hybridfree/eevblog-posts huggingface dataset:
Green thing that came with my T12 Clone? - Page 1
Forum section: electronics / beginners

author: DasDingleberg
author_rank: Newbie
timestamp: May 26, 2021, 09:30:16 am
content: EDIT: SOLVED - it is in fact a spare tilt switch included by the seller(right is just rubber feet)aliexpress(DOT)com/item/32994824865.html?spm=a2g0s.9042311.0.0.49744c4dgOWW6S^product in question, all the documentation should be here cos there isn't any in the boxObviously I'm referring to the "Dongrong SW-200D". I'm an absolute novice who bought this as my first station to put together keyboards. According to Google this is some sort of tilt-switch, maybe I have to install this somehow to get access to the station's sleep function? This is all I found about the sleep/wake on the product page:QuoteAny help here would be greatly appreciated.

author: Jwillis
author_rank: Super Contributor
timestamp: May 26, 2021, 09:46:08 am
content: Tilt sensor for which ever T!2 handle you prefer .

author: bobbydazzler
author_rank: Regular Contributor
timestamp: May 26, 2021, 09:48:06 am
content: I'm guessing if you have an iron holder that green thing can be used somehow to detect when the irons in the holder and put it too sleep.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 26, 2021, 10:28:21 am
content: Replacement fuse?

author: Jwillis
author_rank: Super Contributor
timestamp: May 26, 2021, 11:02:27 am
content: Quote from: bobbydazzler on May 26, 2021, 09:48:06 amNo iron holder required . It just detects movement of the handle . When you park the handle for a period of time the soldering unit counts down with an internal timer and shuts the heat off. When you pick the handle up again the unit will heat up again to the preset temperature.

author: Fraser
author_rank: Super Contributor
timestamp: May 26, 2021, 11:13:40 am
content: I remember reading that the ‘shake to wake’ had issues on some irons. The tilt switch is the shake to wake sensor so either it is for retro fitting into a handle not equipped with such, or it is a ‘known good’ replacement for a failing or unreliable tilt switch originally fitted in the irons handle. It could be just a spare for a known weakness in the design ? The seller may be trying to avoid returns due to failed shake to wake sensors in hand pieces by supplying the required part at time of sale.See here for a review, capacitor failure and no ‘shake to wake’ functioning.https://youtu.be/cowgbwU3b5cAnd the ‘shake to wake ‘ fix is detailed here.....https://youtu.be/xJXJwog7bHYFraser

author: DasDingleberg
author_rank: Newbie
timestamp: May 26, 2021, 11:47:08 pm
content: Have confirmed with the seller that it is indeed a spare tilt switch. Thank you guys!
Greenlee/Paladin PA8000 Crimping Dies - Page 1
Forum section: electronics / beginners

author: PedroDaGr8
author_rank: Super Contributor
timestamp: July 10, 2017, 06:08:06 am
content: So I recently came upon a Greenlee PA8000 crimper for pretty cheap (under $20) but it came with an RJ50 die, which is pretty much useless. Are there any good dies for use in electronics? I am looking to crimp things like headers, insulated connectors and other basic jellybean kinda connectors.EDIT: Apparently, this is also the same thing as the Ideal Crimpmaster-II

author: rs20
author_rank: Super Contributor
timestamp: July 10, 2017, 06:14:36 am
content: Geez, either you're very lucky, or I'm very dumb. I just recently paid a lot more than that for exactly the same thing. I use it to crimp BNC and SMA cables.I think you're thinking about this backwards -- as you work on projects, you can decide whether you want to build certain cables, and then figure out which PA8000 dies would suit that requirement and buy it there and then. It seems a bit odd to me to just buy a bunch of dies without knowing what they're for?

author: PedroDaGr8
author_rank: Super Contributor
timestamp: July 10, 2017, 03:57:06 pm
content: Quote from: rs20 on July 10, 2017, 06:14:36 amI guess I was really bad at explaining myself.Mainly, I am looking at the connectors that I mentioned before.For the insulated connectors like the following:It seems like there are multiple crimping dies for use with these kinds of terminals. I will likely need to figure out which one is the best for this use.My biggest question is that I prefer to crimp the following kind of header connectors and was looking to see if there are any dies which will work with them. These are the arduino style header connectors, nothing special or fancy.https://www.pololu.com/product/1930I can change the kind of connector to a degree if there is one that works better with the 8000. It almost seems like despite reguarly being recommended the 8000 series crimper is really intended for coaxial type applications and not smaller stuff.
Greetings! :D A rookie question! - Page 1
Forum section: electronics / beginners

author: Ohmzilla
author_rank: Contributor
timestamp: September 30, 2016, 03:57:37 am
content: Just getting into the hobbyist field also in my first year of EE school.Is there a resource online that has open access to board schematics?What program do you guys normally use to view them?I have some basic kit in a Hakko 888D ironThe Mastech MS8229 Meter not great but will get me thru school.Currently shopping around for a bench PSU so any advice for one in the $150 range would be helpful and MUCH appreciated.I look forward to picking the communities brain for interesting projects.THANK YOU AGAIN!

author: danadak
author_rank: Super Contributor
timestamp: September 30, 2016, 10:19:21 am
content: "Is there a resource online that has open access to board schematics?"Great archive of many magazines with projects and schematics -http://www.americanradiohistory.com/For actual board design layouts github has a ton of stuff, element14.com as well.Regards, Dana.
Greetings! Power supply advice Lambda LPT-7202-FM - Page 1
Forum section: electronics / beginners

author: petew
author_rank: Newbie
timestamp: July 28, 2019, 08:45:23 pm
content: Greetings to the forum from the high desert of New Mexico USA! I've fiddled around with electronics since forever, and went through coursework at the local community college way back when the 8086 was the newest thing around.I'm putting together some bits and pieces to get a proper lab up and running. I scored a Tektronix 2213 CRO a couple of years ago for a measly five bucks! Works like a champ after some basic cleanup. A Haako soldering station is on the way from Amazon.I've run across what seems a decent deal on a Lambda LPT-7202-FM bench power supply that looks to be in pretty good shape. I have no idea if it works, but the surplus joint I frequent usually checks things out and notes if there are problems. This probably came from Los Alamos National Laboratory, or Sandia Labs.This thing is rated 0-7V at 5A, and two times 0-20V at 1.5A. I downloaded the service manual and it looks pretty basic and straightforward.Is this worthwhile for $125 Yankee Bucks? Seems worth it to me since I found a refurbished one on ebay at close to $400 with shipping. Even if it's a fail, should be good learning material and junk bin parts.What do y'all think?Thanks in advance!

author: bob91343
author_rank: Super Contributor
timestamp: July 28, 2019, 09:07:39 pm
content: How much it's worth is a value judgment. If you can afford it and can't find a better deal, then I guess it is worth the money. I presume you have scanned the web and found the best price, so go for it.Unless the power transformer is bad, the unit is repairable I am sure. I don't think you'll find many, if any, proprietary parts in it that you might have to replace. Maybe the vendor will guarantee the transformer.

author: edavid
author_rank: Super Contributor
timestamp: July 28, 2019, 09:17:52 pm
content: Quote from: petew on July 28, 2019, 08:45:23 pmThat is an OK to slightly high price for a working unit in good condition. Too high for a broken one.QuoteYou need to look at sold items.Quote from: bob91343 on July 28, 2019, 09:07:39 pmIt uses the FBT-00-031/MC1466L which is kind of scarce and expensive these days. On the other hand, they rarely fail.
Greetings all, my first post. Tektronix TDS 320 inquiry  - Page 1
Forum section: electronics / beginners

author: Juno
author_rank: Newbie
timestamp: May 24, 2015, 11:59:46 pm
content: Howdy everyone, I'm new here but not to the community.I'm actually a fluid systems/nuclear power guy but I dabble in all things geeky.My reason for posting aside from introducing myself, is to ask a question of you all. I just picked up a Tek. TDS 320 on eBay for $157.00usd (score). I was wondering if there is anything i should know about this scope, such as bugs, issues, software quirks, etc.Thanks all.
Greetings From a Newb/ Anyone have any info on an ERC  brand logic based clock? - Page 1
Forum section: electronics / beginners

author: Fcsteve777
author_rank: Newbie
timestamp: October 28, 2014, 02:22:49 am
content: Good day to everyone,Getting back into some tinkering with electronics. I have built a couple tube amp kits and repaired a couple things at home but am by no means an EE. Just someone that likes a mental challange.Anyway. I bought a non working digital calendar clock from a surplus electronics place and got it running again. (it was just some bad solder joints.) Its a pretty cool unit all logic based stuff and most of the components are marked mid 1973. I was just wondering if maybe anyone had seen one or had any more info on it.Please excuse the rotated images im on a crap internet connection right now and photobucket is giving me fits. its taken me an hour to upload these and now they wont rotate.Tried googling any combo i could think of these numbers and couldn't find anything. Company was Electronics Research Company from what i can tell.As you can see it only takes the 2 wires to power it (there is actually 2 power rails but someone has previously jumped them internally) so im guessing that the other terminals are for some sort of external display.Im gonna make an acrylic enclosure so you can see the guts and use it as a desk clock at work.My fledgling bench. Already had the Fluke 87V, Weller station and a cheap power supply from some of my other dinking around. I have a blue ESR meter kit on the way and a DS1054Z will be following it as of this Friday. An ESD mat and LCR meter soon as well.
Grid tie inverter - Page 1
Forum section: electronics / beginners

author: Muhammad Nasar
author_rank: Contributor
timestamp: August 03, 2013, 04:12:28 pm
content: I am rather curious why there are 2 LC filters(Having large inductors) in the DC DC converter stage of this Grid tie inverter design,and also about the inductor at DC AC converter stage.Also can any one tell what topology they are using for dc dc converter ?(my guess would be full bridge dc dc converter).Thanks in Advance
Ground bounce on a PCB Plane - Page 1
Forum section: electronics / beginners

author: Freshman
author_rank: Regular Contributor
timestamp: February 28, 2025, 05:39:27 am
content: Suppose in my PCB, due to Ground bounce,the voltage on the reference plane of a PCB, for example, increases by,say 0.2V.In the PCB stackup, the ground plane (or return plane) is typically a separate layer. Given this, my question is: Would the entire reference plane (the ground plane) experience a voltage increase of 0.2V from 0V (typically), or would the voltage increase be localized to specific areas of the reference plane, particularly around the IC where simultaneous switching noise (SSO) is generated?If the latter is true, there would be a voltage gradient across the reference plane, correct?

author: Whales
author_rank: Super Contributor
timestamp: February 28, 2025, 06:01:27 am
content: Both.(1) Voltage gradient. Copper has resistance, there will always be voltage gradients.(2)> Would the entire reference plane (the ground plane) experience a voltage increase of 0.2V from 0V (typically)Your ground plane may appear 0.2V above... what's your reference point? A ground on another PCB? Connected by a thin wire that has resistance?
Ground Channel Coupling - Page 1
Forum section: electronics / beginners

author: jj5
author_rank: Unknown
timestamp: February 24, 2023, 08:41:52 pm
content: I'm reading themanualfor my new Rigol MSO5074 scope (this is my first scope and I'm just starting to learn what it's capable of and how to use it). On page 59 the manual explains three supported channel couplings:When the coupling mode is "DC": the DC and AC components of the signal under test can both pass the channel.When the coupling mode is "AC": the DC components of the signal under test are blocked.When the coupling mode is "GND", the DC and AC components of the signal under test are both blocked.I don't understand GND channel coupling. If you block both the DC and AC components, what's left?

author: ledtester
author_rank: Super Contributor
timestamp: February 24, 2023, 08:45:48 pm
content: GND coupling just means that the scope input is connected to ground. You should just get a straight line on your scope.On analog scopes I think this was useful so you could tell where on the screen where the ground of an input was set to. On digital scopes there is a little marker on the side which shows that.

author: jj5
author_rank: Unknown
timestamp: February 24, 2023, 08:48:06 pm
content: Quote from: ledtester on February 24, 2023, 08:45:48 pmThanks. So that straight line will be at zero volts? What's the point of having ground coupling? I don't understand when it would be useful.

author: AnalogTodd
author_rank: Regular Contributor
timestamp: February 24, 2023, 08:51:18 pm
content: When you set the channel for GND coupling, it does just that--it grounds the channel. The idea is that you will know exactly where the ground potential for the channel is on the scope. It is very useful when you are trying to set where the zero potential for that channel is. You don't always want zero to be the center line of the scope; sometimes you want it to be a number of divisions up or down so you can utilize more of the screen to view your signals.

author: jj5
author_rank: Unknown
timestamp: February 24, 2023, 08:59:43 pm
content: To be clear: if you use ground channel coupling to get a reference for ground on the scope, there's no point in attaching a probe to that channel?

author: TimFox
author_rank: Super Contributor
timestamp: February 24, 2023, 09:02:34 pm
content: If a probe or other cable is connected to the channel that is set to "GND" coupling, its signal will be ignored.When you set that channel to "AC" or "DC", the signal will be displayed.With analog CROs, it was a common practice to set the channel to GND, move the vertical position control to get "0" at the desired location (typically center line or bottom line of the screen), then switch back to AC or DC coupling.Note that on both CROs and DSOs, "GND" input setting does not short the input BNC to ground, so you won't short out the cable to your device under test.
Ground clearance for a chip antenna - Page 1
Forum section: electronics / beginners

author: AlanEB
author_rank: Newbie
timestamp: September 28, 2025, 05:15:27 am
content: Hi all,I'm in the early stages of working on my first PCB project which requires an antenna for BLE. The whole PCB will only be 25 x 25mm, with an MCU, 2 other ICs, 4 tactile switches, flat flex connector, an assortment of passives, and 2 zebra strip terminal arrays. So there's not much space! (side note: I'll be making a prototype board first with everything spaced out for testing etc.)I've been looking for a suitable chip antenna and I think I've found a few that could do the job but I'm wondering about the top layer ground clearance. For a centre-edge mounted chip that's 1 x 0.5mm the spec sheet shows a example layout with a 5 x 3mm ground clearance area with ground plane on all three sides - my question is does the ground plane NEED to be on all three sides or is this just a "don't get any closer than this" suggestion? Given the space constraints, one of the zebra strip terminal arrays will be right next to it, could I have ground plane on the left and right edge but not the bottom edge? If I do need it on all three sides would say a 0.5mm ground plane on the bottom edge be enough?The particular chip I'm referring to:https://www.johansontechnology.com/docs/4417/Antenna-2450AT07A0100001T.pdfI'm also open to other solutionsThanks!

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: September 28, 2025, 03:30:24 pm
content: The yellow rectangle in Johanson’s drawing is a keep-out / ground-clearance area (no copper) that they expect under and in front of the chip. That keep-out should ideally be respected on all PCB layers. It’s not merely a “suggestion” but the recommended footprint for predictable performance.

author: AlanEB
author_rank: Newbie
timestamp: September 29, 2025, 01:37:38 am
content: Thanks ahsrabrifat, I understand that there should not be any metal on any layer within the "keep-out" area. My question is about what's outside the keep out. Does the keep-out area need to be surrounded by the ground plane on all three sides on the top layer (i.e the layer with the chip antenna)?
Ground issue with FTDI MM232R or my computers USB ports? - Page 1
Forum section: electronics / beginners

author: kodapa85
author_rank: Newbie
timestamp: May 31, 2014, 05:04:36 pm
content: Hi everyone!Recently started playing around with PICs and Atmel chips.My question is this. Is it possible that my MM232R has a fault, shorting the VCC30 and GND outputs from the FT232RQ or some other fault to raise the GND pin to 3.3V. Or am I simple doing something wrong?To program a ATMEGA328P-PU I bought a MM232R, wired it up for 5V.Jumper connecting pin 14 and 15Connected both pins 2 and 3 via my breadboard for the positive railPin 13 is supposed to be GND and thus connected it to the negative railTo my surprise the ATMEGA328P didn't seem to do anything. Upon checking the voltage, I found the ATMEGA was only receiving 1.7V. This was because the GND pin was reading 3.3V compared to pin 1, which is connected to the shield.Needless to say I was able to once I connected the negative rail to shield the ATMEGA works fine and I was able to program it, at last.Suppose you will want to know the answer to two questions in return :-Why didn't I just use a TLL-232R-PCB?Photos made it look like there were only 3 terminals, also requires solderingThe MM232R was cheaper (£11.94 vs £14.34) and is more flexible (5V, 3.3V, 2.8V and 1.8V)Why haven't I used a voltmeter to test for a short?Good question, just haven't yet. I'm not the most dexterous person I wouldn't want to short it out. Now that it isn't powered up I certainly could test it.
ground loop - Page 1
Forum section: electronics / beginners

author: ghinckley68
author_rank: Contributor
timestamp: April 14, 2016, 04:15:37 am
content: Is there away to hook up my siginal gnereator which is tied to ground on the pnc to an amp that has no tie to ground with out hum.

author: LaurentR
author_rank: Frequent Contributor
timestamp: April 14, 2016, 05:46:38 am
content: Quote from: ghinckley68 on April 14, 2016, 04:15:37 amIf it's strictly for audio, you could use an audio ground loop isolator (basically a transformer specced for audio frequencies), which are <$10, like this guy:http://smile.amazon.com/PAC-SNI-1-3-5-3-5-mm-Isolator/dp/B001EAQTRI

author: danadak
author_rank: Super Contributor
timestamp: April 14, 2016, 10:28:13 am
content: Use your scope in differential mode -Regards, Dana.

author: ghinckley68
author_rank: Contributor
timestamp: April 15, 2016, 12:40:48 am
content: that was great think you for the video, but i need to go into an audio amp out of my BK 4040A and the audio amp hates that the bnc is tied to earth ground. No 60hz on the output if i hook it up direct to a speaker or a battery powered amp but yeaser when its hooked up to mains powered amp.

author: uncle_bob
author_rank: Unknown
timestamp: April 15, 2016, 01:19:22 am
content: Quote from: ghinckley68 on April 15, 2016, 12:40:48 amHiI'd bet that the real problem is the power supply on the amp rather than the signal generator ....Bob

author: ghinckley68
author_rank: Contributor
timestamp: April 15, 2016, 01:40:21 am
content: so when i use the ebay signal gen hooked to my bench supply no hum. when i use the bk hum. please excuse the amp miising the lm1875t it had a boo boo. the power supply module is a lm317 lm337 job and just a torid core.the amp has 10ohms between the inupt ground and(power supply ground and speaker ground)

author: uncle_bob
author_rank: Unknown
timestamp: April 15, 2016, 11:53:35 pm
content: HiIf everything is hooked to the same power supply, *and* the power supply has a TON of common mode noise .... you will never ever notice it. As soon as you hook any properly grounded gizmo into the mix ... lots of hum.For example: Some supplies will have 60V AC on the chassis. The same 60V is also on the negative when it is hooked to the chassis. It also shows up (in phase) on the output in this case. Hook a voltmeter between positive and negative .... no AC to be seen. Hook a voltmeter to a good ground, check either one .... 60V AC ...Bob
Ground loop - Page 1
Forum section: electronics / beginners

author: iceisfun
author_rank: Regular Contributor
timestamp: June 12, 2017, 06:24:12 pm
content: I'm having trouble finding ground loops on digikey.Solder in loop for hooking probes onto. I'm searching under the wrong term I'm sure. If someone has a link to the proper thing that would be wonderful.Thanks

author: gertux
author_rank: Contributor
timestamp: June 12, 2017, 06:28:41 pm
content: Are you looking for solder on test points like this for instance ?https://www.digikey.be/product-detail/en/keystone-electronics/5019/36-5019TR-ND/3907343Sent from my iPad using Tapatalk

author: iceisfun
author_rank: Regular Contributor
timestamp: June 12, 2017, 06:43:40 pm
content: Nope but I found the ones I was after from that.https://www.digikey.be/product-detail/en/keystone-electronics/4952/36-4952-ND/316326Thanks
Ground Loop - Page 1
Forum section: electronics / beginners

author: kfitch42
author_rank: Frequent Contributor
timestamp: January 30, 2013, 09:25:50 pm
content: The other day I stopped by the local university surplus store, and, on a whim, I bought a signal generator for $5 (Krohn-Hite 5800A). When I got home I looked at it more carefully and realized it had a three-prong power plug. I don't see any switch/button/jumper or otherwise to select the ground for the output signal. So I assume it would be a bad idea to connect this to my oscilloscope (which also has a three prong plug). Is an 'isolation transformer' the only safe way to connect these two bits of kit together?

author: w2aew
author_rank: Super Contributor
timestamp: January 30, 2013, 10:18:49 pm
content: There are two possibilities:1) The output is floating, meaning either side can be safely connected to ground.2) The output is grounded, meaning that the ground of the output must be connected to the DUT / equipment ground.In either scenario, you should have no problem.The only issue would arise if the output is not floating, and you treat it like it was (neither side connected to DUT ground).

author: ejeffrey
author_rank: Super Contributor
timestamp: January 31, 2013, 08:45:41 am
content: There is no problem here. If the FG output is grounded and you connect it to the scope you will end up with a ground loop, but it is probably not a problem and definitely not a safety issue.In most cases you run into in a lab, ground loop potentials are at maximum a few mV and 10 mA. This is not enough to cause any safety issues. In some cases this can cause measurement errors, but for low precision measurements (like most measurement done with a scope) you can just ignore it.For completeness, I should add that ground loops can become more serious when talking about long distance connections, and damage equipment or cause safety hazards. This is something you run into with e.g., ethernet cables going between buildings with separate electrical systems. For use within a lab you don't have to worry.
Ground loops created in PCB copper pour. - Page 1
Forum section: electronics / beginners

author: Faringdon
author_rank: Super Contributor
timestamp: January 18, 2024, 06:49:49 pm
content: Hi,I just did a ground copper pour in the PCB internal layer as attached.But due to the way that the tracks have cut up the copper pour,a ground loop has been created.Would you be too concerned by these?(as far as creating noise to interfere with the circuit, and with otherPCBs nearby)

author: Buriedcode
author_rank: Super Contributor
timestamp: January 18, 2024, 07:13:52 pm
content: Pics or it didn't happen

author: Gyro
author_rank: Super Contributor
timestamp: January 18, 2024, 08:08:57 pm
content: It seems to me that this is effectively a double post and the OP has people replying to both of them!https://www.eevblog.com/forum/renewable-energy/keep-dead-copper-pours-on-pcb-that-needs-cooling/

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 18, 2024, 09:51:11 pm
content: I don't really get it. If you have internal layers - meaning at least a 4-layer PCB - then the usual, and reasonable approach is to dedicate one layer to GND without routing any signal on it, just a single plane and vias.If you have routed other signals/power rails on the internal layer with a GND plane, then you either don't know how to lay out a PCB, or you're not using the right number of layers.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: January 18, 2024, 10:22:41 pm
content: Yes. Noise makes ADCs useless and can cause glitches.

author: Faringdon
author_rank: Super Contributor
timestamp: January 19, 2024, 06:46:39 am
content: QuoteThanks, due to cost, we dont have possibility of >4 layers. Signals had to go on all 4 layers, there was no room otherwise.Yes the inner "ground " plane is badly cut up, but we cant afford 6 layer board.

author: Buriedcode
author_rank: Super Contributor
timestamp: January 19, 2024, 03:25:12 pm
content: The entire point of a board with more than two layers is so that you can have a nice continuous ground/power plane. If you're routing signals like that on all four layers you either have an extremely dense board, or you're bad at routing.I don't suppose you could post the other layers? Or is it some super secret project?Edit: typos

author: Monkeh
author_rank: Super Contributor
timestamp: January 19, 2024, 04:51:14 pm
content: It's always too expensive to do it properly with treez.

author: wraper
author_rank: Unknown
timestamp: January 19, 2024, 04:54:26 pm
content: That does not look that dense so you cannot dedicate one internal layer of 4 layer PCB to GND plane. Looks more like poor layout.
Ground loops in phones in cars - Page 1
Forum section: electronics / beginners

author: kfitch42
author_rank: Frequent Contributor
timestamp: September 27, 2016, 08:24:20 pm
content: BACKGROUND: I recently had a problem with my Nexus 5X phone rebooting periodically. The problem developed slowly over a month or so, starting with a random reboot every few days, but eventually it was more like every 30ish minutes. I tried all the software things (e.g. factory reset), but nothing helped. It was still under warranty (about 6 months old), and Google sent me a replacement which is not experiencing the reboot problem.I have been pondering if there was something I did that might have precipitated the problems. (NOTE: It never experience a severe drop or got wet)Nearly every day I plug it into a car charger and the AUX jack in my car. If I plug in the AUX first, I will notice a hiss/hum start as soon as I plug in the charger. I am guessing this is a symptom of some kind of ground loop. The curious thing is that the hiss/hum goes away as soon as I start to play any audio, even if that audio is completely silent ( one podcast I listen to tends to start with a second or two of silence).So, is it likely I inadvertently damaged my phone, or is it more likely the phone had a defect that took time to manifest?

author: Monkeh
author_rank: Super Contributor
timestamp: September 27, 2016, 08:27:19 pm
content: There may be a ground loop, but that hiss is actually the noise of a floating input. Your phone will not be driving the output until an application opens it.

author: djkoell
author_rank: Newbie
timestamp: September 28, 2016, 09:26:12 pm
content: I resolved the same issue in my car by picking up an $8 ground loop isolator from amazon.

author: sparx
author_rank: Contributor
timestamp: October 06, 2016, 10:53:43 pm
content: Same issue when trying to get my tablet and amplifier working - playing sounds was fine, but when no sound or application driving the headphone output it would always pick up random noise and consequently amplify it...

author: zapta
author_rank: Super Contributor
timestamp: October 06, 2016, 11:40:56 pm
content: Quote from: djkoell on September 28, 2016, 09:26:12 pmSame here, this onehttps://www.amazon.com/gp/product/B004E8YRS0. It solved the noise problem of my BT adapter which is plugged into a cigarette lighter socket and into the aux input of the audio system.
ground loops on pcb's? - Page 1
Forum section: electronics / beginners

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: April 17, 2020, 07:32:52 am
content: I am designing an audio circuit and can't stop thinking about if ground loops are a problem on pcb's.basically I have a few surface mount ic's connected to a ground plane on one side, and I have a ground plane connected inmultipleconnections with the first side, on the other side.will this create ground loops? if so I fix it by the usual "only connect ground in one place or if you can't, connect it in one place really good so the other connections don't matter that much?also, I always think, trying to connect the lower impedance wire to the center lug of the pot, not the side as much as possible for a little bit less exposed metal, so less antenna action. does this matter at all? I mean it should but maybe the resistor surface acts even more as an antena?

author: David Hess
author_rank: Super Contributor
timestamp: April 17, 2020, 11:43:02 am
content: A ground plane is not a panacea for ground loops. In extreme cases, slots can be cut in the ground plane to route return currents away from sensitive nodes.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 17, 2020, 02:23:12 pm
content: The perfect ground is laid out in such a way that offending current loops are not overlapping.The second best is swamping the voltage drops with a very low resistance, i.e., a solid poured and stitched (as needed) plane.Tim

author: Rerouter
author_rank: Super Contributor
timestamp: April 17, 2020, 02:25:21 pm
content: Circuit boards are not too hard to just do the math on to know if it will be a problem, the trace is X long, so it has this resistance, my signal causes X amount of change in current in that trace, A x B and there is your ground noise,So if your circuit is sensitive, its mainly about making sure the current from the larger loads does not cross the sensitive stuff and add to that noise, this is why cutting slots in a plane to cause those currents to flow around the areas can be benificial,The other flip side is a large ground plane naturally has lower resistance, so the noise between say your supply ground and your signal ground is reducedLastly sometimes you care more that the signal ground has no loops, rather than the supply ground, the bias resistors and ground used in op amp circuits is much more important than the one the used to power the op amps.
Ground loops - Page 1
Forum section: electronics / beginners

author: AQUAMAN
author_rank: Regular Contributor
timestamp: July 18, 2014, 06:53:21 pm
content: I have a circuit which is basically just an IGBT with a resistive load. THe gate driver has some measurement circuit on itI get loads of oscillations when the IGBT turns on or offWhen the current is about 1A the oscillations aren't really noticeable, as I increase the current the oscillations get worse and worse. Even with my measurement circuit disconnected from the gate driver the oscillations happenDoes this mean I likely have some sort of ground loop? Perhaps with my probes. Im using one of those proves with a clip for the groundEven when I just probe the ground on my IGBT (the emitter) I get huge oscillations around 0V.. see pic

author: Fank1
author_rank: Regular Contributor
timestamp: July 18, 2014, 10:36:43 pm
content: Looks like you need a snubber across the igbt.

author: rob77
author_rank: Super Contributor
timestamp: July 18, 2014, 11:25:15 pm
content: you got some laws of physics thereswitching large currents doesn't work like switching LEDs. the best would be to reuse an existing circuit - the parts usually considered as "useless stuff" by new players are there to make it work with less oscillations

author: AQUAMAN
author_rank: Regular Contributor
timestamp: July 19, 2014, 11:40:30 am
content: The oscillations have gone away with a differential probeI dont know whyWhen I use a passive probe I attach my ground to the emitter, which IS the ground of my circuit. Of course, in an IGBT module, you have some parasitics between the emitter for the gate and the actual load current emitter, but this must be amplified as my setup is very non optimisedEven when I measure the ground I get the oscillations so:I think that my setup is so bad that there must be a vast difference between the pathway to earth through the 'busbar' and DC-link capacitor (which are just wires about 1metre long) and the pathway through the scope. The frequency of the oscillations also changes if I use a different power supply to charge up the DC-link capacitors.But I have never had this problem before with non-optimised setups, and I would have thought that if the load current (20-30A) was actually taking a path through the probe, I would know about it to say the least. Perhaps its just a small amount that is going through the probe.
Ground plane under transformer? - Page 1
Forum section: electronics / beginners

author: Emil
author_rank: Regular Contributor
timestamp: June 21, 2015, 12:21:24 pm
content: I'm laying out a board with a 50Hz toroidal transformer mounted on top. I have a ground plane on the bottom of the board.Would it be best to avoid having the ground plane under the transformer?What are the pros and cons?

author: German_EE
author_rank: Super Contributor
timestamp: June 21, 2015, 12:35:14 pm
content: A ground plane underneath a 50 Hz transformer will not make a difference, it only becomes a problem at RF. Just make sure that your insulation is good to prevent flashover to ground.

author: SeanB
author_rank: Super Contributor
timestamp: June 21, 2015, 12:40:46 pm
content: No ground plane around the transformer and especially no traces within 10mm of the mains side, just for creepage clearance. If the transformer has holes for mounting screws in addition to the pins make them, leave a clearance of 10mm around them and put in the screws before soldering.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 21, 2015, 01:35:04 pm
content: Doesn't make a difference.Creepage should be covered by the construction of the transformer itself (wrapped with tape and all).Note that you don't want to make a closed loop around the core with the mounting hardware. Usually, they're mounted with a bolt through the center and some flanges or whatever. With ground plane, you have the option of connecting that bolt to ground. Which is fine. Just be careful that nothing wraps around the core, grounding the top end of that bolt, which would form a shorted turn.If this is for a sensitive application, you may want some distance between transformer and circuit, regardless of ground plane. Local fields, due to uneven turns, will be fairly intense near the transformer, but drop off quickly with distance (one or two minor diameters worth).If this will be sensitive to RF, or potentially generate a little, an EMI line filter may be desirable. The transformer will have high capacitance and low leakage inductance, so that line noise coupling (in or out) will be relatively unaffected by the transformer (whereas a bank wound, shell type will have quite high leakage and low capacitance, which still won't cover all your sins, but will drop a lot of noise).Tim

author: Emil
author_rank: Regular Contributor
timestamp: June 22, 2015, 08:13:33 am
content: Thank you for your answers, which I think I can summarize as:A ground plane under a 50Hz transformer is not a problem, assuming adequate creepage distance / insulation.
Ground plane video tutorial? - Page 1
Forum section: electronics / beginners

author: kalel
author_rank: Frequent Contributor
timestamp: November 02, 2017, 09:23:56 pm
content: Do you know of any video (or article/post) tutorial about ground planes? Just what they are, how they are usually implemented, when they are necessary to have, etc.I'm almost sure I have seen something about it a while ago, but just can't remember the channel or video name. Well, they are mentioned almost everywhere, so some type of explanation would be helpful.

author: ebclr
author_rank: Super Contributor
timestamp: November 03, 2017, 05:05:34 am
content: https://pdfserv.maximintegrated.com/en/an/TUT5450.pdf

author: iainwhite
author_rank: Unknown
timestamp: November 03, 2017, 01:14:40 pm
content: I think W2AEW (Alan) did a video on ground planes and decoupling - sorry can't remember title exactly.Edit: I was thinking of "W2AEW #257: Power Supply Decoupling & Filtering" - discusses capacitors & filtering and how they relate to ground planes.
Ground planes  - Page 1
Forum section: electronics / beginners

author: Aztlanpz
author_rank: Regular Contributor
timestamp: January 30, 2018, 08:43:51 pm
content: I am working on a two layer PCB; can I use two planes one for the ground and one for the positive voltage?Aztlan

author: Buriedcode
author_rank: Super Contributor
timestamp: January 30, 2018, 09:08:07 pm
content: Yes.I usually just have top and bottom both GND, but you can have a power plane if the design requires it. Most multi-layer boards have both.
Ground planing on mixed designs with high voltage - Page 1
Forum section: electronics / beginners

author: Pack34
author_rank: Frequent Contributor
timestamp: August 07, 2015, 07:57:13 pm
content: This is sort of additional portion of the discussion I originally started in the below thread in relation to separating ground planes in a mixed signal design. It seems like a general consensus for this was to isolate the circuits such that the return path for higher switching digital signals do not cross the sensitive analog returns. I.E. do not put a buck or boost regulator on one side of the circuit board and sensitive analog on the other side. Also, to keep the rails isolated and filtered with beads, chokes, and caps.https://www.eevblog.com/forum/beginners/separating-grounds-and-stitching-them-together/msg500271/#msg500271A follow-up for this would be, what would be the case for higher voltages (150Vdc +)? If I had a boost regulator to send 5V up-and-up to 150- or 200-Vdc and on the same design had some logic and low-noise analog circuitry going on, would I need to isolate the ground plane for the higher voltage system? Would it be best to use traces for that instead of fills so that the noise can't propagate and reflect off the board edges?Or like in the previous discussion, just keep everything isolated and use the appropriate filtering where needed? (Higher value caps at board inputs, 100n at Vdd pin on each chip, and a bead separating the voltage rails for the analog and digital components so switching noise doesn't propagate through the rails.)I've noticed on some designs (particularly some motor controllers) where it seems ground planes are avoided and traces are used instead. This could just be that the outer layer that I could see was void of a fill and an internal plane was used.So... for higher voltage and higher current designs, how does that change the game? Are different rules of thumb used, or are the same methods employed as per the previous discussion?
Ground referencing the signal received from a simple wire antenna - Page 1
Forum section: electronics / beginners

author: nathanpc
author_rank: Unknown
timestamp: March 20, 2014, 12:06:57 pm
content: I'm fascinated by RF, low frequencies, nothing even near the GHz range yet, but I plan to get there one day. I was playing around building a simple envelope detector for a 1MHz carrier modulated with 700Hz coming from my function generator, it worked beautifully until I decided to test it receiving the same signal wirelessly.I attached a wire to the output of the function generator and cranked up the voltage (it's still a very weak signal so I wasn't interfering with anyone's reception) a bit just to make sure I would receive something. I tested it by attaching another wire to my oscilloscope probe and sure enough I got about a volt peak to peak with the wires very close to each other.So I attached the wire antenna to the input of my envelope detector and the oscilloscope probe to the output. Interestingly enough I wasn't getting the 700Hz, but instead I was getting the full received signal, it passed right through the envelope detector. First I thought it may have been receiving the signals there too but as soon as I removed the antenna from the detector the signal vanished.After troubleshooting for a while (you learn a lot when things don't work, Dave is right) I noticed that when I had the function generator connected directly to the envelope detector and removed the ground lead I would get exactly the same result as I had with the wire antenna, so I realized it must be the fact that the signal being received by the antenna is not ground referenced to the detector circuit (please tell me if my conclusion about the issue is wrong).I Googled about how to ground reference a signal from an antenna, but all I got was how to do it in respect to mains earth in large tower antennas. Could anyone help me on how to ground reference a simple wire antenna in this case?
Ground to inductor to ground capactior mystery - Page 1
Forum section: electronics / beginners

author: sausage
author_rank: Regular Contributor
timestamp: January 25, 2021, 01:38:56 am
content: Hi all.I'm currently troubleshooting a dead Commodore 64C and I found what I thought was a short across C56 which is a ceramic type capacitor. I took the part out and it was fine. Then I looked at the schematic and discovered this:The point of interest is highlighted in blue. The Power Input comes from an external transformer. Pins 1, 2 and 3 on that plug are ground.The mystery for me is this: The incoming grounding path goes through an inductor to the PCB ground. Before the inductor is one side of the capacitor. Essentially both sides of the capacitor will appear as a short, or at least plus the resistance of the inductor.I'd be interested to know what this technique is for, and what it might be called so I can read up on it.

author: M0HZH
author_rank: Regular Contributor
timestamp: January 25, 2021, 01:55:19 am
content: L1 seems to be a common mode choke; the DC return will minimize core flux in L1.C56 will mostly have an effect at high frequencies (transients?).

author: retrolefty
author_rank: Super Contributor
timestamp: January 25, 2021, 01:57:01 am
content: Looks like a high-pass filter (cap/inductor) on the ground line. Helps to filter out noise.

author: sausage
author_rank: Regular Contributor
timestamp: January 25, 2021, 02:27:04 am
content: Thank you muchly to you both.
Ground wires / radials. Insulated or bare, the performance difference? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: September 24, 2015, 03:03:39 pm
content: I have a couple of 2 meter long galvanised ground stakes about ten feet apart as my station earth. I want to operate on LF (136kHz) and need better grounding for my vertical antenna with a horizontal loop wire top hat for capacitance. What performance difference would running radials or long perimeter ground wires in insulated or bare wire make at that frequency, any? If none or not a lot, what frequency would you see a benefit with bare conductors at?Thanks.

author: Fank1
author_rank: Regular Contributor
timestamp: September 24, 2015, 08:52:48 pm
content: Use the bare ones, more surface area in contact with the ground.Wet ground is a better earth also. a little salt around them will also help but they won't last very long that way.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 25, 2015, 01:13:21 am
content: Don't worry about it. Go with what's best suited for the elements.Tim
Grounded emitter amplifier max gain (AoE) - Page 1
Forum section: electronics / beginners

author: Moriambar
author_rank: Unknown
timestamp: April 12, 2020, 09:43:12 am
content: Hi.Here is another AoE (3rd Ed) puzzle that I cannot solve for the life of me.On page 98, §2.3.5B, it is stated:QuoteThe following exercise 2.15 asks to show that is true.Well, I tried calculating, but I don't know what I miss.Usually |G| = Rc/Re. Here Re=re≈25(ohms)/ic(mA).fine so |G| = (Rc*ic(mA))/25.Then I tried calculating ic. I thought the amplifier kinda like a current source powering a resistor. So ic=ie≈0.5VCC/re, where I ignore the diode drop between base and emitter (just for simplicity).But that's kinda it. Substituting icwon't bring me anywhere, e.gic= 0.5VCC*25/ic(mA) => to have amps on the right side I multiply and divide by 1000 soic=0.5VCC*25000/ic(A) => i2c=0.5VCC*25000.substituting this in the other equation does not bring me anywhere either and I start getting confused.After four A3 pages feeling stupid I'm asking you guys what am I ignoring (because there's something I either did not understand or I ignored) or that I show not to have understood.As usual thanks

author: iMo
author_rank: Super Contributor
timestamp: April 12, 2020, 10:36:59 am
content: G = Rc / Re = (0.5Vcc/Ic) / (0.025/Ic) = 0.5Vcc / 0.025 = 20Vcc
Grounded grid linear amp, idling grid current question? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: October 31, 2012, 12:54:20 pm
content: I am restoring and converting a Henry RF generator that uses a 3CX3000A7 valve. I am at the stage where I am running filament current into the valve, running the blower for cooling, and monitoring filament voltage and current, and PA grid current. Filament voltage and current are correct. There is no drive being applied to the amp, and no output load. The OE metering shows zero grid current. Is that to be expected without any HV applied to the anode? I believe it will need the HV turned on to show any idling grid current, but wanted to be sure. Thanks.

author: djsb
author_rank: Super Contributor
timestamp: October 31, 2012, 01:07:34 pm
content: Is it any of these you are talking abouthttp://www.n4tze.com/henryRFgenerators.htmDavid.

author: Chris Wilson
author_rank: Super Contributor
timestamp: October 31, 2012, 01:18:33 pm
content: Similar, it's a 2000D model, manual is athttp://www.gatesgarth.com/henrymanual.zipSchematic of RF section in question below, thanks David