hybridfree/eevblog-posts huggingface dataset:
most performant high-side driver for boost converter - Page 1
Forum section: electronics / projects

author: vectorotter
author_rank: Contributor
timestamp: June 24, 2024, 01:24:38 am
content: I want to use an nmos in place of the diode in an off-line boost converter that will ultimately be used as PFC for a subsequent buck converter stage.I have foundhttps://www.ti.com/lit/pdf/slua618which I think should cover what I'm looking for but I am way out of my depth.I created a boostrap variety of circuit (see attached) which I think would work in a rather lower voltage situation as I think the two drive fets get exposed V_DS-wise to the resulting 400V output.I have attached the embryonic power stage schematic.Is the expensive but best way of doing this via transformers or opto-isolators? I don't want to use a hih-side driver IC as it's a learning exercise and I want to understand fully what is going on.Thanks for any pointers in advance.And before anyone flames, I am building a test rig to feed the thing 12 or 24vac to scale things down while I'm developing it !
Most quiet low ripple power supply architecture? - Page 1
Forum section: electronics / projects

author: 001
author_rank: Super Contributor
timestamp: October 24, 2017, 04:03:02 am
content: I`m looking most quiet / low ripple switching power supply architecture to power up my lab: signal generator, bench multimeters and other projects.Can anybody help me with proper guidelines and/or design manuals?Thanx!

author: frog
author_rank: Contributor
timestamp: October 24, 2017, 04:24:42 am
content: A DC supply? I think that the devices themselves would introduce noise onto the supply so you might consider providing an individual supply per device. But I'd guess most of these devices are AC powered, so perhaps I've misunderstood the question.

author: 001
author_rank: Super Contributor
timestamp: October 24, 2017, 04:40:37 am
content: What type of switching supply have lowest ripple and hum? I mean flyback/halfbridge/fullbridge etc

author: David Hess
author_rank: Super Contributor
timestamp: October 24, 2017, 04:43:31 am
content: Do you mean for offline AC to DC conversion or for low voltage DC to DC conversion?Soft switching power supplies like resonate switching power supplies and sine or saturable inverters (1) are inherently lower noise. Linear Technology makes some switching regulators controllers which include adjustable voltage and current slew rates for lower noise. Check out Linear Technology application note 70 for a discussion of this; it also discusses the half-bridge resonate switching power supplies Tektronix used and their advantages.(1) Saturable inverters are low noise when a separate smaller saturating transformer is used to drive the inverter transistors. Tektronix made great use of this in their early 22xx series oscilloscopes.

author: BravoV
author_rank: Super Contributor
timestamp: October 24, 2017, 05:34:45 am
content: Quote from: 001 on October 24, 2017, 04:03:02 amThis thread is not going anywhere before you define your requirement 1st in numbers.How quite is quite according to you ? Put out a number, not just it "feels" quite.How much "low" ripple do you need ? Whats the ripple number you're expecting at what kind of load ?Answer these, hopefully you will get the aid you need.Other wise people will jump in here with different ideas according to themself on what YOU NEED.
Most reliable and compatible bluetooth serial link - Page 1
Forum section: electronics / projects

author: Hobgoblin612
author_rank: Contributor
timestamp: February 04, 2025, 11:54:52 am
content: Hi, I'm updating a design that used a RN-41 module for a serial bluetooth link.https://dlnmh9ip6v2uc.cloudfront.net/datasheets/Wireless/Bluetooth/Bluetooth-RN-41-DS.pdfBack then bluetooth was much simpler and I'm finding it hard to grasp the new standards, does bluetooth LE have a no-driver serial port class like classic bluetooth?What I need is a reliable, compatible, low baud rate (usually 9600) and long-ish range serial link that just works on old and new devices with no drivers, to be used mainly on windows but also possibly android and iOS.This can either be a dedicated module or a microcontroller with bluetooth and a well established bluetooth stack and library, in the latter case I would integrate the rest of the functionality into this micro as well.Classic bluetooth had class 1 and 2 and I was happy using class 1 as it meant the user could walk away a bit and come back without worrying about it disconnecting.Realistically I'm aiming for a real world LOS range of 50m. It seems that the newer standards don't specify power and range depends on the individual radio and antenna.I would prefer a module with a built in antenna for regulatory reasons, weather that be a dedicated module with a uart interface or a microcontroller module like an esp32.There are so many options out there but its hard to know how compatible they are and how easy they are to get up and running.Anyone's experience is greatly appreciated.Thanks,Tim.

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: February 04, 2025, 03:23:03 pm
content: Since RN-41 is no longer available, ESP32 will be the most reliable option.

author: Benta
author_rank: Super Contributor
timestamp: February 04, 2025, 06:19:43 pm
content: Why not just choose the HC-05 module?Produced millions of times and available all over the world.Integrated antenna, SPP.

author: Hobgoblin612
author_rank: Contributor
timestamp: February 05, 2025, 02:05:27 am
content: There are some esp32s that support classic and LE, are there libraries that support serial over both that works without drivers.The HC-05 is only 10m and is only Bluetooth classic, how common is Bluetooth classic support in newer devices?

author: Andy Chee
author_rank: Super Contributor
timestamp: February 05, 2025, 07:03:58 am
content: This might be one way to get serial over BLEhttps://github.com/Jakeler/ble-serial

author: mark03
author_rank: Frequent Contributor
timestamp: February 06, 2025, 03:58:17 am
content: Quote from: Andy Chee on February 05, 2025, 07:03:58 amEh, I only glanced at this but it seems to build on top of "characteristics" (GATT)---an ugly hack from the olden days. Now that L2CAP "connection oriented channels" are widely supported, that is surely the way to go? But I haven't looked at this lately.
Most simplistic time delay On/Off switch circuit example - Page 1
Forum section: electronics / projects

author: Mecanix
author_rank: Frequent Contributor
timestamp: September 03, 2020, 12:50:20 pm
content: C19 legally allows me to spend time on the breadboard at home and that's what I'm doing today!!!Finished a simple On/Off switch using a 555; it switches up a high-side gate driver and a N-ch mosfet and that all feeds a LDO from an external supply. Fairly happy with this primitive idea although I'd like to add a time delay to the button ON and OFF presses. Sort of mimicking a mobile phone powering on & off button 2~3sec delay sequence thingy...Any ICs that does just that? Might be keywording this improperly in google I haven't found any, or does this need to be achieved with e.g. RC circuitry or anything else?Anyone of you kind, generous and handsome EE engineers care to share a functional circuit of a Press ON/Off delayed switch? I'll donate a liver and half a kidney in exchange for the generosity...ps. I understand this should go in the 'Beginner' section of the forum, pushing/abusing the privileges here, sorry ab that!

author: Ian.M
author_rank: Super Contributor
timestamp: September 03, 2020, 01:46:23 pm
content: I *ASS*U*ME* you mean apart from a PIC10F, an ATtiny, or $0.04 Paduak MCU or similar running custom firmware?

author: Mecanix
author_rank: Frequent Contributor
timestamp: September 03, 2020, 02:03:36 pm
content: Had to google "Paduak", please refrain next time lolNo. Just trying to put up the simplest switch you can possibly put together, with an option to tap from an external supply shall it eventually require large'r current. Just drawn what I have on the breadboard... which works fine as a 'binary style' ON/OFF switch however I'm clueless as to how its engineered in e.g. mobile phones and other portable devices that requires time-delay.I bet there are tons of ICs that does the very same as per att circuit, just wanted to hear from you guys, how its done. No MCU or other Paduak, yet...edit: "toggle" switch, momentary sw, rather...

author: Peabody
author_rank: Super Contributor
timestamp: September 03, 2020, 02:47:51 pm
content: Of course you meant a kidney and half a liver.

author: Mecanix
author_rank: Frequent Contributor
timestamp: September 03, 2020, 03:00:20 pm
content: Quote from: Peabody on September 03, 2020, 02:47:51 pmStill trying to gauge the humor level of EEs, easier in the ME world... there is just none of that lolLet me know if the offer is enough, or not. In exchange for the Ultimate Toggle Delayed Switch I'd do anything today
Mostly manual PCB cad recommendation please - Page 1
Forum section: electronics / projects

author: tkamiya
author_rank: Super Contributor
timestamp: February 06, 2020, 10:55:00 pm
content: Are there any PCB cad software that lets me manually place rounds and vias and hand-route traces? I only need simple 2 layer boards. I do not need any auto-routing capability or capturing circuit diagrams. My ideal candidate would be 2 layer board, 10cm x 10cm or larger, grid line on display, manual placement of rounds and specify size of holes, then manually route traces, and create ground pours. The end result should be a gerber file that I can send to manufacturing.PLEASE - no argument as to why and such-and-such method is better. I have my reasons which I am not willing to share in public forums. (I'm not trying to be rude, please do understand)

author: ve7xen
author_rank: Super Contributor
timestamp: February 06, 2020, 10:56:43 pm
content: I think most ECAD software should be able to handle this. You might need to turn off some automatic ERC checks / push and shove and such but it shouldn't be that hard. It's not like I've tried, of course, but I believe this should be doable in KiCad if you peruse the options and disable the stuff that prevents you from joining dissimilar nets.

author: thinkfat
author_rank: Unknown
timestamp: February 06, 2020, 11:03:00 pm
content: Quote from: ve7xen on February 06, 2020, 10:56:43 pmI'm not sure if KiCad will pour copper fills that are not connected to any net.

author: ejeffrey
author_rank: Super Contributor
timestamp: February 06, 2020, 11:09:47 pm
content: In my experience most eda cad tools can do this but it is more trouble than it is worth. Using AutoCAD or some other generic 2D cad tool might be easier. I gave up and usually just create a dummy schematic.

author: markce
author_rank: Regular Contributor
timestamp: February 06, 2020, 11:20:28 pm
content: I use the Sprint-Layout tool from Abacom for this.It is cheap and very easy to use. Good for small projects and hobby use.You can download a trial copy from:https://www.electronic-software-shop.com/

author: ve7xen
author_rank: Super Contributor
timestamp: February 06, 2020, 11:30:16 pm
content: Quote from: thinkfat on February 06, 2020, 11:03:00 pmIt can, there's a no-net option in the pour settings.It actually seems like you don't really need to disable anything or do much fiddling around to make it work as OP is requesting. Without a netlist loaded it pretty much seems to let you do whatever you want.

author: MarkF
author_rank: Super Contributor
timestamp: February 07, 2020, 12:43:48 am
content: I have probably laid out half of my PCBs without a schematic.Even some fairly complex boards.I agree that most if not all CAD tools should be able to do this.My software of choice has beenDipTracefor many years.Their free version is limited to 2 layers and 300 pins. (Not PCB size).Quick and easy to learn.
MOT at higher frequencies - Page 1
Forum section: electronics / projects

author: sonnytiger
author_rank: Frequent Contributor
timestamp: July 31, 2013, 03:39:22 am
content: I have a brushless DC motor that I found that would work well as a generator. Problem is it makes tons of amps at low voltage. So I thought of rewiring a MOT to operate as a step up transformer. All good so far, however the AC outputted by the generator would, depending on speed, be up 300Hz. How this would work with a mains transformer I wasn't sure, but based on my understandings of transformers, it should fare better than doing the opposite, so I tried running a simulation in LTSpice:This gave these results:The top one is 60Hz, and the bottom one is 240HzThis seems almost too good, and I realized that LTSpice didn't have a parameter in the values for the inductors to allow me to specify anything to do with saturation. This doesn't seem important however as at higher frequencies there would be less current and therefore less flux.Any ideas as to how the transformer would behave?

author: Odysseus
author_rank: Regular Contributor
timestamp: July 31, 2013, 04:19:08 am
content: LTSpice does actually allow you to simulate an inductor with a non-linear core material, and it's documented in the help file. If this is then coupled into an ideal transformer, then it's quite feasible to simulate the core losses due to saturation in the B-H loop, assuming you know the parameters of your core, which is unfortunately unlikely. Maybe you can hunt around on the net to get some good estimates.I've attached a zip of a LTSpice simulation of such a transformer. Notice that I've specified the turns squared for the ideal windings.However, this doesn't really help you answer your question, since this only models losses due to excursions through the hysteretic B-H loop. It does not help you model phenomenon like self capacitance, eddy currents, skin effect, or proximity effect, which get worst with increasing frequency.I imagine eddy currents in the steel laminations will be the biggest thing to watch out for. It might be possible to simulate this with a shorted turn or something.

author: sonnytiger
author_rank: Frequent Contributor
timestamp: July 31, 2013, 03:00:32 pm
content: Quote from: Odysseus on July 31, 2013, 04:19:08 amThanks for the input! I figured the only way to find out stuff would be to just try it haha, it seems transformers don't like to behave the way they are calculated to behave.
Motherboard Repair ASUS P5W DH DELUXE - Page 1
Forum section: electronics / projects

author: krisztian_andre
author_rank: Newbie
timestamp: April 18, 2015, 06:27:52 pm
content: Started repairing this motherboard I recently bought broken and one of the components has a burnt hole in it. it's one of the four sot223 like(I didn't recognize the package, it has 3 pins plus a tab measuring 4.6x2.5mm) packages on the picture, it has AE RZ written on it in capital letters and nothing else. Maybe you can help me identify this component from the layout or maybe you can recommend a way to identify if it's an LDO or something else by testing it out of circuit.

author: kjs
author_rank: Regular Contributor
timestamp: April 19, 2015, 05:21:51 am
content: that's an SOT89 package from the looks. Can't help you with the rest, sorry.Edit: the capacitor on the right bottom side looks like the top is buckled up. Unfortunately well out of focus but I would check. If that's the case it is toast.

author: krisztian_andre
author_rank: Newbie
timestamp: April 19, 2015, 08:13:43 am
content: The two QFNs that on the photo are marvell 88E8053-NNC1 gigabit ethernet controllers, I suspect the parts in question are associaterd with them. There cans are 25Mhz oscillators if I'm not mistaken.

author: bktemp
author_rank: Super Contributor
timestamp: April 19, 2015, 08:52:32 am
content: Looks like it is beeing part of a voltage regulator (big 1206 cap next to each SOT89).AE marking gives BCX52: PNP transistorIf it is used as a voltage regulator then the marvell chip is probably also dead.

author: krisztian_andre
author_rank: Newbie
timestamp: April 19, 2015, 10:20:30 am
content: The PSU takes 12.5W at standby measured at the line. the sot89s measure between their middle and left and between their middle and right pins in this order: lower left0,3.21 upper left(the popped one)0.54,3.22 lower right0.7,3.18 upper right0.78,3.18 The right marvell chip gets too hot to touch, the left one is slightly warmer than the other chips on the board. The PSU is rated at 10W on 5VSB.

author: krisztian_andre
author_rank: Newbie
timestamp: April 19, 2015, 08:09:10 pm
content: I desoldered the 4 transistors, no change. Can I desolder a qfn without hot air?
Moto E6 mysterious signal on test point - Page 1
Forum section: electronics / projects

author: Renate
author_rank: Super Contributor
timestamp: May 11, 2021, 05:49:42 pm
content: If you take off just the back cover of a Moto E6 phone most of the electronics is still covered.But there are five little holes with a contact on the bottom.Three of these test points measure ground, at least when I looked at them.Two of them have this strange 4 level signal at a 2.5 V logic level.The rate of the 12 pulses is 150 kHz.The repetition of the chunks is 3 kHz.What the heck is this?(This is while the phone is operating normally.)

author: ConKbot
author_rank: Super Contributor
timestamp: May 12, 2021, 09:04:25 pm
content: My first instinct was poor probe technique, but the signal isn't extending below the 0V level so, grounding may not the the cause here. The peak and fall to a lower level looks like pre-emphasis but that is a lot of premphasis for a low frequency signal, so probably not for a wired signal. 150Khz is awfully close 156Khz that some RFID operates at. Is there an antenna in the back cover of the phone with contacts to reach these pads?

author: Renate
author_rank: Super Contributor
timestamp: May 12, 2021, 11:14:57 pm
content: Quote from: ConKbot on May 12, 2021, 09:04:25 pmNope, but that's a good guess.The back cover is plain plastic. It would have to have needles to interact with these points.There's no charcoal gray stickers or gold contacts or anything.I certainly looks like some kind of sync signals, there's never any data on it.If we call the levels 3, 2, 1, 0, then 3 and 0 although they kind of look like preemphasis are distinct levels.If it were something RF-ish, why would it idle at level 2 at the end of the burst before going to level 0?
Motor and Motor Controller  - Page 1
Forum section: electronics / projects

author: aalavi
author_rank: Newbie
timestamp: September 04, 2012, 12:49:54 am
content: Hello all,I received two motors and a driver (looks like a PLC i guess) for almost free from an old Ex-Nortel employee who needed to clean up his basement to rent out. I was hoping to receive some ideas as to what you would do with them and how u would utilize them for a hobby/home project. Here are the parts:Oriental Motor M540-201 (Speed Control Motor)Permanent Magnet Servo Motor (R505-1621)Super Vexta U1215GA Intelligent DriverI have no document / manual for either. Any ideas or helps would be much appreciated.These are some photos of partshttp://img826.imageshack.us/img826/7082/20120903200602.jpghttp://img152.imageshack.us/img152/479/20120903200644.jpghttp://img6.imageshack.us/img6/7669/20120903200816.jpghttp://img208.imageshack.us/img208/1436/20120903200858.jpgCheers,AA

author: amyk
author_rank: Super Contributor
timestamp: September 04, 2012, 08:26:51 am
content: Not sure about the second one, but I think the first motor is intended to be used with the speed controller for a variable-speed drive.Here's their product page:http://www.orientalmotor.com.sg/products/sc/

author: Rerouter
author_rank: Super Contributor
timestamp: September 04, 2012, 08:57:27 am
content: http://stevenengineering.com/Tech_Support/ORIENTAL_MOTOR.htmthere you goedit: just hope its not a chopper type variable speed controller, those things inject crud loads of noise back down your ac mains,

author: aalavi
author_rank: Newbie
timestamp: September 04, 2012, 03:45:56 pm
content: Thanks guys! I will go through the two recommended sites to see if I can get an idea of how to work with these motors.If I may, how would you get started with utilizing this motor? The 1st motor has 6 wires. I think 1st two are AC 110V to mains, the other 4 are control wires. Would u use an off the shelf motor driver or would u make ur own driver for it?Thanks a bunch!

author: G7PSK
author_rank: Super Contributor
timestamp: September 04, 2012, 05:30:04 pm
content: Sell them on ebay, a wind power fanatic will snap them up.

author: aalavi
author_rank: Newbie
timestamp: September 04, 2012, 06:22:33 pm
content: I could probably count "sell on e-Bay" as a "use" for these parts. Thanks for the comment though.I am really interested in learning how to use motors in general. I just hope i can get a hint on how to get started with these two parts.Thank you,AA
Motor control: Mixing 48V and 5V on same PCB - Page 1
Forum section: electronics / projects

author: timbos
author_rank: Contributor
timestamp: March 17, 2011, 12:59:48 pm
content: Hi,I'm making a little PCB to control a motor which needs 48VDC to power it. The application is to connect to a little motion stage that I'm making as a hobby machine. I've got to get power and data to the motor, so was going to use a ribbon cable to handle the bending and accommodate the motion of the axis.Now, I'm a little bit worried about putting the 48V supply on the same PCB as the 5V supply, microcontroller and other electronics because I don't want to fry anything by mistake.What is considered good practice in this case? Is it OK to mix voltage levels on the same board, and is there something that I can use to protect the chips incase something goes wrong? I've separated the ground planes for the two supplies, apart from a small cross-link next to the 5V regulator.Thanks!

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 17, 2011, 01:08:37 pm
content: No problem as long as proper clearance is maintained.

author: scrat
author_rank: Frequent Contributor
timestamp: March 17, 2011, 02:05:02 pm
content: As an added safety you can put clamping diodes (zener or supply-ground) at all the interfaces between the two "subsystems".Pay attention at ground, since maybe some relatively fast changing signals must cross the boundary between the two ground portions (as Dave says, ground is "guilty until proven innocent").
Motor control using TRIAC - Page 1
Forum section: electronics / projects

author: danjenkins
author_rank: Contributor
timestamp: January 05, 2019, 05:57:04 am
content: Can I control the speed of a single phase AC motor by using TRIAC? Is it possible to trigger the TRIAC gate using PWM pulse?The motor in question is a Leeson.https://www.regalbeloit.com/Products/Catalog?model=103783.00Or is a variable frequency controller like the following a better option?https://www.valinonline.com/products/esv251n01sxb

author: beanflying
author_rank: Super Contributor
timestamp: January 05, 2019, 08:37:50 am
content: Yes but no and it dependsWhat is your use for the single phase motor?Permanent Capacitor motors don't develop much starting torque and in particular if you are trying to start with any speed control you are asking to stall it and cause you some issues.The VFD you linked to is 3 phase output you can get single phase VFD's and they are compatible with permanent Cap motors such as you have or intend using. High Turndown rates on single phase motors also have some heating among other issues. So what range do you need?Triac control of motors sucks period power factor, heat, poor regulation but it is cheap.If you don't have the motor yet seriously consider three phase or DC.

author: Zero999
author_rank: Super Contributor
timestamp: January 05, 2019, 06:02:51 pm
content: It depends on the motor and the load.If it's a load which doesn't need a high starting torque, such as a fan, it will work perfectly, but don't use PWM, use phase control. PWM using a TRIAC would need a lower frequency, than the mains, which would just cause vibration, the current being drawn in huge spikes and overheating.If it's something which requires a lot of torque, then you need a variable frequency drive.
Motor control - Page 1
Forum section: electronics / projects

author: Ramila
author_rank: Newbie
timestamp: September 28, 2018, 11:58:14 am
content: Hi,I'm making a small drone with 8*16mm coreless 3.7v motors. It controls by a node mcu (A development bored with wifi). When controling the speed of motors nodemcu's output signal ranges from 0v to 3.3v then the supply to a motor should be range from 0v to 3.7v at 2A (may be less but I want to be secure) current (for a one motor).I used one d313 transistor (only transistor) with my 3.7v battery then at highest speed it gives output of 2.5v or less.Can anyone help?

author: Rerouter
author_rank: Super Contributor
timestamp: September 28, 2018, 12:08:45 pm
content: The Collector-Emitter saturation voltage is 1V, meaning no matter what your looking at about supply voltage - 1V, so your values make sense, If you wanted a higher voltage you would need to swap out to a mosfet.

author: Zero999
author_rank: Super Contributor
timestamp: September 28, 2018, 12:41:53 pm
content: Use a logic level MOSFET. The old school IRL540 should work with such a low current.https://www.vishay.com/docs/91300/91300.pdf

author: Ramila
author_rank: Newbie
timestamp: September 28, 2018, 01:59:49 pm
content: Hero999,In that transistor gate-source voltage needs 5v to fully open. But node mcu's output has only 3.3v

author: Zero999
author_rank: Super Contributor
timestamp: September 28, 2018, 02:37:59 pm
content: Quote from: Ramila on September 28, 2018, 01:59:49 pmYour circuit only passes 2A, so the MOSFET doesn't need to fully turn on. Yes, there are more suitable MOSFETs, the PHD38N02LT being one. I just thought of one which is common, cheap and easy to obtain.https://assets.nexperia.com/documents/data-sheet/PHD38N02LT.pdf

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 28, 2018, 02:44:55 pm
content: i have nice little AO3400, maybe suitable for your need..Quote from: Ramila on September 28, 2018, 11:58:14 ami think you mean 3.3V PWM signal to transistor's gate/base? you dont want linear operation bjt.

author: Zero999
author_rank: Super Contributor
timestamp: September 28, 2018, 09:07:04 pm
content: Another possibility is a BJT with a very high Hfe. The MCU will still need to deliver a fair current though: about 20mA.https://www.diodes.com/assets/Datasheets/ZTX689B.pdfhttps://www.diodes.com/assets/Datasheets/ZXTN25012EZ.pdf
Motor Current Sensing - Page 1
Forum section: electronics / projects

author: dreaquil
author_rank: Regular Contributor
timestamp: October 25, 2014, 04:37:04 pm
content: I am building some RC car circuitry from scratch. I want to include a current sensing block. My options are either a hall sensor or a sense resistors (only about 5 Amps continuous current in the motor). I personally prefer the sense resistor option. After deciding that a 0.1ohm resistor should do with max dissipation of 2.5W, i'm thinking of how I can isolate this from my microcontroller as I want my control circuitry isolated from my power circuitry. The only option I've come across are the isolation amplifiers produced by Avago and Texas Instruments. (Something of this sort :http://www.ti.com/lit/ds/symlink/iso124.pdf) Is there any way to do this using an optocoupler? (operating it in a linear way such that i can read the current accurately) Is there another way i could possibly do this without using a transformer?Thanks!

author: DutchGert
author_rank: Frequent Contributor
timestamp: October 25, 2014, 04:57:51 pm
content: Use something like thishttp://www.linear.com/product/LTC6101Wasting 2W in a 0R1 resistor seems silly. If u want it isolated u can use a opto to follow the output voltage of the current sense amplifierSee page 8 of this document for a examplehttp://cds.linear.com/docs/en/application-note/an105fa.pdf#page8Ps. I googled it in 20sec

author: dreaquil
author_rank: Regular Contributor
timestamp: October 25, 2014, 05:03:08 pm
content: how do i use an optocoupler to follow the output linearly and accurately? any application notes i can read?

author: DutchGert
author_rank: Frequent Contributor
timestamp: October 25, 2014, 05:03:58 pm
content: Quote from: dreaquil on October 25, 2014, 05:03:08 pmSee my edit above.

author: Marco
author_rank: Super Contributor
timestamp: October 25, 2014, 06:01:35 pm
content: Quote from: dreaquil on October 25, 2014, 04:37:04 pmIs this really necessary? A common mode choke will remove most of the switching noise (assuming some type of star grounding).That said, linear optocouplers generally use a feedback photodiode and an opamp (IL300 for instance). Not as linear as isolation amplifiers though (which use PWM to get an analog signal across the isolation barrier). You can alsospin your own isolation amplifierout of a digital isolator and some cheap parts.PS. with those hall sensor IC's only costing a little more than the linear optocoupler it hardly seems worth the effort to use anything else ... assuming 80 kHz bandwidth is enough.

author: mjkuwp
author_rank: Unknown
timestamp: October 25, 2014, 06:06:42 pm
content: Allegro ACS712 will do it.Signal will be 2.5V at zero current and up or down from there depending on direction of the current. It is isolated.

author: dreaquil
author_rank: Regular Contributor
timestamp: October 26, 2014, 09:19:44 am
content: Yeah i might move my design to a hall effect IC, I was just concerned on where I'd have to mount it to get a good reading but it seems like the simpler choice.
Motor driver L/R time constant auto measurement  - Page 1
Forum section: electronics / projects

author: Jacobo
author_rank: Newbie
timestamp: September 25, 2017, 05:10:24 am
content: Hi all,I have a stepper motor driver project I'm working on. It's based on dspic33 MCU and I have not problem with hardware part of it. So would welcome any suggestions.I have PID controller implemented for each winding and currently it requires motor parameters to determine PID parameters - Kp, Ki. So idea is to try to measure L/R time constant and use it to derive PID parameters.Here is how I currently do the measurements:1. PWM frequency set yo 32.765 kHz and very low duty cycle - around 7 percent.2. ADC completion interrupt triggered when PWM reaches certain value and reading stored in the buffer, see question 43. Once 64 ADC reading obtained, I shutdown PWM and try to calculate time constant, see question 2.My question is around software part.1. Does it makes any sense to measure L/R to derive PID parameters? it seems commercial ICs doesn't do that and still works very well. What parameters to choose than?2. I think I might need to measure few times with different duty cycles or may be different number of readings, to address the following questions2.1 How to detect that what was measured is actually exponent. what if load is pure resistance?2.2 Does current reached steady stat, what do do if not? re-measure for longer time or increase duty cycle?2.3 Currently I calculate steady state voltage though applied to the motor by multiplying PWM duty cycle by my rail voltage, should work well if I have inductance load, not so well if it's only resistance load.3. Currently I have PI controller, but it has issue retaining current at required level, as it keeps oscillating (this leads to low frequency hum in a few kHz range, very annoying) unless I set PID parameters really low, and which case current raise time get unacceptable (so it can't step as fast as I want to). So I want to explore full PID controller option, as differential part of the controller should calm the oscillation while allowing to keep controller gain high. Does it make any sense to use full PID controller?4. Last one is more about MCU, if I decide to go with time constant auto measurement, I need a buffer to keep ADC reading during the calibration (let say i need 128 Q16 readings for each winging), but once parameters are determined I don't really need that buffer, so what would you suggest for that? I don't really want to go for a full heap management solution. Any lightweight solutions? Driver is written in C, so wants to avoid any assembler if I can help it.
Motor driver or relay module - Page 1
Forum section: electronics / projects

author: gsingh11
author_rank: Contributor
timestamp: February 01, 2023, 07:01:08 pm
content: Hi, i was working on a project in which i am using a water pump 12V to fill a water tank and a solenoid valve to empty it. I wanted to ask that can i use a relay module for both the solenoid valve and pump or if should i use a motor driver for the pump and can someone suggest a good solenoid valve 12V dc.

author: Benta
author_rank: Super Contributor
timestamp: February 01, 2023, 09:26:10 pm
content: If the pump only needs to run on/off, just use a relay. Motor drivers are only needed for speed control.
Motor Driver with Current Sensing to drive Actuators - Page 1
Forum section: electronics / projects

author: bizkits
author_rank: Contributor
timestamp: November 16, 2020, 08:55:49 am
content: Hi, I recently designed a PCB which will control 4 individual DC Actuators running on 24V each. Each actuators draw a maximum of 1A.The board is powered with a 24V PSU with a DC-DC 5V (RECOM 78E5.0-1.0) converter to power an ESP32.It contains 4 individual DRV8876 motor drivers from TI which has many protections and current sensing feature.DRV8876 Datasheet:https://www.ti.com/lit/ds/symlink/drv8876.pdfBasically, I would just send commands to the board to tell it to move forward or backwards.The actuator is mounted on a window frame to push/pull the window handle.The current sensing is used to detect if there's a spike in current so as to detect if any object is stuck in the window as it closes (for example somebody's hand).I am still new in electronics and learnt mostly from videos and reading the datasheets of the components.Hence I would like to request the community here to have a look at my design and see if I made any silly mistakes or could improve in any areas.You can see my schematic and PCB board at this link:https://oshwlab.com/hchc/drv8876_copy.Appreciate any suggestions or comments. Thank you.
Motor drivers onto a daughterboard - due to chip uncertainty! - Page 1
Forum section: electronics / projects

author: rt
author_rank: Regular Contributor
timestamp: November 15, 2021, 09:42:48 am
content: This week's task involves re-spinning our mainboard to move the output section onto a daughterboard. We have no idea which of the suitable driver chips will come back into stock first next(?!) year so we will just design daughterboards around whatever becomes available.Anybody else coming up with good ideas to deal with product variation in response to shortages?rt

author: xavier60
author_rank: Super Contributor
timestamp: November 15, 2021, 10:33:59 am
content: I received a few more of these today,https://au.mouser.com/ProductDetail/STMicroelectronics/STGAP2DMTR?qs=W0yvOO0ixfF%252Bp5Pfo9gPjQ%3D%3DNot many left though.There might be single channel versions available. Beware of the Wide Body types and the SIC versions with a higher output stage UVLO.

author: xavier60
author_rank: Super Contributor
timestamp: November 15, 2021, 10:42:20 am
content: OMO?https://www.omo-ic.com/chip/943/STGAP2DMTR.html

author: rt
author_rank: Regular Contributor
timestamp: November 15, 2021, 02:51:56 pm
content: We've tried RFQs with a bunch of secondary dealers and been quoted crazy prices. Uneconomic. So we will use our existing stock of parts but be ready for whatever becomes available next.rt

author: Doctorandus_P
author_rank: Super Contributor
timestamp: November 15, 2021, 04:28:24 pm
content: Maybe consider of designing your own driver stages from a few discrete components?When integrated drivers are available for cheap this would be silly, but discrete transistors may be the only available parts in these times.
Motor Drivers - Page 1
Forum section: electronics / projects

author: docmur
author_rank: Regular Contributor
timestamp: July 03, 2016, 05:57:01 pm
content: Hey GuysI'm currently using 3 MAX1749EUK+TCT-ND to drive 3 coin cell motors. Does anyone know of any motor drivers which would are in a single package that might be able to drive the motors from one IC, instead of going for the 3 driver arrangement?
Motor EMF  - Page 1
Forum section: electronics / projects

author: bootloader9800
author_rank: Contributor
timestamp: March 12, 2021, 06:31:56 pm
content: Hi Folks, hope all is well.So me and my buddy are installing motors on our quadcopter. It is nothing fancy.So, Instead of using the provided M3 x 0.5 x6 mmButton Head Socket Head Cap Screws, we used M3 x 0.5 x8 mmButton Head Socket Head Cap Screws.The screws go into the holes marked by the red arrows.So here is my question.Will the extra 2mm from the screws somehow interfere with the magnetic field and make the motor work differently than they are intended to? The inside of the motor is also shown below.Thank you for your replies.

author: Benta
author_rank: Super Contributor
timestamp: March 13, 2021, 06:06:25 pm
content: If that's your worry, use brass screws.I'd be more concerned about mechanical interference.

author: Siwastaja
author_rank: Super Contributor
timestamp: March 13, 2021, 06:48:11 pm
content: Not necessarily a problem, but it's theoretically possible. The rotating field will induce currents into stationary iron objects causing them to heat up. Probably not by significant amount in this case, but who knows.I would definitely follow the recommended screw length. If you don't have the right length available, you can file 2mm off the screws in maybe 15 minutes in a screw bench. Carefully deburr and remove any filing dust before assembly.

author: Benta
author_rank: Super Contributor
timestamp: March 13, 2021, 07:37:27 pm
content: Or put a couple of washers under the screw head.

author: Gyro
author_rank: Super Contributor
timestamp: March 13, 2021, 07:44:48 pm
content: I think he's switching to button head to get the head height down (although not explicitly mentioned, I can't think of another reason though).
Motor reversal circuit without microcontroller - Page 1
Forum section: electronics / projects

author: Kev840
author_rank: Newbie
timestamp: January 12, 2016, 04:47:18 am
content: I'm trying to figure out a circuit that will run a 5 volt dc motor in reverse for 1 second when power is applied, then run the motor forward until power is removed. This is for an automatic dog feeder that jams quite often. Running the motor in reverse should clear the jam and allow it to run freely. I'm hoping this can be done without a microcontroller, maby a 555 timer and dpdt relay?

author: sleemanj
author_rank: Super Contributor
timestamp: January 12, 2016, 05:17:47 am
content: Something like this...Feed the output into your H-bridge, 1k and 100uF control the high time.

author: rs20
author_rank: Super Contributor
timestamp: January 12, 2016, 05:57:24 am
content: The chip there is a 555 timer, I assume?

author: sleemanj
author_rank: Super Contributor
timestamp: January 12, 2016, 06:12:32 am
content: Quote from: rs20 on January 12, 2016, 05:57:24 amyes

author: jbix
author_rank: Newbie
timestamp: January 17, 2016, 09:22:58 pm
content: Long live the 555!
Motor speed detect sensor - Page 1
Forum section: electronics / projects

author: vikash23
author_rank: Newbie
timestamp: March 21, 2018, 02:08:37 pm
content: Hi,I am using a motor that spins at 6000 rpm.I would like to connect a sensor to the shaft of the motor to test the speed of the motor .The output of the sensor can be analog or digital.Low cost sensors that I have seen is capable of measuring only upto 5000rpm.Can any one please suggest me a sensor module that can perform my requirement.The working voltage of the sensor. can be upto 24V.I know i can measure the rpm by using the back emf but I need to measure using the sensor and compare the value with the back emf value.Thanks.

author: Zero999
author_rank: Super Contributor
timestamp: March 21, 2018, 02:56:39 pm
content: The easiest method is optical. A piece of reflective foil on a dark wheel or shaft and a reflective optical sensor. The frequency of the pulses can then be counted, to give the RPM.
Motor starting board question - Page 1
Forum section: electronics / projects

author: RyanG
author_rank: Regular Contributor
timestamp: October 24, 2018, 03:32:15 am
content: A while back I asked for some help here on the forums with making a board to start the single phase motors where I work. I used a 555 to disconnect the start winding of the motors after a delay. Those boards have worked great. Now, I have tried to make a new one that fits inside the cap of the motor with all the required connectors to replace the board that typically goes inside the motors that I work on. The problem is that they no longer work. The original boards used a resistor dropper, while the new one uses a capacitive dropper. I wanted to switch to the capacitor because of the large amount of heat from the resistor dropper.I first tested the new boards on a smaller motor that was rated for 1A at 115V. That motor starts fine with my board, but the bigger 6.5A motors that the board is intended for do not work. The motor just hums and draws locked rotor amperage, so I know the start winding isn't getting power.Here is a description of the connections:J1 + J4 = 110v and one side of thermal breakerJ2 + J5 = Neutral, run windingJ6 + J7 = other side of thermal breaker, start winding with capacitor, run windingJ3 = other end of start winding/capHopefully that makes sense.Any help would be great.
Motor testing device - Page 1
Forum section: electronics / projects

author: fubgumfaw
author_rank: Regular Contributor
timestamp: February 25, 2021, 05:32:32 pm
content: Hi,I'm an EV builder. I have wanted a tool that can handle EV grade brushless motors for a while now.Requirements:1. Can can handle 200v AC and DC2. Can monitor all 3 motor phases simultaneously (200 volts)3. Can monitor all 3 motor phases simultaneously (500 amps)4. Can monitor all 3 hall signals simultaneously (5v square waves)5. Can display all 9 signals simultaneously on the same display6. Can be electrically isolated on each input from all other inputs (or at least very high impedance)any ideas?

author: wizard69
author_rank: Super Contributor
timestamp: February 26, 2021, 10:00:22 pm
content: Sounds like you are in DIY territory here. You likely would have to piece together a VXI, PCI-Express or similar solution. You might be able to reduce your need for analog inputs by buffering the encoder (hall) signals into digital I/O ports. That would reduce the need for analog inputs by 1/3 rd which might even allow a 6 or 8 channel scope to do the job with the right probes and a digital input channel.HPAK has this scope:https://www.keysight.com/us/en/assets/7120-1115/data-sheets/Infiniium-MXR-Series.pdf?id=3112062that might do the job if you add the digital input option. You will be spending huge bucks for such a scope though especially after you buy all of the unbundled things you will likely need.it is hard to say what is better, going the DIY route or buying an extremely high priced scope. I guess it comes down to time and the willingness to hack together a solution.

author: fubgumfaw
author_rank: Regular Contributor
timestamp: February 26, 2021, 11:36:07 pm
content: Quote from: wizard69 on February 26, 2021, 10:00:22 pmThat is an epic scope! And out of my price range...My current solution if you want to call it that is using ACS current sensors into 1 channel of a DSO203 and direct connect to a phase into the other channel. No voltage cross over happens since the ACS uses a linear hall to detect current flow. A small lipo powered DC-DC provides the stable 5v to run the ACS current sensor. This does work, but doesn't put the associated hall signal on the same screen. Just those 3 things together on the same small LCD would be great. Repeat for the other 3 signals for the other 2 phases. The DSO203 is limited to 70v, so this isn't a perfect solution, but that's easy to rectify with a voltage divider. I'm not so much concerned about the peak to peak as I am about the wave forms. I want this thing to be pretty inexpensive and yet capable...yes...a contradiction.Thanks for the suggestion. Looks like DIY is the route to take. VESC controllers have a lot of this functionality built into them, but that's useless if I'm using some other controller.
Motor tuned cavity filter for 2100MHz telecom video and explain - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: September 30, 2023, 09:38:56 am
content: my latest video release about WCDMA basestationin this video you find a part that show and explain the motor tuned cavity filterhttps://youtu.be/bwBoA042vVMI have been working with telecom equipment design for 13 yearswe never seem or newer did anything like this :-)so that is why i think this design is worth sharing with youby the way : you see many other good things in this videoimpressive thermal design, clearly worth getting a few ideas fromfor your own high power thermal challenged projects.
Motorcycle 12VAC to DC Headlight Wiring circuit - Page 1
Forum section: electronics / projects

author: Techedz
author_rank: Newbie
timestamp: October 31, 2022, 01:03:26 pm
content: Hi, 1st post so be gentle!I'm trying to convert a 12VAC circuit to 12VDC, but the trick is, it has to output High and Low on an LED Headlight using the original switch. I'm trying to build a 'plug and play' unit to replace the current weak AC Globe. The LED draws from 1.5 to 4 amps depending on which one I use.I've drawn a rough circuit of what I'm thinking but not sure about the earth/AC side? Note there are two bridge rectifiers, one is to convert the higher current for the light, the other just converts a couple of hundred milliamps to switch the relay.Thoughts? Am I on the right track or miles off? I've bought some bits to play but won't be able to start until next week.

author: CaptDon
author_rank: Super Contributor
timestamp: October 31, 2022, 01:33:34 pm
content: If your headlight switch is designed to power both the low beam AND the high beam when in the high position then your circuit will work. HOWEVER I doubt it lights both elements at the same time due to the limited charging current available on motorcycles. It that case your light will not light on high beam because in the high position you would be feeding power to the relay coil but you will have lost your power coming from the low position of your switch. Perhaps a double pole relay and a small wiring change would give you what you want. Or possibly a heavy diode from the high beam side of the switch to the low beam side (Anode on high beam side, cathode on low beam side) and keep the wiring you have already proposed.

author: CaptDon
author_rank: Super Contributor
timestamp: October 31, 2022, 01:39:55 pm
content: Opps, my diode idea won't work, it would only give you half wave rectified power in the high position for you headlight. Not Good.Going to need to change your schematic.

author: Techedz
author_rank: Newbie
timestamp: October 31, 2022, 10:32:52 pm
content: Thank you for the response CaptDon.Good point, that was a mistake on my part. I'll go and check the low and high outputs on my mates bike and see if the power only comes out when they are switched and redo the circuit and repost it.Regards Ed.

author: Techedz
author_rank: Newbie
timestamp: October 31, 2022, 11:04:42 pm
content: Haven't checked the switch but redrew the circuit with the assumption High and Low are separate using 2 rectifiers.

author: moffy
author_rank: Super Contributor
timestamp: October 31, 2022, 11:16:58 pm
content: With the bridge rectifiers the 0V at the output is not the same and shouldn't be connected together. You should use one or the other, a DPDT switch would work. One problem maybe, the low voltage winding is sometimes half that of the higher, will that be enough to drive the LEDs?