hybridfree/eevblog-posts huggingface dataset:
TPS63001 voltage drop under load - Page 1
Forum section: electronics / beginners

author: Lt_Flash
author_rank: Regular Contributor
timestamp: April 25, 2018, 06:49:34 am
content: Hi everyone,I've created a simple board that uses a fixed output 3.3V TPS63001 switch mode regulator. According to the datasheet, I've chosen a 2.8A shielded wire-wound inductor (TDK SPM-LR Series Type 3015 Shielded Wire-wound SMD Inductor with a Metal Core, 2.2 μH Wire-Wound 2.8A Idc, RS Australia stock number 123-3132), input capacitors are 10uF and 100nF, output ones are two 10uF ones, size is 0805. The issue I'm having is that if I connect even one 6.8Ohm 5W resistor - I'm getting a voltage drop on output of about 300-500mV, if I connect two 6.8Ohm resistor to ramp up current to about 1A - I'm getting only about 3.1V output. Input is connected to a lab power supply set to 3.7V and 1.5A of output. On lab power supply I can see that it stays in CV mode and consumption current is about 0.95A-1.1A. I'm measuring output directly at wires connected to resistor(s). According to TPS63001 datasheet output should stay stable at 3.3V up to 1.2A of current supposing input stays at or above 3.6V. Am I doing something wrong in measuring this or there can be something else? Thanks a lot for your help in advance!P.S. I don't have an oscilloscope at the moment, but ordered one to see what's going on inductor and output pins. Maybe inductor is not beefy enough? 2.8A should be sufficient though.

author: Lt_Flash
author_rank: Regular Contributor
timestamp: April 28, 2018, 09:06:03 am
content: Just to answer this question for anyone who has same problem - well, I've just got another confirmation that electrical enginnering is a science all about contactsI was measuring voltage on 6.8Ohm resistor connected to a breadboard with dupont wires. And of course, there was a huge voltage drop due to high current of about 1A over these wires and breadboard contacts/tracks. So, after connecting resistor directly to regulator output I've got a constant 3.3V all the way up to 1.2Amps - as per datasheet. Also I've finally got my oscilloscope and even measured noise - it's less than 100mV under full load, so I'm finally quite happy with my design! Anyone interested please feel free to have a look at design and description here (all the release files are included on that page, including Gerber, schematic and PCB board layout files).https://workspace.circuitmaker.com/Projects/Details/LtFlash/Sandwich-Regulator-board
TPS63060 - Page 1
Forum section: electronics / beginners

author: athosikish
author_rank: Newbie
timestamp: November 23, 2020, 03:01:18 am
content: Hello, I'm making a dimmable LED driver, I chosed TPS63060 and right now I have small problem. I connected PWM signal to EN pin. Frequency of this signal is 180Hz and in LTspice simulation works well but I don't know why I'm scaried that after soldering it won't work good.Will be circuit work properly?https://www.ti.com/lit/ds/symlink/tps63060.pdf?ts=1606046278019&ref_url=https%253A%252F%252Fwww.google.com%252F

author: drdm
author_rank: Contributor
timestamp: November 24, 2020, 07:51:00 am
content: From a first glance at the datasheet the startup time is about 300uS(Figure 9-18). You intend to drive the EN pin with 180 Hz which will enable and disable the device once every 5.56mS. If your duty cycle is 5% you will disable the Boost before it has started up fully.Theoretically this might work, but it is very bad design practice.Instead I suggest to use a high-side or a low-side switch to control the LEDs and use 1kHz frequency.
Trace length deltas and frequency - Page 1
Forum section: electronics / beginners

author: Pack34
author_rank: Frequent Contributor
timestamp: September 08, 2015, 02:37:13 pm
content: In a project I'm working on, I have an odd setup. I'm sending low frequency analog waveforms to a device. Now this device has two sets of pins on opposite sides that need to be externally connected. By low frequency, I mean really slow (10-20Hz).Is there some sort of rule-of-thumb for the allowable difference in trace lengths dependent on frequency? I can meander / trombone / snake the traces but at a higher voltage that I'm working with (150V), I'm thinking that it might cause more RF issues than it would solve... The delta I'm looking at would be on the order of 600mils. It's a lot, but given the wavelength of 20Hz, even at half the speed of light, is on the order of thousands of kilometers. It seems like the delta in my case would be a negligible percentage even in a desired low-noise setup like I'm working with.If I were to meander / trombone / snake the traces to get everything to match, the general consensus for that would be to make sure that there is proper isolation per the voltage (16mils) between the traces and that there is no ground plane between the arcs?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 08, 2015, 03:12:02 pm
content: Trace length is about 5 ps per mm. How much difference does a few nanoseconds make?Tim

author: MagicSmoker
author_rank: Super Contributor
timestamp: September 08, 2015, 03:19:37 pm
content: You are about 6 orders of magnitude too low in frequency to even begin to worry about matching trace lengths...More specifically, you only need to use meanders when you have critical timing requirements for clocks and usually the datasheet for any IC with such a requirement will specify the maximum amount of delay or skew.
Tracing a circuit on a PCB with conformal coating - Page 1
Forum section: electronics / beginners

author: BlackICE
author_rank: Regular Contributor
timestamp: February 12, 2021, 08:41:18 am
content: I have a controller is no longer manufactured and replacements are not available anymore. The circuit has a defect where a relay is not turning on when it should. A schematic is not available and tracing the board is most difficult because it has a conformal coating on it. Any tips on how to proceed giving the coating doesn't allow easy probing of the components. Seems like a two layer board with a lot of small surface mount devices on one side. I see a 3-pin device probably a transistor next to each relay. My guess is it's driving the relay coil. Any tips to ease debugging in reverse engineering given the conformal coating?

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 12, 2021, 09:31:40 am
content: Quote from: BlackICE on February 12, 2021, 08:41:18 amWell if there are any markings on it you should be able to identify it

author: BlackICE
author_rank: Regular Contributor
timestamp: February 12, 2021, 01:57:55 pm
content: I 1st tried melting the coating with a soldering iron. That didn't work too well. The coating came off but a couldn't read anything. Then I tried scraping it off with a knife. The code looks like "3SS D" with a dash "-" above the 2nd S.I found this, but am not sure it any of these are the parts.https://alltransistors.com/search.php?search=3ssThe coating is a PITA can't read part numbers and can probe the parts without scraping or melting the coating off.

author: Manul
author_rank: Super Contributor
timestamp: February 12, 2021, 03:37:56 pm
content: Try acetone soaking. Some cotton sticks. Usually it works good and you can remove it quite easy.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: February 13, 2021, 05:01:03 pm
content: It would be wise to show a photo here

author: ogden
author_rank: Super Contributor
timestamp: February 13, 2021, 05:54:53 pm
content: Get pointy needle probe tip to punch through coating. For example: Hirchmann PRUEF 2600 C2.

author: BlackICE
author_rank: Regular Contributor
timestamp: February 14, 2021, 11:14:28 pm
content: I think I found a problem with Q15 the VBE is only 0.06v when on instead of about 1.4v.
Tracking preregulator control - Page 1
Forum section: electronics / beginners

author: gigabyte091
author_rank: Contributor
timestamp: October 10, 2015, 05:32:36 am
content: Hi, as a part of my diy variable PSU i bought dc-dc stepdown converter from ebay to act as switching preregulator.Everything is working fine but now i need to set switching regulator output about 3-4V higher than linear postregulator output.At the moment, voltage of switching converter is set by multiturn trimmer with resistance of 10k ohms.
Trail camera repair  - Page 1
Forum section: electronics / beginners

author: Robe
author_rank: Newbie
timestamp: July 12, 2025, 06:59:04 am
content: I have a trail camera which was designed for 6v supply but was accidentally connected to 12v, this of course damaged some parts, the damaged components can be seen in the attached image, I am having trouble finding replacement parts, mainly because I cannot even identify what the damaged components are, if someone can tell me what they are I would be very happy, or better still where they are available, sincerely robe

author: ledtester
author_rank: Super Contributor
timestamp: July 12, 2025, 12:29:26 pm
content: My guess is that U5, U6 and U? are power conversion ICs.U5 and U? are damaged, but U6 seems to be ok.Here's a blowup of U6:Looks like BFC... or maybe 8FC...

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: July 12, 2025, 10:59:40 pm
content: Quote from: ledtester on July 12, 2025, 12:29:26 pmI'd agree, as they all appear to have SMD inductors beside them. Additionally they appear to be SOT23-5/SOT25/TSOP-5/SOT753 package.OP needs to post clearer photos where the codes on the IC's are actually legible.
Transacitor, Transductor, Transactance - Page 1
Forum section: electronics / beginners

author: olsenn
author_rank: Frequent Contributor
timestamp: May 10, 2012, 05:05:09 pm
content: Are there any discrete voltage/current controlled capacitors or inductors? A three terminal device in which the state of one pin affects the rate of change of voltage/current of the other two pins?

author: Kremmen
author_rank: Super Contributor
timestamp: May 10, 2012, 06:33:21 pm
content: A gyrator could perhaps work if this is more a signal processing than a power application.Check e.g.http://mysite.du.edu/~etuttle/electron/elect66.htmto see if that could work for you. The gyrator circuit as such is not controllable by an external signal, but incorporating a variable gain amplifier this could maybe be accomplished.

author: w2aew
author_rank: Super Contributor
timestamp: May 10, 2012, 06:56:56 pm
content: Quote from: olsenn on May 10, 2012, 05:05:09 pmWhile not a 3-terminal device, a varactor diode is a used as a voltage controlled capacitance (over a relatively small range of capacitance).

author: codeboy2k
author_rank: Super Contributor
timestamp: May 11, 2012, 04:10:29 am
content: Siliconix used to make something called a Voltage Controlled Resistor, it's basically a high RDS(on) JFET. These had a resistance curve that was fairly linear, I don't know if it was a result of any special manufacturing process or not.These are old, and I don't think you can buy them anymore, and maybe there is something else available now to replace them. Also, you can probably do exactly the same thing now with any number of off the shelf FETs operating in the triode region.Basically my thought is to control the series resistance before your capacitor or inductor to limit the current and slow the energy transfer. This is no problem at DC but you have to be extra careful with this at frequency, as you'll obviously be creating a filter at anything other than DC. So you'll have to decide what a suitable topology will be for your purpose.If your currents aren't too high, you could also use digital resistors.it certainly would be much better if you could control the overall internal resistances of the two terminal devices
transceiver IC advice needed - Page 1
Forum section: electronics / beginners

author: V_King
author_rank: Regular Contributor
timestamp: July 22, 2015, 11:55:25 pm
content: Hello,I am doing a small project connecting a uC to a vehicle ECU. The communication is using kwp2000 protocol, which is basically a half-duplex bidirectional serial line using only one wire (plus gnd reference and +12v from vehicle battery).There are plenty of CAN to UART transceivers online, but they are working in differential mode, so CANlow goes way below ground. Tried googling for kwp2000 transceivers and could not find anything. So I guess there is a generic solution for it? I don't want to use discretes and wonder if anyone can recommend anything.Thanks

author: oPossum
author_rank: Super Contributor
timestamp: July 23, 2015, 12:13:01 am
content: Quote from: V_King on July 22, 2015, 11:55:25 pmGoooooogle for ISO-9141 transceiver. It is the same physical layer as KWP2000.

author: V_King
author_rank: Regular Contributor
timestamp: July 24, 2015, 06:34:10 am
content: thanks oPossum

author: mikerj
author_rank: Super Contributor
timestamp: July 24, 2015, 07:03:53 am
content: Try searching for "LIN bus driver". LIN bus is an enhanced ISO9141 bus standard and uses the same hardware.
Transfer (mal)function of RL High pass filter - Page 1
Forum section: electronics / beginners

author: Anthocyanina
author_rank: Frequent Contributor
timestamp: May 19, 2021, 11:48:46 pm
content: Today trying to explain to someone how the RL high pass filter worked i got stuck explaining the transfer function. I showed them a simulation of the circuit, and the cutoff frequency was as calculated. just that when explaining the transfer function, when i got to how to calculate the voltage gain, at cutoff frequency i wasn't getting 0.707 but 0.59 with the values of R1=130 ohm, R2 28 ohm, and L 1mH. did i get the transfer function wrong? i don't see where i made a mistake, any help would be great. Thank you!

author: jmw
author_rank: Frequent Contributor
timestamp: May 20, 2021, 04:36:24 am
content: \$H(s)\$ looks right. What are you calling the cutoff frequency? The pole frequency is at \$(R_1 + R_2)/L\$ or 25 kHz, and it is close to -3 dB there (not quite exact since the pole and zero are closer than 1 decade apart).

author: ledtester
author_rank: Super Contributor
timestamp: May 20, 2021, 05:11:30 am
content: What did you get for s?What you have written is correct, but remember that s = jw and you want to solve for themagnitudeof H(s) = 1/sqrt(2).I get a corner frequency of about 24.3 KHz.

author: Anthocyanina
author_rank: Frequent Contributor
timestamp: May 20, 2021, 06:48:08 am
content: Quote from: ledtester on May 20, 2021, 05:11:30 amAhh, of course, thank you! this was my mistake, was not solving for the magnitudeQuote from: jmw on May 20, 2021, 04:36:24 amAnd thank you too! i wasn't taking that into account, two mistakes for the price of one! It's always the very basics that get me
Transfer function - Page 1
Forum section: electronics / beginners

author: m.jayid
author_rank: Newbie
timestamp: April 22, 2021, 04:43:40 pm
content: Hello everyone.Could you please tell me what is the transfer function of this circuit.(please see the attachment)Thanks

author: ledtester
author_rank: Super Contributor
timestamp: April 22, 2021, 06:28:03 pm
content: This web page goes through all of the math in analyzing a differential amplifier:https://www.embeddedrelated.com/showarticle/557.php
Transfer function - Page 1
Forum section: electronics / beginners

author: m.jayid
author_rank: Newbie
timestamp: May 05, 2021, 11:23:34 pm
content: Hi everybody.I am a beginner in electronics.Can you please hep me fin the transfer function (the relation between Vout and Vin), its gain, the cutoff frequency of this amplifier and what is it good for .Thank you very much.

author: ledtester
author_rank: Super Contributor
timestamp: May 05, 2021, 11:53:49 pm
content: This is the same circuit you asked about in this post:https://www.eevblog.com/forum/projects/current-sensor/msg3551696/#msg3551696

author: m.jayid
author_rank: Newbie
timestamp: May 06, 2021, 12:07:52 am
content: Now, I just want the transfer function.Since I did not get yet.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: May 06, 2021, 12:10:49 am
content: Quote from: m.jayid on May 06, 2021, 12:07:52 amFind out:https://www.analog.com/en/design-center/design-tools-and-calculators/ltspice-simulator.html

author: ataradov
author_rank: Super Contributor
timestamp: May 06, 2021, 12:32:30 am
content: This sounds like you want us to do your homework. This is not how it works.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 06, 2021, 12:50:19 am
content: There are two general ways to get the answers you are looking for.The first, as suggested above is to enter it into spice. As a hobbiest or a student this is a skill you should develop if you want understand or use transfer functions.The second way is by hand, and is the only way to get a closed form answer for the transfer function, which is probably what a student is being asked to do. I will give you a couple of hints. It is a non-inverting op amp stage. With some additional shaping. Looking at your class notes or the internet you should be able to take it from there. Remember the rules for connecting components in series and parallel and remember that these are complex impedances, not simple resistances.
Transfer matlab simulink to vhdl and simulate it in modelsim? - Page 1
Forum section: electronics / beginners

author: michelle.k28
author_rank: Newbie
timestamp: July 09, 2019, 08:14:47 am
content: Log cabin quiltsare basically the most versatile piece of bedding you can buy--they are great for adding an excess layer of coziness, also light enough to be used on their own even on a hot summer night when things become cold. Additionally, there are all types of fabric variations on the market, from jersey cotton to velvet, all of which add their comfy vibes. All theseHumpine log cabin quiltsare some of the coziest lavish or something a bit and quilts you can purchase online, whether you're looking for something glam and textured. And if you're more of a big comforter type of individual, do not worry, we've got you covered , too.Click hereto check them yourselves.https://humpine.com/product-category/quilts-blankets/log-cabin/Is there anything Humpine does not have? Utilize the retailer as your one-stop store for all sorts of bedding in many different prices and styles.https://humpine.com/product-category/quilts-blankets/log-cabin/
transfer matlab simulink to vhdl and simulate it in modelsim - Page 1
Forum section: electronics / beginners

author: abbas anwer
author_rank: Newbie
timestamp: December 12, 2018, 07:55:03 pm
content: i have a model for PMSM motor and i want to simulate it in modelsim by using vhdl . i red that hdl coder can be used to transfer he system to vhdl from matlab . but the Question is it to use hdl coder in matlab or we should use it with dsp builder.regards

author: rstofer
author_rank: Super Contributor
timestamp: December 13, 2018, 12:51:13 am
content: I have never used HDL Coder but the sales literature says you can take Simulink models and convert them to HDL for programming an FPGA.I have some Simulink models that look a lot like analog computation (continuous time). I wonder how that will get converted to discrete time. That might be worth buying the add-on.https://www.mathworks.com/products/hdl-coder.html
transfering power between two loads. - Page 1
Forum section: electronics / beginners

author: Madrocker
author_rank: Newbie
timestamp: October 20, 2016, 12:35:00 am
content: Hi, I'm a complete newbie and have a problem I'm sure you guys will find easy.I'm trying to control two pumps with one switch, I simply want pump A running when the switch is on and pump B running when the switch is off.I would assume I'm looking for some sort of relay to transfer 240v AC between two loads decided by the switch being open or closed.I just don't know what I'm looking for hardware wise and any help would be great.Cheers Dave

author: JimRemington
author_rank: Regular Contributor
timestamp: October 20, 2016, 01:08:20 am
content: A heavy duty double pole double throw relay would do the job.Make sure the contact ratings are appropriate for the pumps.

author: Towz
author_rank: Contributor
timestamp: October 20, 2016, 03:41:18 am
content: A single pole double throw relay should do the work, as long as it's correctly rated. Else, you might need a contactor.

author: raphaeltube
author_rank: Contributor
timestamp: October 20, 2016, 12:50:25 pm
content: Why not just go with a mechanical "toggle" (double throw) switch.-as with the relay, it will need to be rated appropriately for the loads (pumps).Perhaps you could post the specs of your pumps/pump motors so we can get an idea of the kind of loads you're dealing with.If they're under 15A or so at mains voltage you should find a readily available mechanical solution.-R

author: Madrocker
author_rank: Newbie
timestamp: October 21, 2016, 09:00:18 pm
content: Thanks for the replies, As for the pumps they are 240vac 38w submersible aquarium pumps.

author: raphaeltube
author_rank: Contributor
timestamp: October 24, 2016, 02:07:41 pm
content: Yip, 38W is bugger-all load (<200mA) from your little pumps, so a simple switch will be yuor best bet.-make sure you get a switch rated for 250V, and any switch rated for 250V will havdle the current.Look for somrthing like this:http://uk.rs-online.com/web/p/toggle-switches/0350254/*Take extra care with insulation (& a large dose of common sense) when working with mains voltage & submersible pumps.-R
Transformer - Page 1
Forum section: electronics / beginners

author: Andy56
author_rank: Newbie
timestamp: February 07, 2020, 05:39:15 pm
content: A transformer has a primary winding of 10 turns and a secondary winding of 100 turns. On the secondary side, the transformer is loaded with an ohmic resistance of 1.2 kohm. To what size is this transformed on the primary side?

author: Benta
author_rank: Super Contributor
timestamp: February 07, 2020, 05:49:46 pm
content: This is not really a free "we do your homework for you" page.

author: Andy56
author_rank: Newbie
timestamp: February 07, 2020, 06:04:26 pm
content: Pls help me with this.

author: ArthurDent
author_rank: Super Contributor
timestamp: February 07, 2020, 06:37:58 pm
content: Think ratio

author: TimFox
author_rank: Super Contributor
timestamp: February 07, 2020, 07:14:34 pm
content: Apply the turns ratio separately (in the appropriate direction) to the voltage and current. Past that is homework left to the student.

author: Vovk_Z
author_rank: Super Contributor
timestamp: February 07, 2020, 07:36:04 pm
content: 12
transformer - Page 1
Forum section: electronics / beginners

author: glinjik
author_rank: Regular Contributor
timestamp: November 29, 2020, 06:20:12 pm
content: hi can someone tell what the purpose of this cap on transformer? is it something like an x2 cap?

author: bob91343
author_rank: Super Contributor
timestamp: November 29, 2020, 10:32:19 pm
content: Just an EMI filter.
transformer  - Page 1
Forum section: electronics / beginners

author: abdullahseba
author_rank: Frequent Contributor
timestamp: May 13, 2014, 08:55:11 am
content: What is the cheapest custom transformer maker in the ukI want a 240v in : 115v 15A/65v 20A out

author: GeoffS
author_rank: Unknown
timestamp: May 13, 2014, 09:08:48 am
content: You might get a quicker answer if you give some details of what sort of transformer you're looking for.

author: SeanB
author_rank: Super Contributor
timestamp: May 13, 2014, 05:31:27 pm
content: You probably could look for a building site transformer, you are looking for a 3kVA unit. These have a 110V secondary that is centre tapped, so will give you the 115V and 65V you need. If you need them isolated from each other you will just have to look for 2 2kVA transformers.Either a new transformer or 2 used units from eBay.
Transformer behavior - Page 1
Forum section: electronics / beginners

author: Shock
author_rank: Super Contributor
timestamp: May 16, 2016, 11:51:26 am
content: Can anyone describe whats causing the flattening of the peaks on the top waveform at about 17:10?

author: Monadnock
author_rank: Contributor
timestamp: May 16, 2016, 12:27:16 pm
content: Current only flows at the peak of the AC sine wave when the caps are charged. The impedance of the transformers is high enough that the voltage drop across this impedance during the charging of the caps causes the top of the AC sine wave to get cut off.

author: Circlotron
author_rank: Super Contributor
timestamp: May 16, 2016, 12:42:18 pm
content: Yep. The transformer has no load on it until it's voltage gets as high as the capacitor voltage. Then it has to work! The transformer voltage still rises a little after this, and during this time it is pulling the capacitor voltage up a little too.

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: May 17, 2016, 12:06:47 am
content: Yes, but only when the load resistor is drawing current. If the load were removed then the sine wave peaks would spring back up and the ripple voltage on the load would disappear. Since no current is drawn by the load then none (or almost none) is delivered by the transformer/rectifier combination to the cap.
Transformer calculation abbreviations question - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: May 15, 2017, 01:48:27 pm
content: In this quotation what do the abbreviations stand for when calculating transformer turns ratios please?"I just use whatever feels right and apply the V < 4.44F.N.A.B absolutely rigorously, keeping B to less than 0.1 usually"Thanks.

author: rstofer
author_rank: Super Contributor
timestamp: May 15, 2017, 02:13:56 pm
content: Google has it:https://www.quora.com/Why-as-frequency-increases-the-size-of-transformer-decreases

author: Andy Watson
author_rank: Super Contributor
timestamp: May 15, 2017, 02:22:09 pm
content: F = frequency.N = number of turns.B = flux density.A = cross-sectional area of core.Note, the formula only applies to sine waves.

author: Chris Wilson
author_rank: Super Contributor
timestamp: May 15, 2017, 02:26:01 pm
content: Thanks Andy and rstofer, that will help greatly!
transformer calculator - Page 1
Forum section: electronics / beginners

author: glinjik
author_rank: Regular Contributor
timestamp: January 08, 2020, 04:16:02 pm
content: Little proggie for transformer calculations made by Silvio Klaic 1999 as far as i can tell its freeware

author: Cliff Matthews
author_rank: Unknown
timestamp: January 09, 2020, 12:18:57 am
content: You should really post links to the original source..VirusTotal shows it doesn't appear infected - Any takers?https://www.virustotal.com/gui/file/3f8a12bd5032935ddaf72c7bd2bd717d2ad32f7d26b64943a192a3e0ac1f63c0/detection

author: Jwillis
author_rank: Super Contributor
timestamp: January 09, 2020, 01:06:40 am
content: I've used it before and didn't find any issues .I believe the site I got it from was this one.https://www.electronics-lab.com/downloads/calculators/?page=4Come to think of it there was an issue that it doesn't take any account for the core material and frequency The one I inevitably use was Xformer Designer which has a field for Flux and frequency.https://www.softpedia.com/get/Science-CAD/Xformer-Designer.shtml
transformer core inductance  - Page 1
Forum section: electronics / beginners

author: electronics man
author_rank: Frequent Contributor
timestamp: July 14, 2015, 05:44:05 pm
content: i have a transformer core with an inductance of 4250nH. how many turns of wire do i need to wind to get this inductance I'm confused?http://www.rapidonline.com/Electronic-Components/4250nH-MagDev-RM10-F48-Ferrite-Core-67-1025

author: IanB
author_rank: Super Contributor
timestamp: July 14, 2015, 05:54:28 pm
content: The inductance factor is 4250 nH, so one turn will give this inductance (L = AL* n2, where ALis the inductance factor, n is the number of turns and L is the inductance).

author: electronics man
author_rank: Frequent Contributor
timestamp: July 14, 2015, 05:58:41 pm
content: ah that makes sense thanks
transformer current capability - Page 1
Forum section: electronics / beginners

author: Cali-Sam
author_rank: Contributor
timestamp: July 18, 2012, 11:24:25 pm
content: is there a way to find out how much current or VA a transformer car supply?i have a transformer with no writing on it. only a primary and a secondary windings. i want to know how much current i can draw before releasing the magic smoke...

author: szhighstar
author_rank: Contributor
timestamp: July 19, 2012, 01:48:47 pm
content: can you advise what type the transformer is and core dimension and work frequency? we can infer the transformer power.

author: digsys
author_rank: Unknown
timestamp: July 19, 2012, 02:11:24 pm
content: We'll need the dimensions and weight if possible. Can you measure the primary resistance (thinner wires)and secondary resistance (heavier wires). This will at least help START to identify it !! Do you have a Variac?or maybe even a signal generator?

author: Cali-Sam
author_rank: Contributor
timestamp: July 23, 2012, 07:49:11 am
content: how will all of these variables be used?is there a kind of equation to be used?i know the basics of transformers, nothing fancy.

author: ejeffrey
author_rank: Super Contributor
timestamp: July 23, 2012, 09:33:34 am
content: You can get a reasonably guess on the VA by measuring the size and weight then looking up catalog transformers of the same core design (EI vs. toroidal). You can use a function generator and a voltmeter to measure the turns ratio.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: July 23, 2012, 10:02:01 am
content: can you measure / estimate the temperature of the inner coils?Then slowly increase until its say 30C above ambient. (this is a guesstimate, you might want to look up a figure if you do it this way)

author: johnwa
author_rank: Frequent Contributor
timestamp: July 23, 2012, 10:26:51 am
content: Quote from: HackedFridgeMagnet on July 23, 2012, 10:02:01 amIt is easy enough to find the temperature rise from the difference in the resistance of the winding when hot and cold, and the temperature coefficient of resistivity. Note that this gives theaveragetemperature rise, so you need to allow a bit of a margin for the maximum "hot spot" temperature.As for what is an allowable temperature, this depends on what the winding insulation is rated to. The lowest is "Class A" insulation which IIRC is 105 degrees C. Of course, you must factor in the ambient temperature as well, which could easily be over 50 degrees inside the case of your widget.
Transformer winding current direction - Page 1
Forum section: electronics / beginners

author: steve13579
author_rank: Newbie
timestamp: June 26, 2015, 07:06:41 pm
content: I decided to look up images of transformers and the current in direction on the primary coil and the induced current direction on the secondary coil. The only problem is the images seemed to contradict each other. Which one is correct? Edit: I can only attach one, the only difference is the other one had a different turns ratio and the current on the secondary is in the other direction. Should I make another post and attach it?

author: dadler
author_rank: Unknown
timestamp: June 26, 2015, 09:24:04 pm
content: https://en.m.wikipedia.org/wiki/Right-hand_rule

author: steve13579
author_rank: Newbie
timestamp: June 26, 2015, 09:37:55 pm
content: I want to make sure I am applying that correctly.https://en.wikipedia.org/wiki/TransformerIf you look on that other wikipedia page there are two pictures of transformers where the core flux is displayed and current direction indicated. They seem to be different and I believe image with the blue and red colors is wrong and the image i attached earlier from that page which is only a gray image is correct. Am I correct in this evaluation?

author: IanB
author_rank: Super Contributor
timestamp: June 26, 2015, 11:25:13 pm
content: I believe the diagram on Wikipedia with the blue and red coils is correct, and the gray image attached to the first post is incorrect.This is because the back EMF will always try to oppose the applied EMF, and therefore the induced current will tend to flow in the opposite direction to the applied current. If the primary current is in a clockwise direction the secondary current will be in an anti-clockwise direction. (But turn direction must always be considered relative to the flux direction in the magnetic loop. Before considering clockwise or anticlockwise one must first be facing in the direction of the magnetic flux.)

author: steve13579
author_rank: Newbie
timestamp: June 26, 2015, 11:35:45 pm
content: I had it backwards, thanks for that! I forgot to think of the secondary as an induced current rather than a supplied one!
Transformer current - Page 1
Forum section: electronics / beginners

author: Jimbz
author_rank: Contributor
timestamp: February 07, 2014, 10:33:10 am
content: Hello all, question:How do you calculate the maximum current able to draw in a transformer primary without getting voltage drop ? I assume this has to do with the amount of windings, the more windings, the greater the power you can carry on to the secondary.What is the exact maths behind it ?

author: fcb
author_rank: Super Contributor
timestamp: February 07, 2014, 10:36:06 am
content: Ohms Law basically.You'll always get some drop with ANY load, you need to define how much of a drop is acceptable.

author: Psi
author_rank: Super Contributor
timestamp: February 07, 2014, 10:41:43 am
content: If you have no specs on a 50/60Hz transformer and it's a simple Primary:Secondary arrangement then the quickest way to get an approximate max current is to use the core size to estimate power, then you can get current from P/V.Note: If the transformer has multiple winding then knowing the total power doesn't really help. You could have one thick high current secondary winding plus one thin low current secondary winding.

author: digsys
author_rank: Unknown
timestamp: February 07, 2014, 11:13:12 am
content: And there waaaaay more involved. You have to calculate temperature rise at max load, usually max at 75C-85C, which also dependsto excitation current and saturation (1.5-1.6 Tesla, 1.7+ is pushing it).

author: Jimbz
author_rank: Contributor
timestamp: February 07, 2014, 12:56:36 pm
content: The power is dependant on the core cross section ? We can have say a single winding on the primary with a 4 inch core and it can give us 500 watts without any issues ?

author: IanB
author_rank: Super Contributor
timestamp: February 07, 2014, 03:12:56 pm
content: Quote from: Jimbz on February 07, 2014, 12:56:36 pmThis will be true as a rule of thumb, but it assumes that the rest of the transformer is properly designed as well (right number of windings, right flux density, right window area, right primary and secondary wire gauge, and so on...).
Transformer datasheet question - Page 1
Forum section: electronics / beginners

author: WillHuang
author_rank: Contributor
timestamp: July 15, 2016, 05:27:09 pm
content: Datasheet:http://catalog.triadmagnetics.com/Asset/TCT50-03E07K.pdfIt mentions at the input: (Fuse: 0.500A Max). Does this mean that the recommended fuse should be rated for 500 mA? Also, is this specified as 500mA rms?

author: pelule
author_rank: Frequent Contributor
timestamp: July 15, 2016, 08:30:21 pm
content: It means: the fuse should selected with max. value of 500mA.It's a 50VA transfomer, means nominal ~416 mA @ 120V.That fits to the 500mA.BRPeLuLe

author: uncle_bob
author_rank: Unknown
timestamp: July 15, 2016, 11:28:58 pm
content: HiHow much current will you be pulling from the transformer?What will the load on the transformer look like?Does a slow blow fuse create other regulatory issues for you?Lots of variables.Bob
Transformer doesn't ring... - Page 1
Forum section: electronics / beginners

author: IvoS
author_rank: Frequent Contributor
timestamp: June 04, 2015, 08:03:44 pm
content: I have this test jig called "Quasimodo" that is used to find proper RC+C snubber combination values for power transformer. Actually, it helps to find the RC combination "resistor" value fro two snubber capacitors which are given values of 10nF and 150nF. I tried that on few transformers and it works beautifully. All transformers will ring using this test jig.more about the jig over here:http://www.diyaudio.com/forums/power-supplies/243100-simple-no-math-transformer-snubber-using-quasimodo-test-jig.htmlNow, WITHOUT THE SNUBBER, using 300VA toroidal transformer from Plitron, rectified one side of secondaries and added a 2200M filter cap. Using my electronic load or simple large power resistor, I don't see any ringing on my scope. When I load it with lets say 0.4A, I get nice ripples around 1vpp, but no ringing when diodes switch OFF. I probed the rectified secondary, also probed the AC straight from the transformer and all diodes one by one. No ringing observed!! According to theory, the transformer should ring more or less no matter what as the voltage goes down and diodes turn OFF. I tried regular slow diodes as well as fast schottky diodes for rectifier but got nothing. How come the transformer doesn't ring? Any ideas?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 04, 2015, 08:27:44 pm
content: That looks like a *lot* of hardware to go through, when one measurement and one equation is all you need... I guess you *really* hate math.Offhand, I would guess the toroid has less leakage than others, or a lower transmission line equivalent impedance. Have your other tests used only shell type transformers, or does that include other toroids?Tim

author: IvoS
author_rank: Frequent Contributor
timestamp: June 04, 2015, 09:55:53 pm
content: Other smaller 15VA toroid from Plitron didn't ring either. They all ring when I put them on test jig, but they don't ring without a snubber when loaded. I tried only these Plitron toroids without snubber so far.
Transformer - Dual Primary Parallel connection - Page 1
Forum section: electronics / beginners

author: anishkgt
author_rank: Frequent Contributor
timestamp: December 06, 2016, 09:40:45 pm
content: Just ordered one of these PCB Transformer from Blockhttp://www.farnell.com/datasheets/1821919.pdf?_ga=1.149693054.998134959.1479939742Is it required to connect the dual primary pins in parallel when using 120VAC ? I can see TRIAD suggests to do so. What are the advantages and disadvantage of doing so ?My schematic is here, I was plaing to using jumpers to choose between 115 & 230VAC.

author: helius
author_rank: Super Contributor
timestamp: December 06, 2016, 09:59:06 pm
content: The advantage to it is that the transformer can handle as much power with 120V as with 240V, by drawing twice the primary current. This is limited by core saturation, of course, but a dual-voltage transformer should be designed to handle it.The disadvantages are the more complicated voltage switch arrangement required, and the risk that the primaries could get wired with incorrect phasing.

author: anishkgt
author_rank: Frequent Contributor
timestamp: December 06, 2016, 10:05:24 pm
content: Wanted to know if the wiring correct. The block brand does not have it mentioned l so a bit confused.Sent from my iPhone using Tapatalk

author: Benta
author_rank: Super Contributor
timestamp: December 06, 2016, 10:36:59 pm
content: If the transformer "polarity dots" on your schematic are right, then your wiring of the primaries is correct.Transformers nowadays are highly optimized with regards to copper and iron content.The reason for wiring the primaries in parallel at 120 V is to reduce copper losses due to resistance (=heat) when the transformer is fully loaded.Saturation current has nothing to do with this.

author: Seekonk
author_rank: Super Contributor
timestamp: December 06, 2016, 10:51:23 pm
content: You can use a small wattage lamp in series with primary power for your first. If you wired either the primary or secondary out of phase, it will save your transformer.
Transformer fabrication - Proven Winding Calculator/Software?  - Page 1
Forum section: electronics / beginners

author: Mecanix
author_rank: Frequent Contributor
timestamp: September 09, 2021, 10:39:47 pm
content: Just found out I have to make my own transformer for an off-line/high-freq SMPS I'm hoping to design and learn from (hopefully before getting zapped to my death with 220VAC). Making my own is not a problem hardware-wise, seems we have access to pretty much the whole hardware via eStores (cores, bobbins, mylar, etc etc). What I completely lack of is confidence (knowledge?) in manually calculating wire and sizes, ferrite core shapes and everything else relevant to the great science of transformation, electrons and magnetism...So ranting aside; can someone (please) recommend a software toolkit that offers these calculations?Thanks

author: Jwillis
author_rank: Super Contributor
timestamp: September 10, 2021, 12:25:12 am
content: A couple I use areXformer Designerdesigner andEI Series Transformer CalculationBoth simple to use and fairly accurate . The downloads are free and safe .Other online calculator I some times use isCoil and transformer calculatorwhich is more complex requiring more accurate information .

author: Mecanix
author_rank: Frequent Contributor
timestamp: September 10, 2021, 01:20:30 am
content: Sweet, thanks JWillis. Fairly accurate is good enough-of-a-start for meSeen this? Although never seen, used, nor recommend a.k.a *use at your own risk*https://www.poweresim.com/index2.jsp?topologytype=68&deduct=169&InitNow=T&pc=99309ps. one day I'll get down to the physics and math, promise :/edit: Rather....https://www.poweresim.com/Xformer/Select_Application_Front_Page.jsp?default=T&designator=XF1&pc=1439

author: Jwillis
author_rank: Super Contributor
timestamp: September 10, 2021, 01:32:03 am
content: Simulators and me don't seem to get along .

author: Mecanix
author_rank: Frequent Contributor
timestamp: September 10, 2021, 01:46:25 am
content: Good old Casio Scientific Calculator wins worlds!! Can see a week or two of 'theories' though... so that sim comes quite handy in the sense that it will get me a flyback TR on the benchtop in time for when the PCB and components will arrive. Copper wires and Dbl'ed the order of fuses lol

author: Mecanix
author_rank: Frequent Contributor
timestamp: September 12, 2021, 02:05:46 pm
content: Just a follow-up on the progress and the solution I've settled with. Not a huge fan of promoting anyone's products being clueless about all fronts (I'm sure they are the good guys lol) but I have to say that the application provided by power.com made it happen for a beginner; from schematics, BOM, to the manual fabrication of the magnetics... it just works!!!Serious Plug & Play stuff...
Transformer for an SMPS - Page 1
Forum section: electronics / beginners

author: JKKDev
author_rank: Regular Contributor
timestamp: April 17, 2020, 09:28:46 am
content: Hey guys,I'm working on a PCB to drive a mains motor by turning on an SSR (there's more to it but that's the gist of it).I would like to use the mains coming into the board to also power the logic on it. I've decided that 5V 1A SMPS should be more than enough for all of it.The only difficulty I've got currently is figuring out what transformer to use. I know I need a flyback type and I need one that can supply the 5V 1A output (in reality I'm not expecting anything more than 300mA so this should be more than enough).I'm thinking of usingthis, but I'm not sure if 5V output from the transformer is ok for my requirements. I saw some schematics that used 9V output transformer or even more for a 5V SMPS. Is there a reason for this or is the one I selected just fine? I'll probably use LNK3204 as the switcher IC.I'm thinking of usingthisconfiguration for the SMPS.Any thoughts or concerns are very welcome.Have a nice day

author: Zero999
author_rank: Super Contributor
timestamp: April 17, 2020, 11:35:36 am
content: Why not just use an off the shelf power supply? A mains powered, switched mode power supply is not a project for a beginner and even most professional engineers would simply opt for an off the shelf solution, unless their requirements were very niche but 5V@1A is really common. I appreciate this might not be the most fun solution, but it's normally the most cost effective and safest.

author: wraper
author_rank: Unknown
timestamp: April 17, 2020, 11:43:41 am
content: Yeah, these days it makes little sense to build your own SMPS unless you need something very specific. For example you could solder such SMPS module onto your PCB.https://www.tme.eu/en/details/mfm-05-5/open-frame-power-supplies/mean-well/Also It's a big safety concern, and must be done properly, and preferably Hi-Pot tested to ensure safety.

author: Circlotron
author_rank: Super Contributor
timestamp: April 17, 2020, 12:47:00 pm
content: The transformer the OP is thinking of using is $6.51The suggestedcompletePSU is $7.40End of story.

author: foobie
author_rank: Newbie
timestamp: April 18, 2020, 09:51:35 am
content: I believe, unless you have the stability analysis, these schematics are mostly toys.For instance, how did you figured the value of C8, the integrator?What is the CTR for U2 and how does it relate to the missing resistor at pin 3?
transformer for lab power supply - Page 1
Forum section: electronics / beginners

author: glinjik
author_rank: Regular Contributor
timestamp: December 16, 2019, 01:28:08 pm
content: i got hold of this power stabaliser and was wondering on thoughts of the two transformers no idea what amps they are capable of but on the small one left side puts out 32v and second 62v the windings are together about 92 v the right hand side one about 46v looks like a single winding and the big roud thing is a filter i think it works ok hell of a buzzing noise though it comes from when the power was unstable here everyone had them output is 222.6 vac power from grid is 236 but wavering a bit this device is a very steady voltage output although i only powered it up for a short time got my eye on that big cap dont wanna fry again

author: glinjik
author_rank: Regular Contributor
timestamp: December 16, 2019, 01:40:44 pm
content: or maybe it would be better to keep it as a stabalised power supply and feed my bench supply from it ?

author: SeanB
author_rank: Super Contributor
timestamp: December 16, 2019, 06:50:45 pm
content: Keep it as a stabilised power supply for the bench. might be isolated, might not, depends on the design, and watch out for that capacitor winding, it will run at anything from 100-600VAC across it, and will bite. If it fails replace with the exact value.

author: glinjik
author_rank: Regular Contributor
timestamp: December 16, 2019, 08:58:09 pm
content: hi thank you for your reply although tempting to take the transformers you are right i will leave it in tact i did a few more tests and watched th output in comparison with mains supply it is very stable whilst mains fluctuates 2-3 volts it seems to be built rock solid vey clean copper on the trasformers and that big filter cap is only like 16mf 250v +-10% i measured the esr @ 0.1so its still good made in 1992 does buzz though need to put it at the other end of my play pen

author: Jwillis
author_rank: Super Contributor
timestamp: December 17, 2019, 12:40:21 am
content: Ferroresonant transformer Or Constant Voltage Transformer (CVT) Will buzz or hum ,thats normal.Resonant LC circuit inside makes them hum.That's what the cap is for.

author: t1d
author_rank: Super Contributor
timestamp: December 17, 2019, 01:10:47 am
content: Quote from: glinjik on December 16, 2019, 01:28:08 pmYou got hold of it, or it got hold of you?How are you going to clean it? Looks like a good find, though...

author: glinjik
author_rank: Regular Contributor
timestamp: December 17, 2019, 02:00:52 am
content: its not getting hold of me lol keeping y fingers well away when its powered up. but seriously they are 10 a penny here i stripped a smaller version down a while ago to use the case
Transformer for my JBL active subwoofer SCS140BK/230 - Page 1
Forum section: electronics / beginners

author: etexkathir
author_rank: Newbie
timestamp: January 28, 2021, 07:00:24 pm
content: I have failure transformer from transtec make(JBL active subwoofer).No name plate about secondary voltage and amps.it has 230VAC input and five wires output.service manual circuit end termination shows +15V,-15V,Gnd,+Vsw,-Vsw.I need to buy new one.if anybody having idea about secondary voltage with amps rating pl be post it.