hybridfree/eevblog-posts huggingface dataset:
Inductor design - Page 1
Forum section: electronics / beginners

author: Gowda1
author_rank: Contributor
timestamp: December 03, 2020, 01:44:00 pm
content: Hey Guys,I am designing an Inductor for Ipk-pk= 50A 20u f=85Khz. I went through lot of cores and decided to do with ETD cores. But the problem is I am designing it for very core loss so i decided to keep the maximum flux density of 100mT. But i did not find any ETD cores with this range, i could only get the peak flux density of 330mT (if my formula was right B pk= Inductance x peak current divided by (turns x cross sectional area of the core)) ...I just want to know what are all the ways to get low peak flux density... Awaiting your answers.. Thank you

author: Benta
author_rank: Super Contributor
timestamp: December 03, 2020, 03:16:47 pm
content: Larger core?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 03, 2020, 05:40:02 pm
content: Turns sets flux. Air gap sets current flow. The ratio of the two is defined as inductance (1 H == 1 Vs / A). Flux density of course is flux / A_e.L = N^2 mu_eff mu_0 A_e / l_eIf l_g = 0, mu_eff = mu_r, the relative permeability of the core material itself.As l_g goes up, mu_eff falls. If l_g were infinite (i.e., no core at all), mu_eff --> 1.Approximately, mu_eff = l_e / (l_e / mu_r + l_g)You'll probably find best results with mu_eff around 20-60. This is a practical range for copper wire windings on typical core types.You may not have many options for commercial ETD (or any other shape) core, in terms of off-the-shelf gapped core sets. Gaps can be custom-ordered, but unless you're buying a pallet of them, you're probably better off adjusting normal (ungapped) cores. The center peg can be ground down with carbide abrasives, or the core can be shimmed. Mind that for shimming, the air gap counts twice: once in the middle and once in the outer legs. So if you need e.g. l_g = 1mm, use 0.5mm shims.Tim

author: dietert1
author_rank: Super Contributor
timestamp: December 03, 2020, 07:12:37 pm
content: Unless you are a student, you could try Würth 7443763540220. It's a power inductor 22 uH for up to 40 A DC and usable up to 9 MHz. Maybe it serves the purpose. Those inductors are very special and really i have no idea how they make them: a multiturn coil of flat wire with very small coil diameter, amazing.Regards, Dieter
inductor for boost converter - Page 1
Forum section: electronics / beginners

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: August 29, 2019, 10:15:19 pm
content: Are these any good for a fixed frequency 1.4Mhz boost converter?https://lcsc.com/product-detail/Power-Inductors_Sunltech-Tech-SLP1265S101MTT_C254897.htmlhttps://lcsc.com/product-detail/Power-Inductors_Shun-Xiang-Nuo-Elec-SMDRS1275-221M_C163690.htmlThe current handling is fine however the core material might have such high losses it might melt the solder as there is nothing depicted in datasheets pertinent to their operating frequencies. There are no graphs about inductance to frequency in datasheets.

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: August 29, 2019, 11:31:27 pm
content: What specifically is needed to determine if the core material is capable of a particular switching frequency?

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: August 30, 2019, 12:15:49 am
content: Quote from: blueskull on August 30, 2019, 12:00:49 amGoing to determine if they will increase efficiency, considering the load current is very small.

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: August 30, 2019, 12:28:57 am
content: Quote from: blueskull on August 30, 2019, 12:20:05 amThere are certain values which will increase efficiency, and 100uH might be around that value. These appear fine for the high frequency operation.https://lcsc.com/product-detail/Power-Inductors_Changjiang-Microelectronics-Tech-FXC1040-101M_C191165.htmlhttps://lcsc.com/product-detail/Power-Inductors_Shun-Xiang-Nuo-Elec-SMMS1360-101M_C149534.html

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: August 30, 2019, 12:38:34 am
content: Quote from: blueskull on August 30, 2019, 12:32:07 amDo boost ICs become damaged from no load other than its voltage divider going into its feedback terminal?

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: August 30, 2019, 12:59:11 am
content: These are the same form factor - slightly smaller less expensive but no mention of frequency.https://lcsc.com/product-detail/New-Arrivals_COILMX-MS1040-101M_C380060.htmlWhats this formfactor called? The nice blocks of ferrite.

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: August 30, 2019, 01:28:49 am
content: Quote from: blueskull on August 30, 2019, 01:01:57 amWhat are these inductors good for - which don't have data needed for determining frequency/currents from the manufacturer?Some of those datasheets are entirely vacant of nearly everything but soldering temperature and dimensions.
inductor for buck converter - Page 1
Forum section: electronics / beginners

author: abdulsamaddabu
author_rank: Contributor
timestamp: November 30, 2017, 07:26:35 pm
content: what value should i use for inductor in my buck converter circuit

author: Benta
author_rank: Super Contributor
timestamp: November 30, 2017, 10:38:43 pm
content: It's a SimpleSwitcher. Use the design software, it's free of charge.

author: MrAl
author_rank: Super Contributor
timestamp: December 01, 2017, 05:57:47 pm
content: Quote from: abdulsamaddabu on November 30, 2017, 07:26:35 pmHi,Anything equal to or over about 50uH will work but it partly depends on what your filter cap can handle and what size it is and how much ripple on the output you can tolerate.The software may help with all of this.
Inductor identification - Page 1
Forum section: electronics / beginners

author: Glug
author_rank: Contributor
timestamp: February 03, 2012, 11:46:13 pm
content: I have an inductor and not much experience identifying them. Online guides have only helped with some of the codes. It is inline in an audio signal, is there anything I should beware of when selecting a replacement?I gather that it is 1 uH, and K=10%? But I'm not sure about the rest, or the significant of the O or O after the uH.Thanks!It reads:1uH0C10KPLW75/41

author: Psi
author_rank: Super Contributor
timestamp: February 04, 2012, 12:08:02 am
content: could be thishttp://www.datasheets.org.uk/indexdl/Datasheets-SL1/DSASL0016753.pdfpart- SC55-10-3920-10 value- 1.0uH bodymarking- 1uH0-KOr something similar by the same company.

author: Glug
author_rank: Contributor
timestamp: February 06, 2012, 03:22:41 pm
content: Thank you, Psi.I don't know much about inductors, but I wonder about the significance of the 75/41. The resistance measured .4 ohms. I'll have to get a few and experiment, but it looks like it shouldn't be too difficult to identify a few "typical" high frequency filter inductors for the audio spectrum.
inductor markings - Page 1
Forum section: electronics / beginners

author: m3vuv
author_rank: Super Contributor
timestamp: March 22, 2022, 09:21:42 am
content: hi all,i need a 100uh inductor for a project,i have found this on an old board,sorry about the lousy pic but its the best i can do,the inductor is an smd jobby,just off center in the pic,it is marked 100 on its top face,would that be uh?,its about 4mm square by about 2mm deep.

author: m3vuv
author_rank: Super Contributor
timestamp: March 23, 2022, 06:59:29 am
content: can nobody help?

author: HighVoltage
author_rank: Super Contributor
timestamp: March 23, 2022, 07:13:07 am
content: Sorry, I can not make out anything in your picturesTry this:https://www.google.com/search?q=100+uh+smdAnd look at those pictures
inductor markings - Page 1
Forum section: electronics / beginners

author: m3vuv
author_rank: Super Contributor
timestamp: March 25, 2022, 06:29:33 am
content: Ki all,i have some inductors,all smt with the following markings: 4r7,2r2,6r8,5r6,1r0,1r2,3r9,3r3,3r9,and lastly 1r4,the only time i have seem markings like tis is for resistors on a schematic,i need a value anywher from 100uh to 470 uh,how do i decode these markings and what if ant is the nearest value to use,if any?,tia.

author: Vovk_Z
author_rank: Super Contributor
timestamp: March 25, 2022, 03:19:00 pm
content: 'R' means 'uH' - one micro Henry.So, 1r5 is 1.5 uH etc.

author: m3vuv
author_rank: Super Contributor
timestamp: March 25, 2022, 03:32:50 pm
content: Thank you for that,its clearsd up a mystery,same principal as resistors then.?,just replace ohms with mh?.

author: Vovk_Z
author_rank: Super Contributor
timestamp: March 25, 2022, 05:14:17 pm
content: That 'r' is not for Ohms, it is rather just a decimal point delimiter.It is not mH, it is uH. 'm' goes for 'milli', but our case is about 'micro'.4r7 is 4u7 or 4.7 uH or 4.7 microHenry.I don't know why manufacturers use 'r' instead of 'u', possibly somebody can explain.

author: m3vuv
author_rank: Super Contributor
timestamp: March 26, 2022, 04:34:39 am
content: so is an inductor marked 154J, 154 micro henrys or milli henrys?.

author: TimFox
author_rank: Super Contributor
timestamp: March 26, 2022, 04:40:52 am
content: Neither. "154" means 15 x 104, and inductors are scored in uH, so 150 mH.

author: m3vuv
author_rank: Super Contributor
timestamp: March 26, 2022, 05:27:55 am
content: so 154j is 150 milli henrys then and not micro? as in uh.

author: m3vuv
author_rank: Super Contributor
timestamp: March 26, 2022, 05:29:39 am
content: in that case how would 150 micro henrys be marked as in xxxj ?.

author: Vovk_Z
author_rank: Super Contributor
timestamp: March 26, 2022, 06:43:44 am
content: 150 uH is marked as 151 (15*10^1).

author: m3vuv
author_rank: Super Contributor
timestamp: March 26, 2022, 07:07:07 am
content: would 151j be the same ?

author: TimFox
author_rank: Super Contributor
timestamp: March 26, 2022, 02:05:25 pm
content: Yes, the delimiter j indicates the tolerance (5%).1540f would indicate 154 uH, 1% tolerance (an unlikely value for an inductor).
inductor phase - Page 1
Forum section: electronics / beginners

author: electrolust
author_rank: Unknown
timestamp: May 23, 2017, 10:46:28 pm
content: After watching w2aew #55 I tried to measure a series LC circuit for resonance. I found that the resonance point was where I expected, but I could not get the total signal (across both L+C) to 0V or even close. After some head scratching I realized that it's because the inductor phase was not 90° to the input signal. Am I doing something wrong?Here are traces of the capacitor and inductor alone, with a 50r current sense resistor (annotated "load") to measure the input signal. The inductor is 7m2 with DCR 83r at the test frequency of 5300Hz. Inductor SRF is 1.4MHz. I guess I should test at the SRFbut I haven't come across any information that the frequency affects the phase.In the cap trace, the phase is -91.x and this is within the phase error of the 2 probes.For 20 traces, I found that the probes themselves are out of phase an average of 0° but a max of about 2°. That seems pretty damn noisy to me, is my expectation out of wack? I'm measuring across ch. 2 and ch. 3 which are on different "banks" of the scope, would I get better results if I used ch. 1 and ch. 2 instead? Even if that corrected it or I otherwise solved that issue, note that the inductor phase error is 13° by itself, and that in the LC circuit the phase error L and C is 20°. So the probe error is small compared to inductor "error".

author: electrolust
author_rank: Unknown
timestamp: May 24, 2017, 12:41:02 am
content: Ah.I see now, it is because I'm not near enough to the SRF of the inductor.source:https://meettechniek.info/passive/parasitic.html
Inductor question - Page 1
Forum section: electronics / beginners

author: desertgreg
author_rank: Contributor
timestamp: April 29, 2017, 10:44:22 pm
content: I'm looking at a reference schematic which has an inductor but does not specify the inductance. The inductor is labelled with 0.5amp 120 Ohm 100Mhz. How do I compute the inductance from these values?

author: Brumby
author_rank: Unknown
timestamp: April 30, 2017, 12:22:15 am
content: It might make things easier if we could see the schematic....

author: lem_ix
author_rank: Regular Contributor
timestamp: April 30, 2017, 12:46:18 am
content: Probably a ferrite for about 100 mA current tops?

author: desertgreg
author_rank: Contributor
timestamp: April 30, 2017, 02:12:22 am
content: I've attached a pic of the part of the schematic I'm talking about.
Inductor rise time questions! - Page 1
Forum section: electronics / beginners

author: ZeroResistance
author_rank: Frequent Contributor
timestamp: September 17, 2018, 06:54:08 pm
content: So, let's say I have aC = 1uFL = 100uHRL = 0.5 ohm (which I will ignore for this case)and1. Vc = 100V and I discharge this capacitor into the inductor and next2. Vc = 500V and I discharge the capacitor into the inductor.I would expect that as per the equation VL = L. di/dt. The rate of change of current di/dt is proportional to the ratio VL/L and since L is constant the rate of change of current should increase with V.However for both cases I find (in LTspice) that the current reaches the peak value at the same time. I mean same rise time of current for both cases is the same.I was expecting the case with the high Voltage to reach the peak current value earlier.What am I doing wrong here or is my understanding wrong in this case?!Thanks in advance!

author: Benta
author_rank: Super Contributor
timestamp: September 17, 2018, 08:52:43 pm
content: A sketch of your RLC connection would help. Right now I'm??

author: bson
author_rank: Unknown
timestamp: September 17, 2018, 09:21:37 pm
content: VL drops 5x as fast with the higher voltage, so while di/dt starts higher it also drops correspondingly faster.
[SOLVED} Inductor smd. - Page 1
Forum section: electronics / beginners

author: MasterT
author_rank: Frequent Contributor
timestamp: October 27, 2017, 12:47:22 pm
content: I have a modulehttps://i.ebayimg.com/images/g/4IEAAOSwnHZYmuiJ/s-l1600.jpgThere are several smd inductors supposed to be installed, L2 -//- L6. I can see, that L5 - L6 (left side of the picture, close to SMA output connectors) are replaced with 0-resistors, and its fine, but what bothers me is L2 - L3, both have 68X markings. Same time ohmmeter shows 50 ohms DC resistance. Does that mean they are resistors as well? Why 68X, and not 510 or R51 or whatever resistors should be marked?Edit: google search does help, just have to find right search pattern. "EIA96 or E-96 resistor series"
Inductor sorting series - Page 1
Forum section: electronics / beginners

author: T4P
author_rank: Super Contributor
timestamp: June 23, 2012, 10:38:07 am
content: Another chapter on sorting ..What series do you guys use for inductors?

author: Psi
author_rank: Super Contributor
timestamp: June 23, 2012, 11:37:29 am
content: I don't use many inductors, so i just have 3 boxes separated by their general purpose.- Powdered iron core and other mains inductors- Audio inductors, for filters etc- Switchmode inductors, eg ~10khz-1mhz95% of them are recycled out of old pcbs so i don't really know their value until i go looking for a one using the LCR

author: T4P
author_rank: Super Contributor
timestamp: June 23, 2012, 04:00:19 pm
content: Thanks, anyway, now i find there is no point buying a set of TH inductorI'll collect as much switchmode inductors as i can find, i have quite a few now all of them are from CFL's

author: szhighstar
author_rank: Contributor
timestamp: July 01, 2012, 07:45:25 am
content: if you need inductor and transformer and choke and filter, I can help you.

author: T4P
author_rank: Super Contributor
timestamp: July 01, 2012, 09:21:42 am
content: Quote from: szhighstar on July 01, 2012, 07:45:25 amWhat's the quote for a 300mH 4Amps EI lamination inductor

author: szhighstar
author_rank: Contributor
timestamp: July 01, 2012, 10:55:46 am
content: do you have dimension requirement? because it is a inductor, so only a winding about the part, also advise MOQ, thanks!

author: T4P
author_rank: Super Contributor
timestamp: July 01, 2012, 12:24:08 pm
content: Quote from: szhighstar on July 01, 2012, 10:55:46 amNo size requirement and MOQ probably around 1000Just askingRemember, EI core not Ferrite

author: szhighstar
author_rank: Contributor
timestamp: July 01, 2012, 01:05:33 pm
content: Hi Davy, thanks for your comment.
Inductor symbol with asymmetric pins length, why ? - Page 1
Forum section: electronics / beginners

author: BravoV
author_rank: Super Contributor
timestamp: July 08, 2018, 05:17:49 pm
content: As inductor is non polar, why asymmetric pins printed on this big inductor ? (photo attached below)Its dipped inside the yellow epoxy,and both terminals are identical size & shape.Pretty sure its not label printing error or misaligned, as it looks it was deliberately made.

author: X
author_rank: Regular Contributor
timestamp: July 08, 2018, 05:27:44 pm
content: It looks like the label was meant to be on the top where the pins protude, but then at the last minute they changed it on the side. It looks like it corresponds exactly with the relative positions of the physical pins.

author: IanB
author_rank: Super Contributor
timestamp: July 08, 2018, 05:29:46 pm
content: You are asking what do the "ge" and "rt" mean?Maybe someone from Germany knows what they might be a common abbreviation for.According to the datasheet the part is symmetrical:https://datasheet.octopart.com/B82504W-A-5-EPCOS-datasheet-13704512.pdf

author: Benta
author_rank: Super Contributor
timestamp: July 08, 2018, 05:31:54 pm
content: Because if Siemens had made the drawing symmetric, someone would complain that the terminals are not centered. Siemens was always very precise with this kind of thing.

author: glarsson
author_rank: Frequent Contributor
timestamp: July 08, 2018, 05:42:11 pm
content: Quote from: IanB on July 08, 2018, 05:29:46 pmPerhaps:ge = gelb = yellowrt = rot = red

author: CatalinaWOW
author_rank: Super Contributor
timestamp: July 08, 2018, 06:26:38 pm
content: Information redundancy. The shorter symbol represents the connection on the near side of the device. The longer symbol represents the connection on the far side of the device.The more ways you can tell something to somebody the higher the likelihood that the information will be received and understood.

author: boB
author_rank: Frequent Contributor
timestamp: July 08, 2018, 07:39:53 pm
content: No idea if this has any relevance in this case but sometimes an inductor will need its winding start end (inside of the coil) to go to the "noisy" part of the circuitry and the outside of the winding can go to ground or non-noisy end of the circuit so that the EMI's have a lower chance of emanating from the inductor. i.e., an intrinsic Faraday shield of sorts.boB

author: innkeeper
author_rank: Unknown
timestamp: July 18, 2018, 09:18:53 pm
content: tried to find it out of curiosity...seems to not be on the current epcos version.
Inductor Symbol  - Page 1
Forum section: electronics / beginners

author: Jbliss
author_rank: Regular Contributor
timestamp: January 08, 2018, 02:23:53 am
content: Hi All,Silly question but what type of inductor is this?I believe it is a Coupled Inductor...?could anyone link me. They seem to be difficult to source at 3mhThanks

author: Jbliss
author_rank: Regular Contributor
timestamp: January 08, 2018, 02:32:03 am
content: Quote from: blueskull on January 08, 2018, 02:28:19 amThank-you ! Excellenthttp://au.element14.com/schaffner/rn102-1-02/inductance-3mh/dp/1653729
Inductor time constant - Page 1
Forum section: electronics / beginners

author: the offset voltage
author_rank: Regular Contributor
timestamp: July 06, 2025, 04:47:06 pm
content: Hi. I need some help please. For the circuit from the figure, i have calculated the current (it is 17.64mA, also verified on LTspice, this is ok). Now, i have a problem with my simulation for the time constant. based on my calculation the time constant (5RL) = 735nS, but on LTspice i see a different result. Any idea what i do wrong?

author: Zero999
author_rank: Super Contributor
timestamp: July 06, 2025, 05:54:36 pm
content: Where did you get that formula from?τ =L/R= 100*10-6/680 = 147*10-9sThe current will be about 63% of the steady state after one time constant.The steady state current is 17.64mA.17.64mA * 63% = 11mA which matches your plot quire nicely.https://en.wikipedia.org/wiki/RL_circuit?useskin=vector#Time_domain_considerations

author: Grandchuck
author_rank: Super Contributor
timestamp: July 06, 2025, 07:45:15 pm
content: Thinking of 5RC?I have seen that approximation for full charge or discharge of a cap.

author: TimFox
author_rank: Super Contributor
timestamp: July 06, 2025, 08:35:21 pm
content: L/Rhas the dimensions of time: (Volt x sec / Ampere) / (Volt / Ampere) = (sec)LxRhas dimensions: (Volt x sec / Ampere) x (Volt / Ampere) = (Volt2x sec) / (Ampere2) = (Ohm2x sec), not very useful.

author: Zero999
author_rank: Super Contributor
timestamp: July 06, 2025, 08:54:53 pm
content: Quote from: Grandchuck on July 06, 2025, 07:45:15 pmThat would be approximately 5L/Rfor the current through an inductor to reach steady state.EDIT: I got the fraction the wrong way round. I often lost marks for doing that at college.

author: TimFox
author_rank: Super Contributor
timestamp: July 06, 2025, 09:22:41 pm
content: 5 xL/Ris a time value
Inductor traces vs inductor component? - Page 1
Forum section: electronics / beginners

author: FriedMule
author_rank: Frequent Contributor
timestamp: December 10, 2020, 04:05:50 am
content: I am making a receiver to an RF remote control and in the datasheet for the receiver chip do it show that you (optional) can add a filet, containing an inductor, made as a trace. Is there any good reason for using a trace instead of an inductor component? I mean the trace inductor do take up a lot of space.
Inductors and forward EMF - Page 1
Forum section: electronics / beginners

author: Chai
author_rank: Regular Contributor
timestamp: February 29, 2016, 06:43:28 am
content: I'm trying to understand why the D2 led will light up after the switch is opened in this circuit. I understand that the inductor will resist the decrease in current and continue to provide current for a short period but why wouldn't it just take the easy path to ground rather than passing through D2?

author: BravoV
author_rank: Super Contributor
timestamp: February 29, 2016, 07:01:03 am
content: Cause the polarity of the inductor is reversed when the switch is opened, hence D2 will be forward biased .

author: Psi
author_rank: Super Contributor
timestamp: February 29, 2016, 07:04:02 am
content: If the switch is opened it can't get to positive at all, so why would it go to negative ?ie, there's no completed circuit path out ground

author: bson
author_rank: Unknown
timestamp: February 29, 2016, 07:39:22 am
content: Current will flow top down through the inductor and when the switch is opened it will want continue doing this. But it has nowhere to source the current it needs, so it will form a loop through D2 until its field potential (measured in V) has dropped to where it's no longer able to light up D2. (It's less than D2's forward voltage.) Current escaping to ground would violate KCL. It has to to come from somewhere.

author: Richard Head
author_rank: Frequent Contributor
timestamp: February 29, 2016, 09:37:05 am
content: Lenz's law.

author: Chai
author_rank: Regular Contributor
timestamp: March 01, 2016, 02:33:11 am
content: Quote from: bson on February 29, 2016, 07:39:22 amgreat, thanks.
Inductor/Transformer Kits - Page 1
Forum section: electronics / beginners

author: Element
author_rank: Newbie
timestamp: February 14, 2013, 01:09:50 pm
content: Hi everybody,Can someone point me to inductor/transformer kit that includes the wiring and thecore. Can you also show me where can I find through hole Inductor kits (genericvalues).Thank you in advance

author: mazurov
author_rank: Frequent Contributor
timestamp: February 14, 2013, 07:08:37 pm
content: Coilcraft is one place for (ready-made) inductor/transformer kits.http://www.coilcraft.com

author: Element
author_rank: Newbie
timestamp: February 14, 2013, 11:06:47 pm
content: Thank you very much this is a wonderful website

author: potatogun96
author_rank: Contributor
timestamp: March 11, 2013, 05:52:49 am
content: Jameco has a kit.http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2160681_-1
inexpensive+good test points, spring pins, banana jacks, SMA, uFL, grabbers,...? - Page 1
Forum section: electronics / beginners

author: evb149
author_rank: Regular Contributor
timestamp: March 14, 2022, 01:52:45 am
content: Hi this is about suggested sources / manufacturers / part numbers for test & mechanical accessories foruse with typical PCBAs. e.g.* test points (actual mechanical SMD or TH parts for clipping hooks / grabbers / probe tips etc. to.)* spring pins / "pogo pins" for test probing* micro grabbers, micro / mini hooks and/or assembled leads with such.* jacks / plugs for banana type* IPEX / u.FL PCB mount connectors* SMA / RPSMA PCB mount / edge mount connectorsI know about DigiKey and Mouser and Newark and eBay and AliExpress and so on, but I'm just asking forsuggested manufacturers / parts / vendors since I know quality varies quite a bit from one generic manufacturerto another so finding some options that are both inexpensive and which work well for their purposes would be nice.I see the test points at DigiKey are around $0.10/each@qty=100 and up to multiples of that which isn't horrible for quality parts with vetted supply chain etc. but it also doesn't make me want to run out and buy a reel right now for all my current and future hobby projects and use them dozens here and dozens there etc.Similar but more so with spring pins and such.So what's cheap & decently good enough that it makes sense to use it for low cost hobby projects by job lots?

author: thm_w
author_rank: Super Contributor
timestamp: March 14, 2022, 10:42:21 pm
content: I think you are asking for too many things here.Whats wrong with using a standard dupont header pin as a test point? You can make or buy a probe to dupont female adapter even.If you want hooks then these look OK:https://www.aliexpress.com/item/1005001843784820.htmlMicro grabbers, there are quite a few threads, the recent SDK08 are very good:https://www.eevblog.com/forum/testgear/affordable-micro-grabbers/Connectors, LCSC.

author: TimFox
author_rank: Super Contributor
timestamp: March 14, 2022, 10:49:07 pm
content: For test points, I like Keystone. They are available from the usual stores.https://www.keyelco.com/category.cfm/Test-Points-Tips-Probes-Clips/Test-Points-color-keyed-Thru-Hole-Mount/id/521https://www.keyelco.com/category.cfm/Test-Points-Tips-Probes-Clips/Test-Points-Surface-Mount/id/523Their board-mounted test points work well with micro-grabbers from various sources.
Inexplicable OpAmp Behavior - Page 1
Forum section: electronics / beginners

author: obuone
author_rank: Contributor
timestamp: December 20, 2021, 11:54:03 pm
content: Hello EEVblog folks.I am working on a hobby project making programable DC load. In the design I am using MAX6070 4.096V Voltage reference and MAX5717 unbuffered DAC. Two MAX44246 dual- low offset opamps are used as current sense amp, voltage reference buffer, error amplifier and difference amplifier for remote voltage sensing. The voltage reference is buffered and fed into the REF input of the DAC. The DAC's output goes to the non-inverting output of the error amplifier though 10k resistor.And here comes the issue. Everything works well if the input of the Opamp is below 1.1 V. However above that value the opamp starts to draw obscene amount of current from the input and the DAC output voltage crumbles. I know that the DAC is unbuffered with 2k ohm output impedance and can't drive an appreciable current, but this shouldn't matter. The MAX44246 has mere 1250pA input current by spec but i am measuring 100 uA of input current at DAC Full scale.What the OPAMP is going on? Am I doing something fundamentally wrong? Do i have defective opamp or what. I have attached some images of the circuit and the measured input current and DAC output voltage as a function of code.ps. I have already disconnected the DAC from the Opamp and checked its output. The DAC operates in spec.Thank you!

author: magic
author_rank: Super Contributor
timestamp: December 21, 2021, 12:15:00 am
content: The analog part looks a little scary, are you sure it doesn't start to oscillate at some point?

author: obuone
author_rank: Contributor
timestamp: December 21, 2021, 12:19:47 am
content: Initially it oscillated. I had to remove C1 to stabilize it. That is one of the caps at the at the error amplifier. I also checked it with open loop by disconnecting the output of the amp from the gate of the transistor. I got the same result.Even if it oscillated. How can that affect the input current of the amp?

author: magic
author_rank: Super Contributor
timestamp: December 21, 2021, 12:27:50 am
content: The reason I ask is because many opamps have differential clamping diodes between IN+/IN-. So one reason for excessive input current could be IN- being much lower than IN+ for some reason, like the whole circuit going out of whack due to oscillation.(BTW, the IN- problem may be happening now after disconnection of the power transistor).Connect it back and check if everything is alright with IN-.

author: obuone
author_rank: Contributor
timestamp: December 21, 2021, 12:33:55 am
content: Thank you. Wow i think you cracked this one wide open.The behavior looks kind of diode-y, but never occurred to me to check the other input as well.Straight from the datasheet:"The amplifier inputs are connected by internal back-to-back clamp diodes. In order to minimize noise in the input stage, current-limiting resistors are not used. If differential input voltages exceeding ±1V are applied, limit input current to 20mA."
infared dectator - Page 1
Forum section: electronics / beginners

author: noah_fakelastnamelike_bob
author_rank: Regular Contributor
timestamp: April 19, 2014, 02:42:05 am
content: hello so a beginner would like some help with his really basic design that could be entirely wrong. i want to make a infrared detector then transmit that but would like to stick to the basics. i would like to use a 2n-3904 or 2n-3906 with a detector, transmitter and a couple resistors. i have don't really know what values i should use for the resistors or if i need to find a certain wavelength for my transmitter. i feel like this would be to simple but here it goes. please excuses my bad drawing.

author: electronics man
author_rank: Frequent Contributor
timestamp: April 19, 2014, 10:08:25 am
content: You may not want that resistor before the transistor only the one after between the transistor and before the LED

author: deth502
author_rank: Frequent Contributor
timestamp: April 19, 2014, 11:43:56 am
content: when you say "then transmit" your talking about making a repeater? if so, just about any ir led should work. for most general applications, i dont think you will see a difference between an 850 or 940.the series resistor would be calculated using the led's parameters and your supply voltage, same as any other led.if i misunderstood, and you are just looking to detect, as the title says, any camera can do that much simpler.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: April 19, 2014, 12:20:09 pm
content: QuoteNo can do.Detacted a spelling mistake too.

author: noah_fakelastnamelike_bob
author_rank: Regular Contributor
timestamp: April 19, 2014, 11:04:49 pm
content: i just want to be able to get the signal re-amp it then send it back through i have been told it should work and will post when done

author: noah_fakelastnamelike_bob
author_rank: Regular Contributor
timestamp: April 20, 2014, 01:32:52 am
content: actually could some one direct me to a link from DIGI-KEY for an infrared detector and emitter i don't want to do or mess with specifics there because ill buy some thing wrong. thanks for any help i get
Infinity Mirror LED-Strip - Page 1
Forum section: electronics / beginners

author: modernjack3
author_rank: Contributor
timestamp: April 10, 2016, 06:44:13 pm
content: SO as you can read by the title I am planning on Building an infinitymirror - but not a normal one - I want it to function as a spectrum analyser aswell - so i want to have 7 Channels with diffrent intensities that can be shown in this cool 3d look - what I Need now is a LED Strip where i can Control every LED (also shut off) by its own and I werent able to find one yet... it would be old nice if the LED Strip was cuttable into smaller parts. (I will be using an Andruino btw)Sorry if my english isnt perfect _ I come from Austria and normally speak german !

author: Chalcogenide
author_rank: Regular Contributor
timestamp: April 10, 2016, 06:49:28 pm
content: Look for WS2812 - individually addressable RGB LEDs that only require one serial input, and can be daisy-chained. Libraries available for Arduino as well.

author: modernjack3
author_rank: Contributor
timestamp: April 10, 2016, 06:52:43 pm
content: Hey !Thank you for the reply ! Those LED Strips dont seem to be cuttable or are they ? :/Edit : Sorry I just looked it up they seem to be. Thank you so much for your help !

author: modernjack3
author_rank: Contributor
timestamp: April 10, 2016, 06:56:16 pm
content: Is there also a way to turn the LEDs off one by one ?

author: Chalcogenide
author_rank: Regular Contributor
timestamp: April 14, 2016, 07:48:02 am
content: They are very definitely cuttable. WS2812 can be cut after each LED - they are powered from 5V, but be warned that they require quite a lot of current, so in the case of an infinity mirror power both ends of the strip to reduce the voltage drop.WS2811 are powered from 12V and can be cut every 3.Each LED is controlled by a digital communication, and can be set to display whatever colour - including staying OFF, but still drawing some current for the digital part of the IC. Every LED can have a different colour (that's the point of having individually addressable LEDs).
Info about basic BJT transistor circuit building blocks - Page 1
Forum section: electronics / beginners

author: RogerMc
author_rank: Contributor
timestamp: January 13, 2014, 04:52:15 am
content: Can anyone please recommend a web site or book which comprehensively covers the subject? I can find lots of info on logic but want to know more about circuits like darlington pair and totem pole for example. What others exist?I am not asking about logic gating circuits such as AND/OR/NOT etc.Thanks!

author: Rerouter
author_rank: Super Contributor
timestamp: January 13, 2014, 06:52:33 am
content: http://www.falstad.com/circuit/e-index.htmlyou will need to allow java, but the logic section shows working examples of the types of logic, and even internal mechanisms of sequential and combination logic chips
Info about RF VOLTMETER - Page 1
Forum section: electronics / beginners

author: lion
author_rank: Contributor
timestamp: October 11, 2016, 09:57:16 pm
content: Hello everyone.I've searched everywhere but I cannot find too much info about RF VOLTMETER. Can anyone link me or explain me how it works? This is my last resource.

author: barry14
author_rank: Regular Contributor
timestamp: October 11, 2016, 11:53:17 pm
content: Assuming that RF stands for the usual (Radio Frequency), an RF Voltmeter is a piece of electrical test equipment designed to measure the voltage of electrical signals whose frequencies are in the radio frequency range (usually considered to be anything above about 1 MHz. The frequency coverage of any one such Voltmeter can vary considerably depending on the application. If you are interested mainly in AM broadcast radios, for example, then a meter covering 0.5 to 2 MHz is probably sufficient. For FM broadcasts, the range would have to be increased to at least 110 MHz. For WIFI and other digital radios, the range would again have to be increased to several GHz. Most RF Voltmeters have an input impedance of 50 ohms since that matches the impedance of RF transmission lines and is a widely used impedance level in high frequency circuits. The input level range again will vary with the application but can range from microvolts to volts, with the former for measurements on receivers and the latter more for measurements on signal generators and low power transmitters. RF Voltmeters are manufactured by many companies including Agilent. Just google RF Voltmeter for more information or,if you provide a more specific question, I will expand this response.

author: Len
author_rank: Frequent Contributor
timestamp: October 12, 2016, 12:10:45 am
content: Here's a couple of pages about measuring RF voltages using a regular voltmeter and a special probe circuit:http://n5ese.com/rfprobe1.htmhttp://www.techlib.com/files/detect.pdf
Info - Page 1
Forum section: electronics / beginners

author: GEuser
author_rank: Frequent Contributor
timestamp: August 10, 2013, 12:02:26 pm
content: Q

author: free_electron
author_rank: Super Contributor
timestamp: August 10, 2013, 01:47:16 pm
content: No. This is a solid dielectricum. So they stay where they are.

author: SeanB
author_rank: Super Contributor
timestamp: August 11, 2013, 05:11:07 am
content: The only failure mode I have had with those is they eventually fall apart after a few decades as the green outer coat crazes and falls off. Even with this they still work, and keep within tolerance. The only issue is that when the coating eventually falls off it exposes the outer foil, and if there is something touching it with vibration so the pieces fall away it will short to it. Other than that they are pretty close to everlasting.

author: BravoV
author_rank: Super Contributor
timestamp: August 11, 2013, 05:13:42 am
content: If I'm not mistaken, isn't this particular type of plastic cap has a self healing feature as well ?

author: SeanB
author_rank: Super Contributor
timestamp: August 11, 2013, 05:53:29 am
content: Only with high voltage, otherwise they do not self heal. But with a low voltage they do not break down anyway.
Info on PSU strangeness - Page 1
Forum section: electronics / beginners

author: vaualbus
author_rank: Frequent Contributor
timestamp: February 04, 2016, 06:28:20 pm
content: So I have little bit of question. I have to repair this psu from the lecroy scope I found in a bin at my university (look for my other spot for other reason) and I come out with this strange think.If I have the psu disconnect from the scope all the rail are fine except from the -12v rail that read -3.7v. When I connect all the board the voltage become -12v as normal.Unfortunally if I only connect the motherboard pc connect the -12 is still -3.7v and the voltage protection of the psu disallow the pc to start.It is normal for a rail to have such a difference when between when there is a load and when not?I personally think not. I arleady try to change the regulator ic but it no make no difference.Here the schematics of -12 and -5v supply. Also I'm powering up the psu from an external psu of 19v. In the back of the scope there is a unpopulate dc in with write dc in 19-25v in, it suppose to be enough.

author: EPTech
author_rank: Regular Contributor
timestamp: February 05, 2016, 08:06:29 am
content: Hi There,This is a DC-to-DC converter, so you probably powered it correctly. You need to make it does not buckle, that the 19V stays 19V after you put a load on it.The -12V is obviously an unregulated output. Often you will see that the 5V is the regulated output as in this case. If you do not put a decent (nominal) load on the regulted 5V, the primary will not put enough energy in the SM transformer, resulting in the 12V-winding not being energized enough to give you 12V under load condition. In some poorly designed supplies, leaving an output open may even cause it to go into over-voltage and blow a capacitor.So I think the supply is fine, there may be something else going on with the scope. try the repair section of the forum. You may get more info there.
information about BJT transistor - Page 1
Forum section: electronics / beginners

author: javad2040
author_rank: Contributor
timestamp: September 14, 2017, 06:50:26 am
content: Hi.I want to use BJT transistor for my project. what is their features? what company makes it?what types(PNP or NPN) is better and easy to use?

author: agehall
author_rank: Frequent Contributor
timestamp: September 14, 2017, 11:37:05 am
content: I'd suggest you start by reading some basic literature like The Art of Electronics.

author: kalel
author_rank: Frequent Contributor
timestamp: September 14, 2017, 12:35:37 pm
content: I'm in no way at all affiliated, but I find this kind of interesting:http://www.talkingelectronics.com/CctSymbols/PNP-or-NPN/PNP-or-NPN.htmlI've yet to go through this myself:http://www.talkingelectronics.com/projects/BasicElectronics-1A/BasicElectronics-1A_Page2.htmlSeems useful. Especially appreciated are some simple circuit examples.It's always an inspiration to learn if you can actually start by easily making something small/simple that works, just to spark further interest.A simple simulator also helps to visualize things such as "what happens when I change the resistance".I would suggest this one:http://www.falstad.com/circuit/circuitjs.html- on the basis that it is simple to use and visualize things.
Information about zener - Page 1
Forum section: electronics / beginners

author: rmoyao
author_rank: Newbie
timestamp: August 20, 2024, 10:54:43 pm
content: Hi everybody.Does anyone knows the component in the attached photo. I believe is a zener diode. It comes from a ECU from a car but I haven't been able to find any specifications so I can't find a replacement or a equivalent part.Any help will be greatly appreciated

author: watchmaker
author_rank: Unknown
timestamp: August 20, 2024, 11:18:34 pm
content: Quote from: rmoyao on August 20, 2024, 10:54:43 pmScroll down to post 22 on this link:https://subaru-svx.net/forum/showthread.php?t=59362&page=2Did not read the whole thread but it looks like he got help.

author: rmoyao
author_rank: Newbie
timestamp: August 21, 2024, 07:02:32 pm
content: Thanks for your answer.I red that thread before but unfortunately the specification of 7.2V 10W does not seems to be correct in my case. The thread is about what it seems to be a light control in my case the zenner is used on an ECU so I need to know the exact voltage and power for the part.The two components that they recommend have different voltages so it is not clear.I was hoping someone in the forum would know this specific part as it seems that it has been discontinued long time ago.Thanks

author: floobydust
author_rank: Super Contributor
timestamp: August 21, 2024, 08:11:53 pm
content: From the Subaru board pics, this is a standard automotive TVS diode Nippon Denso used, in a 1980's button package which is obsolete.It is protecting the dimmer board and everything downstream from overvoltage transients and load-dump. Very hard to blow one of these diodes. As you can see, the PCB trace fuses first. What happened to it? I think this board protects power for a bunch of other stuff.It's a Japanese semi, the "T" might be Toshiba, but yellow lettering was Hitachi as I recall. It could be Sanken as well. I could not find the part number "S 5225" anywhere.Modern parts are plastic, the standard is "27V" yet popular parts available are either 26V or 28V. The exact voltage value is not critical. I would use a5KP26A(surge rating 5,000W) and make sure it can fit as it's 2mm longer body. Smaller (surge rating 1,500W) part would be1.5KE27AOK if you don't drive around with a bad battery connection or have a crap electrical system.Original part could be 3,000W like (plastic) ZSA5A27.The damage to the board (melted traces) is due to pulling way too much current through it from a wiring mistake somewhere else.The other parts are vanilla on the board if you need help fixing it.

author: Andreas
author_rank: Super Contributor
timestamp: August 21, 2024, 09:17:52 pm
content: Hello,I would use a LDP24A as replacement. (check for correct polarity)https://www.digikey.de/de/products/detail/stmicroelectronics/LDP24A/1038441Why do you suspect that your diode is defective?Usually they make a "short" in both directions on over load.With best regardsAndreas
Information on Tenma 72-5040 DSO scope - Page 1
Forum section: electronics / beginners

author: oldjim
author_rank: Newbie
timestamp: December 12, 2021, 12:33:29 am
content: Hi FolksI picked up a Tenma 72-5040 scope at a ham radio swap meet. I work on old solid state guitar amplifiers and have a B&K 20M scope that works just fine for what I need but the Tenma says it is a DOS and I thought it would be fun to work with. I've looked everywhere I can think of for a user or service manual with no luck. I did find out that the scope may have been sold under different brand names so I'm hoping someone here will know something about it. I think it was manufactured sometime in the 90's but can't document that either. So I'm posting a picture fo the scope in the hope that someone will recognize it under a different brand name and model that I might be able find a manual for. Thanks in advance for the help.
Infrared LED array circuit and power supply choice.  - Page 1
Forum section: electronics / beginners

author: Peteb
author_rank: Newbie
timestamp: January 23, 2015, 07:07:54 pm
content: Hello, I'm new here but have many electronics questions to come! Although I'm trying to learn electronics, my knowledge is currently very basic so I am hugely welcome to any help. I'm trying to make a small infrared LED array to support a webcam recording at night. I suffer from insomnia and have done for over 5 months now and it would help hugely to see if something is happening at night, i.e. snoring/ restless leg syndrome etc. It would seem best to either confirm or deny and possibility issues at night so I need to create a way to record myself, preferably cheaply.I currently have a lot of components to hand, so should be able to make this up with what I've got, but I'm happy to buy anything in if needed. I'm looking to create an infrared LED array with 20 LEDs rated at 1.5-1.6v 60mA. I believe (using this calculatorhttp://led.linear1.org/led.wiz) I can create four rows of five LEDs with an 82 ohm resistor on each line. However, upon testing any 12v power supply (I have three to hand) I get a reading of around 16v. Does this mean that all the power supplies I have are unregulated and if so, what might be a good alternative? Could I use these or make a circuit with some sort of voltage regulation?I have this circuit for another project, could I use this perhaps?http://www.satisled.com/33w-power-led-driver-mr16-acdc12v-input-dc911v-600ma-output_p1066.htmlAll the webcam recording will be done on my laptop through USB so it's only the infrared array I'm worried about currently.Thanks!

author: Paul Price
author_rank: Super Contributor
timestamp: January 23, 2015, 08:25:12 pm
content: Yes, it does mean they are unregulated, but you are reading the peak output voltage that will drop dramatically with any load. This is not a problem if you can measure the current across the series resistor to the LEDs and see if ohm's law tells you have the correct current feeding the LEDs. If not, adjust the resistor accordingly, and you are all set.If you want regulation, a 7812 regulator or a LM317 would allow you to make a simple regulator to fix or adj. the voltage output to fit your fancy.

author: Peteb
author_rank: Newbie
timestamp: January 23, 2015, 10:45:55 pm
content: Thank you for the reply - I made a quick version of a 20 LED array on breadboard, as per the online schematic. When I used the unregulated power supply it drops to around 11ish volts and around 100mA across the LEDs, plus on the webcam they seem to be hopelessly dim. Although I am aware of voltage regulators, I really wouldn't know where to start. Would you advise looking for a different power source or stick with my 12v 900 mA one and try regulating it? Also, now I've taken a new reading with the power supply under load, would it be expected for the voltage to remain the same 11ish volts that I can now find alternative resistors?