblog-posts huggingface dataset:
LM399H and LM399AH difference - Page 1
Forum section: electronics / general

author: AlfBaz
author_rank: Super Contributor
timestamp: April 22, 2016, 04:42:53 am
content: I remember reading in one of the many ref posts here, somebody suggesting the LM399AH was preferable to LM399H. I don't remember the details, possibly something to do with being able to supply less current to the heater... despite looking around (including data sheets) I cant seem to find the original post or any data on the topic. Anybody shed some light on the subject?

author: Andreas
author_rank: Super Contributor
timestamp: April 22, 2016, 04:57:54 am
content: Quote from: AlfBaz on April 22, 2016, 04:42:53 amI guess you mix it up with the LTZ1000A which has a different isolation against the LTZ1000 (non A).With best regardsAndreas

author: AlfBaz
author_rank: Super Contributor
timestamp: April 22, 2016, 06:56:48 am
content: Quote from: Andreas on April 22, 2016, 04:57:54 amAhh yes. That explains why I couldn't find it again. Thanks Andreas

author: AlfBaz
author_rank: Super Contributor
timestamp: April 22, 2016, 07:02:02 am
content: Quote from: DiligentMinds.com on April 22, 2016, 06:40:30 amThanks for that info.Looking at the datasheets there seems to be only columns for 399H/399AH and 199/299Is it that the specs are the same but the AH has more guaranteed specs than the H?In other words is it "guaranteed to meet better specs" or "guaranteed to better meet specs"?

author: wraper
author_rank: Unknown
timestamp: April 22, 2016, 07:48:56 am
content: Quote from: AlfBaz on April 22, 2016, 07:02:02 amYou didn't read the datasheet carefully. In the ELECTRICAL Characteristics table (page 2, tempco).http://cds.linear.com/docs/en/datasheet/199399fc.pdf

author: AlfBaz
author_rank: Super Contributor
timestamp: April 22, 2016, 10:04:58 am
content: Quote from: wraper on April 22, 2016, 07:48:56 amThanks wraper, to busy looking at the outskirts of the data tables looking for differentiation and not within them
NBS Technical Note 1239 Solid-State Voltage Standard Performance and Design Guid - Page 1
Forum section: electronics / general

author: zlymex
author_rank: Frequent Contributor
timestamp: March 14, 2016, 02:14:05 am
content: I got this link today from the volt-nuts mailing list:https://www.gpo.gov/fdsys/pkg/GOVPUB-C13-2c2d0649085cc34834a8f42deaad328e/pdf/GOVPUB-C13-2c2d0649085cc34834a8f42deaad328e.pdfPublished in 1987, I've been looking for this for ages, thanks very much Marv Gozum!Here are some of my remarks:1. Apparently Fluke designed its 732B out of it, 732A and 4910 did not becuase of the time.2. As far as annual aging is concerned, 732B is the same(if not worse) than 732A(3ppm/a) but specified as 2ppm/a to meet the Goal P13. Fluke also trimmed their design so that the battery operation time for 732B is 72 hours to satisfy Goal P84. Why the noise of <0.1ppm ppm rms so loose? Although 732A specified as <0.1ppm rms at that time but the actual performance is much better, and there exist 4910 which specified as 0.04ppm rms for one cell.5. Very tight tempco requirement of Goal P4 at 0.01ppm/°C that seems no manufacture have ever come close to achieve this.6. There are other goals saying the change should be below 0.01ppm/0.02ppm such as goal P5, P7, P9. My question is: how on earth they can distinguish minute changes as 0.01ppm when noise level at 0.1ppm? Long time averaging?7. Goal P16: A transport standard and its shipping container should be designed to accept g-forces as high as 120 g's in any direction without damage! Wow8. Is this guide valid now? Or there are new replacement?
IR thermometer for lab study - Page 1
Forum section: electronics / general

author: Rachie5272
author_rank: Regular Contributor
timestamp: March 18, 2016, 06:52:55 am
content: I'm doing a study on the electrical heating of graphite rods, and I need a way to measure temperature. Thermocouples are a bit too slow, and their heat capacity will alter the temperature. An IR thermometer seems ideal, but I don't know where to find one suitable for lab use.Consumer models simply display the temperature, with no means of recording it. I want to set up a continuous data logger. Also, I can't find any information on how temperature is determined in regards to the field of view. If half the field of view is at 20 °C, and the other half is 200 °C, would the measured temperature be the maximum, or the average? Is there a way to find the maximum?A proper IR camera would help here, but I can't quite justify its cost when I only need to measure a single point.

author: kleblanc
author_rank: Unknown
timestamp: March 19, 2016, 12:39:45 am
content: There is the Fluke VT02 that seems to have visual IR cheaper than a thermal imager. It does have software available for data logging and a near/far indicator. One possible issue you might have is the emissivity of the graphite might affect it's accuracy depending on the diameter.Omega makes bare fine wire thermocouple that might have a quicker response time (0.025mm @ 0.05 second in still air) than a IR gun. Thermal loss might be to much for you though as you mentioned, just thought I would mention it.http://www.omega.com/pptst/IRCO_CHAL_P13R_P10R.htmlHope this helps you in finding a suitable solution.

author: nidlaX
author_rank: Frequent Contributor
timestamp: March 19, 2016, 01:10:09 am
content: This sounds like a project where a Flir Lepton based sensing setup could make sense. The Lepton 2 will have 9 fps output, so I'm not sure if that's sufficient for your needs.
Datron/Wavetek 4600 transconductance amplifier - Page 1
Forum section: electronics / general

author: jfphp
author_rank: Regular Contributor
timestamp: February 09, 2016, 01:08:32 pm
content: Hello,I am looking for the op and service manual of the Datron/Wavetek 4600 transconductance amplifier. Thank you.

author: quarks
author_rank: Frequent Contributor
timestamp: February 09, 2016, 01:47:40 pm
content: if your unit is working you do not really need a manual, because it is very easy to use.There are two modes:- Solo Mode (without 480x calibrator) you only need to put in Voltage and 4600 gives out the corrosponding Ampere.- Slave Mode, if you want the best possible results, then connect it to a 480x calibrator. You then need a special cable set (details are described in the 480x manual (4600 = Option 60)). In this combination you only need to connect the 4600 output to your DUT and put the 480x in 10A range and do any settings on the calibrator.

author: jfphp
author_rank: Regular Contributor
timestamp: February 09, 2016, 06:43:19 pm
content: Thank you for answer but1. I need to calibrate it ; of course I have the necessary calibrated DC and AC shunts2. J54 is a DB15 but what about the manufacturer of the plug for J56 "analog connect" ?

author: quarks
author_rank: Frequent Contributor
timestamp: February 09, 2016, 08:13:23 pm
content: For the analog cable you need two different connectors from LEMO (male and female). I have to look for the exact part numbers and I can take a picture if that helps.

author: manganin
author_rank: Regular Contributor
timestamp: February 29, 2016, 10:04:25 am
content: Quote from: jfphp on February 09, 2016, 06:43:19 pmDCCalibrated at two output currents 0A and +10A, after that verified at -10A.* 0V in, adjust R411 for 0A out* +10V in, adjust R417 for +10A out* Verify at -10V in / -10A outACCalibrated at 10A 5kHz.* Compare DC and 5kHz AC at 10A by using a suitable shunt / thermal transfer standard. Adjust C424 for null on the thermal transfer standard.
MYSTERY : DONGLE WAVETEK/DATRON - Page 1
Forum section: electronics / general

author: jfphp
author_rank: Regular Contributor
timestamp: January 26, 2016, 11:46:07 am
content: Hello,I have found in a lot of metrology stuff a parallel port dongle SENTINEL Pro from RAINBOW Technologies with the following stickerRB-4AGFCE-B9717U24332Wavetek Datron.Any idea ?

author: crispy_tofu
author_rank: Super Contributor
timestamp: January 26, 2016, 11:55:42 am
content: It's a hardware token for some kind of software, but it'll probably be useless judging that it's parallel...

author: AlxDroidDev
author_rank: Frequent Contributor
timestamp: January 26, 2016, 12:59:19 pm
content: Quote from: crispy_tofu on January 26, 2016, 11:55:42 amI think so too. Rainbow uses to manufacture these copy-protection dongles. Where I work, all of our A3 digital certificate tokens are from Rainbow, but nowadays they use USB tokens.About your dongle, a quick google search shows that Wavetek (formerly Datron) was bought by Fluke in 2000.

author: acbern
author_rank: Frequent Contributor
timestamp: January 26, 2016, 03:31:32 pm
content: It may be for their Cal SW (forgot the part number) that was used when the were still independent. Just a guess. I tried to find some data about it some time ago, but nothing. If anybody has some clue about this SW let us know. It would be nice to know if anybody still has it running.
Weighted Averages For Analogue Signal - Page 1
Forum section: electronics / general

author: chakradhar
author_rank: Newbie
timestamp: January 13, 2016, 05:25:15 am
content: Weighted averages for knowing the brightest spot on a ccd sensor.

author: rs20
author_rank: Super Contributor
timestamp: January 13, 2016, 05:45:01 am
content: You can (at least in theory) find the position of a star in a photograph of the sky to an accuracy of less that one pixel. It's straightforward to do:-- If there's one bright pixel, then the star is centered in that pixel.-- If there's two bright pixels of equal brightness, then the star is halfway inbetween.-- If there's two bright pixels, but one is slightly brighter, then obviously it's closer to that pixel.In practice, you just find the "centre of light" (by analogy to the centre of mass) of the image. A weighted average of the coordinates of the pixels in the image, weighted by the brightness of each pixel.Presumably your device is doing a similar thing, except it's even simpler because it's only 1 dimensional.

author: LaserSteve
author_rank: Super Contributor
timestamp: January 15, 2016, 02:55:46 pm
content: POSSIBLY Diffraction patterns from the edges of the target and interpolation. ALSO can use the intensity distribution of the laser. If the laser was on a piezo, even better.Steve

author: mjs
author_rank: Regular Contributor
timestamp: January 22, 2016, 03:13:16 pm
content: The laser beam probably has about gaussian intensity profile, which hits multiple pixels. Calculating the centroid of the beam can easily give sub-pixel accuracies. You may need to take into account the thermal expansion of the silicon chip, as 50K temperature change expands the chip lenght by about 3umFrom a good quality 2D astronomical image millipixel resolution is easy and there are articles about micropixel resolutions!

author: chakradhar
author_rank: Newbie
timestamp: January 25, 2016, 11:22:00 am
content: Thanks a lot for the replies. This will get me started ... working on the possible algorithms based on the ideas.
Datron voltage reference PCB module pics. - Page 1
Forum section: electronics / general

author: lowimpedance
author_rank: Super Contributor
timestamp: December 04, 2015, 12:26:11 am
content: Here are some pictures of a Datron voltage reference PCB module which plugs onto another plug in card in an old 4800 series calibrator (the calibrator has had a fiery death and is now spare parts for 'other' still operational units!!).I have removed the plastic covers which ,(also have foam installed too), keep air currents off the LTZ1000.To note also the pcb is only 0.6mm thick.After searching around I could not find any pics of this module before posting these, so excuse me if it allready has been posted somewhere else.Also looking at it it would seem to follow the Datron schematic posted in the LTZ1000 thread.

author: TiN
author_rank: Super Contributor
timestamp: December 04, 2015, 04:15:39 am
content: Poor thing cooked itself up. Thanks for posting!

author: pelule
author_rank: Frequent Contributor
timestamp: December 04, 2015, 06:17:42 pm
content: Great posting. I guess its the first time.

author: Macbeth
author_rank: Super Contributor
timestamp: December 04, 2015, 11:31:42 pm
content: Excellent! I've seen that swastika cutout design a few times before.

author: crispy_tofu
author_rank: Super Contributor
timestamp: December 05, 2015, 09:24:17 am
content: Very cool, thanks for sharing!

author: HighVoltage
author_rank: Super Contributor
timestamp: December 05, 2015, 11:11:59 am
content: Thanks for these pictures.Is that PCB with its 0.6 mm still standard FR4?

author: Andreas
author_rank: Super Contributor
timestamp: December 05, 2015, 11:23:02 am
content: Hello,also a big thumbs up from my side.Especially the bottom side pictures is something that I have not seen before.With best regardsAndreas

author: lowimpedance
author_rank: Super Contributor
timestamp: December 06, 2015, 10:45:59 pm
content: Quote from: TiN on December 04, 2015, 04:15:39 amThe 'browned' area of the PCB substrate is in the heater supply circuit. (this area overheating is consistant in 2 other sample 4800's Ive seen)As for the fiery end, the high voltage output amps BBQ'd themselves.Another consistant failure which most likely caused the' cascade' BBQ was the main supply PCB electro's drying out, (only mains linear too), allowing excessive ripple into places it should not be!!.note to any 4800 series owners , servive the power PCB's with new electrolytics asap. and make sure the fan air flow is not impeded in any way!!.Quote from: HighVoltage on December 05, 2015, 11:11:59 amIt certainly has all the appearance of just being standard FR4., ie no different in any way to the other PCB material used in the calibrator.
HP 6642A calibration - Page 1
Forum section: electronics / general

author: jfgilbert
author_rank: Newbie
timestamp: January 19, 2016, 05:41:51 pm
content: Hello,I am trying to calibrate an HP 6642A powers supply. The process, as detailed in the operating manual is quite straightforward and does not require exotic equipment, so I decided to try it even though the supply is not significantly off. I am able to go through the complete process easily and it tracks the instructions exactly. The only difference is that, at the end, when I press the "Cal Save" button and it is supposed to reply with something like "CAL SAVED", nothing happens and it stays on the last message "CAL COMPLETE."Am I missing something, or is that a sign of something seriously wrong with the device?Thank you for any ideas or suggestions,Jacques
Datron 1281 Internal source Calibration Error codes 2202, 2192, & 2162 - Page 1
Forum section: electronics / general

author: starjohn
author_rank: Newbie
timestamp: April 22, 2013, 08:36:52 pm
content: I am working on a Datron 1281 meter.DC voltage calibration at 10v functions ok, but the Internal source calibration failed.This One has errors after Internal source calibration.Error codes:2202 1Kv Range zero magnitude test (P028).2192 100V Range zero magnitude test (P021).2162 10V Range zero magnitude test (P006).Is there anyone that has experience in repairing these instruments?Thanks,John
Vishay Z203 Precision resistor cost? - Page 1
Forum section: electronics / general

author: JBaughb
author_rank: Regular Contributor
timestamp: April 21, 2015, 09:28:59 am
content: Does anyone know the "ballpark cost" of the Vishay Z203 "Metrology standard" resistors (.005% .2ppm, drool-worthy)? I can't find them in all the usual places so it looks like they need to be purchased direct from Vishay. I could email them but I figured I would see if anyone has any experience with these.It would just be single quantity pricing.

author: amyk
author_rank: Super Contributor
timestamp: April 21, 2015, 03:06:29 pm
content: A quick Google findshttp://www.newark.com/vishay-foil-resistors-vpg/y144515k0000v0l/z203-15k0000-0-005/dp/88W7762

author: German_EE
author_rank: Super Contributor
timestamp: April 21, 2015, 03:11:05 pm
content: Considering the accuracy of the component I consider $42,90 a very reasonable price.

author: JBaughb
author_rank: Regular Contributor
timestamp: April 21, 2015, 05:15:53 pm
content: Quote from: amyk on April 21, 2015, 03:06:29 pmI know you'll think Im crazy, but that was not there a couple days ago. I did the "Vishay Z203" google search a went to the third page without getting any hits except the data sheet from the Vishay website.Now they're all over the place. Digikey, mouser, newark

author: TiN
author_rank: Super Contributor
timestamp: April 21, 2015, 06:52:56 pm
content: You can write mail to VPG and ask , they do sell resistors by piece.Cost for "usual" VHP Z202, Z203 is around 20-50$ depends on tolerance and resistance value (hermetic package) and around 7-30$ for plastic Z202's.Get ready for long lead time tho, like 8+ weeks at least.These are no "metrology standard" grade , just very stable usual parts.If you want "drool-worthy", they can age and train special resistors for you, with better than datasheet stability and TC. But get ready, as price goes real high real quick.My1Meg one, shown herecosts $244 a piece and took almost half a year to make. 190 ? + 19? pair is 283$. Still want em?

author: JBaughb
author_rank: Regular Contributor
timestamp: April 21, 2015, 09:09:31 pm
content: Very nice. Another day, perhaps. The metrology grade classification was claimed on the data sheet. Might not be as exact as yours but close enough for my current needs.

author: JBaughb
author_rank: Regular Contributor
timestamp: April 21, 2015, 09:10:42 pm
content: Quote from: JBaughb on April 21, 2015, 09:09:31 pmOh, and in case anyone is interested. I was directed to a supplier from Vishay who quoted me between $26 and $45 for each of the resistors.

author: TiN
author_rank: Super Contributor
timestamp: April 22, 2015, 10:56:08 am
content: Cost vary with resistance value. Why u need them 0.005%?
LiFEPO4 battery installation orientation, does it matter? To me no. - Page 1
Forum section: electronics / general

author: Zucca
author_rank: Unknown
timestamp: May 04, 2023, 02:50:21 am
content: I am planning to build my 16S battery pack with EVE LF280K.I would like to make two horizontal 8s strings laying on long side one on top the other, with terminals on the side (not on the top).I am surprised to find so much discussion on this topic:https://diysolarforum.com/threads/eve-lf280k-orientation.47128/https://diysolarforum.com/threads/lifepo4-on-its-side.5215/To me the installation orientation does not matter in a LiFEPO4.I even asked the EVE representative and in poor English it looks like the orientation does not play a role, as long the insulation between the cells is preserved.If know more than me in this please write a line below....TIA!

author: james_s
author_rank: Super Contributor
timestamp: May 04, 2023, 03:26:36 am
content: No, it makes no difference, they can be operated in any position. The only cells that are sensitive to orientation are flooded cells, mostly lead-acid, but flooded NiCD also exist.

author: Honusnap
author_rank: Contributor
timestamp: October 10, 2025, 11:42:36 am
content: It's wrong??? they can't be stored or used on their large sides.. nor upside down.Only posibilities : Vertically, vent on the top or on their small side.There is still some electrolyte in those ... check for EVE last PDF, they specify expressly NOT to store/use them on the large side.

author: ejeffrey
author_rank: Super Contributor
timestamp: October 10, 2025, 02:21:10 pm
content: The LiFePO4 cells can be operated in any orientation. The "vents" are only emergency overpressure safety valves. The cells are sealed under normal operation and won't leak or care about orientation.The only possible concern is physical forces in a multi cell battery. The housing of primatic cells is thin and not particularly strong. Depending on the pack construction it's possible that the wrong orientation would put pressure on some cells. So do follow the manufacturers directions. Most manufacturers say they can be oriented on any direction, but if yours says otherwise you should follow that.

author: Siwastaja
author_rank: Super Contributor
timestamp: October 10, 2025, 03:43:06 pm
content: The idea of correct orientation originates from manufacturers. I remember Winston/Thundersky actually instructing that the cells must not be oriented up side down. Whether thatreallymakes any difference is a different question. Maybe it was just one more Winston Chung's diversion, a way for them to explain away cell failures. Maybe orientation actually correlated with failures, root cause of course being in crap quality.
Inside Fluke's metrology lab - Page 1
Forum section: electronics / general

author: billclay
author_rank: Regular Contributor
timestamp: April 24, 2012, 10:58:45 pm
content: This article was really interesting and I thought I'd share:http://www.tmworld.com/article/521484-Go_inside_Fluke_s_electrical_metrology_lab.php

author: billclay
author_rank: Regular Contributor
timestamp: April 25, 2012, 12:06:28 am
content: Looks like this same link was already posted by robrenz on the 19th. Sorry, I did not see it.
There is an AD-powered chip that converts a single +24V power supply into a ±15V - Page 1
Forum section: electronics / general

author: BJ1023
author_rank: Newbie
timestamp: September 04, 2025, 08:41:24 am
content: There is an AD-powered chip that converts a single +24V power supply into a ±15V power supply.

author: BJ1023
author_rank: Newbie
timestamp: September 04, 2025, 09:35:58 am
content: Last time, it was about seeking answers.

author: BJ1023
author_rank: Newbie
timestamp: September 04, 2025, 10:00:39 am
content: I'm not a robot.

author: BJ1023
author_rank: Newbie
timestamp: September 04, 2025, 11:08:46 am
content: Dual power supply chip for AD operational amplifier

author: Simon
author_rank: Unknown
timestamp: September 30, 2025, 04:52:45 pm
content: Seriously you can't find a DC/DC converter by yourself?
Identifying mysterious IC in chinese inverter SPWM module (Probably an FMD part) - Page 1
Forum section: electronics / general

author: CharlieD
author_rank: Contributor
timestamp: August 22, 2025, 07:46:28 pm
content: Hello everyone:Due to the energy crisis in my country (Cuba), many people have purchased power inverters from China, of various generic brands (Unizuki, Tataliken, etc.). The main failure is due to human error (accidentally connecting 110V RMS AC to the output because they forget to flip the switch). When this happens, the H-bridge and the SPWM control module fail. The problem is that the module itself often cannot be replaced, and many technicians use the famous EGS002. However, this is a relatively expensive module in our country. If we could replace the IR2110 and the mysterious IC in these modules directly without using the EGS002, everything would be cheaper. The problem is that the uC has its part number erased.This is a module whose numbering hasn't been erased. Supposedly, the manufacturer is FMD and part number B2J5CKM, but no info available.And this is another one whose numbering has been erased, but you can still see the upper part of the FMD acronym.I've already contacted FMD by email, but they haven't responded. The idea is to determine exactly what kind of chip it is, whether it's a SoC or a general-purpose uC, and what possibilities there are for extracting its firmware. And if anyone has encountered these modules who could help with any information.So far I have a datasheet from FMD of several general purpose uC and one of them match the VDD;GND; Data and Clock pins pinout:The datasheet is here:https://share.google/80jtZMdjmGdawLHdvI'll reverse engineer it, and with the schematic it will be easier to identify. When I have it I'll upload it.

author: breeze1113
author_rank: Newbie
timestamp: September 24, 2025, 06:39:39 pm
content: Hi, I am on the same situation and so far have found only one picture which was not erased( the same as your posted picture). Have you had any luck to find any solution?

author: daisizhou
author_rank: Super Contributor
timestamp: September 25, 2025, 01:04:52 am
content: This is a microprocessor chip that generates a PWM signal.In other words, it has EEPROM or FLASH firmware inside.By the way, your email may not get a response, because few Chinese people use email, they usually use mobile phones or text messages to communicate.A reasonable solution is to use another chip to generate a new PWM signal to replace it,The FMD B2J5CKM is cheap, but getting its firmware is very difficult, and writing or reading data to it requires a dedicated programmer.

author: CharlieD
author_rank: Contributor
timestamp: September 25, 2025, 01:51:44 pm
content: No, ai tried contact FMD but 0 response, you can try it. What we do with that is adapt an EGS002 module.

author: breeze1113
author_rank: Newbie
timestamp: September 30, 2025, 10:14:31 am
content: Do have any information on how to adapt egs002? Anything will be halpfull.
Anti spark switch designing for high dc Power  - Page 1
Forum section: electronics / general

author: Chandra Sekar
author_rank: Newbie
timestamp: September 09, 2025, 02:58:58 am
content: Hai to all,Iam designing a antispark switch for my dc system.I need some expert suggestions on my design.Iam handling 80v dc 800 a load ,so i choosing 100v 400A nmosfet for pre- charging the bus by paralleling the 8 nos of MOSFET.I having doubt on whether SMD MOSFET have a capabilities to support or better go with through hole.We need to focus on inrush ,temp,and surge..

author: mtwieg
author_rank: Frequent Contributor
timestamp: September 11, 2025, 12:31:49 pm
content: It may be possible for the FETs to handle the inrush current. Most critical parameter is their SOA curves. SOA limits are not necessarily related to maximum current/power ratings, so make sure to read the datasheet carefully.Usually for handling very large inrush, the best method is to use a circuit like below (drawn with relays as the switches, but could be FETs). First you close RL1, and the bus charges slowly through resistance R. Then once the bus has been charged and current drops to near zero, you close RL2. This means the switches themselves see very little stress when switching, the resistor takes the abuse instead. The resistor can be selected to be much more tolerant of surge conditions than a FET/relay of the same size.

author: CaptainOneAye
author_rank: Newbie
timestamp: September 27, 2025, 12:54:25 pm
content: Never dealt with so much power before, but vacuum relays are often used to switch without a spark. No air, no spark.
Best way to do an ON/OFF controlled Boost SMPS? - Page 1
Forum section: electronics / general

author: makebit
author_rank: Unknown
timestamp: September 30, 2025, 06:26:14 pm
content: Hi,Which one of the following two Boost converters, A or B, is thebest way to do a 3Vin to 5Vout, 6A Boost converter in ON/OFF control mode?A works on the FB pin.B works on the Ith pin. (the "COMP" pin on the LM3478)The controller will actually be the LM3478, so please answer for that.Its similar to the LTC1871.LM3478https://www.ti.com/lit/ds/symlink/lm3478.pdf?ts=1759256751127&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM3478Schem and LTspice sim attached.

author: Claude
author_rank: Newbie
timestamp: October 02, 2025, 06:43:20 am
content: do you want to have no voltage on output when OFF, or no boost performed (mean you will have about 2.6V when off)?

author: nctnico
author_rank: Super Contributor
timestamp: October 02, 2025, 09:03:06 am
content: I don't quite see the reason to have so much circuitry in the feedback loop. This is likely to cause instabilities either way. Besides that the whole circuit looks super complicated for the purpose. I'd look for a boost controller chip with an enable input and synchronous rectification. For example this one:https://www.monolithicpower.com/en/mp3422.html. When the MP3422 is disabled, the output is disconnected as well.Without synchronous rectification, the power dissipation in the diode will be huge. Like in the 3W to 4W ballpark reducing the efficiency significantly. Even for Schottky diodes, the forward voltage is quite high at higher currents.

author: mtwieg
author_rank: Frequent Contributor
timestamp: October 02, 2025, 12:05:47 pm
content: Sounds like you're describingbang-bang control.Usually one adds hysteresis such that transitions between on and off don't happen so often (i.e. you should see it stay in each state for multiple switching cycles). In your simulations there's no hysteresis, so both of these circuits end up behaving more like pulse-frequency-modulated controllers (especially at lighter loads). Try adding 50-100kohm of feedback resistance to your comparators. Also reduce the load a bit, as it is the circuit can hardly maintain the output when on continuously, so you're not going to observe proper bang-bang operation like that.Why would you want to force a current-mode controller to operate as a bang-bang controller?
Automating a Sun GTI Limiter DC Precharge from Battery  - Page 1
Forum section: electronics / general

author: OB1
author_rank: Newbie
timestamp: September 13, 2025, 04:07:00 pm
content: Hello AllBecause the limiters DC input terminals are connected to a lot of capacitance conventional wisdom says connect the negative of the battery to its limiter terminal but before connecting the positive, manually dab a series resistor to the positive terminal for about a second to precharge the capacitors before connecting the positive lead proper to the terminal. Failure to do this will likely damage the limiter because of a very high inrush current.A 1000W limiter is arriving soon, the battery is 48V and I want to use a 100R inrush limiter resistor. A disconnected from battery positive lead is connected to the resistor which in turn connects to the limiter positive terminal. When the positive is connected to the battery need something to sense the arrival of the voltage wait a second before shorting out the resistor. Max dc amps is 1000/48 or approx 21A.In principle need to keep the drain on the battery to a minimum. Thinking of using a DC-DC SSR to short out the resistor.Any thoughts on the best way forward?

author: Seekonk
author_rank: Super Contributor
timestamp: September 24, 2025, 10:06:24 pm
content: Yes, I have thoughts. Don't use a SSR. I don't know what you are talking about when you say a limiter is arriving. BUT, solid state relays are not bidirectional. And if it was only in one direction you would likely need four SSR in parallel for that little 23A. I've taken them apart and done testing. Current claims are exaggerated, and series resistance is high. 100 ohms seems a bit high. This is a once in a while thing that should not be automated, just use the current protection device.
Derivation of Isolated Boost Converter Transfer Function - Page 1
Forum section: electronics / general

author: PeterElectronics
author_rank: Newbie
timestamp: September 14, 2025, 12:28:07 pm
content: I am deriving the transfer function (output voltage wrt input duty) of an isolated boost converter using small signal analysis. I have attached my derivation here with. But when I am inputing duty to the derived transfer fuction, the output waveform is wrong. What mistake I made while deriving?

author: mtwieg
author_rank: Frequent Contributor
timestamp: September 14, 2025, 01:05:15 pm
content: I haven't checked your state space model, but one thing to consider is what happens to capacitor Cc on transitions to modes 1 and 3. It looks like your state schematics assume Tc is an ideal switch and the lower terminal of Cc is floating in modes 1 and 3. But if Tc is a MOSFET, then its body diode will conduct, resulting in Cc being completely discharged. That might be why your state space model doesn't match multisim.Oh wait, if I squint I see that Tc is a P channel FET, ignore my previous comment.Consider the transition from Mode 2 to mode 3. Before the transition, Vc will be equal to Vo/N. Then during mode 3, Cc is completely disconnected so its voltage does not change. However in mode 3, Vo will change due to the load. Thus at the end of mode 3, Vc will be greater than Vo/N. At the transition to mode 4, when Tc turns on, you'd expect Cc to dump a massive impulse of current to C. But this breaks the state space averaging method entirely (requires that currents and voltages only vary slightly within each switching state, and be well-defined during transitions).What is the purpose of Tc and Cc anyways?

author: PeterElectronics
author_rank: Newbie
timestamp: September 15, 2025, 10:08:52 am
content: Tc is an N channel mosfet. I am using Cc and Tc for the active clamping. So that my primary side switches will get protected against the voltage spikes during power transfer modes (modes 3 and 4)

author: mtwieg
author_rank: Frequent Contributor
timestamp: September 15, 2025, 12:22:43 pm
content: Quote from: PeterElectronics on September 15, 2025, 10:08:52 amOkay, the direction of its body diode is what matters though.QuoteIf it's working as an active clamp against leakage inductance, its operation won't be properly modeled unless you also include the leakage inductance being clamped. And commutation of Tc should not be exactly in sync with the other switches. You would need more switching states in your model to properly account for it in the state space model. But I would not expect an active clamp circuit to have a large effect on the transfer function anyways, so that extra model complexity might not be worth much...
Need Help Troubleshooting My First SMPS Design (220VAC to 12V 60W) - Page 1
Forum section: electronics / general

author: synacle
author_rank: Newbie
timestamp: August 21, 2025, 09:49:39 am
content: Hi everyone,I’m working on my first switch-mode power supply (SMPS) design. It’s supposed to convert 220V AC input to 12V DC at 60W output.I’m not an electronics engineer and I don’t have formal training in this field – I’m just a hobbyist trying to learn.The transformer was custom-wound by a manufacturer in China. Here are the specs:Core: EE33Primary Inductance: 82 µHPrimary: 15 turns, 0.65 mm wireSecondary: 3 turns, 1.5 mm wireAuxiliary: 5 turns, 0.2 mm wireWhen I powered up the PCB for the first time, the transistor and Rsense resistors burned out instantly. I suspect my snubber/clamp circuit calculations might be wrong.I’ve attached a hand-drawn diagram of my transformer (see image).Could you please help me troubleshoot this design? I’d appreciate explanations in simple terms since I’m still learning.Thank you very much!

author: Magnethicc
author_rank: Contributor
timestamp: September 06, 2025, 05:50:56 am
content: Upload PCB too, it could be wrong connections.I see no soft-start circuit - could be too high duty on the flyback x'mer saturating it and blowing up the FET and sense resistors.see page 22 inhttps://www.ti.com/lit/ds/symlink/uc3842.pdfand follow their guidelines.

author: temperance
author_rank: Super Contributor
timestamp: September 09, 2025, 12:16:30 am
content: The primary inductance is probably too low.Given the primary inductance, the di/dt is around 3.7 A / µs with an input voltage of 300 V. With 82 µH primary inductance and an on time of 1 µs, you are trying to transfer 115 W to the output when switching at 100 KHz.The primary inductance must be around 450 µH for a DCM mode converter.With 450 µH primary inductance, the transferred power is 77 W when operating at 100 KHz with an on time of 3.5 µs for the primary switch.
Need a rechargable pack solution for product - Page 1
Forum section: electronics / general

author: viper
author_rank: Regular Contributor
timestamp: September 05, 2025, 02:59:35 am
content: Been working on a hopefully production product. Was first hoping I could get it done on a single cell and turns out I will need more voltage anyway, which means cells in series and a pack I'm sure. the main issue is temperature extremes between -20F and 130F. On the extreme ends of that, I may have to deploy other remedies but what I have found is LiFe cells are probably going to be more robust. I would sacrifice Wh but this needs to work in extremes. I already know I would have to reject any solar charging in extreme cold, and likely limit charging in extreme heat.But anyway, I am curious if there are sources for packs that are affordable and not scammish fake cells, with a temp sensor in the pack? I can't reliably modulate charging without that temp.As for the target, I sort of need to know what cell size for config is most economical. As example, the 18650 is a super common Lion size. I'm not bound by any space constraint, just the best Wh for the buck I guess.
MK 16A 2P+E commando connector K9024BLU.... screw torque???? - Page 1
Forum section: electronics / general

author: hazzer
author_rank: Regular Contributor
timestamp: August 22, 2025, 05:17:23 pm
content: RE the MK series on blue 16A plugs and sockets... ie K9024BLU as an example..I was searching for the correct screw terminal torque, found a sort of data sheet athttps://ie.farnell.com/mk/k9024blu/plug-250v-16a-2p-e-ip67-blue/dp/3459162but no mention of the torque or cable strip length (or more importantly the correct ferrule length?)is this something you just judge by feel / eye or has the manufacturer provided any guidance???Harry
Placing inductors and capacitors near IPM(IGBT's + DRV) - Page 1
Forum section: electronics / general

author: Piotr1991
author_rank: Newbie
timestamp: August 17, 2025, 07:29:01 pm
content: Hello everybody. I've just wanted to ask for a power electronics engineer's opinion about the output filter inductors and capacitors(output LC filter) placement next(15mm from the output pin to the inductor) to the "Intelligent Power Module", NFVA33065L42 in my case. Does it look dodgy?This device will drive a resistive load with currents of up to 10A per channel at 40 kHz PWM.This is my first experience in something more complicated than a simple DC/DC converter, and I will be grateful for any criticism of my PCB layout and component placement.The TO-247 MOSFET next to the IPM is the soft-start for the bulk capacitors. There are isolated shunt amplifiers next to the outputs.Thank you in advance.

author: jonpaul
author_rank: Super Contributor
timestamp: August 20, 2025, 05:58:16 pm
content: Dear Piotr:Few "Power electronics engineers" on this site. Very specialized profession , all are busy.We have no ide about the IC you used and have little patience to research the part and mfg:Just the PCB layers are useless to comment on unless you also post the schematic and include a link to the chip or IC used.Follow the IC mfg app notes and spec sheet on component choice, layout, details.Generally DC output LC filters are not critical in PCB placement, but are usually closest to the load /output terminals.Enjoy,Jon

author: mtwieg
author_rank: Frequent Contributor
timestamp: August 21, 2025, 03:04:54 pm
content: Quote from: Piotr1991 on August 17, 2025, 07:29:01 pmLike jonpaul said, output LC filter placement usually isn't super-critical. The extra trace length adds some inductance, but adding a bit of extra inductance to the filter inductor is not an issue. The one possible downside is that if the inductor is far from the switching node, then the switching node will have a larger area and therefore greater parasitic capacitance to other parts of the circuit. Might be an issue for EMC.Note that large ripple currents will be flowing along your ground planes between the inverter and the output filter caps. You should avoid any sensitive circuits or signals using that area as a return path as well.Priority should instead be given to placement of bypass/decoupling capacitors which carry hard-switched currents. In the case of an inverter like this, that would be capacitance across the DC bus. I'm guessing C109 is serving this purpose in your design. Looks okay to me, it's unlikely you could get that loop much smaller without making the design non-manufacturable.
Power Supply Modes: Constant Power - Page 1
Forum section: electronics / general

author: electroalchemist
author_rank: Newbie
timestamp: August 04, 2025, 11:38:50 pm
content: Hi, I’m curious about the applications of a constant power source — specifically, sourcing constant power rather than constant voltage or current. I understand it can be useful when the load changes and you want to maintain consistent power consumption, but what are the practical implications of this approach? In which scenarios is it actually preferred or required

author: TimFox
author_rank: Super Contributor
timestamp: August 05, 2025, 12:39:21 am
content: I have seen power supplies for electrophoresis that have constant-power mode, as well as constant-voltage and constant-current.https://www.thermofisher.com/us/en/home/life-science/protein-biology/protein-gel-electrophoresis/power-supplies-protein-electrophoresis.html

author: electroalchemist
author_rank: Newbie
timestamp: August 05, 2025, 01:13:20 am
content: Thanks — yes, that’s exactly what I had in mind as well. It seems the primary application is in heating control, where maintaining constant power helps regulate temperature despite changing loads and prevents potential issues. According to the specs, you can limit the power in 1W increments. Not very high resolution. Perhaps because biological systems are not sensitive to noise or accuracy?!

author: ejeffrey
author_rank: Super Contributor
timestamp: August 05, 2025, 01:27:40 am
content: Constant power supplies are pretty common for plasma sources such as magnetron sputtering supplies. This helps keep the deposition more uniform as the target is used up.

author: electroalchemist
author_rank: Newbie
timestamp: August 05, 2025, 01:45:42 am
content: Thank you. Yes, I believe their minimum output voltage is 500V to 1 kV, with power levels above 1 kW.
Oddball product issue - Page 1
Forum section: electronics / general

author: Croy9000
author_rank: Contributor
timestamp: July 29, 2025, 09:00:20 pm
content: I wasn’t sure where to post this, but since it’s related to my EcoFlo Power Hub hub figured I would try here.I have custom built a Sprinter camper van and have a AC mains convection microwave running off of the DC to AC inverter of the Power Hub.Since it’s a convection oven, I have installed 2 AC mains computer fans to help with ventilation. And in order to automate them turning on and off I bought a cheap automatic switch that detects the current draw from the microwave. It turns the fans on when it detects at least 30W of draw.It’s all working as expected except for one bizarre issue. Whenever the EcoFlo Power Hub goes into cooling mode, it’s triggering the automatic switch somehow. So essentially when the Power Hub fans kick on, so does the microwave fans I added. as long as the PowerHub fans are running the switch stays triggered.Can anyone think of what might be causing this?

author: thm_w
author_rank: Super Contributor
timestamp: July 29, 2025, 09:06:06 pm
content: Might be some sort of EMI issue.Did you try unplugging the microwave when the "cooling mode" is on and verifying the power outlet still stays switched on?

author: Croy9000
author_rank: Contributor
timestamp: July 29, 2025, 09:16:19 pm
content: Yeah, I did actually. Unplugging the microwave did turn off the automatic switch after its normal delay, while the Power Hub fans continued to run. Which kinda makes it even more bizarre.I will say the Power Hub is pretty far away from the microwave and switch (half a vans length).

author: thm_w
author_rank: Super Contributor
timestamp: July 29, 2025, 09:25:57 pm
content: If you have a AC power meter, put that in series and see if the microwave is drawing any power during that time.Filtering might help, or you could probably modify the unit to not trigger until it sees a much higher power draw (say 300W).

author: paul8f
author_rank: Regular Contributor
timestamp: August 04, 2025, 10:27:05 am
content: What's the brand and model of the automatic switch?Do you have any of its specs available?
Deye Hybrid Inverter Breaker Trip - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: August 04, 2025, 01:50:32 am
content: Another Deye issue:

author: Poroit
author_rank: Frequent Contributor
timestamp: August 04, 2025, 07:05:49 am
content: How hot is the breaker and its adjoining mate during normal operation?

author: EEVblog
author_rank: Unknown
timestamp: August 04, 2025, 07:47:07 am
content: Quote from: Poroit on August 04, 2025, 07:05:49 amWould have to take home the thermal camera. But it wasn't a problem in summer, so can't see how that's a problem in winter.

author: themadhippy
author_rank: Super Contributor
timestamp: August 04, 2025, 10:09:08 am
content: 1:45 "its raining" could be a clue,might want to pop the some covers off and see if any wet stuff has got in

author: rteodor
author_rank: Frequent Contributor
timestamp: August 06, 2025, 05:43:05 am
content: It might be the grid, not necessarily the inverter.It happened to me a few times (before and once after the solar installation). Never found the cause but I tend to blame it on the grid because it happened more often before a big rework on the local grid.

author: EEVblog
author_rank: Unknown
timestamp: August 06, 2025, 09:07:58 am
content: Issue seems to have been that the Deye has an inbuilt earth leakage circuit and it recommends a 300mA RCD at the board (or none)When I did the switch board upgrade a 30mA RCD was accidentally installed.
Full charge detection with older NiMH cells - Page 1
Forum section: electronics / general

author: Circlotron
author_rank: Super Contributor
timestamp: July 23, 2025, 06:06:20 am
content: I have two sets of four size AA nickel metal hydride cells that are used for my radio. Once set is about three years old, and the other one is only maybe three months old. With the older set, sometimes one or two of the the cells when on charge instead of cutting off at about 2800 mAh will go all the way to 4000 or so. Does this mean they are getting towards the end of life and the decrease in charge voltage at full charge is getting less well-defined?

author: Gyro
author_rank: Super Contributor
timestamp: July 23, 2025, 11:27:11 am
content: Possibly an increase in internal resistance that, yes, makes the charge voltage drop (more shallow with NiMH, than NiCd to start with) less well defined. That's only a guess though.To keep them out of e-waste, as long as you're charging when you're around, do a periodic finger test - when they get significantly warm, they're done. It's the end of charge temperature rise that causes the voltage droop.
Ocean View, Hawaii   Having some poverty, but lots of OFF GRID SOLAR - Page 1
Forum section: electronics / general

author: RJSV
author_rank: Super Contributor
timestamp: July 19, 2025, 07:02:18 am
content: The big island, they call it here. Normal resident folks have, often, no power or water formal hook-ups (like electric power poles and wires.Strikes me as a lot of opportunity, for the handyman or contractor-builder types.Many folks have basic solar, for lighting and charging cellphones...things like that. But even an electric clothes washer is often too much; too much in terms of power, but also the water pump needed can be a load management problem. (So down the hill, folks go, to the town laundymat.The drinking water must be sulphur-free (volcanoes, remember) and the (daily) rain can eat your garden tools, vehicles, anything metal left outside. Lots of properties up here (3000 ft altitude) have a kind of 'settler' or colonist look; just starting out. Everyone seems to need a plumber !