hybridfree/eevblog-posts huggingface dataset:
Take a look at this APC power strip - Page 1
Forum section: electronics / projects

author: Kompost
author_rank: Contributor
timestamp: August 12, 2014, 11:20:30 pm
content: http://www.tomshardware.com/picturestory/661-power-strip-bar-surge-protection.html#xtor=RSS-182Scroll to 10th picture, I don't think there's need for any commentsI can't believe they can charge this much AND give warranty for gear killed by this strip if such things is getting past their QC.

author: TimNJ
author_rank: Super Contributor
timestamp: August 12, 2014, 11:28:39 pm
content: Yuck that's some nasty stuff. I have a few APC surge suppressors. Luckily my lab is powered from a Tripp-lite Isobar Ultra!

author: jebcom
author_rank: Regular Contributor
timestamp: August 13, 2014, 01:43:33 am
content: This is part of the MBA Playbook.http://engineerblogs.org/2011/09/weekend-journal-the-mba-playbook/The money they lose from a little bit of bad will, a few apologies, and a smattering of damage control is far less than it would cost to establish and enforce quality. (or so they think.) The words "pride" and "competence" are not in the MBA Playbook.

author: jackbrouno
author_rank: Newbie
timestamp: August 13, 2014, 11:43:51 am
content: too have some APC UPS units, although my PCs are all on Cyberpower APFC units because of the much better waveform; even my hypersensitive SG-650 is happy with those (it will cut out on an APC UPS).

author: Whales
author_rank: Super Contributor
timestamp: August 13, 2014, 12:04:58 pm
content: Compare the creepage on the coax filter board vs mains filter board. Why not use large on both? Are they not both supposed to both protect against HV spikes? I'm assuming it's "we had to" for mains compliance, but no one cared/noticed for the coax board.
taking advantage of Snubber voltage leak - Page 1
Forum section: electronics / projects

author: anishkgt
author_rank: Frequent Contributor
timestamp: June 09, 2018, 06:44:44 am
content: Hey all,here is my circuit. The load here is a MOT and am trying to detect a voltage drop at the primary when the secondary are shorted when the MOT is powered OFF. During the OFF state there is a voltage of 1.2vac and when the secondary are shorted a voltage drops to 0.2.I've come up (with some support of other) with this circuit where the comparator detects a voltage drop at the primary and uses precision rectifier and goes high when the voltage drops below set voltage of 1.2vac and low when it goes higher but for some reason after getting the PCB done i cannot get it to work.I am not very sound with electronics but am glad i've made it this far. The MOT is part of spot welder project where this part acts like contact sense. In other words the spot welder will be activated when the secondary are shorted on a nickel plate or just shorted. If am not wrong the voltage at the primary is actually the snubber voltage that is leaking. Would it be ok to have a lower R value in the snubber circuit R18 and C16.I would really appreciate if somebody could help me here.

author: anishkgt
author_rank: Frequent Contributor
timestamp: June 09, 2018, 07:32:06 am
content: measured outputsPin2 (-) = 0.025vPin3 (+) = 0.002vPin5 (-) = 0.321vPin6 (+) = 0.02v
Talking Electronics "200+ Transistor Circuits" - for eBook readers EPUB/PDF - Page 1
Forum section: electronics / projects

author: MikeGrozak
author_rank: Newbie
timestamp: February 08, 2016, 11:54:53 pm
content: Please note, that I do not benefit from this work, and I do not sell kits from this manual - all original links are saved, and Colin is the only source of themDear colleagues,After months of slow work and text suffering I've managed to complete the full rebuild of great transistor circuit collectionhttp://www.talkingelectronics.com/projects/200TrCcts/200TrCcts.htmlby Colin Mitchell.There is no need to introduce TalkingElectronics - it's a great collection of small, but very useful and workable circuits, perfect for understanding the practical aspects of electronics and training your soldering skills. It's a great guide for beginners, where one can find a lot of 'building bricks', which provide you a way to build more complex circuits.I was always missing proper eBook version of this manual (EPUB/MOBI), with correct internal navigation and proper displaying on my old Amazon Kindle, so one day I decided to do it myself and convert it to pandoc markdown document. The result of this effort is openly accessible as PDF documents:https://github.com/rhaido/200_transistor_circuits_united/blob/master/200_transistor_circuits.pdfandhttps://github.com/rhaido/200_transistor_circuits_united/blob/master/200_transistor_circuits-light.pdf- and as the EPUB document (which can be further converted to MOBI):https://github.com/rhaido/200_transistor_circuits_united/blob/master/200_transistor_circuits.epub.Further proof reading is required and improvements/pull requests are encouraged, and source code is availableMaybe Colin one day will take this as a basis for his PDF version. The original pdf documents can be found on the site of the "200+ Transistor Circuits" project.
Tandy Model 102 'sleeper' mod (adding LiPo rechargeable batteries internally) - Page 1
Forum section: electronics / projects

author: JonathanHerr
author_rank: Contributor
timestamp: October 02, 2023, 04:01:02 pm
content: Kind of a strange idea, but yeah...I noticed that inside of a Tandy Model 102 (that I have torn down at the moment for NiMh battery backup replacement), there is a space down underneath the keyboard that I could potentially add fit some rechargeable batteries into.The area is about:10-11mm deep (in/out of the unit)175-180mm wide (left-right)37-38mm tall (up/down)I found some batteries online that have a part number of 104050/3.7v/2500mAh(as I write this post, I /do/ realize that the 40 in the part number means 40mm and that's definately too 'tall' for my scenario, and maybe even 10mm is too deep for my scenario, but I could just pick another smaller sized battery to fit the space.)That's basically 10mm thick, 40mm tall and 50mm wide.What i'm wondering/trying to possibly do is this: install 3 LiPo batteries into the unit, and charge the batteries using a USB port hidden somewheres under a cover or by tapping into the main-unit's DC-IN jack as a source of power to the BMS, and then discharging the batteries by some sort of step-down converter (to change the 3x 3.7/4.2v voltage to 6v, which is what the 4xAA battery compartment needs.The issue is this:Looking online I see a lot of BMS solutions that are intended to take 2 or 3 18650-style cells and make a chargable/dischargable 12-some-odd volt battery packs, like for drills or RC cars or the like. But I need something that can charge from 5-6v (preferred, since I could just internally tack a wire or two onto the board's barrel jack connections and tack a wire onto the battery holder compartments' wires, also internally, thereby allowing me to charge the internal LiPo batteries and 'run' off of the internal '6v' battery-holder-power-input (what would have been the 4xAA batteries, but instead would be the stepped-down LiPo cells attached in their place)If this is 'confusing' or you can't understand what i'm wanting, ask any sort of clarification-questions and i'll try to answer best i can?
Tantalium caps and aging - Page 1
Forum section: electronics / projects

author: hifihifi
author_rank: Contributor
timestamp: April 24, 2013, 04:41:49 pm
content: Are Tantalium caps aging if they are used at high temperatures like 50°C.Elektrolytic are drying in time.What is the effect for tantalium caps? or are they "never" aging?

author: free_electron
author_rank: Super Contributor
timestamp: April 24, 2013, 05:34:26 pm
content: wet or dry tantalums ?

author: Unknown
author_rank: Unknown
timestamp: April 24, 2013, 10:17:55 pm
content: They become very leaky, and start to short-out... this can cause slow to sudden power supply failure if used to de-couple pre-amp DC supply rails, normally they take out the DC supply resistors.Other problems can be audio distortion, un-balancing of channels, low level sound, and intermittent crackling from channels, where Tantalum's are used in the signal processing.

author: TimNJ
author_rank: Super Contributor
timestamp: April 24, 2013, 11:19:18 pm
content: Most new tantalums you see/buy today are dry type. They don't suffer from the issues of the wet types that were used in the late 70s/80s era.

author: krivx
author_rank: Frequent Contributor
timestamp: April 25, 2013, 12:06:30 am
content: Modern tantalums will let you know if you reverse bias them though. They'll heat up and fail faster than electrolytics in my experience.

author: Mike Warren
author_rank: Unknown
timestamp: April 25, 2013, 05:09:52 am
content: Quote from: krivx on April 25, 2013, 12:06:30 amYes, and if I hit my window with a hammer it no longer keeps the rain out.The trick is to use items in a way they were designed to be used, or you may not get the performance you expect.

author: sorin
author_rank: Frequent Contributor
timestamp: April 25, 2013, 07:32:30 am
content: Quote from: Mike Warren on April 25, 2013, 05:09:52 am

author: amyk
author_rank: Super Contributor
timestamp: April 25, 2013, 10:15:47 am
content: Theystill makewet tantalums, but their price is...

author: krivx
author_rank: Frequent Contributor
timestamp: April 25, 2013, 10:22:58 am
content: Quote from: Mike Warren on April 25, 2013, 05:09:52 amIt's a handy quick failure though, you'll spot it straight after assembly. Sometimes it's better that your window breaks when you hit it than breaking a day later during a blizzard.

author: hifihifi
author_rank: Contributor
timestamp: April 26, 2013, 12:51:45 pm
content: thank for many responswhat about ESR and capacitance over time?
Tapered or notched FPC connector for a straight FPC cable? - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: November 25, 2024, 03:20:27 pm
content: Hi,I have a display that has a straight FPC cable. But just noticed that the connectors come in either "notched" or "tapered" version.Does the straight FPC fit in both? Or is one preferred/needed over the other?Thank you
Tapping Phantom Microphone Signal for Recording - Page 1
Forum section: electronics / projects

author: circuitdoctor
author_rank: Newbie
timestamp: October 25, 2024, 01:25:10 am
content: Hello eevblog family,I require help regarding a project I am working on. I have a drive thru setup of my own where I have a base station microphone, the document says its a phantom powered microphone with +18V, +18V and GND line. The current base station model doesn't support the recording feature so I decided to make my own. I am looking to tap the signals from the microphone and record them whenever a vehicle is present. I have done the tapping of the vehicle detect logic which is a simple relay logic turning on and off. But I am stuck in the microphone tapping phase. Can someone please guide me where should I start with? Your help will be highly appreciated.

author: Kim Christensen
author_rank: Super Contributor
timestamp: October 25, 2024, 03:01:02 am
content: It would be best to modify the base station and tap the audio after the microphone amplifier inside.But, if you must tap the mic leads, then you could use a differential amplifier that's capacitively coupled. Look at any phantom power mic circuit. Just delete the part that injects the phantom power. (DC volts) You'd have to use shielding and proper construction techniques to avoid injecting hum and noise into the mic circuit.
Tapping RF path for spectrum analyzer - Page 1
Forum section: electronics / projects

author: bernroth
author_rank: Regular Contributor
timestamp: December 03, 2014, 06:51:45 am
content: It has been a long time since I did my ham radio license so I would like to know if I am on the right pathI have a transmitter and an antenna both with SMA connector. My spectrum analyzer has a standard N-type connector.Now I would like to measure the signal between transmitter and antenna and tap the SA in between.I was thinking about putting an RF splitter in the path and connecting the SA with an attenuator on the other output.Most splitters are with N-type connectors but I'd like to avoid putting SMA/N adapters everywhere.If this is the right way to go, which splitter is recommended? Frequency of the transmitter is around 1GHz, SA goes up to 6GHzIf not, what may I use?Thanks!

author: IconicPCB
author_rank: Super Contributor
timestamp: December 03, 2014, 07:03:52 am
content: You can doa number of things...directional coupler---power splitter---nothing--- other than correctly rated attenuator padSpecify expected signal level, identify safe input level into the spec anDecide on how much attenuation You will need in any of above cases to NOT blow up the first mixer in your spec anand go for it

author: aveekbh
author_rank: Regular Contributor
timestamp: December 03, 2014, 02:22:11 pm
content: The "technically correct" way to do this is a directional coupler:In: TransmitterOut: AntennaCoupled: Spectrum analyserThe ones I have used have 16 dB coupling loss between the input and coupled ports, and around 40 dB isolation between coupled and output ports. Between input and output ports, the loss is about 0.5 dB. These are for 2-8 GHz, so for 1 GHz the typical losses may be considerably different.Depending on the TX power and the limits of your spectrum analyser, you might need additional attenuation.Of course, you can also use a power splitter, but this will alter the transmitter to antenna path. The ones I have used have 3.5 dB insertion loss (between common and split ports) and >20 dB isolation (not flat vs. frequency) between the split ports. Once again, select a suitable attenuator for safe operation of the SA.

author: Bud
author_rank: Super Contributor
timestamp: December 03, 2014, 08:36:10 pm
content: Why do you need to make a tap. Just bring the SA input coax cable with a small wire pick up loopclose to the coax connecting the transmitter to the antenna. There will be enough leaked signal to pick up and display on SA screen.

author: w2aew
author_rank: Super Contributor
timestamp: December 04, 2014, 12:01:57 am
content: Here's a few videos on the subject:and:

author: bernroth
author_rank: Regular Contributor
timestamp: December 04, 2014, 06:32:10 am
content: Thanks to all for your replies!@w2aew:I will watch the videos in a minute73DB4EC@Bud:It is all about having a stable and defined setup which does not change if I repeat the measurement two weeks later.@aveekbh:I will consider the directional coupler which is probably the best solution. Not bad for measuring reflected power as well--I will post an update soon!
tc5742000 EPROM - how to program ? - Page 1
Forum section: electronics / projects

author: ale500
author_rank: Frequent Contributor
timestamp: February 01, 2021, 04:18:22 pm
content: I have got (yes, aliexpress, yes they are fake, they are being sold as 27C400 but after nail polish remover they reveal themselves as something else) some tc5742000 EPROMs (Toshiba, 256kx16, DIP40). There is a datasheet here:http://www.bitsavers.org/components/toshiba/_dataBook/1990_Toshiba_Non-Volatile_Memories.pdf,page A87. It seems to have the same pinout as a 27C4096. My MiniPro doesn't read or write them, the original part number is not there and as 27C4096 they ignore my puny attemps at read/write.Any ideas ? (besides stop buying fake chips ;-) )

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 01, 2021, 04:26:20 pm
content: These are for Amigas?

author: ale500
author_rank: Frequent Contributor
timestamp: February 02, 2021, 06:38:27 am
content: I wanted them for a CPU project, I don't have any amigas anymore. When you look for this partnumber many amiga-related results pop up.

author: CJay
author_rank: Super Contributor
timestamp: February 02, 2021, 06:56:58 am
content: Are they ceramic or PDIP?

author: ale500
author_rank: Frequent Contributor
timestamp: February 02, 2021, 11:40:02 am
content: Ceramic with window like in...https://commons.wikimedia.org/wiki/File:4Mbit_EPROM_Toshiba_TC574200D_(1).jpg

author: m k
author_rank: Super Contributor
timestamp: February 02, 2021, 05:42:59 pm
content: 27C4096 and 27C4100 seems to have different pinouts.
TCA0372 audio? - Page 1
Forum section: electronics / projects

author: heinrich.hugs
author_rank: Newbie
timestamp: November 25, 2016, 01:33:16 pm
content: This is my first post and the reason I signed upso I primarily build guitar based audio electronics, and I love using loads of different op amps but its always annoyed me that I have to use a transistor based buffer for actually putting a voltage across speakers. So when I saw that this chip was rated for an amp I was quite surprised, is there any obvious downside for using this in audio applications?ThanksDatasheet:http://www.onsemi.com/pub_link/Collateral/TCA0372-D.PDF

author: Zero999
author_rank: Super Contributor
timestamp: November 25, 2016, 01:50:55 pm
content: The slew rate will be too low to faithfully reproduce treble. It's also quite noisy compared to other op-amps such as the NE5532.http://www.ti.com/lit/ds/symlink/ne5532.pdfWhy not use a dedicated audio amplifier IC? What are your load, power supply and power output requirements?

author: heinrich.hugs
author_rank: Newbie
timestamp: November 25, 2016, 02:07:40 pm
content: Oh right thanks, never knew what slew rate meant... I mainly wanted to make a really clean no eq amp for me to put pedals through so maybe like 10W output over 16ohm speaker and a good bass response. I tried a amplifier chip can't remember what it was called but it required a capacitor over two pins that seemed to select the most amplified frequency?? I'm not sure.

author: karoru
author_rank: Regular Contributor
timestamp: November 25, 2016, 04:02:24 pm
content: The most popular power amplifier IC for audio is LM3886, maybe it was that one?

author: heinrich.hugs
author_rank: Newbie
timestamp: November 25, 2016, 06:33:46 pm
content: No it wasn't that but that looks quite good I might try that instead thanks

author: Zero999
author_rank: Super Contributor
timestamp: November 25, 2016, 07:05:30 pm
content: If it's small and low power, it might have been the LM386.
TCS3472 Color sensor sensitivity - Page 1
Forum section: electronics / projects

author: VanitarNordic
author_rank: Frequent Contributor
timestamp: June 15, 2018, 06:04:29 pm
content: I have a project which should distinguish between two colors which could be quite close to each other. Therefore two comparable colors will not be for example Green and Black which are quite different. Two comparable colors could be for example blue and just a little bit darker than the first one. What sensor do you suggest?I have selected the TCS3472 but I am not quite sure if it could handle this sensitivity.
TCXO crystal oscillator project ideas - Page 1
Forum section: electronics / projects

author: Homer J Simpson
author_rank: Super Contributor
timestamp: January 21, 2013, 01:34:04 am
content: I picked this up off Ebay yesterday-not here yet.It was cheap with no bidders. Listed as a new made for Tektronix part.1 Megahertz temperature controlled oscillator.Any one have any project ideas???

author: poorchava
author_rank: Super Contributor
timestamp: January 21, 2013, 10:16:35 am
content: DDS arbitrary generatorFrequency counter

author: Deepak
author_rank: Regular Contributor
timestamp: January 21, 2013, 04:31:06 pm
content: That thing was practically made in my back yard!I second the signal generator suggestion.

author: mamalala
author_rank: Unknown
timestamp: January 22, 2013, 02:43:02 pm
content: TCXO is aTemperatureCompensated oscillator. Due to careful part selection and circuit design the output frequency only has little variation with temperature changes. This is not a controlled or stabilized oscillator.If you want a rather stable crystal oscillator, you have to look for anOCXO, which is anOvenControlled oscillator. That type of oscillator has the crystal and circuitry inside a small, temperature regulated oven. That way the whole thing is kept at a fixed temperature and external temp changes have virtually no effect on the output frequency.Greetings,ChrisEdit: Also, instead of 1MHz it is better to get one with 10MHz, since that is a very common standard/reference frequency for counters and such. If you need an even more stable reference, you can check eBay for a FE-5680A. That is a rubidium frequency standard. There are many of them available as used units, pulled from mobile phone/data equipment towers.

author: poorchava
author_rank: Super Contributor
timestamp: January 22, 2013, 04:20:02 pm
content: I have read somewhere that the line between TCXOs and OCXOs lies somewhere around 0.2-0.3ppm nowadays. It depends on what this particular one has (couldn't find specs for it). If that one you have bought is 2.5ppm, then it is not that great. Of course it is still waaay better than any conventional crystal, that typically would have like 50ppm or more.

author: nctnico
author_rank: Super Contributor
timestamp: January 22, 2013, 06:54:57 pm
content: A 2.5ppm TCXO costs a few dollars these days when bought in single pieces. I'd find out what the specs are first before embarking on a project.
TCXO Digital Quartz Clock - Page 1
Forum section: electronics / projects

author: arielberschadsky
author_rank: Newbie
timestamp: January 17, 2016, 01:46:42 am
content: I am sharing my design for a simple digital clock with light sensor, basedon a highly accurate TCXO quartz oscillator. Attached is a full schematic andnotes and comments, along with some of the relevant data sheets. I hope this material is of use to other beginning electronics hobbyists who might want to build a digital clock and understand how it works. If any ofthe more experienced members of this forum have any comments or suggestionsfor an improved design, it would of course be appreciated. Due to file size limitations, the schematics are highly compressed and low resolution. If you need a higher resolution version, as well as photographs of the finished clock, just send me an email and I will send them to you directly.

author: arielberschadsky
author_rank: Newbie
timestamp: January 20, 2016, 04:16:02 am
content: Photograph of the Finished Clock. Higher resolution available upon request.
TCXO pin out - Page 1
Forum section: electronics / projects

author: And
author_rank: Newbie
timestamp: March 03, 2016, 10:02:18 pm
content: Hello!Someone knows this oscillator?Can you tell me the pinout?Thanks in advance.Ciao.And

author: mmagin
author_rank: Frequent Contributor
timestamp: March 03, 2016, 10:31:06 pm
content: That looks like one of those standard-ish OCXO/TCXO pinouts. I'd try the same thing as another part with the same form factor (look at datasheets from the major brands of that stuff). Certainly the pin that is not insulated from the case is ground. Probably another is 12v, another is the RF output, one is a logic level oven-up-to-temperature output, and one is maybe a EFC input.The tough thing is that a lot of these you find surplus were made with a special part number for a specific customer and you can't find anything searching for the numbers on it. Also, no guarantee that it runs off 12V, just that that's common!

author: And
author_rank: Newbie
timestamp: March 04, 2016, 02:18:11 pm
content: Thank you mmagin for info.After some tests I found that pin 5 is GND, the 4 is OUT, the number 2 if the food with 5 Volt comes out the 26MHz.Absorption is very low, only if food also the number 1 using a 1k resistor then the absorption increases and the output increases, but if the resistance short circuit turns off everything.Some new info?Thank you.

author: mmagin
author_rank: Frequent Contributor
timestamp: March 04, 2016, 08:55:31 pm
content: Cool, though I don't know "food" in this contextIf you're talking about the EFC input, it only can pull the frequency a tiny bit (maybe a couple hertz) for trimming it slightly or use as part of a PLL with an external reference (e.g. gps).In the case of better OCXO's, you'll find that it's probably within 100 ppb (or much better) once warmed up without doing anything to it though.
TDA databook - Page 1
Forum section: electronics / projects

author: Simon123
author_rank: Regular Contributor
timestamp: February 16, 2017, 09:47:24 pm
content: Hy!Does anyone have complete TDA chips databook. Like PDF or something?I know there are seperate datasheets for these chips, but i need a databook or list pretty much complete list of them.Thanks.

author: Kalvin
author_rank: Super Contributor
timestamp: February 16, 2017, 10:59:14 pm
content: Have you searched Archive.org?https://archive.org/details/texts

author: wraper
author_rank: Unknown
timestamp: February 16, 2017, 11:19:18 pm
content: I don't think such thing exists, and there isn't really a point in it. TDA ICs are made by many manufacturers and those ICs are very different, from SMPS controller to delay line on switching capacitors. No point grouping them into the same databook.

author: nctnico
author_rank: Super Contributor
timestamp: February 16, 2017, 11:35:59 pm
content: @wraper: not so fast! I used to have a catalog-ish book with many TDA and other chips listed (short functional description and pin layout). IIRC it was printed in the early 80's and I got it from a book outlet.

author: wraper
author_rank: Unknown
timestamp: February 16, 2017, 11:44:57 pm
content: Quote from: nctnico on February 16, 2017, 11:35:59 pmThe key word here is80's. At those times databooks were popular because there were no datasheets and manufacturer product search on the website you can find on internet nowadays.

author: free_electron
author_rank: Super Contributor
timestamp: February 17, 2017, 12:29:33 am
content: Quote from: nctnico on February 16, 2017, 11:35:59 pmthe yellow ones with the little owl on the front ? those were made by ECA in germany. i had the transistor crossref books.

author: Cliff Matthews
author_rank: Unknown
timestamp: February 18, 2017, 03:28:21 am
content: Some #'s haven't yet been put out to pasture. Eghttp://www.dipmicro.com/store/TDA7294VThere's a good bunch of info aroundhttp://www.st.com/content/st_com/en/search.html#q=TDA-t=keywords-page=1
TDA1085 Washing machine motor speed controller project - Page 1
Forum section: electronics / projects

author: nikifena
author_rank: Regular Contributor
timestamp: July 12, 2016, 09:41:41 pm
content: Hi guys. I'm working on a new design - AC speed controller for motors with tachogenerator. Mostly you can find them cheap from old washing machines, but the motor must be brushed. Checked over the net and found some projects with different chips. I chose TDA1085. At this time I draw the schematics and I'm almost done with the PCB design.There are six 1206 resistors below the 1uF X2 capacitors, but there is enough space for themThe PCB has dimensions 49x90mm I'd like to fit two boards into 100mm with 2mm router between themAny suggestions are welcome
TDA2030 amp problem - Page 1
Forum section: electronics / projects

author: IO390
author_rank: Regular Contributor
timestamp: April 25, 2014, 08:33:41 am
content: I'm posting on behalf of a friend.He's built a TDA2030-based amp (find attached schematics) and it works fine, driving a small speaker when there is an input. When the input is removed, the output becomes high frequency noise at about 3V p-p.The amp has been birds nested (point-point) nicely so I don't see any issue there. All of the small caps are good film types. I've built the same circuit before and had no issues.Any help/advice is greatly appreciated.

author: David_AVD
author_rank: Super Contributor
timestamp: April 25, 2014, 08:45:47 am
content: I think a picture of the constructed unit is an absolute requirement to troubleshoot this.

author: Whales
author_rank: Super Contributor
timestamp: April 25, 2014, 10:46:00 am
content: What do you mean by 'removing the input'? Is the pin on the op-amp physically not connected to anything?Make sure to "tie" all pins to something at all times (ie ground or +Vs) with a high value resistor. "Floating pins" act a bit like antennae on voltage-sensing devices like op-amps: random garbage gets picked up, amongst other things.

author: Anks
author_rank: Frequent Contributor
timestamp: April 25, 2014, 12:24:00 pm
content: Normally you would have a jack plug that grounds out the input when removed but the input line should still be pulled to ground by a resistor say about 1M. The input should ideally be made with a shielded cable that is earthed only at one end but this is more important in high gain amplifiers.You could also try adding a filter but as it works with a input I would say this will just cut off sound in the hearing range.Having a quick look back at the schematic are you using a pot on the input and is one side of it connected to ground?

author: Neganur
author_rank: Unknown
timestamp: April 25, 2014, 10:13:11 pm
content: Make sure you have that 22k input potentiometer attached, it's the one that ties the input to ground without any input source.Is it powered from a battery? If not, try it to see if your PSU might have enough ripple/hum to actually couple to the input via that 100k resistor at the input (1). The circuit has some 30 dB gain in that configuration.Rats nest can also be a fantastic antenna for all kinds of noise like fluorescent desk lamps.You said film caps, the ones decoupling the supply voltage should be electrolytic and ceramic (or something else with nice low ESR)What frequency is the output 3Vpp ? try having an additional RC series circuit from the output (4) back to the inverting input (2), something like 15k and 68pF (= 20kHz upper cutoff)
TDC7200 Power Consumption - Page 1
Forum section: electronics / projects

author: FenTiger
author_rank: Regular Contributor
timestamp: March 04, 2020, 12:14:47 am
content: The Texas Instruments TDC7200 is a precision timing IC which has featured in a few of the projects on this site.Looking at its data sheet, I found this oddity.Somehow I suspect that it doesn't actually need 87 amps of Vdd current just to operate its SPI interface.I think the data sheet isn't displaying properly. I'm guessing that there's a missing µ (micro sign, in case it doesn't show up) in front of all the silly numbers, but that's just a guess. Can anyone confirm it?Does anyone have a (link to a) data sheet that contains sensible numbers?

author: Vgkid
author_rank: Super Contributor
timestamp: March 04, 2020, 12:20:03 am
content: It is uA , though Iqa is mAhttps://www.google.com/url?sa=t&source=web&rct=j&url=http://www.ti.com/lit/gpn/tdc7200&ved=2ahUKEwie1Ia_xf_nAhUJneAKHVTZBLIQFjAAegQIAxAC&usg=AOvVaw2qPxwP-yzSwg-O6hKVv0cSWorks for me.
TDK LAMBDA VEGA 650W modular powersupply, fixed primary pwm, teardown - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: May 26, 2022, 10:42:18 am
content: I just released two videos about this type of powersupplyTDK LAMBDA VEGA 650W modular powersupplyhttps://youtu.be/2064hOTGZi8TDK LAMBDA ALPHA 1000W modular powersupplyhttps://youtu.be/i03fjjAap44Both designs use the same topology, and same style sec sidesthe sec side modules are not interchangeable between those two modelsThe switchmode know-how dudes of this forummight find a few things interesting in the videos,specially the fixed pwm primary common to all sec modulesand the sec module end regulation is done very smart,
TDM Audio transport. Have I f!cked up this design? - Page 1
Forum section: electronics / projects

author: Yansi
author_rank: Super Contributor
timestamp: November 25, 2019, 09:16:02 pm
content: Hello,I have designed an application, that uses the CS4244 audio codec.Datasheet here.I wanted to be able to operate at both 48k and 96k sample rate. I havefixedthe MCLK to 24.576MHz.Now I am not sure if I have fucked up.For 48kHz operation, I designed it so I'll have 12.288 MHz SCLK at 256fs andfor 96kHz operation SCLK will be same as MCLK, 24.576 MHz at the same 256fs.My TDM signal source does not support frame any larger than 256bits (256fs).Now reading through the datasheet, I'm not sure whether this is possible after all.Relevant chapter in the datasheet is for example"6.3 Clock & SP Select (Address 06h)". And then there is this very worrying note below the table"SWITCHING CHARACTERISTICS - SERIAL AUDIO INTERFACE"at page 19, saying:"26. MCLK must be synchronous to and scale with FS".Another relevant is "4.4.3Slave Mode Clock Ratios".I have fixed 24.576MHz, so it does not scale.Y.

author: Yansi
author_rank: Super Contributor
timestamp: November 25, 2019, 09:40:23 pm
content: I try to answer myself, as how do I (or at least did understand the damn datasheet) when I have designed the board in March:48kHz shall be SSM (Single Speed Mode).96kHz shall be DSM (Double Speed Mode). That is clear.According to Table 5. page 27, I in fact can have MCLK at 512fs and SCLK at 256fs, in a SSM, 48kHz.At 96kHz, there is no other option than 256fs MCLK and 256fs SCLK. Good.If I understand the above correctly, I set the device as following, regarding the "6.3Clock & SP Select (Address 06h)" register:BaseRate= 48k (both for 48kHz and 96kHz of my operation modes)MasterClockRate= 010 (512xFs in Single Speed Mode or 256xFs in Double Speed Mode)and the only difference shall be theSpeedMode= SSM for 48k and DSM for 96k. Done.Hopefully, I am correct and these two posts will remain a useless complaint.Thanks for any moral and tech support on this oneI'd rather not bodge the PCB in any way.Y.//EDIT: Typos.
TDR and velocity factor - Page 1
Forum section: electronics / projects

author: asap3210
author_rank: Newbie
timestamp: January 26, 2021, 04:26:14 pm
content: Hello, first post here.I've built the TDR with the 74ac14 as shown at wae2w yt video ()It seems to work fine, but when it comes to test it with a coax 5.55 meters long, I read 72 nS, which according to the average velocity factor of 0.659 it results in 5.77 meters. Is this an error in the Velocity Factor? (I have no way to find out the real VF, all I can read is "Noisless" and a logo)Thank yhou

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 26, 2021, 04:39:18 pm
content: It looks to me like you're not measuring between the same point on the rising edges.If you want a nice treatise on TDR, read the Tektronix 1S2 manualhttps://w140.com/tekwiki/images/b/b9/070-0889-00.pdfAnd thishttps://w140.com/tekwiki/images/1/1d/062-1244-00.pdf

author: penfold
author_rank: Frequent Contributor
timestamp: January 28, 2021, 11:24:05 am
content: hi,Ditto onQuote... but from guessing scale it wouldn't make a substantial differenceThe 0.514 VF you'd get from your numbers looks a little on the low side for common coaxes, but purely speculating maybe if it actually lives up to its name as a low noise variety (it may be a fancy dielectric for low tribolectric noise etc)My advice would be to measure cable impedance by finding whatever termination resistance kills the reflection and measure the bulk capacitance (at as low a frequency as you can) (either with an LCR meter if you've got one or by treating it as a capacitor in an RC network (maybe with 50k-100k so the frequency is low KHz) and measure from cutoff frequency) then you can get a second guess at the VF doing some maths

author: Renate
author_rank: Super Contributor
timestamp: January 28, 2021, 08:22:17 pm
content: Velocity factors for various cables, even the same type is all over the place.I would just calibrate on a long length.I've only used TDRs tomatchcables.

author: rstofer
author_rank: Super Contributor
timestamp: January 28, 2021, 10:33:25 pm
content: So, we're talking 3% using a very short piece of wire... Here is a table of Velocity Factors and they are all over the place:https://www.febo.com/reference/cable_data.htmlTry your test on 100' of cable, terminated and unterminated.You might try some Cat5 or Cat6 network cable. I think the VF is better controlled. Here, for Cat6 the VF is specified as .68 and I would expect the cable to measure pretty darn close:https://www.multicominc.com/training/technical-resources/cat5-vs-cat6-cable/For my purposes, finding faults, 3% would be pretty good. +- 30' in a 1000' run? Sure, that would give me a start.Most of the time I was looking for reflections at patch panels or just kinks in the cable. I already knew the length of run, it was from one building to another building, underground in a duct bank.

author: bson
author_rank: Unknown
timestamp: January 29, 2021, 08:41:52 pm
content: The velocity of propagation varies significantly. That's why we measure it.Don't forget to measure without any cable at all to establish a null.
TDR function in Cisco routers. - Page 1
Forum section: electronics / projects

author: SN
author_rank: Newbie
timestamp: May 04, 2024, 05:50:45 pm
content: Does anyone have intimate knowledge of the characteristic and timeline of pulses sent from the port of a Cisco router or switch during their built-in TDR test function?I expect this is proprietary information and won't be outlined in any technical manual Cisco publishes.It sounds like similar functions are now available from other manufacturer in recent years, so maybe there is more public knowledge available than what I've been able to find online.Thanks in advance!

author: madires
author_rank: Super Contributor
timestamp: May 04, 2024, 06:18:19 pm
content: I don't think any vendor will publish signal details of their TDR function for Ethernet ports. But a DSO might give you an answer.

author: SN
author_rank: Newbie
timestamp: May 04, 2024, 06:31:00 pm
content: Yes. I certainly plan on getting a capture for myself at some point. I am also wondering if other router manufacturers have basically standardized on a signal scheme for TDR functions or if they're all doing their own thing. If I read it right, Cisco requires about 5 seconds per port to run the test. I assume a great deal of that time is for processing/analysis.

author: alm
author_rank: Super Contributor
timestamp: May 04, 2024, 06:56:09 pm
content: I've seen PC motherboards that also incorporate a TDR function. For example usingthis IC. There is some informationhereandhere. TI also has anapplication note on TDR using Ethernet transceivers.

author: coppice
author_rank: Super Contributor
timestamp: May 04, 2024, 07:20:22 pm
content: Isn't cable measurement a standard part of the echo cancelling function for gigabit ethernet and above?

author: SN
author_rank: Newbie
timestamp: May 04, 2024, 07:38:24 pm
content: Quote from: alm on May 04, 2024, 06:56:09 pmThat's exactly the kind of information I was looking for. Marvel's documentation expresses this function as "Virtual Cable Tester" and it seems to be a registered trade name. Thanks!

author: madires
author_rank: Super Contributor
timestamp: May 04, 2024, 08:01:57 pm
content: Quote from: coppice on May 04, 2024, 07:20:22 pmEach side sends training sequences to learn how the echo looks like, to determine what to expect as echo when sending data. If the echo is different then the other side is also sending data. The other's side data is the difference between the expected echo and the received echo.

author: SN
author_rank: Newbie
timestamp: May 04, 2024, 08:44:11 pm
content: Thanks to ALM for turning me to TI's site!While browsing, I found a slightly newer Application Note for working with TI's built-in TDR function.https://www.ti.com/lit/an/snla330/snla330.pdf?ts=1714855065817&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FDP83825I
TDR power supply - Page 1
Forum section: electronics / projects

author: james_s
author_rank: Super Contributor
timestamp: April 23, 2017, 01:08:12 am
content: I did a PCB for the time domain reflectometer presented by the Mr Carlson's Lab YouTube channel. He showed a PCB for it but I never found anywhere to download the board files so I did my own based closely on his design. This is just the power supply portion, I built the avalanche pulser circuit free form in a BNC connector shell without a PCB. I designed the board so that it can be etched as a single layer PCB if you would like to etch it yourself although it uses 0603 parts so you'll need to have the etching process pretty well tuned if you choose to do that. Both KiCad files and gerbers ready for production are provided here. This is a tested and working design, I've built one from this layout. This fits nicely in a Hammond 1590A cast aluminum enclosure along with a single AA or C battery holder.
TDS Sensors - Recommendations? - Page 1
Forum section: electronics / projects

author: amurdoch22
author_rank: Newbie
timestamp: June 08, 2021, 01:40:50 am
content: Good DayI'm working on an automatic nutrient dosing system, and I'm wondering what TDS sensors people recommend?The main three I run into are:https://www.seeedstudio.com/Grove-TDS-Sensor-p-4400.html- Seedhttps://www.dfrobot.com/product-1662.html- DFRoboticshttps://atlas-scientific.com/kits/conductivity-k-1-0-kit/- AtlasThe first two look identical, and they're probably are, but is there a good reason to go with the Atlas products? It will be unlikely for the PPM to exceed 1200, as the plants will be in DWC.Ang suggestions are welcome.

author: SmallCog
author_rank: Frequent Contributor
timestamp: June 08, 2021, 05:28:44 am
content: We use a lot of these at workhttps://in-situ.com/pub/media/support/documents/AquaTROLL100-200_Spec-Sheet.pdfProbably overkill for what you're doing.We mostly talk to them over SDI-12 but they also do Modbus and 4-20mAPretty neat bits of kit

author: amurdoch22
author_rank: Newbie
timestamp: June 09, 2021, 01:57:56 pm
content: Thanks, I'll take a look
TDS3000 Series Oscilloscope replacement knobs - Page 1
Forum section: electronics / projects

author: vinovino
author_rank: Contributor
timestamp: April 08, 2025, 04:53:51 am
content: I currently have a TDS3000 series oscilloscope with broken knobs, and I am having trouble finding exact replacements.I see knobs for the TDS2024 and TDS220 oscilloscopes on the market.Do the knobs for the TDS2024 and TDS220 fit the TDS3000 series oscilloscope?

author: calibrationfixture
author_rank: Regular Contributor
timestamp: April 22, 2025, 07:08:41 am
content: Hi vinovino,The Knobs (Hard Style) used on your TDS3000 are:- 366-0771-00 and- 366-0772-00Source: Page 131 of the free downloadable TDS3000 Series Service Manual: 071-0382-01. With looking at the other series Service Manuals you can see similarities. And yes these Partnumbers are the same as used on the TDS2000 Series. There are also functional comparable Soft Style Knobs (used on for example TDS5000(B) Series).Calibrationfixture
TE Standard Power Timer (SPT) terminal crimp tool? - Page 1
Forum section: electronics / projects

author: r-mm
author_rank: Contributor
timestamp: December 22, 2020, 12:41:39 am
content: Hi allWondering if any intel on a crimp tool for TE's SPT (Standard Power Timer) terminals. Here is an example. A 'regular' open terminal crimp destroys the terminal.https://www.waytekwire.com/item/38291/TE-Connectivity-927835-2-Standard-Power-Timer/I make low volume sub harnesses for Euro cars so I want a good tool but do not have a production level budget so to speak. The best I've found so far is the following die for the Pressmaster MCT:https://www.alliedelec.com/product/pressmaster/4300-3426-aab/70746791/

author: Simon
author_rank: Unknown
timestamp: December 24, 2020, 10:28:06 am
content: TE usually have a range of tools, they will always be expensive. I just made work spend £500 on a tool to make 300 crimps as trying to get 300 crimps right with the wrong too did not bear thinking about.

author: r-mm
author_rank: Contributor
timestamp: January 11, 2021, 01:20:20 pm
content: For future generations reading this post. Hello. I hope the world is a better place. I incorrectly stated a 'normal' open barrel terminal deforms the SPT. I was mistakenly using SPTwith sealterminals. "regular" SPT terminals crimp fine to the naked eye. I also bought the ~$100 die I linked to and they crimp nicely with those as well.
tea heater like, power connector - Page 1
Forum section: electronics / projects

author: tozitom
author_rank: Contributor
timestamp: December 18, 2020, 11:43:18 am
content: Hi forum,I've searching for a tea heater like power connector - the quick connect one - for one of my project. Could not yet found anything commercial... any suggestions?The idea is to to power supply (230V - max 1A) to a moving trolley when it's on its docking station - the trolley is battery powered, but will need 230V when docked...

author: Gyro
author_rank: Super Contributor
timestamp: December 18, 2020, 07:27:37 pm
content: I can' really help you with sourcing (if it is for more than one-off), unless you can use spare parts, but you may have more success on the web using the search term 'kettle base connector'.Edit: Other than that, you could maybe use something like a standard IEC connector with additional mechanical chassis locating pins and cones to achieve alignment before the connector mates.

author: mag_therm
author_rank: Frequent Contributor
timestamp: December 18, 2020, 07:32:21 pm
content: Take a look at Wampfler's site. search "contacts" etcEdit maybe search this company: Conductix-Wampfler, fully owned by Delachaux Group

author: Benta
author_rank: Super Contributor
timestamp: December 18, 2020, 09:24:11 pm
content: For this kind of application, I'd look into magnetic contactless power transfer instead.

author: mag_therm
author_rank: Frequent Contributor
timestamp: December 19, 2020, 12:49:35 am
content: Quote from: Benta on December 18, 2020, 09:24:11 pmYes, maybe, but Cost (+) , Efficiency (-)Moving contacts are ubiquitous, highly developed

author: tozitom
author_rank: Contributor
timestamp: December 19, 2020, 09:24:56 am
content: thanks all.Will have a closer look at Wampfler's...Contactless is not an option at this stage of prototyping, to much cost involved for this kind of power, and also need direct 230V, so contacts is the way to go.Anyway, I've already ordered parts from china to test later, but for now, as I cannot wait 1 or 2 months to get parts from china, I think my old kettle will be part of this proto... but will have to buy a new one for inhouse, I don't think it will go unnoticed!