hybridfree/eevblog-posts huggingface dataset:
Component advice needed: smallest footprint 1W LED driver - Page 1
Forum section: electronics / projects

author: poorchava
author_rank: Super Contributor
timestamp: February 23, 2015, 11:31:06 pm
content: So I have this project, in which I need to stuff 20+ LED drivers on a single PCB. Drivers are powered from 12V rail (either ATX or an industrial power brick of some sort), each one driving a single 1W Luxeon Rebel diode at 300-350mA.I'm trying to find a solution which occupies the least PCB real estate. Right now the design uses Macroblock MBI6652 chips with an SRN6045-680M inductor. I was also looking at LM3405 as it offers higher switching frequency, which translated to smaller inductor. Do you know any particularily compact solutions I may have oversighted? Multichannel chips are fine (although I haven't seen any for power LEDs). I'd like the chip to be under 1.5€ (ideally <1€) a piece in quantities of several hundred, so LT is quite likely off table.Any suggestions appreciated

author: Corporate666
author_rank: Unknown
timestamp: February 24, 2015, 11:03:16 pm
content: Richtek RT8471 or Diodes Inc AP8803. Same part, just knock-offs of each other.It comes in an SOT23-5 package and only extra components needed are catch diode, inductor, sense resistor and a reservoir cap. Cap is ~2.2mF which if you'er driving one LED your Vf is low and you can get in an 0402 package. Sense resistor in an 0402 package too, no problem. There are plenty of 0.5A to 1A diodes in SOD-323 package, and that just leaves the inductor. There's plenty of 3mm x 3mm units with plenty of overhead on saturation current for this application, even some in the 2.5mm x 2mm range. I didn't do the math for your specific LED Vf and If but you might even be able to get away with an even smaller inductor, 1206 or something.Anyway, with the components above you should easily be able to get the whole driver to fit in a 7mm square area - certainly smaller than the heat sink copper area for a Lumileds Rebel LED.Hope it helps.

author: poorchava
author_rank: Super Contributor
timestamp: February 25, 2015, 10:45:29 am
content: Hm, seems like those will do the trick, thanks.I think I'm gonna go with SRN3015-470M inductor. 3x3mm footprint will be fine. Too bad Richtek chip only seems to be available from DigiKey, but AP8803 is in stock in both Farnell and RS.

author: tszaboo
author_rank: Super Contributor
timestamp: February 25, 2015, 10:56:16 am
content: Cant you connect the LEDs in series? If you need to be able to turn them on one by one, you can just short one with a MOSFET maybe, than you only need one constant current driver, and one boost.
Component choice and Swap - Page 1
Forum section: electronics / projects

author: chrischina
author_rank: Contributor
timestamp: June 04, 2016, 06:52:41 pm
content: I have two questions in one:I have collected some schematic from datasheet from manufacturer of chip. Inside the datasheet there are the following circuit shown below.1./ The manufacturer don't provide the BOM, so I don't have part number for all those small passive components. How to decide which one to use in terms of tolerance, X5R/X7R, Voltage, package ?2./ On some schematic there are some polarized capacit, typically some round cylinder space consumming. By what type of SMD can I replace those big cylinder to make the circuit smaller ?While answering this question, please explain it so I can understand what logical methodology you are usingThank you
Component / heatsink positioning - Page 1
Forum section: electronics / projects

author: upl8
author_rank: Contributor
timestamp: October 13, 2015, 04:50:22 pm
content: I am installing this phase angle controllerWeb page:http://www.united-automation.com/psr-25/Datasheet:http://www.united-automation.com/content/X10205%20-%20PSR-25.pdfOn this heatsinkhttp://www.altronics.com.au/p/h0582-128-x-100mm-extra-heavy-duty-heatsink/The load will be drawing about 13 amps, which requires about 3°C/W according to the datasheet. The heatsink is rated to 1.3°C/W. There is a 120 X 38 fan mounted directly below the heatsink, but it's mounted on the same wall as the heatsink. So air won't be blowing directly over the heatsink from the fan. I haven't measured the enclosure temperature yet, but it's going to be warmer than the ambient.Should I install the controller at the bottom of the heatsink, or in the middle for best cooling? I initially thought the middle so the heat could conduct evenly in all directions, but the bottom might be better if the heat will rise towards the top of the heatsink.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 13, 2015, 07:24:58 pm
content: It won't make much difference. Put it in the middle so it's most evenly distributed.If you have thermal problems, consider adding a little deflector, just in front of the fan, so air is forced over and along the heatsink fins. Should be much better than convection.Tim
Component ID - Page 1
Forum section: electronics / projects

author: OpenCircuit
author_rank: Regular Contributor
timestamp: March 22, 2020, 01:24:49 am
content: "ZDW 38" SOT 23 Board designation is Q10 Cant seem to find any specs. Thanks for any help finding the pdf.

author: MLXXXp
author_rank: Frequent Contributor
timestamp: March 24, 2020, 02:58:27 pm
content: Maybe a PBSS5350T PNP transistor?https://assets.nexperia.com/documents/data-sheet/PBSS5350T.pdf
Component ID for SOIC-8 chip labelled ICW 4008 - Page 1
Forum section: electronics / projects

author: xchg.ca
author_rank: Contributor
timestamp: June 25, 2021, 03:35:33 am
content: Here is the photo of the suspect, labelled ICW 4008Pins 5-8 are connected together and to + of the 200V capacitor ( right above the chip )Searched all over the Google,Mysterious power ICPlease help to identify
Component identification (led driver) - Page 1
Forum section: electronics / projects

author: vinicius.jlantunes
author_rank: Regular Contributor
timestamp: January 20, 2018, 03:27:56 pm
content: Hope someone here can help me identify this component.It is in a LED driver circuit from a small 5W light fixture. The code in the package is 26453 (and 9420 at the top which I suspect is a the fab date?).The schematic is very simple, also attached. When fed with 127VAC it's output is ~170 VDC. I believe it is a constant current LED driver or a regulator wired as a constant currrent source. What caught my eye though is the fact that it can take a high input voltage (basically rectified and filtered mains, no transformer).I have salvaged 6 of these from a dumpster and the LED's are fried in 5 of them, but I want to reuse the fixture and put new LED's on it. So I would like to reverse engineer the driver circuit and adjust accordingly.The driver circuits seem to be all working, so I just wanted to see if I can adjust its current by changing the feedback resistor R1 so it matches whatever new LED's I put in it (most likely a small string of SMD LEDs that I have laying around, in series).

author: amyk
author_rank: Super Contributor
timestamp: January 20, 2018, 05:11:07 pm
content: Winsemi WS9420.Your schematic shows the diode backwards.

author: vinicius.jlantunes
author_rank: Regular Contributor
timestamp: January 20, 2018, 06:55:38 pm
content: Thanks!And about the diode too, doh!
Component identification   - Page 1
Forum section: electronics / projects

author: Mikeyjf
author_rank: Newbie
timestamp: February 24, 2020, 11:13:01 am
content: Hi guys,We have some battery LED uplighters at work which are used for architectural lighting and two have very corroded PCBs!There are 3 small components that I am having trouble identifying. Printed to the board is D1, D2, D3 so are they just diodes?On one PCB they are marked YP 11A and on the second PCB they are marked YP 19A…Image here -https://ibb.co/8dTKRDRBit of a stupid question but what are they? One has fallen off the PCB tracks and I am gonna attempt to repair…Michael

author: gamalot
author_rank: Super Contributor
timestamp: February 24, 2020, 11:22:31 am
content: SMAJ36CAhttps://www.littelfuse.com/~/media/electronics/datasheets/tvs_diodes/littelfuse_tvs_diode_smaj_datasheet.pdf.pdf

author: Mikeyjf
author_rank: Newbie
timestamp: February 24, 2020, 10:43:16 pm
content: That’s great! Thank you very much!
Component identification - Page 1
Forum section: electronics / projects

author: retrev
author_rank: Contributor
timestamp: June 12, 2021, 12:19:15 am
content: An old alarm system in my house has a bunch of these. I'm assuming the 10nJ is a power tattooing and it's some sort of surge suppression on the sensor lines but I'm not sure what kind.

author: bob91343
author_rank: Super Contributor
timestamp: June 12, 2021, 02:15:00 am
content: 10n probably means 10 nF and the J means 5% tolerance.
Component identification - Page 1
Forum section: electronics / projects

author: gaminn
author_rank: Frequent Contributor
timestamp: May 07, 2024, 04:06:09 pm
content: Hi,any idea what is this?The circuit is a low power switching power supply. The controller of the switching power supply is a hybrid IC (under the black heatsink).

author: gaminn
author_rank: Frequent Contributor
timestamp: May 08, 2024, 06:10:26 am
content: It is SGL41-40 schottky diode.
Component Identification - Page 1
Forum section: electronics / projects

author: echodreamz
author_rank: Newbie
timestamp: March 15, 2017, 03:29:41 am
content: Trying to identify what this part is (the IC) on this board. Google'd for days and cannot find anything.Anyone have an idea? Thank you! This is a brake light control module.Love the youtube videos Dave!

author: amyk
author_rank: Super Contributor
timestamp: March 15, 2017, 09:54:13 am
content: It could be a custom ASIC or a remarked standard logic gate. Reverse-engineer the schematic and see how it is used.
Component Identification 'F7546' TO-39 device - Page 1
Forum section: electronics / projects

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: September 11, 2017, 09:53:03 pm
content: Anyone knows who used the marking 'MCT' or 'MCT1'?Component is 3-pin TO-391st Line: MCT12nd Line: F7546I found 2N7546, but that's a die. Also IRFR/IRFB7546, but no trace of TO-5/TO-39

author: Cerebus
author_rank: Super Contributor
timestamp: September 11, 2017, 10:48:07 pm
content: Fairchild sometimes produce a part that's a standard part but with slightly tighter specs and replace the common prefix with an 'F'.MCTcanstand for MOSFET Controlled Thyristor, although that seems unlikely in a TO-39.OK, that's all I got.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: September 12, 2017, 12:30:39 am
content: Quote from: Cerebus on September 11, 2017, 10:48:07 pmI hanen't dug out a older Fairchild discretes databook yet, but worth a try!Quote from: Cerebus on September 11, 2017, 10:48:07 pmSaw that too, but concur with you..

author: Benta
author_rank: Super Contributor
timestamp: September 12, 2017, 06:43:22 am
content: Don't know the MCT1, but F7546 I'd interpret as Fairchild, produced 46th week of 1975.
Component Identification - Black 0805 Ferrite/RC? - Page 1
Forum section: electronics / projects

author: mc172
author_rank: Frequent Contributor
timestamp: June 28, 2020, 04:06:14 pm
content: I've got a mystery component on the bench and could do with some help identifying what it is please. It's black, 0805 in size and has nothing written on it. It looks like this:I just assumed it was a ferrite bead, but upon further inspection I don't think it is. I put it on my LCR bridge and got the following for series L and C vs frequency:There's some funny business going on at a few of the points, resonance?At DC (which my LCR bridge won't do) it measures about 10k. Here's the series resistance vs frequency results:Q is zero until about 1 MHz on the LCR bridge, at which point it goes up to 0.2 at 5 MHz (the upper frequency limit of my bridge).I've also got a VNA, so I made a little test fixture as follows:Measuring for transmission impedance I can look at the series impedance, and that looks like this:This looks like a high pass filter to me, but I didn't even know they made these in 0805 or even 2-pad packages? If it were a ferrite bead as I initially thought the plot would be roughly the reciprocal of what I see.Has anyone got any idea of what this could be please?Thanks.

author: mc172
author_rank: Frequent Contributor
timestamp: June 30, 2020, 12:03:49 pm
content: Anyone?

author: brabus
author_rank: Frequent Contributor
timestamp: June 30, 2020, 12:27:00 pm
content: If it's a ferrite bead, you will notice some effect abore >50MHz maybe.Where dit it came from?

author: mikerj
author_rank: Super Contributor
timestamp: June 30, 2020, 01:02:16 pm
content: Unlikely to be a ferrite bead, the DC resistance is far too high.

author: mc172
author_rank: Frequent Contributor
timestamp: June 30, 2020, 01:35:17 pm
content: Quote from: blueskull on June 30, 2020, 12:57:49 pmWhy didn't I think of that?! Easy to say in hindsight, eh. It was part of a bias circuit in an RF amplifier so I was single-track minded going down the path of something RF.I just warmed it up whilst measuring it and sure enough, it's an NTC. Thank you.

author: cdev
author_rank: Super Contributor
timestamp: March 21, 2021, 02:06:13 pm
content: Good idea to use the stripboard to measure series impedance. Think I will make a series fixture with pogo pins like that
Component Identification: Case Code BR 51 SOT-23 - Page 1
Forum section: electronics / projects

author: amaschas
author_rank: Regular Contributor
timestamp: September 23, 2025, 05:06:53 am
content: I'm currently working to repair a board that has a burnt component on it. The component in question appears to be a SOT-23 with case code BR 51, and there are quite a few of them on the board. I was thinking they were potentially a transistor, but the voltage drops across the pins are not characteristic of either a BJT or a MOSFET. The pins all have measurable voltage drops between each other, and in one direction they're about 0.7-0.9V, and reverse about 1.2-1.9V. Pretty baffled as to what this might be? Possible a zener of some kind?If we're labeling from top to bottom pins 1, 2 and 3:- probe pin 1, + probe pin 2 : 1.25V, reversed 0.9V- probe pin 1 + prove pin 3 : 0.684V reversed 1.9V- prove pin 2 + probe pin 3: 0.681V reversed 1.95V

author: uer166
author_rank: Super Contributor
timestamp: September 23, 2025, 06:22:37 am
content: Have you tried measuring out or circuit? This looks like a PNP in SC-70 at a glance many options for PNs such as:2SB1218A-R2SB0709A

author: amaschas
author_rank: Regular Contributor
timestamp: September 25, 2025, 04:46:14 am
content: That definitely helped, I pulled it out and its almost certainly an NPN transistor of some kind. Having a hard time identifying the package, but it appears to be some SOT-23 variation, as it's 2.9mm x 1.7mm, almost like a SOT-23-5 but with 3 pins? Pin 1 at the top appears to the base, and while the voltage drop to the other two pins is very similar (0.690V, 0.695V) I believe pin 2 is the collector and pin 3 is the emitter. This part is off a BK Precision 9131B, and as I mentioned before its used pretty heavily in the design, so it probably a very common part.
Component identification help - Thermal sensor - Page 1
Forum section: electronics / projects

author: Joarek
author_rank: Newbie
timestamp: April 30, 2019, 04:04:21 pm
content: Hello and thanks for taking the time to read my little post.I tried to post this once already but it failed somehow(i bet it was due to trying to attach/upload too big images)So here i try again using Imgur..I am trying to identify the thermal sensor on this board so i can either extract it and re purpose it, or measure it and buy a substitute with the same values.Long story made short: Late 2011 27" iMac. Replaced faulty HDD and aftermath is 100% fan-usage due to an "Apple moment" with proprietary sensor instead of standardized S.M.A.R.T. usage for disk thermal monitoring.Can anyone lend their me their eyes and knowledge and identify any thermal sensor. I have tried and failed all the ways i know how so any input or sugestion is appreciated and welcome (unless you mention OWC Cable)I tried to crop and flip, scale, tweak to make it as human able to read, but let me know if you want any better images of a specific chip/area.Backside
Component Identifying Code - Page 1
Forum section: electronics / projects

author: mehmet.ali.anil
author_rank: Newbie
timestamp: November 26, 2017, 07:10:48 pm
content: Hi!I would like to know the different schemes that are used by people for component IDs. (Design Item ID in Altium)Our company uses RES# CAP# TRS# DOD# for prefixes, maybe few letters or numbers for categories and a numeral indication of the value/part number followed by it. I don't know for sure, but it can be a coding scheme that was adopted from an old old Phillips scheme.e.g. RESE24001003 is a resistor in the E24 set, 402 size, with 10 * 10^3 ohmsI see that Altium example designs use CMP-2008-04561-4 where first is indicative of a year, and rest could be just a incremented value.What other standards are available? I failed to find an official standard that I might start from, like an IPC standard.
[Solved] Component manufacturer identification for 2N1893 - Page 1
Forum section: electronics / projects

author: deepfryed
author_rank: Unknown
timestamp: September 02, 2023, 01:55:03 am
content: I came across a few 2N1893s, but cannot make out the manufacturer. The letters printed look like SSS, is that Sony ?Some of these have a 80 Vceo and others 120 Vceo, I'm trying to find the datasheet for it.

author: deepfryed
author_rank: Unknown
timestamp: September 02, 2023, 02:02:55 am
content: I think it might be SGS Thomson, gee they make it hard to decipher.

author: moffy
author_rank: Super Contributor
timestamp: September 02, 2023, 02:21:30 am
content: Saw an ebay seller selling purported SGS 2N2905 and the logo picture and printing looks very similar.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: September 02, 2023, 10:30:10 am
content: Yes, that is SGS Microelettronica. They became the 'S' in ST when they merged with Thomson.

author: magic
author_rank: Super Contributor
timestamp: September 02, 2023, 10:34:30 am
content: If you can't find information elsewhere, try one of the discrete transistor databooks:http://www.bitsavers.org/components/sgs/_dataBooks/editStill on ST website:https://www.st.com/resource/en/datasheet/cd00003216.pdf

author: deepfryed
author_rank: Unknown
timestamp: September 02, 2023, 12:10:17 pm
content: Quote from: magic on September 02, 2023, 10:34:30 amThanks @magic, that's a treasure trove!Quote from: HwAoRrDk on September 02, 2023, 10:30:10 amthanks, I worked it out just after I posted the question. The date code is from the time when ST was still SGS Thomson, it took me a few minutes for my brain to register that
Component Placement tool with Clearance Constraint tool in Blender - Page 1
Forum section: electronics / projects

author: Schottky
author_rank: Regular Contributor
timestamp: December 27, 2023, 01:21:25 am
content: I've been developing a tool to implement a PCB electrical clearance constraint rule using geometry nodes in Blender. This is useful when creating initial layout and component placement studies especially for high voltage designs. Also, can be used for documentation purposes.You can see in this video how warnings are displayed when components get too close to each other based on whatever clearance distance is set, also you can visualise the clearance boundaries in 3D, not just in 2D.For those familiar with Blender's geometry nodes, I first assign components (pins and pads) belonging to the same Net Class to a vertex group, and then use the "distribute nodes on faces" node and the "proximity node" to determine how each point belonging to one vertex group (i.e. Net Class) is further away from another point belonging to another vertex group.This tool can be more powerful than most pro PCB design software as they only implement clearance rules in 2 dimensions (X&Y) and rely on the footprint pads definition. To use this tool, you will need to have a library of component models in Blender. These models can simply be STL meshes than can be created by any CAD software and then imported into Blender or can be made completely in Blender. I will be making my library of components available soon.You can see more of work on Twitter/xhttps://twitter.com/samerps,and some my other posts on this forumhttps://www.eevblog.com/forum/chat/renders-and-animations-of-pcbs/

author: temperance
author_rank: Super Contributor
timestamp: December 27, 2023, 07:36:50 pm
content: QuoteComponent clearance is defined by a courtyard as defined in IPC 7351. Where the courtyard is a 2D projection of the component itself + PAD's + some clearance. That's how this is implement in most pro PCB design software.
Component reeling service - recommendations? - Page 1
Forum section: electronics / projects

author: Corporate666
author_rank: Unknown
timestamp: April 09, 2015, 04:03:32 pm
content: So I just received 5,000 SOT-23-5 regulators from Verical... in a damn screw-top canister.I didn't realize they were loose - I thought they were on a reel. Can anyone recommend a reeling service, and/or give an idea what the cost of such a service is? I'm hoping to send them somewhere and get them reeled, if it's not too expensive.Thanks
component reference  - Page 1
Forum section: electronics / projects

author: yalect
author_rank: Regular Contributor
timestamp: July 10, 2017, 11:21:47 pm
content: Hello,I would like to ask you if you can determine what is the compenent appeared on the attached picture, they look like a transistors, mybe the reference printed on the package helps more.thank you

author: B-Skunktail
author_rank: Newbie
timestamp: July 11, 2017, 01:39:03 am
content: Based on the symbols beside the parts and a quick search on the part number (ss101), I think you will find they're Schottky Diodes.If anyone has better info, I'm happy to be corrected on this.

author: Simon
author_rank: Unknown
timestamp: July 11, 2017, 06:52:10 am
content: Please do not make duplicate threads. It is annoying and highly offensive to people trying to help you. It won't get you help any quicker and will mean people are less inclined to help.
Component Selection Monitor for Buck Converter  - Page 1
Forum section: electronics / projects

author: Cirro
author_rank: Newbie
timestamp: November 09, 2022, 03:18:39 pm
content: Hi,I am currently working on a fun little project featuring a 24->10V buck converter rated for 5W. The purpose of the circuit is to show how varying the output filter and frequency can influence device behaviour, including operation of continuous (CCM) or discontinuous conduction mode (DCM). To do this the circuit features two output Inductors and Caps, which, by pressing a DPDT it will change the conduction path to a larger/smaller component size.To provide an educative aid to my circuit I’ve decided to add LED's which will switch on depending on which inductor/capacitor has been selected. To trigger these LED's I have a potential divider dropping the 24V ripple down to be fed into a flip flop. The change in input values then allows the flipflop to provide the logic levels that I can use to light the appropriate LED. I have attached my circuit diagram below.The zeners clamp the voltage to prevent spikes damaging the flip-flop, and the caps provide a filter to remove any high frequency spikes that may inadvertently retrigger the flipflop when the inductor is being changed. The scope refers to the inputs and outputs of the flip-flopThe simulation results are promising however my questions are – is there a more elegant way I could go about achieving the same result and am I missing a fundamentally important issue that will arise when I start testing?Any input on this would be greatly appreciated!Regards,Cirro
Component Storage and Organization Questions - Page 1
Forum section: electronics / projects

author: Zenwizard
author_rank: Regular Contributor
timestamp: January 30, 2023, 06:17:50 pm
content: I find my self with a growing inventory of parts stretching the decades. My current needs are I have to deal with vacuum tube all the way up to surface mount transistors and 0402 components. And I am drowning in boxes of parts on the floor. I am in desperate need of some storage units for the components.I am curious if anyone has a recommendation as to a shelving system and organizers that can be used to store these parts. I am also looking to source the cardboard ½ boxes that are used to hold large components. I keep getting them in shipments of used equipment but I would like to get a source for new if they are available If any one know what they are called.I will attach a picture when I get back in to the lab tonight.Zen

author: edavid
author_rank: Super Contributor
timestamp: January 30, 2023, 07:14:35 pm
content: If you are talking about the attached, they are called bin boxes, shelf bins, or parts bins.I like to combine them with coin envelopes. The 8" wide boxes can be divided in 3 with cardboard strips and will fit 3 rows of #3 coin envelopes. The 4" wide boxes will hold #7 coin envelopes neatly.I bought BINMT412 and BINMT812 from Staples, but their current prices are not very good. If you live in a city there is probably a box supplier that stocks them.

author: Zenwizard
author_rank: Regular Contributor
timestamp: January 30, 2023, 10:21:02 pm
content: That is exactly what I am looking for. I will get some on order.Zen
Component suggestions for 2x6S battery pack? - Page 1
Forum section: electronics / projects

author: dobsonr741
author_rank: Frequent Contributor
timestamp: March 25, 2023, 11:50:56 pm
content: I'm looking for component suggestions for a metrology oriented battery pack. Thinking of the following requirements:1. Able to supply two 24V independent/isolated output by two chains of 6S 18650 ~2000mAh Li batteries. Max load is 1A on each chain.2. 100M Ethernet interface, simple web interface to monitor and manage.3. Built in charger, supplied from POE or a 12V input.4. Should be able to limit charging to 4.0V.5. Should be able to balance in the range of 40..100mA.6. It's a one-off buildout.Initial thoughts were to use the TI BQ series components, however open for the Analog/Maxim/Linear parts.

author: Psi
author_rank: Super Contributor
timestamp: March 26, 2023, 12:12:36 am
content: I've used the analog device LTC4162 battery charger IC before, seems pretty robust.I used the lead acid version but they have a lithium version too LTC4162-LSadly the lithium version doesn't include a cell balancer, so you'd have to add that.And you'd need a MCU to turn the I2C stats into LAN/webpage.Not saying its the best option for your metrology oriented use case, just saying its an option to check out.Analog devices have more complex charger ICs that are probably also worth checking out.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: March 26, 2023, 10:13:51 pm
content: I'm about to settle with the following stack:TPS2378 + LM5160 to source isolated power from POELTC4162 for charging2x BQ76952 to protect/balance/measure for the two 2S cell banks3x ISO1644 for galvanic isolationRaspberry Pi 3 B+ to run the show12V powering is no longer an option/need. Critiques are welcome.
Component values for a telephone line interface circuit - Page 1
Forum section: electronics / projects

author: Phaseseeker
author_rank: Regular Contributor
timestamp: January 27, 2025, 02:10:34 pm
content: I'm working on an interface circuit for an old payphone I've been reverse engineering; the thing uses two phone lines, one which is an absolutely standard PTSN line used for voice, and a secondary line used for data communications.This second line works with what they call "telegraphic" signalling; basically they're sending "packets" which consist of a long "start" pulse, thennshort pulses wherencorresponds to the digit being sent (think pulse dialling) and then a long "stop pulse". To achieve two-way data comms, for data going in theCentral Office -> Phonedirection is sent by inverting the phone line polarity, whereas the pulses going in thePhone -> COdirection are sent by the phone changing the load on the line (and thus the line voltage); there's an example of this in the attached pictures.The line interface circuit on the phone side is quite trivial (again, see 2nd attached picture).My problem is on the other side, where I'm trying to simulate the CO side of things; looking through patents, I've found a schematic of an actual line interface card used by the phone company (relevant part redrawn in the third picture), but the scan is poor and it's missing all the values for the components.I understand the basic idea of what they're trying to achieve with this circuit, but I'm confused enough by the all the Zeners that I can't figure out how they would've picked the values for those.I was also thinking of replacing the whole thing with a simple H-bridge + a high enough series resistor on the line to detect the change in current being drawn, but I'm not sure there's any subtlety in their circuit I'm missing (since the comms line also needs to provide power to the phone)...Thanks in advance for any idea.PS: In the line card schematic, keep in mind "earth" here is positive i.e. connected to 48V battery's positive terminal. That sent my brain in a loop for a while
Components clearance in Altium - Page 1
Forum section: electronics / projects

author: Nikos A.
author_rank: Regular Contributor
timestamp: June 18, 2021, 09:01:40 pm
content: Hi everyone,I am facing an issue that I cannot workaround. I have set 0.254mm clearance for all components as you can see from the screenshot below and I use the Moving [Push: avoid] option while placing the components. For some components the clearance differs from what I have set in design rules. For example, I can place R22 0.254mm close to another component BUT if I rotate R22 then the minimum distance I can place it close to that component is around 3.3mm. I can place it closer only if I use Moving [Push: Ignore] option.What is the problem behind this issue? This could be related to the footprint, or is there any design rule I have to check, or maybe this is somehow related with system preferences? This issue also applies for some other components. I also attach the 3D view in case that it is helpfulHere I have rotatedR22and as you can see I cannot place it closer than 3.3mm
components cross sections - Page 1
Forum section: electronics / projects

author: zofz
author_rank: Regular Contributor
timestamp: April 21, 2019, 12:04:38 pm
content: Really great tweet by @TubeTimeUS, a series of components cross sections with a bit of explanation:https://twitter.com/i/moments/1112130787694931968

author: chagli
author_rank: Contributor
timestamp: April 21, 2019, 12:57:47 pm
content: Great link, thanks !

author: harnon
author_rank: Regular Contributor
timestamp: April 21, 2019, 01:21:56 pm
content: Cool photos. Amazing how simple the construction is for a lot of the components.
Components for brushless DC motor driver - Page 1
Forum section: electronics / projects

author: cyberfish
author_rank: Regular Contributor
timestamp: February 23, 2013, 06:44:42 pm
content: I have a project that needs to drive 5 DC brushless motors, 15V, ~2A max. continuous.Right now I am using L6234 (http://www.st.com/web/en/resource/technical/document/datasheet/CD00000046.pdf). It works, but requires huge heatsink areas on PCB due to high Rds(on) of 0.3 ohms per FET (2.5W per chip * 5 chips = 12.5W). Adding a heatsink is not an option due to space constraint.In the past I have also used AO4616 (http://www.aosmd.com/res/data_sheets/AO4616.pdf) with external gate drivers. That works very well thermally thanks to the 0.02 ohms Rds(on), requiring no heatsinking at all. However, that requires ~5 chips per motor, or 25 chips total...Does anyone know of a chip like L6234, but with low Rds(on)? Or even something like PMOS + NMOS pair with integrated level shifters?I have looked for a few hours and didn't find anything.Interface doesn't matter. They will be driven by an FPGA.Thanks!

author: mazurov
author_rank: Frequent Contributor
timestamp: February 23, 2013, 08:09:39 pm
content: I made a BLDC controller based on A4960 a while back ->https://www.circuitsathome.com/diy-2/advanced-brushless-dc-motor-controller. It is a pre-driver, therefore heat depends on external MOSFETs. PSMN4R3-30BL (pictured) are slightly warm at 50A per phase.

author: slashguitar
author_rank: Contributor
timestamp: February 23, 2013, 08:28:50 pm
content: Take a look at this board made by AVNEThttp://www.em.avnet.com/en-us/design/drc/Pages/Xilinx-Spartan-6-FPGA-Motor-Control-Development-Kit.aspxThe schematics are available if you create an account. It uses DRV8312 from TI (80 mOhm Rdson)
Components price - Page 1
Forum section: electronics / projects

author: gaminn
author_rank: Frequent Contributor
timestamp: September 26, 2019, 11:59:34 am
content: Hi,I'm going to production with a product I developed and I'm looking for best supplier of components.I can always buy from Mouser or Digikey but I also inquired components from some local distributors.Is it possible to get 50 - 80 % better price than what Mouser or Digikey has from local suppliers and get the same quality components?The local supplier can supply e.g. (50 - 100 quantities):WM8213SCDS/V Cirrus Logic (0.63 USD vs 3.3 USD on Mouser)https://octopart.com/search?q=WM8213SCDS%2FVDRV8837CDSGR Texas Instruments (0.15 vs 0.57)https://octopart.com/search?q=DRV8837CDSGR%09LP5562TMX/NOPB Texas Instruments (0.29 vs 0.71)https://octopart.com/search?q=LP5562TMX5M160ZE64C5N ALTERA (1.65 vs 3.47)https://octopart.com/search?q=5M160ZE64C5N%09

author: tszaboo
author_rank: Super Contributor
timestamp: September 26, 2019, 01:17:34 pm
content: At 50-100 quantities, you shouldn't be worried about pricing of components.And yes, it is possible to get large discounts on the Digikey pricing. Digikey is NOT a company who sells you stuff for production. They sell you stuff, if you dont have other options, due to time.It's like DHL. You can find better deals than DHL shipping, but if you need to send one thing, it is usually not worth the trouble to look for an alternative.

author: gaminn
author_rank: Frequent Contributor
timestamp: September 26, 2019, 01:26:37 pm
content: Good to know. It is like 1000 USD discount on whole order which is pretty nice for me. And actually, it is 70 - 250 quantities.

author: DTJ
author_rank: Super Contributor
timestamp: September 26, 2019, 01:45:39 pm
content: Try putting your BOM into Octopart.com

author: gaminn
author_rank: Frequent Contributor
timestamp: September 26, 2019, 01:50:41 pm
content: The prices I got from my local supplier are far better than what is on Octopart.

author: DTJ
author_rank: Super Contributor
timestamp: September 27, 2019, 02:46:13 am
content: Well you know where to purchase them from hey!
Componets to Test Homebrew Reflow Oven Temperatures - Page 1
Forum section: electronics / projects

author: beaker353
author_rank: Unknown
timestamp: January 11, 2016, 01:41:38 am
content: I have a freshly built reflow oven built from a toaster oven and a kit ControLeo2 kit fromhttp://www.whizoo.com. I want to build some test boards with some cheap components before I start throwing in expensive ICs. I've read in a couple of places that the yellow Tantalum caps are a good indicator of too much heat as they will start to turn brown if temps are too high. I was wondering what would be ideal to test for too little heat in a worst case scenario? My first thought would be something with a large thermal mass like a high current LDO in a TO-263 (D2PAK) package. However, I debating which would actually be a tougher test for my oven; a TO-263 WITH or WITHOUT a large ground plane thermally directly attached to the heat-sink. Anyone have anything to add?-EM

author: TorqueRanger
author_rank: Frequent Contributor
timestamp: January 11, 2016, 04:35:55 am
content: Try googling thisSMT SMD Component Welding Practice PCB Board Soldering DIY Kits BE

author: beaker353
author_rank: Unknown
timestamp: January 11, 2016, 05:26:26 am
content: I've seen those bouncing around for quite a while. I believe it's designed more to test manual solder dispensing and hand placing skills more than oven performance. I would have to duplicate the design down to the faction of a mm to create a paste stencil, so it's not practical in the least. I guess I more asking what components/configurations are an absolute pain to get proper flow.-EM

author: kuromaku
author_rank: Newbie
timestamp: January 11, 2016, 08:31:37 am
content: In my experience, for IR ovens like that something short that's shaded by a really tall one, like a small BGA right next to a big inductor.
Composite to COLOR VGA - Page 1
Forum section: electronics / projects

author: billybobpickle
author_rank: Newbie
timestamp: January 21, 2015, 01:33:17 pm
content: I have a microprocessor board that I am going to build. It outputs only composite video out and I would like to make aCOLORVGA converter. I was wondering what it would take to build a Composite to VGA converter. I could only find how to convert composite to black and white vga.

author: Skimask
author_rank: Super Contributor
timestamp: January 21, 2015, 01:43:36 pm
content: http://lmgtfy.com/?q=composite+to+vga+converter

author: bktemp
author_rank: Super Contributor
timestamp: January 21, 2015, 01:49:39 pm
content: If your composite Video is NTCS you need to double each line to get 640x480 progressive video instead of 640x480 interlaced.Using modern parts it is a singe chip solution, but it is quite hard to get those ICs in small quantities.But it is possible to avoid those special parts:http://elm-chan.org/works/sc/report.html

author: netdudeuk
author_rank: Frequent Contributor
timestamp: January 21, 2015, 02:04:14 pm
content: I bought one of these to go with my Z80 homebrew system -http://www.ebay.co.uk/itm/TV-CCTV-DVD-AV-Composite-RCA-S-Video-To-VGA-Monitor-PC-Video-Adapter-Converter-/290631299043?ssPageName=ADME:X:eRTM:GB:1123It works just fine but not sure how good the wall wart is.I've since disconnected the external mono video interface and added a Propeller based colour VGA adapter to it.It works very well.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 21, 2015, 05:18:00 pm
content: Quote from: billybobpickle on January 21, 2015, 01:33:17 pmJust go on eBay, these things are more or less commodity items. Going home-made on this is not a beginner's project. Not impossible, just harder than it looks.

author: Richard Crowley
author_rank: Super Contributor
timestamp: January 21, 2015, 05:28:21 pm
content: By comparison, your microprocessor board is a trivial project compared to a color composite to VGA converter.Not recommended as a DIY project. You can buy a working commercial unit for less than you would pay for the parts.Not to mention the effort to build it from scratch.
Composite Video buffer amplifer circuit using transistors.... - Page 1
Forum section: electronics / projects

author: peteb2
author_rank: Regular Contributor
timestamp: February 14, 2020, 12:23:48 am
content: I'm having one of those moments where i just can't recall an arrangement of a couple (or more) transistors that will act as a buffer & increase the level of good old fashioned composite video. The amplitude needs to be overall 1V peak to peak (driving into 75 ohms) consisting of positive going +700mV of the 1Vp-p from 0V (=blanking) for actual video while 0V to -300mV is negative going for the sync. It will end up terminated by 75 ohms so the final output would need to be from a transistor's emitter to sink such a low impedance.... Obviously such a configuration will need split supply rails say +5V, 0V, -5V..... and it'll need an input trim pot to tweak the final output level (i guess). This is a PAL colour video signal & yes i could use an opamp but i have hundreds of transistors in the junk spares bin that could do with being put to use...Appreciate any input. This kind of thing was a common issue a few years years back when analog video ruled the roost and any digital video was but theoretical only!

author: mikerj
author_rank: Super Contributor
timestamp: February 14, 2020, 01:02:36 am
content: Something like this maybe?http://electronschematics.blogspot.com/2011/06/video-amplifier.html
Composite Video Distribuition / amplifier - Page 1
Forum section: electronics / projects

author: rauloliv
author_rank: Contributor
timestamp: May 28, 2014, 11:59:32 am
content: Hi guys,Sometime ago i was asked to do a simple composite video switchbox for a bar.4 inputs from sat receivers -> 4 outupts to video projectros / LCD tvsCables are RG6 and video is from composite output. The cable lenght is not the same for all the screens, shortest is 5 meters, longest is about 25The goal was to be able to select the input for each screen, alowing the same input to be displayed in multiple screens.What i done was a mechanical switchbox with 4 quality rotary switches (one for each output).Selecting the same input on 3 or 4 outputs would decrease the video quality a bit but my client was aware of that and was happy with it.Now they have made some changes on the bar moved all the receivers to the upper floor and the sat receivers also changed. Now i'm facing some problems when selecting the same input to more than one output - loss of video quality (low contrast picture) but the worst is ground loop interferences ( horizontal bars on picture)The simple solution that comes to my mind would be just adding amplifiers on the 4 outputs. Could this solve the problems i'm having?Any sugestions?Thanks

author: nihilism
author_rank: Regular Contributor
timestamp: May 28, 2014, 12:31:56 pm
content: http://www.krameraustralia.com.au/products/model.asp?pid=1010&sf=49http://www.extron.com.au/product/product.aspx?id=mavavrcaseries&subtype=130&s=4

author: SL4P
author_rank: Super Contributor
timestamp: May 28, 2014, 01:40:28 pm
content: Amps on each output is what you should have done first time.Or at the least - used a passive 75R source splitter to isolate/set the source impedance of each output - and terminated each end-of-cable.The other alternative is to daisy-chain the video (in-out-in-out-in-75R) - with no termination at each drop - except the last (end of cable) TV.

author: rauloliv
author_rank: Contributor
timestamp: May 29, 2014, 08:37:13 am
content: Quote from: nihilism on May 28, 2014, 12:31:56 pmFunny as the Kramer device phisicaly is very much identical to the one i built.Costs more than 500usd ?! Would love to see whats insideQuote from: SL4P on May 28, 2014, 01:40:28 pmCan you elaborate more on this?I know i left the thing unfinished, but because at that moment it suited my friends needs i left it to work as it was.Regards,Raul
composite video signal problem !!! - Page 1
Forum section: electronics / projects

author: xcoder
author_rank: Contributor
timestamp: January 30, 2014, 11:34:54 am
content: hi all im xcoder from moroccothis is ma first post sorry for ma bad englishmy problems is about compiste video sync B&W composite video so there is no decoding no pal no secam no ntsci received a autorefractometre from friend that have integret camera problems so basicaly an autorefracto is text imposed on camera video singal !!so now the camera cells failed and didnt found the part becose its a bit oldso the schema is likethe camera is connected to motherboard and motherboard mix camera composite video signal with text video signal to the monitor !! so now i want to install another camera and when i did syncs didnt get on the same frequency so my question is there anyway to change my camera syncs or somehow remove syncs from camera and insert back the text syncs to fit in the same frequency?
Compound Pair vs Darlington Pair - Page 1
Forum section: electronics / projects

author: Lucky-Luka
author_rank: Unknown
timestamp: December 26, 2019, 05:04:51 pm
content: Hi allI've read that Sziklai pair are more thermically stable than Darlington ones.Is it because since Q5 has half Q10 voltage bias it dissipates half the heat and the configuration is in such a way more thermically stable?Is that so? Anything else?Happy holidays

author: edavid
author_rank: Super Contributor
timestamp: December 26, 2019, 05:11:24 pm
content: Douglas Self ("Audio Power Amplifier Design Handbook, 5th Ed") says:QuoteSo, I suggest you get a copy and read Chapter 15!

author: exe
author_rank: Unknown
timestamp: December 26, 2019, 05:12:52 pm
content: Check this one:https://sound-au.com/articles/cmpd-vs-darl.htm. Explains topic quite in in-depth.

author: Lucky-Luka
author_rank: Unknown
timestamp: December 26, 2019, 10:03:36 pm
content: I've also read that Szikai configuration should behave better against distortion... Is it true?I've tried a comparison but it looks like that Darlington behaves better. Am i wrong?

author: Kleinstein
author_rank: Super Contributor
timestamp: December 26, 2019, 11:47:01 pm
content: The Szikai configuration likes an addition base to emitter resistor with the larger transistor.Another point to look for it that the Szikai configuration is more prone to oscillation, especially if the driving side is higher impedance.The distortion in the class AB power stage depends on the standing current - both types tend to prefer a slightly different current. Better thermal stability leads to a more stable standing current and could this way cause less distortion. The simulation tends to no include that thermal effect.

author: David Hess
author_rank: Super Contributor
timestamp: December 27, 2019, 01:54:47 am
content: The link Exe provided covers it better than I could. I have used both structures in class-ab power amplifiers and regulators without problems. The compound pair takes more care to prevent local oscillation but either can oscillate under the wrong conditions.

author: MiDi
author_rank: Frequent Contributor
timestamp: December 27, 2019, 01:43:24 pm
content: Quote from: Lucky-Luka on December 26, 2019, 10:03:36 pmWhen both EF and CFP are biased for lowest crossover distortion, the CFP is better.There are more distortion sources, recommend readingSelf: Distortion in Power Amplifiers.

author: graybeard
author_rank: Frequent Contributor
timestamp: December 28, 2019, 02:55:13 am
content: Quote from: exe on December 26, 2019, 05:12:52 pmnice article!
Computer controlled logic outputs - Page 1
Forum section: electronics / projects

author: HKJ
author_rank: Super Contributor
timestamp: May 13, 2019, 12:41:43 pm
content: After making the solid state relay and exaggerate a bit on the software, I could see that a box with logic outputs running the same software could be very useful.Functions:Can turn on/off any of the 3 outputs from a command or from buttons on the box.Can generate PWM with a frequency from 1Hz to 100kHz on up to 3 channelsCan generate push pull PWM with dead time on one channel using output 1 and 2.PWM frequency can be specified either as frequency or period time.PWM duty cycle can be specified either as percent or as high time.PWM has a resolution up to 0.1%Frequency can be specified with on decimalPWM duty cycle can be specified with on decimalTime is specified default in milliseconds with two decimals, some other time units can be selected by a letter after the value.Timed commands works up to 10 hoursTime specifications below 4 seconds uses hardware timers with available resolution down to 10usTime specifications above 4 seconds uses software timing with 10ms resolution.Output 1 & 2 are synchronized, output 3 can be up to 1us late.Can sequence the outputs, either with pulse length or when they turn on.Commands can be stored in the device and activated with a button for off-line usage.Outputs can work at either 3.3V or 5V logic levels.Can deliver pulses below 1us in PWM mode.Full project here, including schematic, software and gerber files:http://lygte-info.dk/project/LogicOutputs%20UK.html

author: MarkF
author_rank: Super Contributor
timestamp: May 13, 2019, 01:16:59 pm
content: Don't multi-post. The group frowns upon it.Original:https://www.eevblog.com/forum/projects/computer-controlled-solid-state-relay/msg2360859/#msg2360859

author: HKJ
author_rank: Super Contributor
timestamp: May 13, 2019, 01:19:05 pm
content: Quote from: MarkF on May 13, 2019, 01:16:59 pmI did not, this is another project. The first one is with high current mos transistors for output, this one is with logic level output. This means different PCBs, but the software is the same.