hybridfree/eevblog-posts huggingface dataset:
What can I do with this - Garmin Handheld GPS circa 2000 - Page 1
Forum section: electronics / projects

author: xrunner
author_rank: Super Contributor
timestamp: April 21, 2015, 09:21:58 pm
content: Cleaning out a drawer I found this - an old Garmin GPS I got to do geocaching. It's old school black and white and serial RS-232 port. I don't have any need for it now. Runs on 3V, last time I had it on it found the satellites. What can I do with it? Can I get some kind of frequency standard out of it? Any ideas? I'll take it apart but I haven't found out how yet.Might have to be a destructive tear-down.

author: Lightages
author_rank: Unknown
timestamp: April 22, 2015, 12:53:57 am
content: The standard NMEA output over RS232 will not be accurate enough for any kind of time reference. Maybe inside you can find something that is stable but I doubt it.

author: linux-works
author_rank: Super Contributor
timestamp: April 22, 2015, 03:04:17 am
content: it will be within half a second. for clocks that 'set themselves' that's good enough.maybe you can find a PPS signal on a chip or trace somewhere, inside?the gps modules I buy from ebay are $15 and have serial nmea as well as pps (via a led). gps is cheap, these days, even with pps output.

author: Rick Law
author_rank: Super Contributor
timestamp: April 22, 2015, 03:24:58 am
content: Another vote as clock - I've been using my old TomTom as the time standard for the house.The serial data doesn't give me fractional seconds, but good enough that I know I am +-1 second from real time out there.

author: wkb
author_rank: Super Contributor
timestamp: April 26, 2015, 10:04:48 pm
content: Why wreck it? If it still works sell it, give it away to someone who can use it. E.g. my Legend became a backup-GPS aboard a sailing vessel.Wrt use as a clock: these units do not have particularly sensitive rx so your clock better be close to a window.Don't understand all these people wrecking functional stuff. As if we do not have enough e-thrash

author: aargee
author_rank: Frequent Contributor
timestamp: April 27, 2015, 01:35:13 am
content: I gave my old Magellan hand held to a local fisherman at Vanuatu.He religiously takes the batteries out when not used and it helps to find home if things go pear shaped.
what can i use instead of this cap? - Page 1
Forum section: electronics / projects

author: navidrct
author_rank: Regular Contributor
timestamp: May 18, 2016, 07:29:50 am
content: hiin this capacitor power supply i use film cap 2.2 uf for input and its large.i want to have small power supply without transformer.what can i use instead of this c2 cap?it be cool if i can use smd cap in seri or somthingi want 3.3 v and 200 mA in output and input is 220 AC .

author: Gyro
author_rank: Super Contributor
timestamp: May 18, 2016, 09:21:05 am
content: A transformer or small smpswouldbe a more sensible replacement because:1. 200mA is a lot of wasted power - you are pulling a whole 200mA from the mains supply to feed a <1W circuit2. A 2.2uF X1 rated capacitor (yes, it does need to be X1 rated for safety, you won't find anything in SMD) is going to be large and potentially expensive.3. A transformer or small SMPS is likely to be smaller.4. Isolation from the mains supply is always preferable.Capacitive droppers are certainly widely used, but for lower current supplies, usually at higher voltages so the efficiency is much better that you have here.

author: navidrct
author_rank: Regular Contributor
timestamp: May 18, 2016, 10:44:29 am
content: Quote from: Gyro on May 18, 2016, 09:21:05 amthanks alot that was helpful

author: Miyuki
author_rank: Frequent Contributor
timestamp: May 20, 2016, 11:03:12 am
content: This is good alternativehttps://ac-dc.power.com/products/linkswitch-family/linkswitch-tn/

author: tggzzz
author_rank: Super Contributor
timestamp: May 20, 2016, 02:05:14 pm
content: Forget about how a circuit like that works; defineallthe failure modesfirst.Don't forget to be very veryverysure that, when (not if) a component malfunctions, that failurecannotharm anybody. I don't particularly care if you harm yourself; that's your business. Harming an "innocent" third party is a different matter.

author: navidrct
author_rank: Regular Contributor
timestamp: May 20, 2016, 02:07:02 pm
content: Quote from: tggzzz on May 20, 2016, 02:05:14 pmI'll use it in a plastic case in a lumpSent from my HTC Desire 820ts using Tapatalk
what causes issues with LED replacement bulbs into ballast fixtures? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: May 25, 2019, 09:10:06 pm
content: So I got a buncha lightbulbs to replace old tubes. In some fixtures, I had bizzare behavior with certain phillips bulbs. Like they would turn on for 2 seconds and turn off, no matter how much I finagled with it. Then when I replaced the old bulb, it would not work at all. However, I got NEW phillips bulbs from a different home depot and installed them, that worked. So I put the old ones I bought last week back in, and they worked.. its almost like the warm white bulb fixed the daylight bulb.It's in the attic and I don't want to work up there because its very hot... is it just a random connection problem or some thing like the ballast having some kind of memory?It's hard to believe its a connection problem because I was up there for like 15 minutes replacing a buncha bulbs and rotating them and stuff, and the new bulbs just seemed to fix the old ones, and they have been working fine for a long time.*Another fixture in the garage did the same thing last week, and I also replaced the phillips daylight with the phillips warm and then put the daylight back in and it worked... they look identical but I did not do anything crazy like try to measure the pins with a caliper etc. They 'felt' the same during insertion.It very consistently would turn off after being turned on for like 4 seconds, then had to be powered down for a bit before it worked again.Did something maybe get bent by slightly different pin orientations or something? This only happened with the phillips daylight bulbs, 4 foot T8, the phillips warm white bulbs all worked and seemed to 'fix' it. It's to the point where I was about to take the fucking thing apart to remove the ballast but I thought 'maybe' it will fix it, and it did. What the fuck. I kinda wanna replace the fixture, but its also in the god damn attic and working up there is a complete bitch.
what chips do I need to charge 2 18650 batteries? - Page 1
Forum section: electronics / projects

author: abdelhaleem
author_rank: Newbie
timestamp: February 12, 2023, 07:00:09 am
content: I need to charge 2 18650 batteries with one single chip, don't want to use 2 tp4056.

author: mariush
author_rank: Super Contributor
timestamp: February 12, 2023, 08:26:46 am
content: Here's a thousand or so, with around 100 in stock :https://www.digikey.com/short/m3n32z25for example MCP73842 :https://www.digikey.com/en/products/detail/microchip-technology/MCP73842T-840I-UN/593745MCP73844 lacks the temperature sensor pins, and it's cheaper if you don't need temperature monitoring of the battery cells.MCP73844 with 8.4v cut-off :https://www.digikey.com/en/products/detail/microchip-technology/MCP73844T-840I-MS/593753MCP73844 with 8.2v cut-off :https://www.digikey.com/en/products/detail/microchip-technology/MCP73844T-820I-MS/593752
what comes first reverse protection or EMI filter? - Page 1
Forum section: electronics / projects

author: slloyd
author_rank: Contributor
timestamp: October 16, 2021, 05:39:44 pm
content: hi all, for functional reasons i'd like to put the reverse protection circuit ahead of the EMI filter. does this affect how well the EMI filter will work due to the reverse circuit's body diode?

author: Gyro
author_rank: Super Contributor
timestamp: October 16, 2021, 07:18:05 pm
content: It certainly puts more components, PCB area, and tracks before the filter. These can all act as antennas, reducing the effectiveness of the filtering - and exposing the active semiconductors to the unfiltered supply.It's not ideal to have anything before the filter.
what component could this be? - Page 1
Forum section: electronics / projects

author: Cicada
author_rank: Regular Contributor
timestamp: November 01, 2023, 01:42:30 pm
content: HiIs this a resistor or diode or something else. With my fluke on diode test and the red probe on top of the left hand side component and the black at the bottom common point I get 2V. When reversed I get OL.With the red at the top (+ symbol) on the right hand side I get 1V. Not sure what the rest of the circuit looks like.EDIT: They are small. They are the same size as an axial resistor (size 0623 as shown in the link)https://docs.rs-online.com/8f1a/A700000008491009.pdfThe resistor of the same size have the footprint hole spacing at 400 mils = 10mm just like these components.Please help?Thanks

author: Gyro
author_rank: Super Contributor
timestamp: November 01, 2023, 01:47:47 pm
content: They look like axial tantalum capacitors, I'm surprised that there are no part markings visible though.

author: Cicada
author_rank: Regular Contributor
timestamp: November 01, 2023, 01:57:17 pm
content: Quote from: Gyro on November 01, 2023, 01:47:47 pmPlease see my original post. I have updated it.

author: TimFox
author_rank: Super Contributor
timestamp: November 01, 2023, 02:15:52 pm
content: Axial tantalum capacitors in that package have the + terminal on the beveled end.Usually, that package is yellow.0.4 inch between hole centers is possible for a low-valued unit: the data sheet below includes units with 0.260 inch body.https://www.mouser.com/datasheet/2/447/KEM_T2039_T322_AXIAL_T323-3316824.pdf

author: Cicada
author_rank: Regular Contributor
timestamp: November 01, 2023, 03:11:49 pm
content: Quote from: TimFox on November 01, 2023, 02:15:52 pmAwesome, awesome, awesome. I love this website.Ok so I had a colleague with very good eye site have a look at the marking. After a lot of struggling he could make out the following marking. 125k 35V+ And the line beneath read 305 with a 2 in a circle.I also measured the case size Lenght = ~ 7mm or 8mm and the diameter = ~ just below 3mmSo from the datasheet supplied above I was able to establish what part this is.125 = 1200000pF = 1.2uF As shown in the table top of page 2k = +/-10% tolerance in same table35V = 35 Volt dc rating.According to the dimensions table on page 3 this is a case size B.Punching this into mouser and selecting the T322 series from KEMET brings this results up. I think this is 100% correcthttps://www.mouser.co.za/c/passive-components/capacitors/tantalum-capacitors/tantalum-capacitors-solid-leaded/?capacitance=1.2%20uF&m=KEMET&series=T322&tolerance=10%20%25&voltage%20rating%20dc=35%20VDCI consider this problem solved.

author: TimFox
author_rank: Super Contributor
timestamp: November 01, 2023, 03:37:55 pm
content: I have used tantalum capacitors of this type, and I remember that the absurdly small lettering was very hard to read even on a brand new part.
Alternative for LP2980AIM5-4.5 - Page 1
Forum section: electronics / projects

author: fx991ex
author_rank: Contributor
timestamp: August 09, 2018, 10:39:31 am
content: I need to replace a LP2980AIM5-4.5 ultra low dropout regulator on a circuit board. The regulator was made by National Semiconductor but is no longer in production. Is there an alternative that I can replace it with?

author: RobK_NL
author_rank: Frequent Contributor
timestamp: August 09, 2018, 02:21:19 pm
content: The LP2980 is a bit tricky to repkace, since it is a semi-precision device with a very low dropout voltage. The NCP699 might do.

author: fx991ex
author_rank: Contributor
timestamp: August 12, 2018, 12:06:58 pm
content: Thank you Rob!LP2985 and NCP699 seem to be interchangable. I would rather buy from TI because they are more easily accessible where I live.Is there any difference between LP2985 and LP2980 except for the putout current? LP2985 is still available in 4.5V.

author: RobK_NL
author_rank: Frequent Contributor
timestamp: August 12, 2018, 06:41:40 pm
content: Mmmh, don't know why I missed the LP2985. Must have been because I searched on my 'phone.The LP2985 seems a good replacement, although with higher output voltage tolerance (1%vs. 0.5%). Dropout voltage is the same, so thatwon't cause any issue.
What component is this? - Page 1
Forum section: electronics / projects

author: vovoj
author_rank: Newbie
timestamp: January 19, 2019, 04:20:24 pm
content: Hi,I was trying to fix this board when I stumbled with these components, which are highlighted on the images attached, that seem to be resistors. Does anyone know what component is this? If it's indeed a resistor, what kind of resistor is this?

author: floobydust
author_rank: Super Contributor
timestamp: January 19, 2019, 05:37:51 pm
content: I believe those are Siemens thermistors. The resistance number is for 25ºC.They seem to be monitoring temperature of the power resistors/IC nearby.

author: vovoj
author_rank: Newbie
timestamp: January 19, 2019, 06:15:32 pm
content: Interesting. I will review the board to see if it makes sense they being thermistors. Thanks.
What component is this? - Page 1
Forum section: electronics / projects

author: Pantelis
author_rank: Newbie
timestamp: December 07, 2019, 11:12:53 pm
content: Does anybody can find which cpmponent is this? it is |RC41

author: exmadscientist
author_rank: Frequent Contributor
timestamp: December 08, 2019, 09:17:46 pm
content: Any chance it's aTorex XC6368? It's a SOT23-5, and the marking code for XC6368F/100kHz/2.4V would beRC4, with the1being a lot mark. Pin 4 on that part is ground, which matches the fat traces you show.

author: t1d
author_rank: Super Contributor
timestamp: December 08, 2019, 11:38:56 pm
content: Please tell us what the device is. And, where the component is in the circuit, if you can tell... Part of the power supply circuit, part of the volume control circuit, etc... It would give us some much needed clues.
What components do I need to power a ceramic heating element on the go? - Page 1
Forum section: electronics / projects

author: crunchercrunch
author_rank: Newbie
timestamp: February 19, 2015, 12:02:12 am
content: Hello all.I've got one of these:http://www.ebay.com/itm/12V-150W-AC-DC-PTC-heating-element-heater-Electric-heater-ceramic-Thermostatic-/261397773653?and I want to bring it around with me. What options do I have to power it so I can use it whenever and wherever I go?

author: Mr.B
author_rank: Unknown
timestamp: February 19, 2015, 12:10:53 am
content: A trampers frame pack and a couple of car batteries...

author: ajb
author_rank: Super Contributor
timestamp: February 19, 2015, 12:18:20 am
content: Taking the eBay specs at face value, you'd need a power source capable of providing 12V at 12.5A for as long as you want to run it. If you want to run it for an hour, you'll need a battery with a capacity of at least 150 watt-hours. For comparison, a typical 18V Li power tool battery is 50-60 Wh.

author: crunchercrunch
author_rank: Newbie
timestamp: February 19, 2015, 12:20:53 am
content: Thanks guys. It really seems like a giant battery will be what I'll need. Any tips for safely handling connecting the terminals?It seems the standard voltage for car batteries is 12V. If my heater was at a higher voltage (for example, just say, 48V), is my cheapest option to just tie the batteries together in series? Or are there other options for higher voltages?

author: Whales
author_rank: Super Contributor
timestamp: February 19, 2015, 12:31:13 am
content: Running it at a lower voltage will reduce power draw and heat output but it will still work fine. If it says something like 48V then that's what the other ratings (eg wattage) are for.For this power level connecting batteries in series isprobablyyour best option. A 'boost' converter to get higher voltages is a great solution in a lot of situations, but if you need to be delivering more than several amps it's probably quite costly.
What conformal coat thickness should I spec for automotive PCB - Page 1
Forum section: electronics / projects

author: Psi
author_rank: Super Contributor
timestamp: July 07, 2023, 04:36:01 am
content: I'm getting some PCBs made at PCBway and I want to get them conformal coated.They are for automotive purposes. PCB will be in a small box that is in a bigger box that is mounted on a trailer.PCBway have said their normal conformal coat thickness is between 50-150um but they can do more coats to get it thicker if I need.What is a good thickness without being excessive? 50-150um seems pretty thin to me.

author: Karmaslap
author_rank: Newbie
timestamp: July 07, 2023, 08:01:02 am
content: I do not work in automotive, so I can only lend an opinion and not talk from experience. To me, 6 mils already seems thick for a conformal coat. As you said, the PCBs will already have their own enclosure to protect them, and its even inside another box. The conformal coat here just needs to keep any dust that works its way in out (and maybe help dampen vibrations).So, what would the benefit be to making the coat any thicker? The dust shouldn't be hitting the PCB at high speed. You should use adhesive to hold anything else in place.If you really feel like 6 mils is insufficient, or you are worried about vibration, you might want to just skip the conformal coat and pot the whole thing to keep it as safe as possible. That's what I'd recommend anyway for something going on a trailer, unless you need access to the PCB.

author: Shonky
author_rank: Frequent Contributor
timestamp: July 07, 2023, 08:07:17 am
content: 150 um/micron is plenty enough IMO. They are usually meant to be breathable too so more isn't always better.Here: wikipedia even says 25-250 micron is typical.https://en.wikipedia.org/wiki/Conformal_coating

author: coromonadalix
author_rank: Super Contributor
timestamp: July 07, 2023, 05:21:12 pm
content: one solution is to dip the pcb's, protect all the connectors, and do the dip ...to protect the connector(s) we used peeloff "foam spread"or there is one, can't recall the name, but looked like soft gelatine, that way you can do rework easily and patch it back

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: July 07, 2023, 06:45:06 pm
content: No idea, but some additional advice. To keep costs low, if you need a minimum, specify it. If you don't need a maximum, don't specify it. It's always harder to guarantee falling within a window, then to just achieve at least a certain thickness. Easier for the QC people too. Read the coating manufacturer's literature and data sheets to see what they suggest. Chances are that they know best.

author: liaifat85
author_rank: Regular Contributor
timestamp: July 10, 2023, 07:51:22 am
content: A coating thickness of 50-150um is generally considered suitable for automotive applications.

author: Psi
author_rank: Super Contributor
timestamp: July 10, 2023, 09:07:14 am
content: Ok cool, Thanks everyone.I will leave the spec as the default 50-150um unless I encounter problems.
What connector is this? - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: July 09, 2024, 10:43:27 pm
content: Hi,does anybody know what connector family/model this is?It looks like it is mains rated, 20mm long by 8.6mm wide, wire-to-wire and one of the short sides has both corners chamfered.Thank you

author: David Hess
author_rank: Super Contributor
timestamp: July 10, 2024, 12:32:45 am
content: Molex series 1396 or Standard 0.093".https://www.molex.com/en-us/products/part-detail/03092031It can definitely be used for line voltages. The smaller Standard .062 can also be used for line voltages.

author: stj
author_rank: Super Contributor
timestamp: July 10, 2024, 01:57:05 am
content: those are used to connect 240v mains cables into arcade games and vending machines,they are very reliable.

author: ricko_uk
author_rank: Super Contributor
timestamp: July 10, 2024, 10:44:21 am
content: Thank you both
What connector is this ? - Page 1
Forum section: electronics / projects

author: marcus67
author_rank: Newbie
timestamp: October 15, 2025, 10:01:29 am
content: Hi guys ,in this picture I want to show you my 14 PIN debug connector from an older MSI GT70 Notebook.Does anyone know which female plug I can buy ?All ribbon cables I have found have two rows. But this has only one row and the pitch should be 1,27 mm I guess not 2,54 mm.See Attachment , pls. I do not know how to put a picture in my post.
What connector is this - Page 1
Forum section: electronics / projects

author: Cicada
author_rank: Regular Contributor
timestamp: September 15, 2017, 12:03:57 pm
content: HelloCan anyone tell me what connector this is. it would be great if you can tell me what manufacturer and what part number. I have google image searched but can't find a match.Thanks a lot.Cicada

author: Monkeh
author_rank: Super Contributor
timestamp: September 15, 2017, 12:10:15 pm
content: Looks awfully like a Molex Picoblade.

author: Cicada
author_rank: Regular Contributor
timestamp: September 15, 2017, 12:37:54 pm
content: Quote from: Monkeh on September 15, 2017, 12:10:15 pmThe body of the connector does look like the Molex Picoblade but..... the front face of the connector does not. The molex connector have one row of pin holes on the front of the connector. See attached picture.The pictures I posted have what looks like two rows of pin holes. One row is bigger and looks like (also in same position) the molex connector's. But they are blank. I.e. there is only indentations in the palstic but no pin holes. The actual pin holes is the smaller row on the bottom. You can see the crimp terminals in this position/row when you look at the picture where the connector is turned around.I should have measured the connector dimensions. This would have being a good clue. I think this is 1.27mm spacing.I will do a post with dimensions when I am at home. I hope this post will still have some life in it by that time.

author: Cicada
author_rank: Regular Contributor
timestamp: September 15, 2017, 07:50:54 pm
content: It is indeed a molex picoblade connectorThanks Monkeh
What connector looks like a 4-pin IEEE 1394 connector, but is slightly smaller? - Page 1
Forum section: electronics / projects

author: daloev
author_rank: Contributor
timestamp: May 12, 2022, 04:17:46 am
content: I'm trying to find a connector that will fit into a 4 pin port on an Endace DAG 9.2X2 network capture card. It looks like an IEEE 1394 4-pin connector, but is slightly smaller. I have been unable figure out what it is or, more importantly, how I can get a plug that will fit. Does anybody have any ideas? Attached is a picture showing a 4-pin IEEE 1394 cable on top and the connector in question on the bottom.

author: JDubU
author_rank: Frequent Contributor
timestamp: May 12, 2022, 04:57:17 am
content: The datasheet says that it's a IEEE-1394 connector:https://stordirect.com/wp-content/uploads/woocommerce-products-data/product_documents/endace-dag-9.2x2-datasheet.pdf

author: Haenk
author_rank: Super Contributor
timestamp: May 12, 2022, 07:16:59 am
content: https://tecklink.fr/produit/ineck-firewire-ieee-1394-cable-4-vers-4-broches-2-m/Just a random link. This should be it?Edit: Pretty much confirmed. This is known as FireWire 4-pin; used "back then" for DV cameras.(If you were located in Germany, I'd just send you a couple of these cables, I have plenty in storage...)

author: daloev
author_rank: Contributor
timestamp: May 12, 2022, 11:15:27 am
content: Thanks. With your confirmation that it is indeed a 1394 connector, I applied my 4-pin cables again and they do fit. It is very tight, so it requires perfect alignment and a bit of force to get it started. At least it won't be falling out.
What core alloys are most typical in audio and power (50/60hz) transformers? - Page 1
Forum section: electronics / projects

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: July 27, 2023, 08:52:27 pm
content: I rarely found even mentions of core materials. Only that "you can't just use a power transformer as an output transformer it will sound like crap"... Which I know it does. But I'd like to have some insight as to why. What core alloys are used for mains power transformers and what are used for audio output, and coupling transformers?

author: oz2cpu
author_rank: Frequent Contributor
timestamp: July 27, 2023, 09:58:17 pm
content: the best audio transformers i find athttps://www.lundahltransformers.com/They got several good pages about technical stuffthey are normally also keen to answer technical questions,

author: Benta
author_rank: Super Contributor
timestamp: July 27, 2023, 10:02:57 pm
content: Generally iron with around 3% silicon.For audio, grade is typically M111-35N rolled and treated to be anisotropic (="grainy").

author: jonpaul
author_rank: Super Contributor
timestamp: July 28, 2023, 02:58:52 pm
content: Hello been designing asnd building for production transformers since 1980s.1/ Mains 50/60Hz:0.014" silicon steel laminations are used for low eddy current losses, and high inductance.Designs can be optimized for a Trise/ambient and to minimize core loss, but tradeoff is cost and avaiablity.Laminationsfrom Tempel Steel, etc.Alternative s tapewound toroids or tapewound cut core, but similar or small thickness.Vendors like Arnold and Magnetic Metals. VERY costly but smailler size and lower losses.All except toroids are asy to gap is needed.2/ Audio: To achive a wideband transformer, with good LF response you need a large core area and very thin laminations or tapes.Bell Labs developed high per materals like Supermendur in 1950s.The cores are special lams or tapewound trorois or cut cores.Vendors can be Vaccumsmeltz in Germany or Arnold, Magnetic Metals, etc,Expect special windings and some small guage wire.3/ FabL Bobbin and toriod winding machines are automated nowadays but hand machines are also used.See Micafil /Metor in Switzerland or Adams Maxwell in USA for winding machines.Bon Chance!Jon
What could be causing this discrepancy between boards? - Page 1
Forum section: electronics / projects

author: LoveLaika
author_rank: Frequent Contributor
timestamp: December 04, 2023, 11:24:29 pm
content: I built a DC switching power supply that takes in a positive DC voltage (~+14 volts, 3 amps) and outputs both a positive and negative voltage with a buck and an inverting buck-boost configuration respectively. After running simulations on it, I ordered the board and components, laid it out, and it works. It really works with dummy loads of power resistors as shown in the schematic. Compared to my previous supply, the goal was to mitigate the inrush current as well as provide flexibility as to when the positive and negative voltages would reach their peak.After building the first board and verifying that it worked with 20-ohm loads at both positive and negative output voltages (~500 mA each at a +10/-10V output), I went to build another board. However, upon building the board and powering it up with no load, this board was shorted. Troubleshooting revealed that the problem was the negative voltage regulator IC. It was somehow causing a short between the power input for the ICs to the board's ground plane.After replacing the faulty chip, the second board was no longer shorted and could output voltages, but the negative voltage regulator side could no longer handle a 20-ohm load. When a 20-ohm load was attached, the output voltage only went to -3.1 volts. The positive voltage regulator side could maintain +10 volts with a 20-ohm load, so there seems to be no problem with that. With no load, the board was outputting +10 V and -10 V, same as the first board. (Strangely enough, the negative regulator could output -10 volts with a 27-ohm load, so I don't see why 20-ohms would not work). I tried replacing components such as the regulator ICs, the inductor, and the capacitors, but to no avail. This phenomenon is really strange considering how the first board worked fine. It also occurs when the positive voltage regulator is disabled (so all of the current being drawn is from the negative regulator). Can anyone help me with possible thoughts as to why this is occurring?

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 05, 2023, 12:07:54 am
content: Have you looked at the transient of the negative output (relative to GND) when powering on the board (at no load)?

author: LoveLaika
author_rank: Frequent Contributor
timestamp: December 05, 2023, 12:12:57 am
content: Not too closely. Using an oscilloscope, I observed that the negative output reaches it desired value after roughly 380 milliseconds. I did observe some low amplitude ringing as well, but that was done looking at the signal as an AC input.
What could be done better with my light project ? - Page 1
Forum section: electronics / projects

author: Ehaze
author_rank: Contributor
timestamp: January 26, 2022, 11:28:28 am
content: I am trying to turn this busted amazon light into a better functional light .I am using 2 cree xml2u24c1+Wired every as best I could , and it sorta worked , it turned on constantly from a 3.7 battery direct , but was having trouble from a 4p 3.7 18650 pack with an outlet usb port bms I took from a few broken battery banks , tried 2 and they do work on my phone , but dont seem to be able to power on the light , and it turns on really funny with the usb bms light button . ( I tried to recycle them they do seem to work on my phone , maybe i need to order a non usb bms )I got it turn on but it started to get super hot , and melt the tape i put across the driver .It was looking to be an easy project but I guess I have to start over and try a different way .What should I be doing ?I really want to make this into a reliable light that can mount right under my garmin and not be at big as my other light pods!!!

author: MacIntoshCZ
author_rank: Regular Contributor
timestamp: January 26, 2022, 11:34:50 am
content: Powering experimental circuit from yours smarthphone is really clever (its actually stupid). Use please phone charger instead (Some chargers also comunicate with phones).Phone power bank comunicate with phone. When its not detected it will power on for few seconds, than turn off.Current increase rapidly when certain voltage on LEDS is reached. On lower voltage, it will not shine.LEDS does get hot! They are placed on coller....
what crimp is used on square pins on PCB - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: January 15, 2020, 01:34:09 pm
content: square pin on PCB come in many flavors, sometimes with housings and sometimes by themselves with single wire connectors, which sometimes latch.If you want to make wires to connect ports to equipment (without following a connector dielectric standard) what pins are used? For technician type work, I need a best fits all so I can make nice cables to custom terminators for troubleshooting. I know I only really see 2 (maybe 3) common pin sizes for power, signal.The idea being to reliably connect to as many pin connector types as possible with the minimum of inventory for repair or prototyping purposes. solid machined crimp points for the wire are preferred, I don't like the folding ones despite cost benefits and strain relief.Some kinda grabby one would be good, so it can be used to attach to pins in Dsub ports and multipin cables without all the inventory required for long term connections.the idea being to glue it inside of a thin tube

author: Buriedcode
author_rank: Super Contributor
timestamp: January 15, 2020, 03:17:05 pm
content: Are you talking about the standard 0.1" pin headers and the associated female crimps? "Dupont" wires as they are mislabelled all over the web?

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: January 15, 2020, 10:11:29 pm
content: Quote from: coppercone2 on January 15, 2020, 01:34:09 pmThat is such a vague question it's impossible to answer.Every connector had a specific pin type and a different type of crimp, there aren't any generic types.

author: larrybl
author_rank: Regular Contributor
timestamp: January 15, 2020, 10:31:54 pm
content: Wire wrap with the proper tool will make a reliable connection to a square pin.

author: coppercone2
author_rank: Super Contributor
timestamp: January 16, 2020, 02:30:27 am
content: the wire wrap will damage the pin. I was hoping something existed that was good enough for short term use on alot of different things

author: tautech
author_rank: Super Contributor
timestamp: January 16, 2020, 02:44:57 am
content: Quote from: coppercone2 on January 16, 2020, 02:30:27 amSMD or TH ?Trace side or component side ?Press on or clip on connection ?Signal level or power level connection ?

author: CatalinaWOW
author_rank: Super Contributor
timestamp: January 16, 2020, 03:28:20 am
content: Back in the 70s to 80s someone marketed contact pins with a shallow helix form for the inner contacts. The were purported to be long life and tolerant of dimensional variations. I don't remember the company, and a brief google session didn't turn anything up, but if these are still being made or available they might be what you want. They weren't the double helix product that google did turn up.Maybe my comment will trigger someone else's memory, or someones google fu will be better than mine.
What DAQ devices work with both open source drivers and with Labview? - Page 1
Forum section: electronics / projects

author: cdwijs
author_rank: Regular Contributor
timestamp: November 23, 2019, 10:59:03 am
content: Hi All,TLDR: What DAQ devices work with both open source drivers and with Labview?At work we use National Instruments DAQ devices to connect the Labview programs to the outside world. Some are USB like the NI USB 6009I would like to move away from Labview. I don't like graphical programming, Labview is not as multi platform as I would like, and it's closed source.I would like to move to Qt, and I've been trying to get the NI USB 6009 to work. Labview offers a C driver for this , and while it does support windows, macintosh and linux, it only works on x86 and amd-64 processors, so not on the Raspberry Pi.So I would like to move to other DAQ devices, but to keep everybody in the office happy, they have to work with both open source drivers as with Labview.Do you know of such DAQ devices?Cheers,Cedrichttps://www.ni.com/nl-nl/support/model.usb-6009.htmlhttp://www.ni.com/en-us/support/downloads/drivers/download.ni-daqmx-base.html

author: awallin
author_rank: Frequent Contributor
timestamp: November 23, 2019, 06:26:32 pm
content: what performance do you need?https://labjack.com/?Keysight DAQ970A ? (Ethernet LXI)

author: EmmanuelFaure
author_rank: Regular Contributor
timestamp: November 24, 2019, 02:11:57 am
content: Anything using a COM port.
what dc-dc converter to go from 12v to 48v 600mA max? - Page 1
Forum section: electronics / projects

author: ddavidebor
author_rank: Super Contributor
timestamp: May 06, 2013, 06:50:50 pm
content: hi guysi'm the lucky owner of a gpsdo board that run with 48v.this tipe of board need a looooot of time to lock-up, so ups is necessary.here in the local store there are a car battery charger that maintain and charge the battery.so, for do this, i need a 12v battery, the battery charger and a dc-dc converterBUT all the dc-dc converter i've found arrive at max 35v.do you know any available and cheap solution?thanks,

author: c4757p
author_rank: Super Contributor
timestamp: May 06, 2013, 06:55:11 pm
content: External transistor? For example, you can build acascodewith an external NPN transistor and the internal transistor in an MC34063. Of course, I don't know what the power requirements are. Edit: Yes I do, it's in the title...

author: jahonen
author_rank: Super Contributor
timestamp: May 06, 2013, 07:08:35 pm
content: How aboutLM2590HV?Regards,Janne

author: grumpydoc
author_rank: Super Contributor
timestamp: May 06, 2013, 07:23:58 pm
content: QuoteThat's a buck converter - he needs boost.Edit: sorry, apologies. Yes that would work to replace the (almost certainly present) internal 48V->5V(or whatever) supply. Is that what you were thinking?Have you had a lookin** the GPSDO. -48V is common for equipment designed to go in telecom racks as that is the usual power supply there. However if you open it up you'll probably find a DC-DC converted down to 5V or 3.3V to actually run the electronics. As long as there aren't any odd voltage rails it might be easier to replace the 48V DC-Dc converter with a standard mains switch mode supply, or even a 12V in module.There are, however, these ones on ebay -http://www.ebay.com/itm/DC-DC-Converter-Regulator-12V-Step-Up-to-48V-3A-150W-/120764254558which would appear to fit your original requirement.**Don't turn it on, take it apart!!

author: ddavidebor
author_rank: Super Contributor
timestamp: May 06, 2013, 08:57:11 pm
content: Too much expensive...Yes they use a lot of dc-dc converter but generate +- 12v so they need 24v+marginI'm actually running it on 32v.It work, but i don't know how i can trust it with this voltage.

author: brabus
author_rank: Frequent Contributor
timestamp: May 07, 2013, 03:22:59 pm
content: If an unregulated supply is enough, I would go with a *really basic* open loop boost converter, using a correctly made mosfet-inductor-diode power stage, and a basic 555 manually adjusted variable duty cycle driver. To have a minimum safety margin, I would add a comparator to monitor the output voltage; if it gets higher than, let's say, 50V, the system shuts down. That's all... dumb but rather cheap.Personally, I would use a TPS40210 boost controller, you can fine any info on TI website. Use TI simulation software to design every part of the converter, and you're OK. I have used the '210 in a LOT of application, it's simply amazing. It's a pity it there's no version with internal Mosfet, but that's it!
What device could this be?? DC Solenoid Driver - Page 1
Forum section: electronics / projects

author: guscrown
author_rank: Regular Contributor
timestamp: August 23, 2024, 04:55:32 am
content: I'm trying to understand a circuit on a board I have, but the IC has no markings, but from looking at the PCB layout this is what I can gather:I know that all four pins on the bottom are connected to the output to the solenoid. This is a DC latching solenoid, and it works by either applying a VSOL+ pulse to latch it open, or a VSOL- to latch it close.There is a duplicate of this circuit that goes to the common of the solenoid, the common being the reference, it either goes LOW (GND) and the output to the solenoid goes to VSOL+, or it goes HIGH (VSOL+), and the output to the solenoid goes to VSOL-.So this IC up there can either connect VSOL+ or GND to its output using what appears to be two control signals.Any idea what it could be? I was thinking some kind of motor driver maybe?

author: coromonadalix
author_rank: Super Contributor
timestamp: August 23, 2024, 06:08:54 am
content: could be some mosfets in that package
What did I do wrong in LTSpice - Page 1
Forum section: electronics / projects

author: mkiijam
author_rank: Regular Contributor
timestamp: July 14, 2024, 11:22:50 pm
content: I simulated a op amp based little guitar pedal for fun and then build it. I had tons of problems with the AC coupling I was doing and DC building up on the caps. A lot of which I solved by adding resistor to various places. But my question is: the issues didn't show up in spice. I was just using generic op amp models, should I make the op amps and the caps more realistic or something?

author: langwadt
author_rank: Super Contributor
timestamp: July 14, 2024, 11:32:37 pm
content: you have to show what you did, no one can guess what you did. It sounds like you randomly added resistors in random places without understanding why, that is probably not the best way to go out it

author: SiliconWizard
author_rank: Super Contributor
timestamp: July 14, 2024, 11:38:45 pm
content: How can we know if you don't post your LTSpice schematic, and your simulation parameters?What do you mean by "generic opamp models"? Which did you use? LTSpice has a ton of models for real opamps, and even if there isn't exactly the one you're gonna use, just pick something similar.I don't know what their "generic opamp" does, but apart from having probably ideal characteristics, one thing that will be missing are internal diode clamps on inputs, which may make a big difference if you're not biasing the opamp properly (were you using a single supply?)

author: Ian.M
author_rank: Super Contributor
timestamp: July 14, 2024, 11:49:43 pm
content: LTspice UniversalOpamp models default to 500Meg input resistance. In most circuits that keeps the input bias current under a few tens of nA. Most real OPAMPs not specifically sold as ultra-low input bias current ones have significantly higher and often asymmetric input bias currents. You also have to consider board surface leakage. The general rule is both inputs must have a DC path to either the output or to ground for an OPAMP to function, and in high impedance or high accuracy circuits, ideally the equivalent resistance to ground as seen by each input should be equal so the offsets caused by the input bias current flowing through the resistances feeding the inputs tend to cancel out.

author: mkiijam
author_rank: Regular Contributor
timestamp: July 15, 2024, 03:29:33 am
content: Quote from: Ian.M on July 14, 2024, 11:49:43 pmThank you so much.
What diodes can I use for a 1.4GHz downconvrt mixer? - Page 1
Forum section: electronics / projects

author: yammy_96
author_rank: Newbie
timestamp: September 11, 2024, 12:59:39 am
content: I want to apply these diodes in the circuit attached to this post. RF and LO will be fed into a hybrid coupler, then through the 2 mixing diodes. I want to down convert 1.4GHz to around 20-50 Mhz.What are the diode characteristics to look for when choosing one for a mixer at some frequency?How do I know what input powers to feed for LO and RF to have the diodes mix?Can BAT54s or BAS16s work?What are some diodes I can use?

author: moffy
author_rank: Super Contributor
timestamp: September 11, 2024, 01:26:05 am
content: Found this:https://www.infineon.com/dgdl/Infineon-AN_1807_PL32_1808_132434_RF%20and%20microwave%20power%20detection%20-AN-v01_00-EN.pdf?fileId=5546d46265f064ff0166440727be1055I would guess you need a matched pair in a single package.

author: Simon
author_rank: Unknown
timestamp: September 11, 2024, 07:08:59 am
content: don't double post, you will just annoy everyone.
What do te numbers on a LiPo pouch cell mean? - Page 1
Forum section: electronics / projects

author: Starlord
author_rank: Frequent Contributor
timestamp: February 22, 2015, 09:02:34 am
content: A friend of mine bought a cheap 12V LiPo pack from China and after the first charge, it died on him. I cut it open to investigate and as expected there were three rather small cells in a battery advertised as 9800mAh.I was hoping to find out what the capacity of the individual cells really was, but to my surprise they don't say, and the numbers on them are indecipherable. Also, it appears one of the batteries is different from the others, perhaps having a different manufacture date. It's the same size and shape of course.Anyway, here are the numbers on each cell:C2917 QHC 5C2120809 C07369A2956 BGP 3C2110720 B05995D2888 QHC 5C2120810 C04998I'm guessing that 110720 is a date code. YYMMDD. If so, that would mean these batteries were manufactured quite a while ago.I have no idea what the other numbers might mean though.

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: February 22, 2015, 09:06:46 am
content: Off the top of my hat:5C2 means that the capacity is 2000 mA and the max discharge current is 5 times the capacity.

author: amyk
author_rank: Super Contributor
timestamp: February 22, 2015, 03:55:24 pm
content: Quote from: blueskull on February 22, 2015, 12:43:56 pm12 x 8 x 10 mm is... nearly cubic, and nowhere near enough volume for anything close to 9800mAh. Not to mention all 3 cells having slightly different dimensions, and the middle cell being 20mm in its 3rd dimension... no.

author: Starlord
author_rank: Frequent Contributor
timestamp: February 22, 2015, 06:06:48 pm
content: Quote from: amyk on February 22, 2015, 03:55:24 pmYeah, they're not cubic.But I also doubt they're 9800mAh. I suspect they added the mAh of the three cells then wrote that as the capacity even though they're wired in series.And their actual size is 90x35x5mm.

author: Starlord
author_rank: Frequent Contributor
timestamp: February 22, 2015, 09:05:44 pm
content: Quote from: blueskull on February 22, 2015, 06:30:00 pmThere is no other identifying text on the individual pouch cells than what I wrote, and otherwise they look like any other pouch cell. The batteries came in a generic blue box. Search Ebay for 12V CCTV 9800mAh and you'll see a bunch of them.

author: MrAl
author_rank: Super Contributor
timestamp: February 22, 2015, 09:09:17 pm
content: Hello,You could do a single discharge test to test the capacity. That wont tell you the brand new capacity, but it will tell you the current capacity of the cell.You might also consider the dimensions as compared to another cell and see if you can estimate the capacity when new.

author: Starlord
author_rank: Frequent Contributor
timestamp: February 23, 2015, 12:10:25 am
content: The battery is dead and won't take a charge. That's why I cut the thing open.
What do these footprint markings mean? PowerSSO-12 - Page 1
Forum section: electronics / projects

author: pauljmccain
author_rank: Contributor
timestamp: August 19, 2015, 03:34:16 pm
content: Hello,Does anyone know how to read the recommended footprint pattern below? It's from an ST Microelectronics part, package size PowerSSO-12. Direct datasheet:http://www.farnell.com/datasheets/1698007.pdfSpecifically, any idea on what you're supposed to do for the rectangles and the circles inside them? Paste pullback? Certainly can't be mask, right?Thanks for any assistance!

author: poorchava
author_rank: Super Contributor
timestamp: August 19, 2015, 03:49:52 pm
content: Most likely the white rectangles are soldermask, so that vias are tented. This is to prevent solder wicking down the vias instead of reflow in under the chip. At least that would be my guess.

author: Godzil
author_rank: Frequent Contributor
timestamp: August 19, 2015, 03:52:47 pm
content: Your device have a pad linked with VCC on the bottom, the circle are ST recommandation for thermal via if I'm not mistaken.And the rectangle would not be soldermak this would be bad for thermal transfer, they are more likely to be solderpaste recommandation

author: pauljmccain
author_rank: Contributor
timestamp: August 19, 2015, 03:56:41 pm
content: I thought the circles were thermal vias, but then if the rectangle is just paste pullback, as poorchava said, wouldn't the solder wick into the vias? Or does the small amount of paste pullback prevent that?And if the rectangle is mask, wouldn't that screw up the mounting? Device just has one big rectangular slug on the bottom.Ticket has been submitted with ST for clarification.

author: Godzil
author_rank: Frequent Contributor
timestamp: August 19, 2015, 04:07:30 pm
content: A ticket to ST is a good idea, but I fear that you will not get an answer really quicklyBut *I* don't think that if the via get filled by solder it would be a big thermal problem, but I may be wrong.Any expert on that?By the way, chapter 8 of the chip datasheet is dedicated to thermal design, have you look at this chapte? It may explain a lot of thingsEdit: Ok no text on that chapter at all.. All the things I love in ST datashit (pun intended) some components are well describes, some like this one have nearly meaningless chapter if you are not an expert in this area, honestly the table 10, equation 4 or even the Figure 10 are just useless to me as I don't understand what they want to tell me here

author: pauljmccain
author_rank: Contributor
timestamp: August 24, 2015, 09:05:30 pm
content: Thanks again for the suggestions guys. No reply from ST.Based on this protoboard, I'm just going to go with exposed copper and vias, and consider the squares to be paste pullback.