hybridfree/eevblog-posts huggingface dataset:
ultrasonic cleaner dimensions/power - Page 1
Forum section: electronics / projects

author: tekguy
author_rank: Contributor
timestamp: October 01, 2022, 03:48:58 pm
content: Hi all,i am putting together au/c it has 5x 50watt transducers at 40kc,the tank is approx 14"x10" and a usable depth of about 4",is that a good power level for the size of the tank or will it damage things beeing cleaned,Cheers.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: October 01, 2022, 05:04:08 pm
content: That seems a lot different then what I'm used to, but I don't know about the higher frequency designs. For half that frequency the depth would be near 10" and maybe two transducers. There's quite a lot to designing these things to avoid standing waves and such. The standard test is how quickly it will perforate aluminum foil, so yes, you can damage small parts. The high frequency designs get into smaller area and are probably safer for small parts, but I'd want a power control.

author: tekguy
author_rank: Contributor
timestamp: October 01, 2022, 05:48:57 pm
content: it has 2 driver boards,1 is 2x 50watt and the second driver is 3x 60 watt,i plan on having a two way switch to power the drivers seperatly so i can switch from 100watt then to 250 watt,it has a 300 watt heater so i plan to power that on in the high power position.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: October 01, 2022, 11:02:59 pm
content: That sounds pretty good. I'd still wonder about making it deeper; you've got plenty of power so why not accommodate larger items?

author: tekguy
author_rank: Contributor
timestamp: October 02, 2022, 08:38:25 am
content: its size is down to that being the biggest size tank i could find on aliexpress,would have gone bigger but that was the largest i could find,i think it holds about 15 ltrs approx of liquid,has a 300w heater pad too.

author: tekguy
author_rank: Contributor
timestamp: October 03, 2022, 05:38:31 pm
content: can anyone make sense of this chinglish nonsense?,i am trying to work out the polarity of the tabs on the transducer but am not sure,any suggestions folks?.

author: 1001
author_rank: Contributor
timestamp: October 03, 2022, 08:07:14 pm
content: Positive terminal is between the two piezop rings, the negative terminal is the one connected to the metal part of the transducer, the two metal parts of the transducer are electrically connected to each other with a screw.

author: Halcyon
author_rank: Unknown
timestamp: October 03, 2022, 10:39:58 pm
content: I have banned tekguy from posting any further as he is the same person behind the user account m3vuv who was banned after repeated warnings. Since he refuses to discuss the matter and continues to play dumb, I'm left with no other choice.
Ultrasonic cleaner project for large parts (PC motherboards, etc) - Page 1
Forum section: electronics / projects

author: LeonR
author_rank: Regular Contributor
timestamp: July 01, 2018, 09:34:12 pm
content: I've started looking for projects for a DIY ultrasonic cleaner for large formats (I've seen boards with SSI CEB/EEB formats, up to 305x330mm) since those are pretty expensive to buy and really large/heavy.My questions are:* How does passive components like solid state/electrolytics caps, crystals, etc on the board being cleaned behave while the cleaner is on?* Is frequency sweeping a plus or a requirement for good cleaning?* Aliexpress got some options on power boards/transducers (up to 300W). Are they any good, reliability-wise or should I go with another option?* People seem to use a myriad of stuff on theirs cleaners - IPA, deionized water, special soaps, etc. I assume it depends on the materials being cleaned?* How does the heating/cooling on those are implemented? Peltiers?
Ultrasonic Industries - NY - Page 1
Forum section: electronics / projects

author: hazmoment
author_rank: Contributor
timestamp: June 24, 2022, 09:23:29 pm
content: Hoping someone can help with this random piece of equipment..I have picked up this old "Ultrasonic Industries" (made in NY) piece of equipment up from my local recycling centre which has a 826 Transmitting Triode. (I had to have it when I saw the tube- only cost $5) and is quite a simple design- only has a few other components. I have drawn a schematic showing the components and how they are in circuit. I don't understand what it is, but at a guess and looking at the data plate on the back, I imagine its a sort of 90kHz Ultrasonic therapy unit for some kind of health clinic? It looks like there was once a plug-in attachment that would go into the nylon 2pin socket, maybe for a transducer or something? There are two controls on the front. The first is a rotary power on/off switch. The second is a nylon rod with a chunk of lead? on the end. This can be moved in or out (I think to change how strong or weak the output is by coupling/decoupling the magnetic field between the two coils)I have powered it up with my current limited supply and can probe the output and without any loading it is putting out approximately 95kHz. The output voltage is off the scale of my scope. I think I need a differential probe to measure it properly. I can measure close to 1kV ac with my multimeter in circuit when the unit is running, but I cant understand where this is coming from. The Transformer just seems to have a centre tapped filament winding only...I have no need for a 90kHz oscillator, but what would be super handy would be to modify it for 40kHz (or adjustable frequency) and connect it to a transducer for use in an ultrasonic cleaning bath. Can anyone tell me if this is practical/possible?Does anyone know what the large metal cylindrical thing is in the chassis? I've drawn it as a capacitor on the schematic, But is marked with "400 42" onlyThere's a 47ohm resistor with 9 turns of wire in parallel with it too, which I have never seen done before. I general work on Tube amplifiers, not RF stuff. I imagine that this would be more understood by someone with a background in RF and oscillators. So hoping somebody can help me out!Much Appreciated,Thanks, Harry.

author: Stray Electron
author_rank: Super Contributor
timestamp: June 25, 2022, 02:54:52 am
content: That looks like it might be a part of an old medical Diathermy machine. The construction looks typical of the 1960s and the fact that it's labeled in CPS instead of Hz also indicates that it is pre-1970. Those tubes are frequently dated, did you look and see if there is a date on it? Be careful the markings are easily rubbed off of the old tubes.

author: hazmoment
author_rank: Contributor
timestamp: June 25, 2022, 03:12:17 am
content: Thanks! I think you are right saying it could be a diathermy unit. I think its definitely 60's or even earlier. Dont know about date codes but hand written on the inside of the Kenrad glass tube down at the base looks like:339 716. Cant make out any other indications regarding date on the unit.
Ultrasonic module for distance measurement between pairs? - Page 1
Forum section: electronics / projects

author: allanw
author_rank: Frequent Contributor
timestamp: June 02, 2010, 02:25:38 am
content: Does anyone know any commercial solutions for determining the range between two objects using an ultrasonic sensor mounted on each? Ideally it'd be small and integrated (ie, with PCB all ready to go) and sense with a range between 1" to 3 feet. Also, I'd need it to have a wide angle, like an entire hemisphere. I was thinking if one ultrasonic transducer were to transmit in all directions, the second one could pick up the signal as long as it was anywhere in its line of sight. Both would be synchronized by the same microcontroller, so that the timing between the send and receive could be used to determine distance. I'm just not sure what to search to find products like this.Or alternatively, I'd like to know about any other commercially available solutions for measuring the distance between two moving objects.

author: joelby
author_rank: Frequent Contributor
timestamp: June 02, 2010, 08:36:21 am
content: I don't know if there's an off-the-shelf version, but I once read an interesting paper on doing this using only standard Windows Mobile devices:http://portal.acm.org/citation.cfm?id=1322265Let me know if you don't have access to the ACM Digital Library.

author: saturation
author_rank: Super Contributor
timestamp: June 02, 2010, 09:41:15 am
content: Radar could work, measure the doppler shift, you need only one unit. You can get kits:http://store.qkits.com/moreinfo.cfm/VM125and take it from there; the output may be accurate enough for your needs.To measure only two objects just increase the radar signature of the other, so it predominates the area.Quote from: allanw on June 02, 2010, 02:25:38 am

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 02, 2010, 01:20:35 pm
content: maybe you can modify this?http://cgi.ebay.co.uk/Ultrasound-Motion-Sensor-Robotic-Basic-Stamp-/350360926557?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item519323795d

author: Bruwer
author_rank: Newbie
timestamp: June 03, 2010, 02:42:47 am
content: Try:www.maxbotix.comThey specialise in sonar items.
Ultrasonic probe - Page 1
Forum section: electronics / projects

author: Rachie5272
author_rank: Regular Contributor
timestamp: November 06, 2015, 06:42:45 pm
content: I found a neat ultrasonic probe at a university sale, and I'm trying to figure out what to do with it. It doesn't have a power supply, and I can't find any documentation. What sort of drive characteristics do these things typically need? Is there a simple way to make a power supply?I'm hoping I can use it for welding plastic.

author: daqq
author_rank: Super Contributor
timestamp: November 06, 2015, 07:22:22 pm
content: Read the patents listed:https://www.google.com/patents/US3328610https://patents.google.com/patent/US3524085A/enThey give hints as to how it works inside.

author: helius
author_rank: Super Contributor
timestamp: November 06, 2015, 07:24:22 pm
content: It appears to be designed as a disperser wand for immersion to mix suspensions or colloids. Ultrasonic welding requires an arbor to apply pressure to the joint during welding, which I don't see how you would be able to use this device.

author: Someone
author_rank: Super Contributor
timestamp: November 06, 2015, 09:37:39 pm
content: Those can be very dangerous, along with mixing they can be used for "cell disruption" better described as turning plants and animals into goo (bones can be fractured through flesh for instance). The power supplies are resonant drive with up to a few hundred volts, just like a piezo element.
Ultrasonic transducer driver - Page 1
Forum section: electronics / projects

author: ifonlyeverything
author_rank: Regular Contributor
timestamp: May 27, 2023, 06:48:33 pm
content: I want to build an ultrasonic transducer driver for use in a DIY ultrasonic cleaner. I have one of thesehttps://www.piezoelements.com/piezoceramic-transducer/60w-40khz-ultrasonic-piezoelectric-cleaning.htmlwhich claims 60W rated power with 25 ohms resistance at resonance. Since P = V^2/R and V=IR, I believe this is ~38V and ~1.6A to drive it at rated power.I did some Googling but I'm not finding a lot of reference designs or tutorials suitable for a hobbyist like myself. It seems some off the shelf Chinese ultrasonic drivers are using a self-oscillating design (Royer oscillator?) to generate 200-300V for a 60W transducer.Why are they doing this -- shouldn't ~40V be sufficient?If ~40V is sufficient, can I use a transformer with a 1:4 windings ratio to boost 12V input to unregulated 48V output? Notwithstanding the viability of this, my thought is something along the lines of this with snubber values TBD.
ultrasonic transducer driver/receiver schematic - Page 1
Forum section: electronics / projects

author: seandepagnier
author_rank: Newbie
timestamp: January 18, 2018, 02:24:00 am
content: I'm trying to design a schematic to drive ultrasonic transducers for pinging objects underwater (sonar) The transducers I am looking at are 40khz used for ultrasonic cleaning, and rated to 50 wattsI want to make the schematic as simple as possible while still functional. This means I don't want a lot of hardware drivers or filters if possible. Instead, the stm32 uC have fast adc, and can easily output pwm in the desired frequencies.DriveA and DriveB signals are produced by the microprocessor at the right frequency as inverted waveforms with dead time.The T1 transformer will have 15 turns for each primary, and a secondary with 100-200 turns to produce a drive voltage of 200 Vp-p to the transducer.The resistor R2, I am not really sure the correct value, I will try with 280 ohms to start out.The Diodes D1 and D2 are fast recovery.The idea of the diodes D1-D4 and R3 (also not sure of optimal value) to allow measuring the millivolt returns from the transducer, but not allowing the large drive voltages into the receiver.C2 is to balance the transformer capacitance to ground.TR1 transformer could be an audio transformer with a few hundred turns windings, probably 1:2 ratioThe opamp is to amplify the return signal for the adc range, I can tune the gain with a screwdriver. The actual filtering (besides the simple high-pass filter) is to be done in software.Almost all other examples I see have a lot of filters in hardware which significantly complicates the design, can this really be avoided? Filtering in software allows for changing the transducer frequency, operating at secondary resonance frequency (170khz) as well as for detecting frequency change (doplar shift) of moving targets. I can also produce waveform of variable duty cycle to reduce power consumption depending on target range.Will this work? How could I improve it? Recommended components? Am I missing anything critical?Would it be better to have two transducers, one for transmit, and another as receiver?
Ultrasonic transducer question - Page 1
Forum section: electronics / projects

author: Rory
author_rank: Frequent Contributor
timestamp: May 01, 2015, 04:03:29 am
content: Asked a reasonable question, got a single smartass answer that did not help. Thanks for wasting my time. Never again.

author: Richard Head
author_rank: Frequent Contributor
timestamp: May 01, 2015, 07:57:08 am
content: The second response from Google provided the datasheet!

author: Rory
author_rank: Frequent Contributor
timestamp: May 01, 2015, 03:06:24 pm
content: ... Makes no sense to continue this thread.
Ultrasonic Transducer Values - Page 1
Forum section: electronics / projects

author: Nickcasio
author_rank: Newbie
timestamp: February 10, 2014, 09:43:45 am
content: Howdy,I am working on a project which requires me to transmit ultrasonic pressure waves using Piezo Transducers, i have found the transducers i would like to use but the datasheet is a little light on values.One of the selected transducers is sourced from Element 14:MULTICOMP - MCUSD14A40S09RS-30C - TRANSCEIVER, 40KHZ, 14MM, METALElement 14 Part Number : 2362678The Datasheet states the Capacitance (pF) @ 2,500 ± 25% at1kHzand Allowable Input Voltage (Vp-p) 160V.How can i work out the other properties of the XTAL Transducer, for instance series resistance, inductance and Capacitance?Can i use a LCR meter and if so what values should i set.My intention is to modify the resonace frequency by adding a series capacitor any thoughts ?

author: tszaboo
author_rank: Super Contributor
timestamp: February 10, 2014, 12:41:36 pm
content: I've used a LRC plotter before to characterize ultrasonic transducers (years ago), I'll try to find back the information. I dont think what you describe is doable. I mean it has a mechanical peak frequency where it has ~70dB sensitivity peak compared to the other frequencies. So for transmit, it will be less loud, for receive, it will be less sensitive, if you change the frequency.

author: Nickcasio
author_rank: Newbie
timestamp: February 10, 2014, 06:53:22 pm
content: Thanks for the swift reply you have raised a very good point.I was planning on using two transducers one as a transmitter and the other as a receiver.I think i get what you are getting at; that by altering the electrical characteristics the ability to transduce the mechanical pressure wave will be degraded.I have order 5 sets of the multicomp transducers, i think i will carry out some experimentation.There is a post i found linked from HaD, which i found interesting:http://hackaday.com/2012/01/30/powering-an-ultrasonic-transducer/I have access to a lab here at the University of Bordeux with lots of fancy Hp/Agilent (CRO, Spectrum Analyzers etc) gear and an Anionic chamber!!!
Ultrasonic Transducer - Page 1
Forum section: electronics / projects

author: randyyork
author_rank: Newbie
timestamp: April 27, 2017, 07:33:46 pm
content: I'm trying to drive a small ultrasonic transducer I found laying around (MA40S4S). Currently I've got a 40 kHz PWM signal fed into one channel of an H-Bridge (SN754410). Output is a square wave, around 20 Vpp (0-~20V square wave signal).I've seen some designs for drivers that use a tank circuit to ensure the transducer is driven at resonance. I'm just trying to see if the output I'm getting is going to be much improved with the LC or other driver designs.Thanks!-Randy
Ultrasonic transducers, electromagnetic signal and interference - Page 1
Forum section: electronics / projects

author: raff5184
author_rank: Regular Contributor
timestamp: June 09, 2021, 06:54:00 pm
content: Hi,I have 2 piezoelectric transducers that work at 300kHz, I'm using them to transmit/receive data. The issue that I'm having is that the receiver transducer, besides the acoustic signal, also receives an electromagnetic "copy" of the signal. If for example I keep the 2 transducers next to each other, without anything in between, but air, I can receive the EM version of the signal. I'm sure it is EM because there is almost no delay between the tx signal and the rx, while I see the delay in the acoustic version.Is there any common practice, or something that I can use to filter the EM noise?

author: Marco
author_rank: Super Contributor
timestamp: June 09, 2021, 07:30:28 pm
content: Just making sure ... you aren't putting them on a solid surface when putting them "next to each other"?

author: raff5184
author_rank: Regular Contributor
timestamp: June 09, 2021, 07:51:46 pm
content: Quote from: Marco on June 09, 2021, 07:30:28 pmNo, I avoided that just to be sure
HCSR04 ultrasonic detectors,can we use without the module part - Page 1
Forum section: electronics / projects

author: dave_j_fan
author_rank: Regular Contributor
timestamp: March 01, 2020, 02:04:45 pm
content: hc sr04 module is there with me.one person extracted the Tx and Rx elements so that transmitter element can be fed with 40khz from 555reciever is fed to a vu level meter .his demo shows led levels without Microcontroller usage.Question:if we remove the module..will there be false trigger and cause problem?

author: dave_j_fan
author_rank: Regular Contributor
timestamp: March 15, 2020, 07:39:24 pm
content: no replies
Unable to Find Datasheet 71F7279 ?? (or 7278) - Page 1
Forum section: electronics / projects

author: Adam J.
author_rank: Newbie
timestamp: October 07, 2024, 04:32:07 am
content: Hi, if anyone has any ideas about the ICs in the picture attached please let me know here. I've tried googling the part numbers as best as I could in different variations but nothing... I can't even figure out what type of IC they may be! Any help is appreciated, thanks!

author: Analog Kid
author_rank: Super Contributor
timestamp: October 07, 2024, 05:11:31 am
content: Using an incredibly clever Google search string, I did find one possible source of infohere. Site appears to be in the Philippines. (But they give a company location in Hong Kong.)The page that comes up shows a link to a MC71F7279 datasheet. Unfortunately, if you click on it you get a page that says "Sorry the datasheet is not available online, please contact us by email:info@exshinetech.com". WTF do they even have that link there for in the first place? Are they just trying to harvest email addresses? I hate that kind of shit.The site has a live chat feature which I tried using to ask for the datasheet, but all I got was "all our agents are busy or away", and then they ask for your name and email. No thanks. Maybe you'll have better luck.It looks like it might be the right datasheet.

author: Adam J.
author_rank: Newbie
timestamp: October 07, 2024, 06:18:58 pm
content: Thank you so much for trying and yes sorry I forgot to mention that I had sent an email to that website last year and never heard back. You're right there's something fishy about them. But thanks again for taking the time to help!
Unable to programme my ESP32 - What am I doing wrong - Page 1
Forum section: electronics / projects

author: ioncoder
author_rank: Newbie
timestamp: May 30, 2020, 04:36:13 pm
content: I am now on my third PCB and am not able to connect to my ESP32. I have attached my schematic, PCB and the ESP32-D pin out, please could someone tell me if there is anything wrong with my wiring. I am quite new to electronics and this is starting to get quite frustrating. I tried originally with a dev board and everything worked, but building my own PCB is proving frustrating. I have checked the continuity on my pcb tracks that is fine.I am powering the PCB from batteries (3 1.2V rechargeable AA's) and sharing GND with my programmer (Which works well with other DEV boards).and here is my PCBHere is the ESP32-D pinoutThank you.

author: nuclearcat
author_rank: Unknown
timestamp: June 02, 2020, 07:35:58 am
content: Pictures are not visible

author: pvint
author_rank: Newbie
timestamp: June 02, 2020, 11:35:47 pm
content: From the blurb I saw on your post I was keen to help, but as mentioned above - the pictures aren't visible.
Unable to run Arduino Bluetooth Control android app - Page 1
Forum section: electronics / projects

author: bikasgaur
author_rank: Newbie
timestamp: April 13, 2018, 12:08:03 pm
content: Today my Google Pixel 2 XL had an upgrade from Android 7.1 to Android 8.1 and now as I am trying to open the ABC App it only loads a blank white screen during its startup and crash itself after few sec automatically. Is there any way to get the app working normally once again? Thanks a lot in advance...
unable to source Bluetooth SPP module - Page 1
Forum section: electronics / projects

author: tatus1969
author_rank: Super Contributor
timestamp: November 16, 2017, 07:40:03 pm
content: I want to use ST's SPBT3.0DP1 or .0DP2 module in a project, in order to provide a BT based virtual UART (SPP profile). Two years ago, I have successfully used a predecessor of these with success, after having tripped on flaws in similar products from other manufacturers. For this reason, I want to stick with ST because their software stack has shown to be been stable.As these modules support encryption (as probably most BT implementations do), it seems that the US government has decided that they must now be export controlled (they weren't two years ago...), and I have trouble importing them to Germany.Has anyone had the same experience, and maybe solved it somehow?

author: Benta
author_rank: Super Contributor
timestamp: November 16, 2017, 07:55:55 pm
content: Why on earth would you want to "import" them? They are made in Italy and freely available at Farnell and others in Germany.

author: tatus1969
author_rank: Super Contributor
timestamp: November 16, 2017, 08:07:35 pm
content: This is what I also thought. I talked with Farnell on the phone and the lady told me the same at the beginning. But then she started digging deeper, and told me that they would be in fact import controlled. She ended with saying that she would investigate this and come back to me, but I shouldn't expect an answer too soon.A few months ago I tried to order a similar model (SPBT2632C2A), and that order finally got cancelled by Farnell due to the same reason...
Unbalanced mic input - Page 1
Forum section: electronics / projects

author: tedbar
author_rank: Contributor
timestamp: September 18, 2022, 03:38:49 pm
content: There are some great op amps for microphone pre amps available (INA849, That 1512 etc). The "typical application" circuits in the data sheets all use balanced microphone inputs. Can these op amps be used with an unbalanced input? If so what is the correct topology for the input?

author: richnormand
author_rank: Unknown
timestamp: September 18, 2022, 04:17:03 pm
content: This should help:https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.305.873Download the pdf link to the Jensen document.

author: tedbar
author_rank: Contributor
timestamp: September 19, 2022, 06:34:11 am
content: Thanks, that certainly sheds some light.

author: magic
author_rank: Super Contributor
timestamp: September 19, 2022, 08:41:50 am
content: These are integrated instrumentation amplifiers, not op amps.You could ground IN- of those chips and drive IN+ with single-ended signal. Bandwidth will be same as normally, not sure if there is distortion penalty for doing that, you could try.At low closed loop gains low noise opamps in ordinary noninverting configuration could work - LT1028, AD797, OPA211, NJM2122, depending on price, other specs and which brand you are a fanboy of.At high closed loop gains the in-amps will win on bandwidth and maybe on distortion.

author: Zero999
author_rank: Super Contributor
timestamp: September 19, 2022, 09:01:07 am
content: Those are instrumentation amplifiers.I agree with the above, especially the NJM2122.https://www.mouser.co.uk/datasheet/2/294/njrc_s_a0009641155_1-2279373.pdf

author: SiliconWizard
author_rank: Super Contributor
timestamp: September 19, 2022, 06:14:54 pm
content: I don't see the benefit of using an instrumentation amplifier if you're going with a single-ended input here.And we don't know what kind of microphone and gain you are talking about. If this requires high gain, single-ended is likely to be pretty disappointing in terms of noise, even with an instrumentation amp. If this is low gain, then any decent opamp will do.

author: magic
author_rank: Super Contributor
timestamp: September 19, 2022, 06:43:06 pm
content: Quote from: SiliconWizard on September 19, 2022, 06:14:54 pm3GHz gain-bandwidth product (THAT1510 at +60dB) is not something even AD797 could matchNot sure if there are current feedback opamps with similar low frequency noise specs?

author: Terry Bites
author_rank: Super Contributor
timestamp: September 19, 2022, 06:52:21 pm
content: You can, but its wise to ground the unused leg with a resistor similar to the mics output Z.It can be useful to bring the single ended mic' ground back to the amp. A pseudo differential connection.Make sure you have an isolated jack with a switch so you can lift it above chassis ground via the 10 Ohm resistor.Make that part a SE Diff switch and keep your options open.In general Inst amps make poor audio amps. They're designed with low frequncy and DC in mind.Add RFI protection or you'll have an expensive AM radio on your hands.The masters of Mic amps are the "THAT corporation". Their app notes a goldmine.
Unbalanced opamp current - Page 1
Forum section: electronics / projects

author: JJalling
author_rank: Unknown
timestamp: August 03, 2013, 08:24:26 am
content: Hi all,I'm still working on my headphone amplifier. While testing the output stage of my circuit (see this schematic:http://stuff.jalling.net/Headphone-Output.PDF, I notified that the I/V stage (OPA4134) and the DAC was getting quite warm. I measured the current on the power rails and got the following numbers:I/V:+9V: 12mA-9V: -47mADAC:+5V: 30.8mAIf i disconnect the DAC from the opamp, the current is:+9V: 12mA-9V: -36mAIs this normal behavior? The unballanced current consumption I mean. I would expect the positive and negative rail to be somewhat similar.The current consumption of the TPA6120 isn't included in the numbers above.BR Jonas

author: Andy Watson
author_rank: Super Contributor
timestamp: August 03, 2013, 09:46:01 am
content: Quote from: JJalling on August 03, 2013, 08:24:26 amThe DAC can only source current (no negative supply), so that means that the op-amps have to sink 7.8mA on each channel. Additionally, the output of the op-amp is working into a 2k load - an extra 3.9mA per channel. So yes, I would expect the current draw to be unbalanced by about 23.4mA.QuoteDepends on the clock speed - but it doesn't look out of line with the data sheet.QuoteAre you sure you disconnected the DAC? I would measure the voltage at the output of the op-amps. The outputs should be identical - 0v with DAC disconnected, or an average of -3.9V with the DAC connected (assuming zero audio signal).

author: JJalling
author_rank: Unknown
timestamp: August 03, 2013, 02:00:31 pm
content: Thanks Andy,I think my lesson here was: Don't mess with electronics too early in the morning.BR Jonas
unclear "wave train..." signal description - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: December 29, 2020, 07:54:02 pm
content: Hi,I was reading some incomplete paragraphs of a presentation so I don't have much context in trying to understand the following signal description:- "monopolar 800Hz square wave carrier"- "square wave modulation: 3,000Hz, 3,100Hz, 3,500Hz, 4,200Hz and 5,000Hz wave train interrupted at 2.0 Hz intervals"that is word by word the two bullet points. But cannot understand what they mean exactly.How would you interpret the above description and how would the waveform look like just by reading the above words as they are?Thank you

author: Kibabalu
author_rank: Regular Contributor
timestamp: December 29, 2020, 08:28:12 pm
content: Most likely the writer is a German native speaker. In German sometimes the Word „Wellenzug“ is used for the meaning of „wave form“. The direct translation of it can be „Wave Train“, because the German word „Zug“ can also has the meaning „train“.BTW, both is wrong, because a „wave“ is a moving oscillation in space, but this was not the question here ;-)My interpretation of the text is: The frequency of the square wave is switching from 3kHz to 3.1kHz to 3.5kHz to 4.2kHz to 5kHz every 0.5 second.

author: ricko_uk
author_rank: Super Contributor
timestamp: December 30, 2020, 07:34:21 am
content: Thank you Kibabaluthe guy is actual American and a scientist. Which is why I found that language vague and why am trying to understand what he really meant.If it was as you suggested, then it still leaves out the "800Hz carrier..."Any other suggestions?Thank you

author: ledtester
author_rank: Super Contributor
timestamp: December 30, 2020, 11:41:56 am
content: Quotemonopolar probably means the same thing as "unipolar":https://www.encyclopedia.com/computing/dictionaries-thesauruses-pictures-and-press-releases/unipolar-signalFor "carrier wave", see:https://en.wikipedia.org/wiki/Carrier_wave

author: ricko_uk
author_rank: Super Contributor
timestamp: December 31, 2020, 05:50:58 pm
content: Thank you ledtesterthat is not what I meant. What I was wondering about was how the original description (of the presenter) was suggesting to modulate the 800Hz carrier.There are at least two ways to interpret the original description:a) the logic level 1 of the 800Hz carrier is modulated sequentially through the other frequencies (3000 to 5000). That is half of the 800Hz carrier period. Then during the other half is just constantly 0 (i.e. not modulated). But then how does the 0.2Hz interval comes in? What does that mean?orb) those discrete frequencies from 3000 Hz to 5000 are generated in sequence and restart every 0.2Hz. But then how does the 800Hz carrier comes into play?Which way is correct? Or maybe there is yet another way to interpret it?Thank you
Underfill for CSP suggestions - Page 1
Forum section: electronics / projects

author: SydB
author_rank: Contributor
timestamp: February 18, 2015, 04:46:13 pm
content: Can anyone point me to a product and supplier of a suitable underfill for CSP (chip scale package) in the UK? For that matter, any BGA underfill product and supplier would also likely suffice. These products exist but I just cannot find any UK distributor. Production is low volume so these need to be obtainable in small quantities.I realise that a general purpose black epoxy 'might' do but specific products exist that have all the ideal qualities desired and it is those I am after.
Underground cable fault locator thumpers  - Page 1
Forum section: electronics / projects

author: Mugiwara303
author_rank: Contributor
timestamp: March 27, 2022, 03:09:18 pm
content: Hi everyone,I need some help with surge generators "thumpers" that are used to locate faults in underground cables, especially the receiver like digiphone+2, how does it detects the surge pulse is it acoustic or electromagnetic, and how it's detecting only the surge pulse sound, I couldn't find any information online

author: Terry Bites
author_rank: Super Contributor
timestamp: March 27, 2022, 04:53:59 pm
content: Thumping sounds like a gunshot at the sending send! Its looking for insulation failures where the thump, a high energy discharge, induces an accoustic and EM wave at the flashover point.the detector is both a radio reciever of sorts and an siesmophone. Its not fantastically accurate and TDM will be used to try and pinpoint the failure.

author: Mugiwara303
author_rank: Contributor
timestamp: March 29, 2022, 11:56:55 am
content: Thank you
Underground use of gyro ? - Page 1
Forum section: electronics / projects

author: Darren Zimmerman
author_rank: Newbie
timestamp: February 06, 2023, 04:48:19 pm
content: HiI am on a auger boring crew (jack and bore). We use very caveman style directional indicators such as plumb bobs and a water level. Our company installs underground utilities using trenchless technology.I would like to install a gyro on our bore head with precise pitch and yaw with a wire ran back to our bore pit for live data. But I don't know the first thing about sensors or which one I would use.Any comments or contact recommendations would be appreciated.Thanks

author: rstofer
author_rank: Super Contributor
timestamp: February 07, 2023, 04:17:50 pm
content: I'm betting the real answer gets complicated. In terms of MEMS devices (semiconductor gyros) here is a little reading material. There is plenty more on Googlehttps://www.st.com/en/mems-and-sensors/gyroscopes.htmlGoogle for 'gyro for tunnel boring' and you will get replies for commercial gyros designed for the purpose of tunnel boring.https://www.ixblue.com/north-america/customer-story/providing-tunneling-boring-machines-unmatched-navigation-accuracy-through-fog-technology/
Understading the footprint information from datasheet - Page 1
Forum section: electronics / projects

author: Sai teja
author_rank: Regular Contributor
timestamp: March 01, 2019, 01:56:04 pm
content: Hello,I am trying to draw a footprint ofType A Male USB connectorfor an application.Details of the part are as follows:Part Number :- 48037-0001Datasheet :-https://www.molex.com/pdm_docs/sd/480370001_sd.pdfIn the datasheet sheet I am unable to find the radius of curvature for mounting pads at the ends. Please help me in this regard.I am attaching the image of the footprint for the reference.Thank you.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 01, 2019, 02:13:14 pm
content: Ends are semicircular, so radius equals half the pad width.They don't dimension pads because those are up to the designer, PCB fab, and assembler to determine.Typically an annular ring (pad radius minus hole radius) of 5 mil minimum is required, plus about half the hole radius. So a 20 mil dia. hole gets 5 + (10 / 2) = 10 annulus, or 40 mil dia. pad.Tim

author: Doctorandus_P
author_rank: Super Contributor
timestamp: March 01, 2019, 10:52:42 pm
content: The only reason the holes have a radius is that the're supposed to be made with a mill.perfect rectangular holes would also work, but are dificult (and therefore expensive) to make.Beware of tolerances. you need a bit of room between the holes and the stuff that fits into the holes.Size of pads are indeed not given. For machinal soldering you can get away with thin anular rings around the pads, but for hand soldering it's easier to make the pads a bit bigger, for better heat transfer from you soldering iron to the plated through hole.
Understand Current Limit Vs Duty cycle graph - Page 1
Forum section: electronics / projects

author: anishkgt
author_rank: Frequent Contributor
timestamp: January 09, 2021, 12:53:42 pm
content: Hello all,I am looking at ways to work with 12V from a wide input range, preferably 5V to 40V. Are buck or boost converters tolerable when Vin=Vout ? or should they be always a Volt low or high ?I came across this (https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MP3213/document_id/1111) where it says the switch current is 3.5A and most of its graphs are limited to 1000mA reading. The i see the Current Limit vs Duty Cycle graph where it shows up to 3.5A. Based on the calculated duty cycle of 67% i get close to 2.7A current limit. Does this suit my purpose of sourcing 2A from the IC ?The 12V from the IC is further stepped down to 5V to power an LCD and an Atmega328 and the 12V would supply an n-mosfet driver. The FETS are switched on for a max 200ms Max with intervals of 1second between each trigger.
Understanding a fan controller to adjust the temperature response - Page 1
Forum section: electronics / projects

author: Agent24
author_rank: Regular Contributor
timestamp: May 11, 2019, 10:07:41 pm
content: I have an Anteq Basiq 350 Watt power supply. I've just replaced the capacitors as most of them had failed.I want to modify the fan controller circuit so that the fan runs faster, but preferably keep some kind of dynamic control so it doesn't just run at full speed all the time.I've seen a basic modification which is to add a 2k2 resistor in parallel with the thermistor, but I don't know if this will do what I want. I'd also like to understand the circuit in more detail anyway, for my own curiosity.The schematic I've reverse engineered from the fan controller PCB is attached.I think I understand most of it, except how to actually adjust it.Here's how I think it works - if I've made any errors please correct me and explain!...The 150R resistor provides a minimum voltage to the fan so it cannot stall, even if the controlling transistor is in cutoff.C1 provides a kick-start feature to ensure the fan runs at full speed for a few seconds at power up, and won't stall if the controller is at minimum speed(Voltage across the fan was only about 3v when cold)Once C1 charges, the controller takes effect. However, C1 must be discharged when the PSU shuts down, to ensure the kick-start feature works on next power up.This is done via D1 and the 3k resistor, while the 300R resistor, R6, keeps D1 reversed biased when power is applied, to prevent discharging of C1 during operation.I assume R5, being 1%, had something to do with the actual temperature/speed curve. I am not so sure. Some quick research on thermistor circuits suggests this resistor is there to linearise the thermistor's response in the targeted working range.I wonder now if R1 and R2 may have something more to do with the actual parameters of the fan controller, since the base drive to the A733 transistor is derived at this junction anyhow.
Understanding best practices - Visual PCB Inspection - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: December 02, 2017, 08:39:46 pm
content: I've been having what I would consider to be gratuitous yields recently from my assembly house. Some things are easy to spot such as shorts on TSSOPs, solderballing, unconnected leads on connectors.I want to put together a checklist with pictures for production and assembly so there's no question what they should be looking for and when to put the board back into the bag and send back before powering it on.Does someone have a good reference for insufficient, sufficient, and over applied solder for surface mount components? From my recollection, you want to be able to see concavity from the top of the lead to the pad. Is this the case? Or is 50% enough?I've also been noticing an inconsistency between pads on different parts of the PCBs. Some pads are shiny and other dull. What are the precise causes of this and how much of a quality flag is it?

author: Niklas
author_rank: Frequent Contributor
timestamp: December 02, 2017, 09:52:05 pm
content: IPC-A-610 is good start. That standard has separate chapters for different types of technologies and package types. You will also find pictures and illustrations of where to look and how to judge. Solder wetting, component placement, damage and scratches, solder balls and a lot of other things are covered.Note that you will have to define an acceptance class, 1=least demanding to 3=most demanding. The acceptance class should be agreed upon with the assembly house when you place the order. Acceptance class 3 can affect the design of the solder paste stencils as it requires higher heel fillets for some package types.
Understanding chinese motor codes - Page 1
Forum section: electronics / projects

author: Puffie40
author_rank: Regular Contributor
timestamp: March 04, 2021, 04:48:53 pm
content: I've been looking at some electronic motor codes and want to try to understand them.An example:50TKYJ24-4-55335BYJ412PSo far I have determined that the first two numbers are the outside diameter of the motor in millimeters (50mm and 35mm respectively), and the numbers in the middle are an indication of the operating voltage (24V and 12V respectively).The 35BYJ412P motor has 5 wires, so is likely a unipolar stepper motor and maybe referenced by the 4. The 50TKYJ24-4-553 motor, according to AliExpress searches(https://goot-motor.en.alibaba.com/product/60640667632-801270118/Multifunctional_ac_permanent_magnet_synchronous_motor_for_wholesales.html), is a synchronous motor, and the "-4-" is likely a reference to the RPM.So the mystery is the letters in the motor code. is there a reference for determining what kind of motor I have?Thanks!
understanding circuit logic of PID blocks in ltspice circuit - Page 1
Forum section: electronics / projects

author: john23
author_rank: Frequent Contributor
timestamp: March 07, 2025, 03:38:17 pm
content: Hello, There Is this great working PID system I am trying to understand its logic.I am trying to compare this circuit to the classic diagram of PID feedback system.Two questions:1. what is the analog logic of block I designates as 1,how can I analize its tranfer function?2. Why are they inverting the output signal before going into PID?https://github.com/HemakanthNatkunaraja/PID_controlerDesign_in_LTSPICE_Project/blob/main/EC5030_DesignProject_2020e050.pdfLtspice and photos are attached.

author: john23
author_rank: Frequent Contributor
timestamp: March 07, 2025, 05:51:25 pm
content: UPDATE:Hello , what is the logic of all these inverters stages 1 and 3?how does it make our systems feedback functioning?Thanks.

author: tooki
author_rank: Super Contributor
timestamp: March 07, 2025, 06:20:37 pm
content: Well, you are familiar with basic op-amp configurations, right? Trace the signal polarity through the system and it should become obvious why inverting buffers are needed here and there.

author: john23
author_rank: Frequent Contributor
timestamp: March 07, 2025, 08:54:28 pm
content: Hello tooki ,in PID i am not sure if the outcome is suppose to be that way or inverted ' we need to compare the reference signal to the actual signal ,where can I see that the result is inverted for no good reason?Thanks.

author: AussieBruce
author_rank: Regular Contributor
timestamp: March 08, 2025, 03:53:08 am
content: Re 2: The output polarity of a PID is application dependent, sometimes you need the output to go up with increasing input measurement, and sometimes down. It depends on your process. A versatile scheme will be able to swap over with a jumper or whatever.Overall this schematic looks over complicated, a basic PID can be easily done in a 4-pack, or even less if you don't want full functionality.

author: john23
author_rank: Frequent Contributor
timestamp: March 08, 2025, 10:35:04 am
content: Hello,they just inverting twice the output at different stages.So I wonder how can I know If I need to invert the out put of a stage or not to make this functioning.I uploaded the LTspice file.given the signals of the output at time domain at each stage how do i know if i need to invert?Thanks.
Understanding current flow in this converter - Page 1
Forum section: electronics / projects

author: Red_Micro
author_rank: Regular Contributor
timestamp: June 01, 2020, 01:33:45 am
content: Hi,See below a picture fromthis Reference Design.I want to understand the min and max current that can flow to Vin pin. This is what I think:Imin = 235/1.88M = 125 uAImax = (914-500)/1.88M = 220uAIs my thought right?
Understanding hall-effect sensors and why a motor controller won't work - Page 1
Forum section: electronics / projects

author: Fallingwater
author_rank: Contributor
timestamp: May 03, 2023, 05:24:06 pm
content: I have acquired two second-hand electric scooters, one working which we'll call A, and one not working which we'll call B. Note that non-working scooter B has a fascinating variety of mechanical and battery-related issues, but is perfectly able to spin its own motor if a working battery is connected to the power input.Both come with hall-effect sensors in the motor, but the working one has been modified by the previous owner to work with a sensorless controller. With the hall sensors disconnected and the controller finding the rotor's position on back EMF alone, the motor in scooter A spins perfectly happily.I don't like this controller, however, because it's a large overpowered e-bike unit that takes a huge amount of space in the scooter's shell and overloads the battery. Since I have the controller from non-working scooter B available and it has a much more reasonable power level, I want to use it in scooter A - but since it doesn't do sensorless mode I have to connect the hall sensors.However, when I connect B's controller to A's motor, I can't get it to work. If I apply throttle or if I spin the motor by hand *at all* I'll get an E-01 error message on the display, which signals a motor malfunction.I've opened the motor to have a look-see and found the sensors positioned like the picture in the attachment.After a fair bit of testing I've developed a suspicion: while metering them I've noticed that while all three change state as I spin the wheel, sometimes all three are high or low. Judging by what I know, this shouldn't be happening - at least one sensor should always be triggered. Indeed if I power up the controller when the sensors are in one of these all-on or all-off states, I get E-01 without having to spin the wheel by hand.The other scooter's motor never goes all-on or all-off, and I assume this is why the controller is happy with it.Is there a legitimate hall-effect configuration that allows for all-on and all-off states that the controller I have simply does not understand, or is something wrong in the sensors? If something is wrong, then what could it be? I understand that they usually either short or fail to switch states, which isn't what I'm encountering here.