hybridfree/eevblog-posts huggingface dataset:
JBC T245 pinout - Page 1
Forum section: electronics / projects

author: kuzm1nsk1
author_rank: Contributor
timestamp: April 25, 2023, 08:54:30 pm
content: Hi, I'm planning to design a controller for JBC T245 handle (C245 cartridges) but can't figure the right pinout for the cartridge. I have come across two different pinouts for the cartridge and don't know which one is the right one because I haven't purchased it jet. One picture shows cartridge measured with Fluke instrument and it's clearly different pinout from the picture that has been posted on EEVBLOG by a johnmx who reversed engineered the whole JBC station. Then I came across this post:https://www.eevblog.com/forum/projects/jbc-handle-cartridge-data/and someone said that the Fluke measured one is the correct one. Do you have any experience with JBC cartridges so you could confirm one pinout over the other.

author: thm_w
author_rank: Super Contributor
timestamp: April 25, 2023, 10:56:47 pm
content: Welcome, we have lots of threads discussing T245, please read through them.I would trust the pinouts from this site, in the post you linked:http://adgd.ru/2021/01/04/jbc-soldering-cartridges-pinouts/The reality is either way will work when implemented, JBC seems to run the current through the thermocouple:https://www.eevblog.com/forum/projects/yet-another-controller-for-jbc-t210t245/msg3102782/#msg3102782

author: DavidAlfa
author_rank: Super Contributor
timestamp: April 25, 2023, 11:03:45 pm
content: This pinout is correct

author: kuzm1nsk1
author_rank: Contributor
timestamp: April 26, 2023, 08:44:27 am
content: If I'm not mistaken, Weller, Hakko and probably some other brands also have this type of cartridges with 3 pins. Is there a reason why they don't add a fourth pin to make life easier?

author: thm_w
author_rank: Super Contributor
timestamp: April 26, 2023, 09:54:15 pm
content: Quote from: kuzm1nsk1 on April 26, 2023, 08:44:27 am- More expensive to manufacture the tip- More wires and contacts in the handle, means larger handle and thicker cableYou've seen the schematic, JBC does not seem to care about complexity at all.If they logically designed their tips, you could support all of their tips with a micro, a few FETs and an ADC. But for whatever reason everything is all flipped around.
JEITA guide for charging Li-ion batteries in single-cell handheld applications - Page 1
Forum section: electronics / projects

author: brumbarchris
author_rank: Regular Contributor
timestamp: January 23, 2024, 09:50:46 am
content: Hello all,I am trying to determine the original source of the Figure 3 (JEITA guidelines for charging Li-ion batteries in single-cell handheld applications) mentioned in the TI SLYT365 Li-ion battery-charger solutions for JEITA compliance application note (https://www.ti.com/lit/an/slyt365/slyt365.pdf?ts=1705929786146&ref_url=https%253A%252F%252Fwww.google.com%252F):This graph also appears in other published papers, like for instancehttps://www.researchgate.net/publication/356935564_Improvement_of_Lithium-ion_Battery_Charging_from_The_State-of-the-Art_Industrial_JEITA_Guidelines_to_A_Hybrid_Temperature-Regulated_Current_Control(it is Figure 1 b there).Nevertheless, I fail to find the original JEITA source for this profile. I have access to both the 2007 and the 2021 versions of the guideline:-https://home.jeita.or.jp/upload_file/20210407112651_JbDgUSWGiB.pdf-https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/196/JEITA-Doc.pdfBut nowhere in that guideline do I see the a statement concerning"single-cell handheld applications", and the JEITA guideline seems to be concerning "notebook" type of applications (so multiple-cell, in principle).In particular:I cannot find in the JEITA guideline anything concerning the two separate smaller voltage thresholds (4.15V and 4.10V) above 45Celsius.I am concerned that in this hand-held profile, there is no voltage derating in the 0...10Celsius temperature interval; this would be somewhat contradicting the info I find in the JEITA guideline, which indicates derating of the voltage too, in this temperature interval. Admittedly, the JEITA guideline does say that charging is allowed in this 0...10Celsius interval by changingeither or bothof the maximum charging current and the upper limited charging voltage. So presumably limiting just the charging current would be sufficient, and then Figure 3 would not violate the guideline.Does anyboy know where such a profile for "single-cell handheld applications" might be originally coming from? Is it a different JEITA guideline? (I did search and was unable to find one).
Jellybean FPC connectors that are footprint compatible from 2+ brands. - Page 1
Forum section: electronics / projects

author: Psi
author_rank: Super Contributor
timestamp: July 05, 2024, 01:15:17 am
content: I'm adding a FPC connector to a product and I'd like to use one that is available from more than 1 manufacturer (eg footprint compatible).But checking them 1 at a time and looking for others that are the same is super time consuming.Any ideas for FPC connector series names that are considered Jellybean?Probably 1mm pitchProbably be 8 or 14pos depending if I have room and want to double up conductors.Doesn't realty matter if it's top or bottom contacts.Needs to have a locking latch.
Jellybean SMD Diode - Page 1
Forum section: electronics / projects

author: Sam__
author_rank: Regular Contributor
timestamp: May 24, 2014, 08:25:29 pm
content: Just wondering what people around here use for low current (>1A) jellybean smd diodes? Looking for something to make a voltage doubler with and trying to avoid through hole.

author: fcb
author_rank: Super Contributor
timestamp: May 24, 2014, 08:41:26 pm
content: BAS16 (100mA)GS1A (1A)SS310 (3A schottky)These are my goto parts.

author: mariush
author_rank: Super Contributor
timestamp: May 24, 2014, 08:47:28 pm
content: http://uk.farnell.com/diodes-small-signalhttp://uk.farnell.com/diodes-schottkyhttp://uk.farnell.com/diodes-rectifiersCheck in stock, check exclude extended range, apply. Sort by price then pick whatever you see smd and available in large enough volume and doesn't require you to buy 2500pcs at a time.Knock yourself out.

author: Sam__
author_rank: Regular Contributor
timestamp: May 24, 2014, 08:48:59 pm
content: Thanks a lot guys

author: Bored@Work
author_rank: Super Contributor
timestamp: May 24, 2014, 08:55:37 pm
content: BAW78 (also as dual diode). MBRS and MURS series, like MBRS120, MURS120. Zetex S1 series.

author: theatrus
author_rank: Frequent Contributor
timestamp: May 24, 2014, 09:36:26 pm
content: B360A is my goto on the schottky.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 24, 2014, 10:39:46 pm
content: Not very specific, so take your pick...In order of current capacity, high speed junction / schottky types.BAT54 (A, C, S suffixes) (SOT-23, SOD-323, etc.)BAV99 (~dual 4148, SOT-23)MMSD4148W (and other prefixes for various sizes: SOD-123, 323, MELF, etc.)MBR0540 (SOD-123, etc.)MBR160 / B160 (anything from 130-1100 for different breakdown voltages; SMA)ES1B (and other suffixes for different voltages; SMA)B340 (SMB)ES3B (SMC)B540 (SMC)and so on. Bigger devices are available in DPAK and such but really, by the time you're over 5A schottky / 3A junction, you need a heatsink.Tim

author: Evil Lurker
author_rank: Regular Contributor
timestamp: May 25, 2014, 04:57:52 am
content: I'm guessing for a simple voltage doubler some M4's or M7's would do the trick.

author: TMM
author_rank: Frequent Contributor
timestamp: May 25, 2014, 05:07:46 am
content: using BAT54 and BAW56 here.Edit: saw you need >1A

author: poorchava
author_rank: Super Contributor
timestamp: May 25, 2014, 08:17:07 am
content: for small currents BAT54 (all variants), BAV99 and 1N4148.For bigger currents SK and SS series.

author: Sam__
author_rank: Regular Contributor
timestamp: May 25, 2014, 10:22:58 am
content: So many options! That's so much. Ordered some BAT54's, will see how they do the job.Thanks again.
JFET Common Source Amplifier Calculator - Page 1
Forum section: electronics / projects

author: madladlabs
author_rank: Newbie
timestamp: August 10, 2022, 10:34:22 pm
content: I'll preface this with "I'm not an EE by education, but occasionally do some EE stuff."While working with a high impedance transducer, I recently realized that I had no idea how to calculate the gain of a transistor-based amplifier. After doing some reading and watching a YouTube lesson on the matter, I decided to make an online app that does the calculations for a JFET common source amplifier. During my research on JFET pre-amps, I also got fed up with references to JFETs that are either out of stock or obsolete, so I added a table of the top ≈150 cheapest in JFETs on DigiKey along with the classics (like J201) to the app.Dear viewer, I present to you the apphttps://madladlabs.net/modules/electronics/jfet-common-source-amplifierIt's pretty straightforward. Select a JFET and enter in some values. It does a very simple check to make sure the voltage drop across the drain resistor does not exceed the supply voltage.Any improvements I should make?
Jfet matching - Page 1
Forum section: electronics / projects

author: ch_scr
author_rank: Frequent Contributor
timestamp: November 26, 2018, 09:14:54 pm
content: I bought some MMBFJ108 from China where i wanted to match some for a project. My 34970A was begging for use. This is what happend.I looked around online and found the nice "volt meter and voltage source" trick to V_GS(off) here:http://stompville.co.uk/?p=112I realized i could measure R(DS) with the ohms measurement of the DMM. It's not a parameter field, but good enough for a start.Normally the two measurements would interfere (say done with two dmm and a power supply at once), but that's what the 34970 is forI rummaged in my pile of pcb's for a small one with a suitable footprint, kicked the old parts off, and put 3 nice solder blobs on the footprint I wanted to use. Later I filed the blobs flat on top to stop the parts from slipping away when i pressed on them to make good contact while measuring.I wrote a Python script to do the measurement and log data. Measuring the 26 parts took about 20 minutes. This includes one dead jfet where i thought it didn't make contact and messed around. I also did a repeatability test where i put on one part, let it do the measurement, took it back off, rinse and repeat. The file is also attached and honestly it came out more stable than I expected.

author: David Hess
author_rank: Super Contributor
timestamp: November 27, 2018, 09:42:21 pm
content: A simpler test is to place a chosen resistance between the gate and source which sets the operating current. Then with voltage applied, either the voltage across the resistor or the current is measured.
JFET Super Cascode Topology - Page 1
Forum section: electronics / projects

author: rej
author_rank: Contributor
timestamp: May 26, 2025, 01:56:06 pm
content: Do I understand correctly that this circuit is dimensioned specifically for switching a certain voltage?As I understand it, the diodes are used to determine how the voltage is distributed across the JFETs. If you switch voltages that are, for example, lower than those for which die circuit was created, the voltage is no longer evenly distributed across the JFETs.Source of the circuithttps://www.osti.gov/servlets/purl/1883496

author: moffy
author_rank: Super Contributor
timestamp: May 26, 2025, 11:24:37 pm
content: The diodes according to the text are Avalanche diodes which will tend to balance the voltages across the JFETs, though they might require some degree of matching.

author: rej
author_rank: Contributor
timestamp: May 27, 2025, 09:08:09 am
content: Yes, you are right, they are Avalanche diodes. As these have a fixed breakdown voltage, I assume that the circuit is designed for a specific switching voltage. If you now want to switch a lower voltage, for example, the voltage is no longer evenly distributed. At least that is my understanding of the circuit. Can anyone confirm this? Or have I overlooked something?

author: PartialDischarge
author_rank: Super Contributor
timestamp: May 27, 2025, 10:11:08 am
content: Yes, that circuit, in which they use zener diodes (but instead everyone mentions avalanche diodes to look more cool) only balances voltages perfectly at one voltage, not at others.
JFET with configuration SDG (source ,  drain , Gate) - Page 1
Forum section: electronics / projects

author: haseeb zaib
author_rank: Contributor
timestamp: November 16, 2021, 05:32:29 am
content: hello everyoneI have this transistor in TO-92 package. Now the number on it is all gone, I checked it using transistor tester it came out to be a jfet with configuration of SDG. I have attached a picture of transistor tester. Now I cant find jfet similar with this configuration. So does anyone here knows about any jfet with this configuration? please tell me if you know about any.

author: moffy
author_rank: Super Contributor
timestamp: November 16, 2021, 08:05:19 am
content: Sorry, but it looks like a straight forward NJFET, the tester is just using a slightly different symbol to what most are used to(the diode is normally drawn in the gate rather than the source).

author: Kleinstein
author_rank: Super Contributor
timestamp: November 16, 2021, 08:20:12 am
content: With nearly all JFETs drain and source are interchangable. At least the transistor tester will have a very hard time to tell them apart. So for the pinout the main point is finding one with the gate on the right side. An example would be J111-J113 or J201/J202. For a replacement one can turn TO92 parts the other way around with no big problem.

author: haseeb zaib
author_rank: Contributor
timestamp: November 16, 2021, 10:18:16 am
content: Quote from: Kleinstein on November 16, 2021, 08:20:12 amThis is exactly what I am saying to my senior engineer but he want everything same XD

author: Kleinstein
author_rank: Super Contributor
timestamp: November 16, 2021, 10:39:30 am
content: There are JFETS in To92 case with the gate on all three pins, though some may be hard to get by now:BF245 , BF256 : gate on the leftSK117,SK170 : gate in the middleJ111 etc. : gate on the rightFinally there is a really odd one from Motorola (but I think this is more like a typo):

author: BrokenYugo
author_rank: Super Contributor
timestamp: November 16, 2021, 05:45:08 pm
content: Quote from: haseeb zaib on November 16, 2021, 10:18:16 amMany JFET data sheets note that drain and source are interchangeable, if that's what they're worried about.

author: mag_therm
author_rank: Frequent Contributor
timestamp: November 16, 2021, 09:03:14 pm
content: 2N4416 123 : SDG To72It has a 4th pin on the circle connected to the case
Jim Miller simple GPSDO modifications - Page 1
Forum section: electronics / projects

author: Bryan
author_rank: Frequent Contributor
timestamp: September 11, 2016, 09:45:34 am
content: Hello:I have been following the Jim Miller simple GSDO build project athttp://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm. I have a few OCXO's kicking around, but wondering what would the formula be to provide the correct components for R1,R2, C1, C2 to provide the PLL filter. I assume the PLL filter needs to be designed to accommodate a specific oscillator specifications, or maybe it doesn't really matter?. Also curious as to why in the parts list tantalums are spec'd for the capacitors in the filter?
Jittery video display - Page 1
Forum section: electronics / projects

author: netdudeuk
author_rank: Frequent Contributor
timestamp: January 11, 2014, 03:22:23 pm
content: HiI've got one of these video generators that produces a perfectly steady output onto a TV or monitor with a composite video input but as soon as I try and generate a VGA signal using the below video converter, the output is bright and sharp for a split second before going dim and jittery. Every time I connect the source it repeats this. Any ideas as to why this happens and if there is an easy fix please ?Video circuithttp://searle.hostei.com/grant/MonitorKeyboard/index.htmlVideo converterhttp://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290631299043&ssPageName=ADME:X:eRTM:GB:1123Thanks

author: netdudeuk
author_rank: Frequent Contributor
timestamp: January 11, 2014, 03:40:04 pm
content: Hmm, just worked it out myselfI noticed that the monitor OSD was showing that the converter was settling on 60Hz, even though I'd got the video circuit configured for PAL. Anyway, I hooked up R3 to select NTSC 60Hz,rebooted it and now it's steady.
JK Flip Flop with Set and Reset Clarification - Page 1
Forum section: electronics / projects

author: craigfoo
author_rank: Contributor
timestamp: March 27, 2014, 02:50:20 pm
content: I'm trying to get a better understanding of JK Flip Flops that have the Set and Reset pins. I understand how a regular JK Flip Flop works but a little fuzzy on what the Set and Reset pins would do.Here's my understanding, if I have this condition:J=1K=0Q=1~Q=0If I put a 1 on the Set pin and wait for the next clock pulse, nothing should happen.If I put a 0 on the Set pin and wait for the pulse, I should get Q=0 and ~Q=1 no matter what J and K are doing.This would be the opposite for the Reset pin.If my assumption is correct, do I need to keep a 1 or 0 on the Set pin to change the condition or can it just be a pulse to permanently change the state of Q/~Q?I hope that makes sense. Thanks!

author: craigfoo
author_rank: Contributor
timestamp: March 27, 2014, 03:07:38 pm
content: Looking into this a little more. It looks like the Set and Reset are asynchronous meaning that they have to be held in order to create the condition.Found this article,http://www.allaboutcircuits.com/vol_4/chpt_10/7.html

author: craigfoo
author_rank: Contributor
timestamp: March 27, 2014, 03:28:06 pm
content: I think I have my answer, great tutorial on JK Flip Flops:http://youtu.be/1mnowDsoAx0
JLCPCB 3D printing! - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: January 04, 2022, 02:57:45 pm
content: I think we are living in an amazing time!Has anyone here tried it yet?

author: eugene
author_rank: Frequent Contributor
timestamp: January 04, 2022, 05:47:35 pm
content: Tried what? Contracting someone else to do 3D printing? Yes, I've tried that.
JLCPCB and XMOS - Page 1
Forum section: electronics / projects

author: SpacedCowboy
author_rank: Frequent Contributor
timestamp: July 19, 2025, 08:45:39 am
content: Anyone else having issues getting JLCPCB to find XMOS chips ? Generally with the 'global sourcing' page, I can type in a part that's at digikey and have them buy/ship it - usually with a little markup, but still.Just tried that with XU316-1024-TQ128-C24 and although I can see 27 of them at digikey, it comes up empty. I contacted 'help' via chat, and they recommended requesting a new part, but after doing that I got backQuoteHmm. I'm wondering if they just did a search using their system... It's gonna be tough to find "alternative parts" to an XMOS chip without redesigning for an FPGA...

author: bson
author_rank: Unknown
timestamp: July 19, 2025, 08:32:03 pm
content: For a one-off, or a production run? For just a prototype, given it's a pretty small QFP, just buy from a distributor and use hot air and and a little paste to solder it yourself. Let JLCPCB mount all the tedious jellybean stuff.

author: bson
author_rank: Unknown
timestamp: July 19, 2025, 08:34:14 pm
content: BTW, yes, their parts catalog interface is that poor. One hypothesis is that they have multiple locations and you can't mix parts between locations where they are in stock, but who knows. It's pretty much useless.
JLCPCB Assembly Flashing LED? - Page 1
Forum section: electronics / projects

author: pacmann
author_rank: Contributor
timestamp: January 19, 2022, 07:06:23 am
content: Any body knows if JLCPCB assembly offers self flashing LEDs in the parts library?

author: rpiloverbd
author_rank: Regular Contributor
timestamp: January 20, 2022, 02:34:16 pm
content: Couldn't find. I think you'd better e-mail them directly for technical support.

author: DIYGUY Chris
author_rank: Contributor
timestamp: January 30, 2022, 02:47:53 pm
content: Self flashing LEDs ! any references could help us to help you in a better way.If you mean the Fast/slow Flashing LEDs then I tell you it is not available at JLCPCB parts.You still can get them from Aliexpress :https://fr.aliexpress.com/item/32831615076.html?gatewayAdapt=glo2fraOr I recommend also these ones from globalsources :https://www.globalsources.com/LED-component/RGB-SMD-LED-1170310432p.htm
JLCPCB delivery (UK) - Page 1
Forum section: electronics / projects

author: PerranOak
author_rank: Frequent Contributor
timestamp: August 22, 2019, 03:00:25 pm
content: I ordered my first set of PCBs from JLCPCB and was very pleased to see how quickly they completed production and posted them.Now, I opted for a cheapo delivery and so am not expecting too much. I chose "Shipping Method: GB Special Air Mail".However, when I use their link to track the delivery, the site it gives cannot recognise the carrier from the code number that begins "jjd"!Any ideas which carrier it is in the UK?

author: Monkeh
author_rank: Super Contributor
timestamp: August 22, 2019, 06:26:04 pm
content: It'll turn up via the Royal Fail. Eventually. I wouldn't bank on any actual tracking.

author: ddavidebor
author_rank: Super Contributor
timestamp: August 22, 2019, 06:28:46 pm
content: It will get in the UK in unspecified ways. The ability to track these kind of shipment will be very limited until then.

author: PerranOak
author_rank: Frequent Contributor
timestamp: August 23, 2019, 10:20:16 am
content: OK cheers both.

author: PerranOak
author_rank: Frequent Contributor
timestamp: August 29, 2019, 09:34:07 am
content: My PCBs arrived (via Yodel in fact) on Tuesday, exactly two weeks after the order. They ended up (after USD translation) at 46.7p each for ten - though there was a discount as it was my first purchase.They are EXACTLY as I expected - no disappointment! How often can you say that about bespoke manufacturing?There was only one problem: I had misunderstood how my switch actually worked - what a numpty. Even so, a quick bogde wire sorted that!This may be by-the-by to you experienced bods but I was so impressed that I had to comment.

author: bd139
author_rank: Super Contributor
timestamp: August 29, 2019, 10:58:07 am
content: They're pretty good. I've done 38 board runs with them now and zero problems!It would have been about 1/3 of that many if I had also done things like understanding switch pin arrangements as well. Well all make that mistake occasionallyI will say that when you do cock stuff up, which I do often, the boards withstand a lot of rework without any problems of plated holes dying or pads lifting. They are excellent quality.
JLPCB Assembly board cleaning extra charge? - Page 1
Forum section: electronics / projects

author: rcbuck
author_rank: Frequent Contributor
timestamp: August 07, 2024, 03:43:00 am
content: I am going to have JLPCB assemble 20 boards for me. I see under Advanced Options, there is an extra charge to clean the boards after assembly.Are the boards not cleaned after assembly as a matter of procedure? Or is this charge for some kind of special circumstance?If you have had them assemble boards for you, were they clean and free of solder flux when you received the boards?I had a chat conversation with them and they said the boards have to be evaluated after assembly. I have no idea what that means.
JM  Nixieclock standard V3.1  - Page 1
Forum section: electronics / projects

author: peo007
author_rank: Contributor
timestamp: January 22, 2022, 07:13:36 am
content: HelloDoes anyone have a manual for the watch, or know what the connector D01 1-4 is for.https://de.aliexpress.com/item/1005002477665857.html?gatewayAdapt=glo2deuRegards Peo

author: peo007
author_rank: Contributor
timestamp: January 30, 2022, 09:18:20 am
content: answers myselfnixie point between hh / mm and mm / ss
jMicron datasheets - Page 1
Forum section: electronics / projects

author: stj
author_rank: Super Contributor
timestamp: August 28, 2016, 12:08:39 am
content: looking for the full datasheet for JMS539 if anybody has it.

author: amyk
author_rank: Super Contributor
timestamp: August 28, 2016, 02:51:29 am
content: http://www.usbdev.ru/?wpfb_dl=2964As full as you are likely to get at the moment.

author: stj
author_rank: Super Contributor
timestamp: August 28, 2016, 03:20:43 am
content: a good document, but probably old,it claims the device is 64pin, but the one i need to replace is 48pin!
Joining Li-Ion Charge Boards for Higher Voltage (7.4V) Applications - Page 1
Forum section: electronics / projects

author: firworks
author_rank: Unknown
timestamp: May 01, 2016, 09:08:30 pm
content: This might be a really stupid idea but I can't actually find much information on this. There's tons on li-ion charging 18650s but it's almost always one charger board with one cell. I've never seen anyone charging multiple in series without a RC car balancing charger module and that's not really something you could or would build into a project case. I was wondering if I could join together two or more of the very cheap single cell Li-Ion charger boards in order to charge and use say 7.4V for a project instead of the 3.7V from one cell without using a DC booster. I recognize my input current is limited due to USB and so it may not charge very quickly but would it work?Taking something like this:http://www.amazon.com/gp/product/B00QGVP944Running a wire from IN+ on board 1 to IN+ on board 2 and same with IN-. That way plugging in MicroUSB to one would provide power to the second board. Then wiring the cells in series, and having charger board wired to cell 1, and charger board 2 to cell 2. They should each only see the voltage across a single cell and so should be able to balance their cell and charge it appropriately... I think. I'm not sure if it will actually work though. It could be a really stupid idea. I know there are balancing chargers that can do this but I was hoping to build it into a small project box so they could be charged easily and not have to remove the 18650 cells each time to charge them.

author: Kilrah
author_rank: Unknown
timestamp: May 01, 2016, 09:17:00 pm
content: B- and IN- (and OUT-) are typically all connected together, so if you do that you're shorting a cell.

author: firworks
author_rank: Unknown
timestamp: May 01, 2016, 09:30:13 pm
content: Quote from: Kilrah on May 01, 2016, 09:17:00 pmYeah that does seem probable. B- and Out- I think are connected/disconnected by a pair of MOSFETs in the discharge protection IC, but IN- is probably connected to B-. I wish I had one of the boards to check that. Maybe I can deduce it from the datasheet for the charge IC.Does anyone have any other suggestions for a way to accomplish this without using an external RC battery charger?EDIT: Yep, TP4056 datasheet shows the BAT- being connected to input GND. Dang.

author: laneboysrc
author_rank: Contributor
timestamp: May 01, 2016, 11:23:03 pm
content: You should be able to make this work if you use two isolated power supplies.
Joining PCBs for Power Applications - Page 1
Forum section: electronics / projects

author: gmr1981
author_rank: Contributor
timestamp: April 16, 2024, 08:18:00 am
content: Hi,I'm designing a product that uses a buck/boost converter that can handle about 10A, input voltages range from 10V to 60V and output voltages are nominal 24V.I want to structure the system so that several 10A buck/boost boards can be mounted on to a motherboard and their power connections connect to that - but the boards need to be detachable. The buck/boost board is entirely surface mount. I was thinking some kind of conductive pillars and copper screws? Anyone got any suggestions for connection hardware like this?Thanks,Greg

author: uer166
author_rank: Super Contributor
timestamp: April 16, 2024, 03:54:20 pm
content: 10A is not much. You can easily use 3-5 pins of a standard 100mil header for this, or choose from other SMT connectors. If the board is top single-side SMT, you can get through-board female headers and let the male side (which is soldered to motherboard) poke through your converter PCB.

author: Siwastaja
author_rank: Super Contributor
timestamp: April 16, 2024, 04:17:24 pm
content: Classic card edge connectors (think ISA bus), or 0.100" pitch pin headers. Such solutions are typically rated for about 2A/contact, check the datasheet. Parallel enough pins + a few extra and you are done.

author: tooki
author_rank: Super Contributor
timestamp: April 17, 2024, 11:14:22 pm
content: Quote from: gmr1981 on April 16, 2024, 08:18:00 amWürth has a bunch of solder-in standoffs and the like that lend themselves to being used for this. Fundamentally, even ordinary brass standoffs, screwed to PCB pads, will work, though you definitely want to have generous pads to ensure plenty of contact surface, and possibly lots of vias in the pad to provide current carrying capacity.But don’t discount the suggestion above to use normal headers (which you can also get in larger versions, and in versions with latching connectors). For example, Molex KK uses a friction latch and has both male and female PCB headers that would give you a substantial amount of retention force.Are you under any particular space constraints?

author: thermistor-guy
author_rank: Frequent Contributor
timestamp: April 18, 2024, 05:47:34 am
content: Quote from: uer166 on April 16, 2024, 03:54:20 pmI use Amphenol D-sub connectors on my test jigs. Contacts are rated at 3A each, so a high-density 15-way connector can handle a lot of current, in principle.For some prototyping and one-off applications, I drill out the connector shells at the screwlock holes. The shells then separate, making the contacts (through-holemale and female) available as loose parts. The loose parts are useful when you want to make low pin count, board-to-board connections, and don'thave room for the full connector shell.OP is designing a product, though (in quantity?). So if there is room for the shell, and a through-hole style connector is ok, I'd at least consider a HD15-way D-sub. Cheap and effective.
Joule Meter: High Resolution Measurement of Energy Consumed - Page 1
Forum section: electronics / projects

author: electronupdate
author_rank: Regular Contributor
timestamp: April 10, 2015, 03:35:26 am
content: I am doing some work where I need to know exactly the amount of energy consumed by a circuit. I could not find any commercial solution which does this so I made my own. [Does such a commercial solution exist which has the resolution of at least 0.01 Joules?]A Joule is a watt-second.... by using a Arduino Uno which comes with some built-in 10 bit A/D converters and running a timer based interrupt to measure every 100 ms I was able to get the resolution I needed. The front-end is a bit simplistic but it was good enough for me to evaluate two different design approaches.Video at this link:

author: Marco
author_rank: Super Contributor
timestamp: April 10, 2015, 04:50:14 am
content: TI hasenergy tracethat's about it for commercial solutions.Ton of academic papers about instrumenting switching power supplies for energy consumption measurement though (the quantized nature of the energy transfer makes things a lot easier).
Joule thief on breadboard - Page 1
Forum section: electronics / projects

author: kalel
author_rank: Frequent Contributor
timestamp: July 22, 2017, 05:06:33 pm
content: My first Joule Thief on Breadboard.The man himself pointed me to using a cap and a diode to get an RGB LED working. Otherwise, it will appear fixed in the starting color (I guess restarting constantly).The coil is improvised from a lamp driver, keeping one original coil and somehow (not very neatly) wrapping the other using some thin wire. Both have about 0.4 mH.The cap is also taken from something, and is 100 uF. There's a standard diode, NPN and ~220 ohm resistor.I have no idea or way to measure the frequency, but the only important thing is - it works.No matter if something is simple, every success is nice.
Joulescope "universal USB" front panel - Page 1
Forum section: electronics / projects

author: liteyear
author_rank: Regular Contributor
timestamp: October 09, 2024, 02:48:14 am
content: I own a Joulescope JS220, which is a high precision logging DC power meter. It comes with banana jacks for connection of power and load, but also freely defines the front panel so you can make your own. More and more of the devices I measure are USB powered, and I've long had the intention of designing a universal USB front panel. That way I can measure anything that comes across my desk, and free up a drawer which is currently fully of cut up USB cables!I finally did it, and it works a treat first go. Fast becoming my preferred front panel for all devices, not just USB devices.Would others find this useful if I make it available?

author: liteyear
author_rank: Regular Contributor
timestamp: December 10, 2024, 11:17:38 pm
content: Now available!GitHub-hosted design files for your DIY benefit, and ready-to-purchase units in stock.https://www.tindie.com/products/empirical-ee/uusb-front-panel/
jovy  turbo ir benchtop station - Page 1
Forum section: electronics / projects

author: peter2
author_rank: Contributor
timestamp: October 21, 2021, 08:22:26 pm
content: please give a picture of the inside off the handset of this station.or a spare part number of the heating element.i need a picture and it is verry helpfull getting one.or somwone they have this station.
Joystick conversion question - Page 1
Forum section: electronics / projects

author: Delcion
author_rank: Newbie
timestamp: December 31, 2013, 05:05:56 am
content: I'm a lowbie electroinics tinkerer and modder <greetings!>. I'm currently trying to figure out how to replace the 500k standard pots in a vintage game console joystick with these 250k mini pots from a modern controller. I know I can't do a drop in because the voltage sweep probably won't be great enough. I've through about trying to drive a digital pot with the analog input from the mini pots or try to drive a transistor to get the sweep I need. I haven't sat down and measured the voltage range it actually uses, but I know it's a 5V input. Any ideas or suggestions?

author: Maxlor
author_rank: Frequent Contributor
timestamp: December 31, 2013, 05:25:46 am
content: Why do you have to use 250k pots? Are no other ones available?Have you analyzed the circuit in which the pots are used? If they're supplied with VDD and GND directly, the pots value won't matter much and a 250k will work just as well as a 500k. If there are other resistors nearby, it might be easiest to change those too to accomodate the 250k pot.More details would make it easier to give a better answer

author: Rerouter
author_rank: Super Contributor
timestamp: December 31, 2013, 05:28:41 am
content: I agree with maxlor, for a joystick, short of resistors on top and bottom to limit the range i can't see why they would be connected to anything more than VCC and ground..

author: Delcion
author_rank: Newbie
timestamp: December 31, 2013, 05:31:50 am
content: If this helps any, I have the schematics for the I/O on the system. It's an Atari 5200.https://atariage.com/5200/archives/schematics/Schematic_5200_IO_High.htmlthe reason I'm wanting to use 250k mini pots like in Playstation joysticks is I haven't found 500k versions of the mini pots.

author: Rerouter
author_rank: Super Contributor
timestamp: December 31, 2013, 05:50:20 am
content: pin 9 is your supply, 10 is horizontal, and 11 is vertical, it works through a time constant to work out the position,but now looking at it... boy did they go the extra mile to not use a separate ADC, a constant current driver feeds pin 9, and the 1nF and 47nF caps you see on pins 10 and 11 make up the RC time constant,try your 250K pot, but double those capacitor values, that should square things up.

author: Delcion
author_rank: Newbie
timestamp: December 31, 2013, 06:03:33 am
content: awesome stuff. Thanks a lot!
JS lib for parsing Rigol waveforms - Page 1
Forum section: electronics / projects

author: teddydestodes
author_rank: Newbie
timestamp: March 14, 2015, 11:29:48 am
content: Guess this will be my first Post after lurking the eevblog for so long...I've created a tiny JS library for parsing Rigol waveforms.I started this since I'm more comfortable in software than using the knobs on the DS1054Z.Be aware that while parsing the samples is pretty fast, rendering the actual linegraph isn't and will most likely freeze your browser.https://github.com/TeddyDesTodes/wfmjsAs a Bonus: there is a software spi-decoder in there.Also: Thanks Dave for the great reviews of the DS1054Z, I guess I'm not the only one who bought one based on your reviews.
JST connectors 3D model download confusion - Page 1
Forum section: electronics / projects

author: voltsandjolts
author_rank: Unknown
timestamp: February 20, 2023, 11:11:34 am
content: I'm trying to get a STEP file for a ZH connector (S5B-ZR) but am failing!https://www.jst-mfg.com/product/index.php?series=287You are forced to the 'enter your details here' form which I fill in correctly but I just get returned to the previous screen. I also get no email.Question for someone who has downloaded JST models - how is this supposed to work?!Wurth Electronics is the best in this regard, just a few clicks and you got all data you need, including Altium libraries. Nice coloured STEP models too.

author: ajb
author_rank: Super Contributor
timestamp: February 20, 2023, 03:24:30 pm
content: The file should download as soon as you submit the form. You won't get an email and there's no validation on the form inputs as long as they're not blankDo you have a pop-up blocker installed? Anything that would prevent an automatic download?

author: nali
author_rank: Frequent Contributor
timestamp: February 20, 2023, 04:33:19 pm
content: I had the same issue, and yes, it was my popup blocker.

author: voltsandjolts
author_rank: Unknown
timestamp: February 20, 2023, 06:59:19 pm
content: Jeez, thanks guys, it was indeed the standard popup blocker in firefox.First time I've seen that block a download.
JST connectors SH and SHD connectors' pin compatiblity - Page 1
Forum section: electronics / projects

author: palpurul
author_rank: Regular Contributor
timestamp: August 21, 2024, 07:27:00 am
content: Hello,I am working on a project where have a 50-pin 1mm pitch 2 row connector and bunch of 4-pin 1mm pitch connectors.We break of to 4-pin connectors from 50pin connector.We use the following connectors:4-pin connector SH connector50-pin connector SHD connectorI am thinking about using these cables to connect these connectorscablesThe cables are compatilble with the 4-pin SH connectors, but it doesn't specifically say it's compatible with the SHD.I checked the contacts for both pins and they look quite similar.Information about the contacts can be found here:SH datasheetSHD datasheetHas any ever tried inserting SH's pins into the SHD connector?

author: tooki
author_rank: Super Contributor
timestamp: August 21, 2024, 01:31:55 pm
content: The fact that the two contacts use the identical tooling tells me that all the key dimensions must be identical. But it turns out that if you look at the JST online shop, on the SHD housings, it says “use SH contacts”.The contacts listed in the SHD datasheet are gold-plated (hence the G in their part number), while the ones on the SH data sheet are tin-plated (hence the T in their part number).You do not want to mix gold and tin platings: the plating of the header and contact should be the same.So if you get tin-plated SHD headers, then the wires you want to use are fine.

author: palpurul
author_rank: Regular Contributor
timestamp: August 21, 2024, 04:26:17 pm
content: I just checked the shopping website.It does actually say that.The basic dimensions are the same as you said.I am afraid there is not tin plated one for the 50-pin connectorWhy do you think it's not a good idea to mix gold and tin?Thanks for the response, I really appreciate it.

author: thm_w
author_rank: Super Contributor
timestamp: August 21, 2024, 11:31:35 pm
content: Mixing gold and tin is not recommended for high reliability, you can just google to find the reasons why:https://www.te.com/content/dam/te-com/documents/industrial-intelligent-buildings/global/Connectors%20101_What%20Lighting%20Designers%20Need%20to%20Know_0217.pdfhttps://electronics.stackexchange.com/questions/574411/problems-with-gold-plated-connector-mated-with-tin-plated-connectorhttps://www.microcontrollertips.com/gold-tin-contacts-just-dont-mate-together/That said, we have thousands of units with mixed contacts and I have not seen an issue that would indicate the mix was at fault. But they don't get moved around, shaken, or regularly unplugged.

author: palpurul
author_rank: Regular Contributor
timestamp: September 10, 2024, 07:36:03 am
content: I just confirmed that the pins of SH and SHD series connectors are compatible.

author: tooki
author_rank: Super Contributor
timestamp: September 11, 2024, 07:00:57 pm
content: Well yeah, we figured that out a few weeks ago.Glad it worked out for you!
JST Connectors TYPES - Page 1
Forum section: electronics / projects

author: Looking For Help
author_rank: Newbie
timestamp: December 22, 2021, 09:22:01 am
content: Hello there!Someone can help me to recognize this type of JST connector ?TNKS

author: jpanhalt
author_rank: Super Contributor
timestamp: December 22, 2021, 10:22:46 am
content: https://www.jst.com/products/

author: Looking For Help
author_rank: Newbie
timestamp: December 22, 2021, 10:45:08 am
content: Yes tnks actually seems that there are various type of JST connectors, some one able to recognize this specific one ?

author: jpanhalt
author_rank: Super Contributor
timestamp: December 22, 2021, 11:20:18 am
content: There is a huge number of connector types. Yes, your connector looks like it might be JST, but other brands are white and partially shrouded.Start by posting some measurements. The most important one is pin spacing, aka "pitch." A picture of the female contacts can also help

author: Looking For Help
author_rank: Newbie
timestamp: December 22, 2021, 12:08:56 pm
content: The pitch is actually 2mmThere some photo

author: Looking For Help
author_rank: Newbie
timestamp: December 22, 2021, 12:12:48 pm
content: Some others

author: mon2
author_rank: Frequent Contributor
timestamp: December 22, 2021, 12:21:30 pm
content: Hi. Contact this company whom we have sourced parts for some OEM designs with success.https://www.lhecn.com/category/wire-to-board/2-0mm-pitch/They can cross the JST line.Our contact details from the last transaction:Quote

author: Looking For Help
author_rank: Newbie
timestamp: December 22, 2021, 04:24:16 pm
content: Ok tnks.I have wrote them for see if they can recognize what type of JST is.

author: Leo Bodnar
author_rank: Frequent Contributor
timestamp: December 23, 2021, 12:29:47 pm
content: Are you sure the pitch is not 2.50mm?https://www.we-online.com/catalog/datasheet/68800511722.pdfLeo

author: Bud
author_rank: Super Contributor
timestamp: December 23, 2021, 02:11:25 pm
content: The way i do it is go to Digikey and in parametric search filter by parameters such as number of pins, pitch, pin shape (rectangular,round,blade), shrouded or not, if the shroud with lock, pin length above PCB, connector size, etc. Then browse the filtered results.

author: Leo Bodnar
author_rank: Frequent Contributor
timestamp: December 23, 2021, 02:48:50 pm
content: I am confusion!Quote from: Looking For Help on December 22, 2021, 12:08:56 pmLeo
JST type connector identification - Page 1
Forum section: electronics / projects

author: AloyseTech
author_rank: Regular Contributor
timestamp: July 03, 2019, 02:19:42 pm
content: Hi,I'm trying to find the correct connector to connect a BEITIAN GPS :The vendor descirption state it is a 4 pin 1.25mm connector, that's all. Maybe the JST SM04B-GHS-TB connector could work but it seems a bit different...Other possibilities :Molex 530470410Hirose DF13-4P-1.25DS

author: Monkeh
author_rank: Super Contributor
timestamp: July 03, 2019, 02:40:44 pm
content: Looks like a Molex Picoblade.

author: voltlog
author_rank: Regular Contributor
timestamp: July 03, 2019, 03:23:44 pm
content: Wikipedia hasthis page dedicated to JST connectorsand we have a table with the different sizes. It looks like you need a JST-GH connector for 1.25mm pitch. You can find these on ebay or aliexpress if you can wait the long delivery time.

author: Monkeh
author_rank: Super Contributor
timestamp: July 03, 2019, 04:48:27 pm
content: The GH has a latch, so no, it's not a JST GH.

author: voltlog
author_rank: Regular Contributor
timestamp: July 03, 2019, 04:53:29 pm
content: I thinkthis connectorwill work for you.

author: AloyseTech
author_rank: Regular Contributor
timestamp: July 04, 2019, 08:36:18 am
content: I'm looking for the PCB side connector reference. I will try to sample some Molex and JST connector to try. But the JST is different from the one mounted on the GPS PCB so I guess this is not a GH serie connector.

author: rbm
author_rank: Regular Contributor
timestamp: July 04, 2019, 11:27:03 am
content: If the pitch is 1.50mm then the connector is likely a JST-ZH series.

author: Monkeh
author_rank: Super Contributor
timestamp: July 04, 2019, 11:29:00 am
content: Quote from: rbm on July 04, 2019, 11:27:03 amIf you ignore the fact that they look nothing alike:Again, this looks like a Picoblade:

author: rbm
author_rank: Regular Contributor
timestamp: July 04, 2019, 11:32:11 am
content: Sorry, I missed the text under the picture which stated 1.25mm. I was going by the general appearance of the female housing shape in the picture.
JT500UA Mifare reader manual/software - Page 1
Forum section: electronics / projects

author: Harvs
author_rank: Super Contributor
timestamp: September 11, 2016, 11:32:58 pm
content: I've got some DESFire cards I wanted to try out a concept with, so I picked up a reader from ebay:http://www.ebay.com.au/itm/191627567984Which the manufacturers page is:http://www.uhf-reader.com/en/productss_show.php?id=297I'm trying fruitlessly so far to get hold of the example code, or any sort of documentation on this device that describes the protocol to talk to it (it's just a virtual COM port that doesn't respond to anything I've tried or to a card being placed on it).The manufacturer doesn't have a download link or email address (only phone, which doesn't work too well when I don't speak the language) and the conversation with the ebay seller hasn't netted anything yet.If anyone has a copy they'd like to share please PM me.Thanks

author: Harvs
author_rank: Super Contributor
timestamp: September 12, 2016, 12:48:34 am
content: I should have known - it's appears it's essentially a clone of the Stronglink SL500 units, and the Stronglink software and DLL's work with it...
JTAG: can I resynchronise TDO using a flip flop? - Page 1
Forum section: electronics / projects

author: LightBlue
author_rank: Unknown
timestamp: June 13, 2014, 09:20:50 am
content: Dear JTAG guru,I have an interesting problem that requires some detailed knowledge about the internal workings of JTAG.In my application, I have a requirement to program a large number of FPGAs (>30) from a single JTAG interface due to access restrictions once the system is assembled. Programming speed is not important but the target TCK frequency is 4 MHz. The FPGAs are not close together and due to distance and fanout I intend to buffer the signals (which has worked perfectly on individual boards containing up to 8 FPGAs).My main concern is skew between TDO and TCK, which gets worse each time the clock goes through a buffer and the serial data comes back through another.I have considered several schemes but my preference is to resynchronise TDO to TCK using a flip flop or two (like the diagram in Figure 9:http://www.intellitech.com/products/..%5Cpdf%5CCJTAG-Concurrent-JTAG-multi-site-test.pdf). My question is, will this delay matter? When you scan the chain, will this be ignored and perhaps interpreted as a bypass or unknown device? Can anyone link to any documentation that says this definitely will or won't work?If you have alternative solutions, please let me know. I have considered bussing the TDI/TDO signals so I can disable parts of the circuit but I still have a long distance to drive the signals. Many boards are manufactured already so I cannot simply throw in long-distance drivers like LVDS, RS232 etc.