hybridfree/eevblog-posts huggingface dataset:
Dual entry female pin header 0.1" - Page 1
Forum section: electronics / projects

author: gaminn
author_rank: Frequent Contributor
timestamp: January 23, 2024, 11:33:19 am
content: Hi, I'm looking for 0.1" (2.54 mm) Through hole pin header like this? Preferably 2x13P.There are some on AliExpress:https://www.aliexpress.com/item/1005003619191633.htmlbut not 2x13P. I don't want to split larger header or merge shorter headers.Do you know where to buy? Mouser, DigiKey?

author: gaminn
author_rank: Frequent Contributor
timestamp: January 23, 2024, 02:29:17 pm
content: There are some dual row dual (bottom) entry available, but all I found is SMT. The one I'm looking for is through hole.

author: tooki
author_rank: Super Contributor
timestamp: January 23, 2024, 04:30:28 pm
content: Quote from: gaminn on January 23, 2024, 11:33:19 amWhat stopped you from finding it on Digikey? It took me just a minute to drill down the parametric search to find the one matching item in stock, 71991-313LF.

author: gaminn
author_rank: Frequent Contributor
timestamp: January 23, 2024, 06:49:23 pm
content: Thanks, I'm sorry, it took me a minute to filter out 1049 products in this categoryhttps://www.digikey.cz/en/products/filter/rectangular-connectors/headers-receptacles-female-sockets/315(2 rows, 26 positions, 0.1" pitch and through hole mounting). I should have also selected "in stock", then I can see thee product you mentioned on the second page.

author: tooki
author_rank: Super Contributor
timestamp: January 23, 2024, 07:39:55 pm
content: It also lets you filter by through-hole and by dual-entry. So within seconds you can find the matching part.
Dual Lithium Battery Charging / Management ICs Topology?  - Page 1
Forum section: electronics / projects

author: Chendy
author_rank: Contributor
timestamp: March 21, 2017, 03:49:49 pm
content: Hi,I want to charge a couple of 18650 lithium cells, connected in sort-of-parallel to provide double capacity. I dont want to rely on cell matching, so want to use a couple of linear charging/management ICs. I also want 'pass-through charging', the ability to power my load and charge the batteries simultaneously, when plugged in to the charging source.This low costBQ21040looks of interest. (if anybody has any other recommendations please lmk)Is it possible?.. how would I got about connected this up? Like the picture below?:

author: Siwastaja
author_rank: Super Contributor
timestamp: March 21, 2017, 03:57:25 pm
content: Just parallel the cells properly. No special matching needed, just don't use completely random or totally crap cells. Match the voltage once, when you first time weld the cells together.This is exactly how 18650 cells aredesignedto be used.Your complex scheme is asking for disasters.

author: Chendy
author_rank: Contributor
timestamp: March 21, 2017, 06:24:06 pm
content: Okay great.But the problem is planning not to weld them together. But use a simple 18650 holder...hmmm

author: Siwastaja
author_rank: Super Contributor
timestamp: March 21, 2017, 07:40:30 pm
content: Oh, 18650's are definitely not meant for that. Those holders serve a purpose (for example: a low cost item for hobbyist cell analyzers/testers), but it is absolutely not OK to let end user insert loose cells into those holders, using them in an actual product. Unless it's for yourself only and you know what you are doing. (Using these as generic holders will result in a shorted cell and a melted holder after some usage.)This holder thing should be some kind of a FAQ item, it pops up all the time.The only way 18650 is designed and supposed to be used is to be welded to make a pack.If you want user-insertable battery, the only acceptable way is to weld the 18650's in parallel, add some sort of casing and a connector. A fuse inside the pack is a good idea.The possibility to insert two cells that are then paralleled is an extremely stupid idea and requires rather complex circuitry and algorithms; to the degree that the fact that people ask about it here is often a good sign it is too big of a task for them. It provides no benefits, either; there are only downsides. That's why it's never done.Don't do it the weird and complex way, do it the way it's designed!

author: Chendy
author_rank: Contributor
timestamp: March 22, 2017, 03:07:46 pm
content: Great thanks, valuable input!
Dual LM1815 VRs' on one board - Page 1
Forum section: electronics / projects

author: Old Grey
author_rank: Newbie
timestamp: June 23, 2016, 01:47:19 am
content: This is probably a very simple question for you boffins, but bare with me as I'm only a beginner.If I dual the LM1815 on one board am I doubling up on components on the 5V+ side, basically can I get rid of R15, R14, C13 and tap from the other circuit.I made one circuit sch and just duplicated it, and wondered if I can cut down on parts because the board is small - has to be THT -.
Dual LM317 Current & Voltage Regulator For Laser Diodes - Questions  - Page 1
Forum section: electronics / projects

author: KJ-90
author_rank: Contributor
timestamp: January 03, 2017, 05:07:57 pm
content: I recently found the following circuit online for driving laser diodes at:http://www.homemade-circuits.com/2013/03/simple-laser-pointer-dc-current.htmlIt is the lower down circuit that uses two LM317 three terminal voltage regulators. One of them limits the current, the other regulates the voltage. However, I was wondering:(1) the voltage and current stages are reversed(2) why the voltage regulator stage is using a 10K trimmer resistor instead of the standard 5K value, commonly used in such a circuit.(3) what the Pd in watts is of the variable resistor being used in the LM317 current regulator circuit.Also I was wondering what people think of the circuit itself.

author: ajb
author_rank: Super Contributor
timestamp: January 03, 2017, 07:34:13 pm
content: Putting a constant voltage stage *after* a constant current stage doesn't make any sense, especially for a current-driven device like a laser diode (or LED). If you did want a two stage regulator (say for more optimal power dissipation), you'd put the constant voltage state first, and probably make it a switching stage rather than linear. But for 40mA load, it's probably not worth the trouble unless the supply voltage is very high or efficiency is a really high priority.The power dissipated in the trimmer will be I^2*R, where R is the trimmer's resistance and I is the current through the resistors/laser diode. I'm not sure how well-behaved an LM317 is in constant current mode. Laser diodes are quite sensitive to transients, so small glitches or shenanigans during startup/shutdown can dramatically shorten their life span. I'd be inclined to go with a discrete or op-amp based constant current driver, or maybe look at some of the integrated linear LED drivers that are available depending on exact requirements.
Dual LM317/337 supply sequencing - Page 1
Forum section: electronics / projects

author: bdivi
author_rank: Regular Contributor
timestamp: February 19, 2015, 10:28:13 am
content: Hello,I am building a bench power supply and I am using +/- 15V auxiliary supply for the high side control circuitry. That aux supply is based on LM317/337.As I am finalizing the project it turned out that were are random spikes from the main supply when I turn it on because of the aux supply - in order to fix that I need to delay the +15V rail by 100-200ms relative to the -15V rail.Any ideas how to do that without going digital ?

author: MrAl
author_rank: Super Contributor
timestamp: February 19, 2015, 04:46:37 pm
content: Hi,I am not entirely sure what problem you have having, but it sounds like a large capacitor might work.Maybe you could explain the problem a little better too.

author: void_error
author_rank: Frequent Contributor
timestamp: February 19, 2015, 05:13:51 pm
content: Quote from: bdivi on February 19, 2015, 10:28:13 amLM393. Half of it is a comparator to detect that the negative rail has reached 15V, the other half a delay circuit. Use a TL431 or a zener as the reference for the comparator. Some extra transistors might also be needed.

author: C
author_rank: Super Contributor
timestamp: February 20, 2015, 05:04:24 am
content: see figure 36 inti's datasheethttp://www.ti.com/lit/ds/symlink/lm117.pdfC

author: bdivi
author_rank: Regular Contributor
timestamp: February 20, 2015, 07:55:56 am
content: Quote from: C on February 20, 2015, 05:04:24 amThat would not work for me - it is slow start from 1.25V and not from 0. Should be something that do not rely on the output to charge a capacitor.
Dual monolithic N-channel JFET - in 8-pin DIP? - Page 1
Forum section: electronics / projects

author: icon
author_rank: Regular Contributor
timestamp: October 17, 2012, 09:41:37 pm
content: HiI've just finished a very long troubleshoot  of an ancient Telequipment D1010 analogue scope which wouldn't sweep. I eventually found the point in the circuit where a rising voltage across a capacitor ought to have been 'followed' by a JFET source follower, but wasn't. The source follower depends on a dual N-channel JFET in a through-hole 8-pin DIP. The schematic calls it an SU2603. The actual device in the scope is a 1125-00. In the intervening 32 years, both devices seem to have disappeared without trace. It's TR74 a and b:I've bunged in two of the only N-channel JFETs I have in stock, which happen to be 2N5484s. This has (hooray!) got the old girl going again, but before I screw it back together again does anyone know of any modern equivalent to an SU2603 or 1125-00? Failing that, would a different discrete device be better? Should I blob them together with epoxy to make the junction temperatures at least similar?CheersJohn Only because of my electronic ineptitude

author: free_electron
author_rank: Super Contributor
timestamp: October 17, 2012, 09:55:29 pm
content: sounds like an old siliconix partnumber...

author: Bored@Work
author_rank: Super Contributor
timestamp: October 18, 2012, 12:03:44 am
content: Siliconix ended up with Vishay (Vishay really collected manufacturers left right and center ...). And Vishay dropped all JFET production.There is a company called Linear Integrated Systems, still making some dual N-channel JFETs. Maybe they could suggest a replacementhttp://www.linearsystems.com/products.html#GlossD

author: icon
author_rank: Regular Contributor
timestamp: October 18, 2012, 05:07:07 pm
content: Quote from: Bored@Work on October 18, 2012, 12:03:44 amAnd it turns out their UK distributor, Micross, is located about 20 mins drive from where I live! I've picked up a couple of what they had on the shelves, which are in TO-71 and SOIC - I'll see how they work.CheersJohn
Dual output with a single TL497a - Page 1
Forum section: electronics / projects

author: ZILtoid1991
author_rank: Newbie
timestamp: November 26, 2015, 01:13:06 am
content: Schematic:Instead of either making an isolated converter or two different converters, I came up with the idea of combining the buck-boost with a flyback converter. Would this work in practice?

author: nickm
author_rank: Regular Contributor
timestamp: November 26, 2015, 01:32:07 am
content: Yeah that's a flybuck. I didn't check if you had the dots correct, but it doesn't look like you hooked up the controller correctly though.

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 26, 2015, 02:09:31 am
content: Essentially the same circuit I found at TI. I am experimenting with making a board that will take a typical 18-20V laptop "line-lump" power input, and generate + and - 15VDC for audio circuits.http://www.ti.com/lit/an/slva369a/slva369a.pdfhttp://www.ti.com/product/tps54340http://www.ti.com/tool/PMP10090.2
Dual package equivalent of LM339 quad package? - Page 1
Forum section: electronics / projects

author: Chris Wilson
author_rank: Super Contributor
timestamp: December 21, 2016, 10:30:14 am
content: Is there an 8 pin dual package equivalent of the LM339 quad package please? Thanks

author: wraper
author_rank: Unknown
timestamp: December 21, 2016, 10:32:08 am
content: LM393

author: Chris Wilson
author_rank: Super Contributor
timestamp: December 21, 2016, 10:40:51 am
content: Hi again wraper, thanks for that.
Dual port DSI panel only half accessible - Page 1
Forum section: electronics / projects

author: david_geng
author_rank: Newbie
timestamp: June 04, 2017, 10:41:17 am
content: Hi,I'm trying to use a sharp LCD panel with R63419 control via the command mode only to save some interfacing cost as the picture update rate is very low.So far I think I can configure those registers and turn on the display. However, when I wrote the pixel data to the R63419 framebuffer RAM, only half of the RAM was actually accessible. So far the test and results are,1. build-in test runs ok and show the full display;2. set_all_pixel_on show all pixel on;3. control of the TE output signal ok.So by the 3 tests above, can I assume the register setting and the memory mapping/scanning are ok?The forth test did annoy me a lot,4. after setting 0x2a and 0x2b (col and row address), I tried to write the framebuffer RAM through LP command mode, i.e. by the 0x2c and 0x3c long packet command. Data could be written, but only showed on half of the panel.4a. since I was writing the whole frame data, I could see the data been overlap twice during the writing procedure, i.e. twice on half of the panel. but I've set the 0x2a to 0x00 0x00 0x05 0x9f which is the full width.4b. if I change the 0x2a, for example, to 0x03 0x00 0x05 0x9f trying to force writing the other half, I could only see a vertical line in the middle.4c. since this is a dual link DSI panel, I tried to use N0B and P0B instead of N0A and P0A, nothing showed up.So my question is, would it be possible to access the full RAM via LP command mode? did I miss any register setting? If the LP mode has some limitation or bug, would HS command mode give the full access to the RAM?Any thoughts or experiences would be most appreciated.regardsDavidPS the pixel is uncompressed 24bit data, and I did try to write a block of two lines at a time according to requirement of the datasheet, but not making any difference.

author: bktemp
author_rank: Super Contributor
timestamp: June 04, 2017, 07:23:56 pm
content: That behaviour sounds familiar.On some dual channel MIPI-DSI displays the lanes are hardwired to the left and right half of the screen. So the first 4 lanes can only drive the left half of the sceen and the second 4 lanes the right half.LP mode is implemented only on the first lane of the first channel, so it is probably impossible to drive the full screen via LP mode.
dual power supply for +v &-v generation  - Page 1
Forum section: electronics / projects

author: hussamaldean
author_rank: Unknown
timestamp: October 24, 2018, 06:03:40 am
content: Hi allI hope you are okanyway, I have lab bench power supply and I need to generate positive voltage rail and negative power rail for OP-AMP and I have also 24V power supply which I will step down converter to step the voltage to 12Vhow shall I connect these two power supplies in order to get both positive and negative power rail ?I hope you can help me though

author: MarkF
author_rank: Super Contributor
timestamp: October 24, 2018, 06:36:19 am
content: If you just want to split the 24V supply and don't need a lot of power, you could do something like this:

author: hussamaldean
author_rank: Unknown
timestamp: October 24, 2018, 06:41:37 am
content: Quote from: MarkF on October 24, 2018, 06:36:19 amis there any other way ?because there is holiday here and no shop will be open for the next week

author: MarkF
author_rank: Super Contributor
timestamp: October 24, 2018, 06:58:19 am
content: Do you have a MC7812 or MC7912 three terminal (positive or negative) voltage regulator to step-down the 24V? You would then just wire the two supplies in series.Depending on your voltage requirements, you could just wire a few batteries in series until you can get parts.

author: hussamaldean
author_rank: Unknown
timestamp: October 24, 2018, 07:07:49 am
content: I just remembered that I made this power supply which I build like a year ago but I have not use it fir a while and I forgot itit doesn't look the best but functionality is flawless

author: cdev
author_rank: Super Contributor
timestamp: October 24, 2018, 11:53:00 pm
content: Thats exactly like what most of my projects look like too.

author: hussamaldean
author_rank: Unknown
timestamp: October 25, 2018, 03:57:52 am
content: Quote from: cdev on October 24, 2018, 11:53:00 pmwell, as engineer I think regarding functionality not the look of the thing
Dual power supply from two buck converters (LM2596) - Page 1
Forum section: electronics / projects

author: trevortjes
author_rank: Contributor
timestamp: November 15, 2020, 10:02:51 am
content: Hey all,So the main goal is creating a +-12V power supply (around 1A postive and negative) from a single higher than +12V DC supply. Now I looked around the internet and found out about using cheap LM2596 buck converter modules in a special arrangements (fromhere).Only to find out that for some odd reason this just doesn't work for certain types of LM2596 like the JM97HS (goes into short circuit condition). But otherwise others had confirmed that this does work but with other types of LM2596. Now I'm not sure if my question is, what's the difference between those types of IC while all the ICs should be identical in functionality (I might be terribly wrong on this one), or what I can do to actually make it work.The latter would be more interesting for me tho. So is there any way to make one behave like inverting buck converter? Or are there other ways to deal with this? Or should I just invest in a quite "expensive" center tapped transformer...

author: Ian.M
author_rank: Super Contributor
timestamp: November 15, 2020, 11:04:32 am
content: *Most* of those modules have fake LM2596 chips - many of the fakes are easy to spot in a simple test jig - just check the switching frequency (at pin 2 of the IC) under load. Genuine LM2596 chips run at 150KHz. Most of the fakes run at approx 52KHz. *IF* you can get a fake to work in the inverting configuration, you'll be lucky to get over 300mA out of the negative rail, and they are only good for about 500mA continuous in the normal positive configuration.A (genuine) LM2596 in the inverting configuration needs up to 5A for up to 2ms to startup correctly. If its supply is current limited at under 5A, or worse has foldback limiting, it is unlikely to start unless you mod the module by lifting pin 5 and adding the RC network for delayed startup from datasheet fig. 23, (also see fig. 27).You must also consider if the positive rail coming up first will be problematic for your load. You may need to mod the positive module to also delay its startup, or worst case, for particularly fussy loads, add a supply supervisor IC and MOSFET switching in both outputs to only connect the load when both rails are up and stable.
Dual rail +/- 12v DC supply from batteries or external DC supply.  - Page 1
Forum section: electronics / projects

author: djsb
author_rank: Super Contributor
timestamp: April 14, 2025, 05:56:37 am
content: My not yet built class A stereo headphone amplifier needs a +/-12v DC supply at a minimum of 250mA. It's a similar problem to this posthttps://www.eevblog.com/forum/projects/dual-rail-supply-from-a-battery/I have an old 20v 3.5A laptop supply I could use as a last resort but would prefer to use rechargeable batteries of some kind. Or an external plug in AC to DC wall adaptor and a DC to DC convertor or 2 would be good. Not too worried about efficiency as I'm likely to use this on my workbench or just at home. Anything I can try? Thanks.

author: Konkedout
author_rank: Frequent Contributor
timestamp: April 14, 2025, 11:34:19 pm
content: Are you up for laying out a PCB for a switching converter?I would use a SEPIC-Cuk converter. Makes 2 outputs. I have built a few of those. I am looking for a good app note on the web. There are many but none of them are showing quite what I want.I would do it with a single multiwinding coupled inductor such as Coilcraft "Hexapath". It can also be done with two 2-winding coupled inductors.
Dual rail DC supply from one battery and two step up DC converters? - Page 1
Forum section: electronics / projects

author: Adam Harzuf
author_rank: Newbie
timestamp: July 14, 2021, 07:41:45 am
content: Hi!I have a 12V portable power bank and I wish for a powerful street setup for bass guitar.I purchased this power module, which needs a dual rail supply:IRS2092S 500Whttps://www.ebay.de/itm/203510847720I have one of these step-up converters and was thinking to get another one, in order to provide a dual-rail supply:https://www.ebay.de/itm/353482875194I'm not educated with electronics. My question is, can it work and if so, how should I connect it?FYI, until now I had the TDA7498E power module, but unfortunately, it's not loud enough.Thank you!

author: Kjelt
author_rank: Super Contributor
timestamp: July 14, 2021, 08:11:16 am
content: Or you need a single rail input, dual rail output dc-dc converter.Or you need besides the one you already bought one that will output a negative voltage.The reason is you only have a single dc source so the grounds will be common.Another possibility is another of those portable powersources to create two times seperate 50+ voltages and then put them serial.Which means the first powersupply gnd V_1_0 will become the negative rail, the V_1_+ is connected to the gnd of V_2_0 , and the V_2_+ will become the positive rail.WARNING: you say you are not an experienced electronics person, the generated DC outputs of each rail and esp the combined dual rail can be lethal. It is powerfull enough when touched to make your heart stop or at least result in heavy burns. So be very carefull, take all insulation precautions and when in doubt let an experienced person check your work.
Dual rail reverse voltage protection - Page 1
Forum section: electronics / projects

author: lk.dgironi
author_rank: Regular Contributor
timestamp: January 05, 2022, 08:40:49 am
content: Hello,I'm more on the embedded dev rather than pcb design, so sorry, my question may sounds dumb.I'm working on a board with dual rail supply (-15 0 +15 V).On single rail supply I use a P-Mosfet reverse voltage protection circuit like the on you can find attached.Not sure how to use this on the dual rail supply, I'm talking about the negative side. Can someone point me in the right direction?Thanks!

author: Terry Bites
author_rank: Super Contributor
timestamp: January 05, 2022, 11:30:10 am
content: Use an N-ch in the-ve side:

author: lk.dgironi
author_rank: Regular Contributor
timestamp: January 05, 2022, 11:51:20 am
content: Thank you!Something like the attached image?

author: Terry Bites
author_rank: Super Contributor
timestamp: January 05, 2022, 12:35:04 pm
content: esatto

author: lk.dgironi
author_rank: Regular Contributor
timestamp: January 05, 2022, 01:06:17 pm
content: Grazie

author: Terry Bites
author_rank: Super Contributor
timestamp: January 05, 2022, 02:02:51 pm
content: prego

author: dietert1
author_rank: Super Contributor
timestamp: January 05, 2022, 04:11:47 pm
content: Need to exchange S and D of the n-channel mosfet. Look at the direction of the parasitic diode!Regards, Dieter

author: lk.dgironi
author_rank: Regular Contributor
timestamp: January 05, 2022, 04:15:40 pm
content: Thank you!Find attached as reference
Dual rated switches  - Page 1
Forum section: electronics / projects

author: viji_rookie
author_rank: Contributor
timestamp: June 14, 2016, 11:56:46 am
content: Can i use Dual rated switches in low level switches to switch one of my micro controller interface..say with 0.4VA max @20V AC/DC and same around 5A @125VAC ///2A@250VACI don't take chance to operate on DC, fear of switch lead arching and pitting.Any suggestion , plz

author: Ian.M
author_rank: Super Contributor
timestamp: June 14, 2016, 12:12:55 pm
content: As long as they are brand new and you use an adequatewetting currentthey should be fine.However if they've ever been used in a power circuit, the chances are that arcing (in normal operation) has oxidised and roughened the contact faces, making them unreliable for small signal switching.

author: ConKbot
author_rank: Super Contributor
timestamp: June 15, 2016, 08:57:35 am
content: Yep, what Ian said. Some manufacturers do gold over silver plating on the contacts. The gold finish is fine for low level signals. Once you use it to switch power the gold gets eroded and youre left with the silver plating.

author: viji_rookie
author_rank: Contributor
timestamp: June 15, 2016, 04:15:43 pm
content: Quote from: ConKbot on June 15, 2016, 08:57:35 amErode can effect my printed circuit board quality over the time ? Or induce concerns on cleaning and washability !?
Dual series switch diodes - Page 1
Forum section: electronics / projects

author: anishkgt
author_rank: Frequent Contributor
timestamp: September 29, 2017, 10:31:59 pm
content: hi All,For the attached schematic the series diode D8 were 1N4148 in a series configuration. Since i was running out of room on my PCB i was thinking replacing them with an off-the shelf 'Dual Series diodes' (https://www.digikey.com/product-detail/en/on-semiconductor/BAV99LT3G/BAV99LT3GOSCT-ND/1967036). I am just not sure if the specs match. The Max forward Voltage for 1N4148 and BAV99LT3G are1V @ 10mAand1.25V @ 150mArespectively. Seems like they would fit.need a second opinion on this.Thanks in Advance.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 29, 2017, 10:33:23 pm
content: BAV99 is an excellent part to have in stock, for just situations like this, yes.Tim

author: anishkgt
author_rank: Frequent Contributor
timestamp: September 29, 2017, 10:35:36 pm
content: Thanks that was quick

author: anishkgt
author_rank: Frequent Contributor
timestamp: September 29, 2017, 10:39:19 pm
content: A bit off subject, i am just getting used to opamps, actually learning as i work with them. The gain control is done by the pot R23 and eliminating R24 gives a the same output, named 'iSense'.Would it be ok to eliminate it ?
dual slope integrating ADC - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: December 09, 2013, 12:54:15 pm
content: hi guys ,Somebody tell me what is meant by gain of the integrator in integrating ADC. how to calculate the raising time period required and the resolution of integrating ADC.

author: free_electron
author_rank: Super Contributor
timestamp: December 09, 2013, 02:33:37 pm
content: The gain of the integrator is how many volts a second it can riseI dont know what you mean with raising timeThe resolution is determined by how accurately you can fragment time.

author: electros6
author_rank: Regular Contributor
timestamp: December 10, 2013, 02:09:45 am
content: sorry , Raising time means ramp up time .how to determine the ramp up time (ie) the time required to charge the integrator capacitor by the input voltage since its is a varying parameter , if the ramp up time is determined by the maximum input voltage , at low voltage the capacitor gets charged quicker then the fixed ramp up time. Since the output is given by Vin * T2/T1 , the ramp time affect the output. please explain

author: free_electron
author_rank: Super Contributor
timestamp: December 10, 2013, 02:43:26 am
content: homework ? do your own ...One time is a constant derived from a reference. the other is derived from input.

author: electros6
author_rank: Regular Contributor
timestamp: December 10, 2013, 02:47:13 am
content: please send me any links about integrating adc or books

author: free_electron
author_rank: Super Contributor
timestamp: December 10, 2013, 03:05:39 am
content: internet must be broken....http://en.wikipedia.org/wiki/Integrating_ADCgoogle for dual slope adc

author: codeboy2k
author_rank: Super Contributor
timestamp: December 11, 2013, 06:02:12 am
content: Quote from: free_electron on December 10, 2013, 03:05:39 amI hate it when that happens
Dual Tracking power supply regulator wanted! - Page 1
Forum section: electronics / projects

author: BobbyK
author_rank: Regular Contributor
timestamp: March 29, 2013, 01:57:08 am
content: I was wondering if anyone had any schematics lying around or could point me to something useful. What I have in mind is a fully regulated, and current limited dual tracking supply. No need for fancy control scheme - pots will do. The problem has been finding something that can handle +- 70V (i.e. 0-70Volts on each output) and at least 1 Amp on each output. I'd appreciate any schematics that could be modified to suit my needs. Thanks in advance.

author: c4757p
author_rank: Super Contributor
timestamp: March 29, 2013, 02:28:41 am
content: What on earth do you need ±70V at 1A for?

author: BobbyK
author_rank: Regular Contributor
timestamp: March 30, 2013, 01:44:24 am
content: Power amplifiers!Oh, and I have already built a suitable power supply (~800VA) that I could use, but I really would like to be able to limit the power to my devices, and also to ramp up power slowly before putting the final touches on this amp. The parts alone have cost me upwards of 600 USD for the amp boards - don't want to damage them. And regulation would be awesome too, to test future amps,....hence the need for a current limiting dual tracking power supply
Dual zone wine cabinet hacking. - Page 1
Forum section: electronics / projects

author: jt750430
author_rank: Newbie
timestamp: August 22, 2017, 05:38:26 pm
content: Hi!Hopefully, this is in the right section of the forum.I acquired a Dual-zone 'wine cabinet', which functions exactly like a fridge, except there's a valve to divert refrigerant between the two zones. There's also a small heater unit in each zone too.The refrigerant valve is:Product Type Description SDF ---- pulsed electromagnetic valve code0.8 ---- solenoid valve diameters: 0.8mm3/2 ---- Feature code: Indicates a two state, three connecting pipePower supply voltage: 220VFrequency: 50 / 60HzRated operating voltage: 165 ~ 253VInsulation resistance: 500MElectrical strength: 1500V, 50HZ sinusoidal AC 1minSolenoid valve control power: solenoid valve driver needs at least four sinusoidal 50 / 60Hz positive or negative half-wave pulse (drive pulse waveform of FIG. See in particular), a state of the switch into another state of the time interval is not less than 30sWhich I think requires the use of a half-wave rectifiers x2 (?) to send either the upper or lower parts of the AC sine wave, in a pulse, to operate the valve. If that's correct, excellent! If not, please do let me know.In order for me to build the circuit to control this valve, I think I need an oscilloscope to see what portion of the wave is being sent at any time?My goal is to build an IoT beer fermentation/conditioning cabinet, using something like BrewPi or CraftBeerPi to handle the control, though this isn't set in stone.I haven't really touched any electronics for a good few years, maybe a decade or so. It's very much a learn-on-the-job approach which suits me, especially as I'm not in a rush to complete it.In order to design a circuit that can be activated with, perhaps, 2x GPIO connections to control refrigerant flow direction in the valve, would a half-wave rectifier be a suitable proposal?Completely appreciate I'm coming at this with very little knowledge so any help would be enormously appreciated. I intend to document the project as I go and publish the details so others can mod/hack wine cabinets too.Thanks!
Dubilier Nitrogol capacitors, do they contain PCBs? - Page 1
Forum section: electronics / projects

author: Aggropop
author_rank: Newbie
timestamp: August 19, 2019, 01:18:41 pm
content: I looked around on the internet, including this forum, and couldn't find any solid information one way or another, so I thought I would sign up and ask directly:Do Dubilier Nitrogol paper-in-oil HV capacitors contain PCBs?I found a bunch of them at work (new old stock, models B1384 and B1385, tested OK at low-ish voltage) and I'm undecided on what to do with them. Obviously they don't belong in the dumpster, but I don't want to add them to my parts bin either, if it turns out they contain poison.Thanks!Reference Pic:

author: ebastler
author_rank: Super Contributor
timestamp: August 19, 2019, 01:33:40 pm
content: This report lists two specific types of Nitrogol capacitors asnotcontaining PCB -- see page 63.Not sure whether you can conclude that all Nitrogol capacitors are harmless though.http://www.nepc.gov.au/system/files/resources/378b7018-8f2a-8174-3928-2056b44bf9b0/files/anzecc-gl-identification-pcb-containing-capacitors-information-booklet-electricians-and-electrical.pdf

author: Aggropop
author_rank: Newbie
timestamp: August 19, 2019, 01:44:18 pm
content: Yeah, I've seen that pdf. I'm hesitant to extrapolate from that, since the models listed in there are significantly different from the ones I have.

author: factory
author_rank: Super Contributor
timestamp: August 19, 2019, 01:52:54 pm
content: There are newer ones branded "MPE" Nitrogol, like this one with a 1992 date code, I'm fairly certain PCB's were banned years before that.Edit:QuoteThe TCC/Plessey Visconol apparently contain PCB's.Personally I wouldn't bother using them as the oil can leak out of them, something which was a common problem with the smaller Plessey 1uF ones used on heat & vent units we repaired at work, thankfully now all replaced with film types.David

author: Aggropop
author_rank: Newbie
timestamp: August 19, 2019, 03:03:06 pm
content: That's very interesting, thank you. My best guess as to when my examples were made (based on the kind of stuff that was stored with them) is the 1970s, so it looks like they could be either way, unfortunately. I don't suppose there is some kind of test to determine PCBs?

author: james_s
author_rank: Super Contributor
timestamp: August 19, 2019, 04:09:49 pm
content: Don't worry about it either way. PCBs are fairly benign to us, the problem is that they are extremely stable compounds so when they get into the ground water they stay there, over time this is a problem because you don't want to be drinking the stuff. It's a problem at scale though, millions of huge utility transformers, millions of tons of discarded consumer and industrial goods, that adds up. A handful of capacitors though? I wouldn't hesitate to have them in my house even if I knew they contained PCBs.
Duinomite Mega - Page 1
Forum section: electronics / projects

author: DFW2012
author_rank: Newbie
timestamp: November 14, 2012, 09:06:24 pm
content: Dear DaveThere are some online fellow(Prius Chat)(John Lopez)and (JDH)Anyhow they are and my sparked interest to make a OBD/Carcomputer. The interestis to better control and get more specific data that comes out of Toyota Prius Gen2(04-09)They have started with a Duinomite Mega, Liliput vga screen......?AnyhowKinda confused because the scanguage 2 I currently use has some of the data I want but display and otherlimitation s
Dum dum de Dum - Page 1
Forum section: electronics / projects

author: Konkedout
author_rank: Frequent Contributor
timestamp: December 15, 2024, 05:53:14 am
content: I recently bought some components from Digikey. Tonight when looking at BBCs website I see a Digikey advertisement for Rohm IMX8T108 dual SMT transistor.I am mildly curious, so I click on it and get to the datasheet. Each page of the datasheet says "Not recommended for new designs."

author: coppercone2
author_rank: Super Contributor
timestamp: December 15, 2024, 06:04:01 am
content: everything MUST GO!!!

author: Krotow
author_rank: Regular Contributor
timestamp: December 15, 2024, 06:27:44 pm
content: Ads circulating through various ad pushing rings sometimes have a little relation with real situation. Though it can be that Digikey simplly wants to get rid of old stock.

author: coppice
author_rank: Super Contributor
timestamp: December 15, 2024, 06:33:08 pm
content: The Amazon app on my phone is telling me to prepare for Halloween. Seems a bit early for that, when Christmas is approaching.
Dumb question about PCB surface finishes - Page 1
Forum section: electronics / projects

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: July 18, 2018, 01:41:14 pm
content: This seems like a really beginner level question but I cant find an obvious answer...Typical PCB surface finishes like ENIG, Immersion silver, Electrolytic Ni/Au etc etc... are they usually applied to the whole board before solder resist is applied or are they applied to just the pads after solder resist. So are the traces under the solder resist always bare copper or would they have the Ni/Au/Ag/whatever on them?I'm dealing with an issue related to high frequency boards which need to be gold wire-bondable so I'm wondering about the pros and cons of having nickel all over the place...Maybe there is no 'usual' and some will plate before solder resist, and some after?Cheers!

author: Siwastaja
author_rank: Super Contributor
timestamp: July 18, 2018, 01:48:57 pm
content: Just pads, after solder resist.In the past (80's and before), sometimes HASL tinning was applied before the soldermask, but this often resulted in cracked soldermask either due to uneven tinning to begin with, or during wave solder when the tin layer melted below the soldermask.ENIG, on the other hand, is quite expensive, so pads only makes more sense anyway.

author: In Vacuo Veritas
author_rank: Frequent Contributor
timestamp: July 18, 2018, 02:02:03 pm
content: Yeah, there is a process called SMOBC, Solder Mask Over Bare Copper. You'll find that under the mask it's just bare copper.And as for "high frequency", as usual, one man's "high frequency" is another man's rounding error. What frequency? You'll find that the foil roughness UNDERNEATH can be more of a problem than the surface finish.See:https://www.rogerscorp.com/documents/749/acs/Copper-Foils-for-High-Frequency-Circuit-Materials.pdf

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: July 18, 2018, 02:48:52 pm
content: Thanks! In the grand scheme of things, not very high. Up to 1GHz probably. I think the compatibility with the gold wire bonds is going to be our main thing to consider.

author: In Vacuo Veritas
author_rank: Frequent Contributor
timestamp: July 18, 2018, 02:56:56 pm
content: Quote from: DenzilPenberthy on July 18, 2018, 02:48:52 pmLike I said: DC.

author: JS
author_rank: Frequent Contributor
timestamp: July 18, 2018, 11:42:29 pm
content: Quote from: In Vacuo Veritas on July 18, 2018, 02:56:56 pmFor me it's µwavesJS
Dumbest USB PD sink controller - Page 1
Forum section: electronics / projects

author: jmw
author_rank: Frequent Contributor
timestamp: September 22, 2023, 02:55:51 pm
content: Looking for a low-cost & low-component count controller that can negotiate a voltage without a µC; effectively using the type C connector as nothing more than a DC power jack. So far I've found Diodes' AP33771, which fits the bill: requested voltage settable by pull-up/down on 3 pins, no need to use a SPI or I2C bus to configure it, though a little annoying it lacks an integrated high-side switch. Any others?

author: thm_w
author_rank: Super Contributor
timestamp: September 22, 2023, 10:47:31 pm
content: https://www.lcsc.com/product-detail/USB-ICs_WCH-Jiangsu-Qin-Heng-CH224K_C970725.htmlhttps://www.lcsc.com/product-detail/Interface-Specialized_INJOINIC-IP2721_C603176.htmlsome notes:https://hackaday.io/project/172187-ts100-flex-c-friend/log/179029-ip2721-version-built-but
dummy load does not draw all current - Page 1
Forum section: electronics / projects

author: kind2011
author_rank: Newbie
timestamp: April 08, 2016, 06:36:17 pm
content: i have made a dummy load specs 10a 19v with 6x parallel mosfets, dac, op amp and push pull driver for mosfets, something is wrong, when i set to 6amps and connect to a supply of 5v its draw 4.1a when increasing supply from 7v to 19v it draws constant 6amps that is fine but below 7v the currents drops, at first i guessed that was the supply source impedance , then i connect two 1ohm 100w in parallel equals .5ohm to the supply to test and draw 7.4amps at 4.6vsupply gives 0.621ohms so the supply impedance is not the problem,i do not know whats going on herethanks in advance

author: EntropyWizard
author_rank: Contributor
timestamp: April 08, 2016, 06:55:40 pm
content: It would help to see a schematic, check your Vgs and the voltage drop on your sense resistor(s).

author: kind2011
author_rank: Newbie
timestamp: April 08, 2016, 08:35:42 pm
content: vgs 9.4v and vsense 2.6v and rsense 500milliohms vsupply 5.1v still gives 4.2amps im confusedschematic attached.

author: dom0
author_rank: Super Contributor
timestamp: April 08, 2016, 08:36:43 pm
content: I, too, am confused by that schematic.

author: wraper
author_rank: Unknown
timestamp: April 08, 2016, 08:45:47 pm
content: What a mess, I'd be ashamed to post something like this frankly, and would spent some time to tidy the looks of it.

author: kind2011
author_rank: Newbie
timestamp: April 08, 2016, 08:57:38 pm
content: the first op amp (tl072) scales the input 0 to 5v , -1 to 6v , -1 when 0 to full turn off mosfet its plus pin is connected to 5v to full to output 6v that goes to the second op amp that is the voltage follower the two transistor are actually tip122 and tip127, this two takes the output from second op amp and provides more current to gates of mosfets the resistor between base and emitter is to starts giving current to gates of mosfets its what i read somewhere, the 500milliohms is the sense resistorsimulated results gives more aproximated output 9ampssorry for the mess

author: kind2011
author_rank: Newbie
timestamp: April 08, 2016, 09:50:59 pm
content: sorry for the mess here is a more clear schematic

author: kind2011
author_rank: Newbie
timestamp: April 08, 2016, 10:56:55 pm
content: more my english is not my native language

author: dmills
author_rank: Super Contributor
timestamp: April 09, 2016, 12:26:21 am
content: T2 looks very, very wrong to me.Regards, Dan.

author: moffy
author_rank: Super Contributor
timestamp: April 09, 2016, 01:15:41 am
content: The chances of the MOSFETs oscillating without gate degenerating/series resistors near to each gate is very high.

author: Christopher
author_rank: Frequent Contributor
timestamp: April 09, 2016, 08:19:20 am
content: Much better way to do it is to have a opamp&sense resistor per mosfet,also 100ohm resistor between opamp output and gate, forget the push pull driver, as this can cause problemsi see no high frequency decoupling for the opamp, something like 200pF between the current sense input and output
Dummy load for an ATX power supply upgrade ! - Page 1
Forum section: electronics / projects

author: Charybdis
author_rank: Contributor
timestamp: April 12, 2019, 07:11:45 pm
content: Hi there, I'm following the amazing tutorial from this guy:And he said to use a dummy load of 10ohm 10W to make stable the PS output.I'm still finishing this project (since 4 years)but I made a quick continuity check with my multimeter and it BEEPS when it comes to 5V rail and GND. Is it right to say that if I would have switched on this PS it would have get fried ? I assume the 6,8 Ohm 11W resistor I had it's not enough right? How can I choose wisely a resistor to make a dummy load without frying everything?Thank you

author: james_s
author_rank: Super Contributor
timestamp: April 12, 2019, 10:08:44 pm
content: Most continuity modes beep whenever there is less than about 50 Ohms so this is not surprising. Use Ohms law to calculate the draw of your load, 6.8 Ohms, 5 Volts, it is trivial to calculate exactly how much current it will draw and how much power it will dissipate.

author: ogden
author_rank: Super Contributor
timestamp: April 12, 2019, 10:51:42 pm
content: Quote from: Charybdis on April 12, 2019, 07:11:45 pmAnything in 5..10 Ohms range is OK as idle load for 5V rail of ATX supply. Place your 6.8 Ohm resistor into the air flow and you will be fine.

author: Charybdis
author_rank: Contributor
timestamp: April 13, 2019, 12:42:00 am
content: Quote from: ogden on April 12, 2019, 10:51:42 pmThank you Ogden, so how can I understand if I will make a shortcircuit or not?I thought 5Ohm were not enough to prevent a shortcircuit.Quote from: james_s on April 12, 2019, 10:08:44 pmWell actually I was more concerned by a possible shortcircuit, but thanks I didn't know about the 50 Ohm thing

author: james_s
author_rank: Super Contributor
timestamp: April 13, 2019, 01:06:47 am
content: A short circuit is 0 Ohms, you cannot create a short circuit by connecting a resistor across.I told you everything you need to know to calculate the amount of power any resistor will draw, use Ohms law, look it up if you're not familiar with it, you will use it constantly doing any sort of electronics work. Once you calculate the current, compare that to the current the power supply is rated to deliver, and calculate the power and compare that to the wattage rating of the resistor.

author: Charybdis
author_rank: Contributor
timestamp: April 13, 2019, 11:49:28 pm
content: Quote from: james_s on April 13, 2019, 01:06:47 amOK I think I got it.The current through the resistor should be 0.73A while the wattage that the 11W resistor will handle will be 3.65W. So it should be perfectly fine right ?Thank you
Dumping SPI RAM frame buffer to SPI LCD directly - Page 1
Forum section: electronics / projects

author: Koen
author_rank: Frequent Contributor
timestamp: December 02, 2019, 10:37:48 am
content: Hello,is it somewhat possible to transfer directly from a SPI RAM chip to a SPI LCD ?The microcontroller would set up both for it but then the SPI RAM would transfer the pixels to the LCD directly without involving the microcontroller ?I feel like I've seen something similar for SDRAM and parallel LCD interface.Thank you !Koen

author: jhpadjustable
author_rank: Frequent Contributor
timestamp: December 02, 2019, 11:55:14 am
content: TFT LCDs generally accept raw raster data and sync pulses and shift it directly into the LCD matrix, and do not have their own command processors on board. SPI LCDs have a somewhat intelligent controller which has its own integrated frame buffer RAM and command processor, which only gets in the way of such a scheme. Yes, you could, but it would be redundant and pointless. The only adjacent worthwhile application that comes to mind would be for a very limited MCU (PIC16-class) to send fixed images and supporting commands from an external serial flash to a disproportionately large SPI LCD.

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 02, 2019, 02:43:27 pm
content: Given that both devices have a slave SPI interface, you can't. (At least I've never run into any SPI RAM or SPI LCD that could act as a master.)The usual way would be to set up DMA transfers within your MCU, which would take almost no CPU time (apart from starting the transfers, a couple of cycles if done right). If it doesn't support DMA, you're out of luck. Of course you could always add some kind of small FPGA/CPLD in between to take care of the transfers, but I guess that would be way beyond what you intended to do.

author: Gribo
author_rank: Frequent Contributor
timestamp: December 02, 2019, 05:54:39 pm
content: You can try and hack it and connect them in daisy chain, MCU data out to DRAM data in, DRAM data out to LCD, with CS lines to allow configuration of LCD. Good luck.