hybridfree/eevblog-posts huggingface dataset:
Grounding a spinning motor shaft - Page 1
Forum section: electronics / beginners

author: captainscarlet
author_rank: Contributor
timestamp: December 11, 2014, 12:56:07 pm
content: Hi all,I have this motor:http://tinyurl.com/lf85rwqand I need to ground the shaft while the motor is spinning at 6kRPM.I tried a spring loaded test pin, but there's too much friction and noise at high speedsI'd imagine there's some sort of brush that can make contact with either the shaft or the cylinder at the rear of the motor but I can't find anything on RS or Farnell that can do this.Anyone have any ideas on how this can be achieved?

author: fcb
author_rank: Super Contributor
timestamp: December 11, 2014, 01:13:39 pm
content: Have you talked to MAXON (the makers of the motor) - they will have done this before.

author: N2IXK
author_rank: Frequent Contributor
timestamp: December 11, 2014, 01:14:20 pm
content: Look for a scrapped VCR.They use a graphite button on a BeCu spring to ground the shaft on the video head motor assembly.

author: Zero999
author_rank: Super Contributor
timestamp: December 11, 2014, 01:16:56 pm
content: Just one question: why? It's 24V so it's not required for safety.The shaft is probably in fairly good electrical contact with the motor frame, although you shouldn't use the bearings to carry any current.

author: SeanB
author_rank: Super Contributor
timestamp: December 11, 2014, 05:15:13 pm
content: You will need the grounding carbon button to make contact with the back of the shaft, or replace the grease in the bearings with a graphite loaded grease, which in this small bearing will be both hard an will reduce bearing life considerably. the thing with a spinning bearing is that the inner and outer race tend to be separated by a thin film of oil from the grease, effectively insulating it, and if the applied voltage is high enough then the breakdown of the grease causes a small arc which eventually erodes the bearing raceway and the balls. When you open one it is full of black deposits and the raceways and balls are badly pitted.

author: WarSim
author_rank: Frequent Contributor
timestamp: December 12, 2014, 04:32:30 pm
content: Isn't a pin bearing on the shaft end an acceptable method? I have seen it done in allot of safety gear. Older stuff, I haven't been into the newer stuff.

author: SeanB
author_rank: Super Contributor
timestamp: December 12, 2014, 05:18:35 pm
content: Pin does wear eventually and can stick fast with wear or overload, that is why the preferred method is to use the copper loaded graphite button so that it will still conduct and not stick. As well it has low friction.

author: Richard Crowley
author_rank: Super Contributor
timestamp: December 12, 2014, 05:19:28 pm
content: Exactly how (and where) did you "tried a spring loaded test pin"?Is the shaft exposed on the "back side" of the motor? That would be the place for a spring-loaded contact.If you are having a problem with "much friction and noise at high speeds" then you need to properly prepare (polish) the surfaces.
Grounding hard disk cage? - Page 1
Forum section: electronics / beginners

author: rthorntn
author_rank: Frequent Contributor
timestamp: May 29, 2021, 10:30:54 pm
content: Hi,I basically ripped the 24x SAS/SATA drive cage and backplane out of an 7-year-old Supermicro 216BA-R920LPB case that was running 24/7 for 5 years (drilled the rivets out), the backplane (SAS216A, photo attached) has 6 long horizontal gold traces right at the bottom (below the molex connectors), the 216BA-R920LPB case has a long thin metal bar attached that touches those 6 traces, I'm going to run it "barebones" externally wondering if I need to worry about it?Thanks!CheersRichard

author: Manul
author_rank: Super Contributor
timestamp: May 30, 2021, 12:22:40 am
content: My guess is that these contacts are there for EMC reasons. So basically you do not need to worry about it, unless you have sensitive radio equipment nearby, that sort of things. Of course it is not good practice to disrespect electromagnetic emissions, but to be fair, there is so much radio pollution everywhere (from cheap consumer stuff, cell towers and who knows what else), that it almost does not matter anymore.

author: fordem
author_rank: Regular Contributor
timestamp: May 30, 2021, 10:09:59 pm
content: Just remember that EMI/EMC is a two way street, but, that's not my real reason for posting - if you plan on running 24 disks, you'll need to consider some sort of forced air cooling.

author: rthorntn
author_rank: Frequent Contributor
timestamp: June 03, 2021, 12:56:41 pm
content: Dang I lost my last post.Thanks!I got to thinking with this backplane, will it be OK to run it from a different ATX PSU to the PSU that's powering the motherboard?Just being paranoid.CheersRichard

author: fordem
author_rank: Regular Contributor
timestamp: June 03, 2021, 11:44:44 pm
content: As long as the DC grounds are bonded together, which they will be through the data cables, I see no reason why there should be a problem. Have you ever seen/used an ESATA external drive with a separate power supply?That's the equivalent of what you're attempting.

author: rthorntn
author_rank: Frequent Contributor
timestamp: June 03, 2021, 11:54:24 pm
content: Thanks @fordemMy thinking was the "external" SAS cables (SFF-8088, SFF-8644) tended to have metal casings on the connectors, the "internal" cables (SFF-8087, SFF-8643) have plastic casings, I'll be using SFF-8087 to SFF-8643 cables.Now I'm thinking the metal might just be for durability.

author: fordem
author_rank: Regular Contributor
timestamp: June 04, 2021, 02:40:09 pm
content: I'm not talking about data cable connectors, I'm talking about the data cables themselves - google SAS or SATA pinout and look at the connections, you'll see the two pairs of differential connections, and grounded wires in between them (to reduce cross talk) - a SATA data cable has one pair of connections for transmit, a second pair for receive, and three separate ground connections.
Grounding high frequencies 2 - Page 1
Forum section: electronics / beginners

author: testtube44
author_rank: Regular Contributor
timestamp: August 25, 2018, 06:09:50 pm
content: I'm having trouble understanding how to shield high frequencies, if the frequencies are so high, that the ground cable would act like an antenna too. Would it be a bad idea to shield the ground cable () and connect that shield to ground in a slightly different spot? This should create canceling fields and prevent the ground cable from emitting more radiation. Is this correct, or would it just cause more problems?

author: HB9EVI
author_rank: Frequent Contributor
timestamp: August 25, 2018, 06:20:01 pm
content: Often the screen of a RF signal cable actually acts like an antenna; that always happens, when the current flow is not fully differential; that's a so called common mode signal with makes the shield of a coax cable radiating RF; the origin is often feeding a balanced system with an unbalanced feed line.Those common mode signals can be radiated also over the supply lines of an RF circuit - the solution, whereever it might happen are common mode chokes - that's all it needs.

author: testtube44
author_rank: Regular Contributor
timestamp: August 25, 2018, 07:05:14 pm
content: What if you're not allowed to change the frequency content of the line? Is there any other way to create a canceling field? I think differential pairs (one opposite the other) would do just that.

author: David Hess
author_rank: Super Contributor
timestamp: August 25, 2018, 08:52:20 pm
content: Sometimes a tuned ground counterpoise is used but that does not stop the ground from radiating. Some improvement can be made by using a ground connection which has lower inductance like a braid or strap which is like using the shield of a coaxial cable.

author: HB9EVI
author_rank: Frequent Contributor
timestamp: August 25, 2018, 10:47:36 pm
content: Quote from: testtube44 on August 25, 2018, 07:05:14 pma common mode choke doesn't alter or attenuate the frequency content on a signal line, since those are differential currents; if you hook a snapon ferrite onto a usb or an ethernet cable, you are actually filtering common mode signals; the data signals are not affected by the inductance the ferrite forms on the wires.if you think of differential pairs as a balanced signal line, you have to watch out as well to not end up with unsymmetries resulting in radating signals from the wires. of course this issue is no one-way problem only; missing or incomplete symmetry can cause the signal wire acting as a receiving antenna; that's a considerable topic when designing balanced audio gears, it's all about the common mode rejection ratio
Grounding high frequencies - Page 1
Forum section: electronics / beginners

author: testtube44
author_rank: Regular Contributor
timestamp: July 10, 2018, 05:14:32 pm
content: I just learned that grounding antennas doesn't actually stop EMF. So how can one ground a high frequency signal without creating EMF?

author: Karlo_Moharic
author_rank: Regular Contributor
timestamp: July 10, 2018, 07:09:35 pm
content: Could you define what acronym EMF stands for in this case?

author: testtube44
author_rank: Regular Contributor
timestamp: July 11, 2018, 03:05:56 am
content: Electromagnetic fields. I'm trying to ground some high AC noise. I'm afraid my grounding line will turn into an antenna.

author: vk6zgo
author_rank: Super Contributor
timestamp: July 11, 2018, 03:28:24 am
content: Quote from: testtube44 on July 11, 2018, 03:05:56 amRule of HF circuits: - Short connections .If the length of the connection isverymuch shorter than the wavelength of the undesired frequency it will not radiate (or receive) to any significant extent.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: July 11, 2018, 03:24:23 pm
content: I think you should be more clear as to what it is you are trying to achieve. The entire point of an antenna is to generate electromagnetic fields which can then form waves and propagate.

author: testtube44
author_rank: Regular Contributor
timestamp: July 15, 2018, 03:23:40 am
content: I'm trying to plan ahead for my new ethernet connection (shielded), and I'm not sure if it needs to be grounded or not. The foil shield may be enough without the ground, am I wrong?
Grounding issues... - Page 1
Forum section: electronics / beginners

author: Hrvoje-CRO
author_rank: Contributor
timestamp: March 14, 2014, 04:34:15 pm
content: Hello!I have a problem with TDS2002B scope and DDS function generator.It is quite simple but i am a little bit confused because sometimes strange things happens with electricity in my house. (Sometimes my glamox radiator with digital thermostat stays ON (LED display only) when i switch it off.)First of all, the problem occurs when i switch off DDS generator on it's power switch, it stays still ON! Fully is powered OFF only if i disconnect scope's ground probe. So what to do? Is that normal behavior without isolation transformer or i have grounding problem in my home?Thank you in advance!

author: facumedica
author_rank: Contributor
timestamp: March 15, 2014, 02:33:20 am
content: Maybe, yes. Maybe the live or hot (IDK how you call it) is in short with ground, and ground is not properly grounded. I don't know if this is your problem, look for a professional if you don't know what to doAnd hey! Nice scope! I don't have even an analog one

author: sleemanj
author_rank: Super Contributor
timestamp: March 18, 2014, 08:02:36 pm
content: Sounds like DDS switch is on the neutral line, so when you switch it "off" the active line is still connected, but with your scope ground connected to it, there is a current path remaining...Watch

author: sigxcpu
author_rank: Regular Contributor
timestamp: March 18, 2014, 08:07:14 pm
content: If that's the case, there should be mains potential between DDS ground and oscope ground. Easy to measure. Easy to "feel"
Grounding loops of chips on shared heatsink ? - Page 1
Forum section: electronics / beginners

author: MathWizard
author_rank: Super Contributor
timestamp: March 29, 2021, 05:54:00 pm
content: I'm building a 5.1-channel stereo, on proto-type boards, with some TDA2030A AB-class audio amps. So far I have a main PWR board w/ Gnd rail, and made a star grounding w/ each little board (inputs/preamp/driver-outputs) having 1 GND branch into.As for the 6x TDA2030 output chips, their tab is on the negative supply, so for me that's just GND. And I put them all on 1 great big aluminium heatsink, w/ thermal compound. So it's probably not even a good GND connection really.Each TDA2030 still has it's own gnd wire, back to the driver boards (3 boards, for L/R, RL/RR,Center/woofer)looks about like thisSo should I be isolating them from the shared heatsink or not, the shortest signal path and lowest impedance should still be back to the originating driver/output board ?The only mains earth connection, is on the input jacks from the computer, power is from a non-grounded transformer.

author: wraper
author_rank: Unknown
timestamp: March 29, 2021, 06:06:49 pm
content: Tab is connected to -Vs, not GND. It's just a negative power pin as far as you should be concerned. What matters is no ground loops in input and feedback circuit. But I do not suggest using it to begin with. It's no longer produced by ST. What you can buy are knockoffs of different level of crappiness. Not it was that good to begin with.
Grounding Myself - Page 1
Forum section: electronics / beginners

author: bwclark
author_rank: Newbie
timestamp: April 12, 2015, 09:45:24 pm
content: Can I ground myself to my power supply?

author: TimFox
author_rank: Super Contributor
timestamp: April 12, 2015, 09:53:08 pm
content: If this is a normal laboratory power supply, note that neither the positive nor negative terminal is grounded. There is usually a ground post on the front panel to allow you to ground either end, depending on the application. That "ground" is technically the metal case of the supply that connects to the green (or green/yellow) lead in the three-wire power cord that goes to your building's electrical ground.Are you just looking for a convenient place to connect an anti-ESD ground strap? I would ground that,following manufacturer's instructions, to a ground (such as conduit) that does not involve a power cord.

author: bugs
author_rank: Contributor
timestamp: April 13, 2015, 10:20:09 am
content: Don't ground yourself! It is a recipe for disaster. You have a good chance at a shock if you do.For ESD you always have a high impedance ~1meg to ground.Ground is not the same everywhere and transients can realy ruin your day.If you accidentally touch anything live you will ensure a big shock, while if you are not grounded the high impedance to ground may offer a little more protection (protection by limited impedance, in IEC terms).Just stick you voltage meter between your PE conductor and for instance Cable TV, Central Heating, your tap, coax Ethernet (if you still have it, etc. and you can imagine how it would feel
Grounding of KSGER T12 with V2.05 PCB - Page 1
Forum section: electronics / beginners

author: makken
author_rank: Newbie
timestamp: December 15, 2021, 08:47:18 pm
content: Hello EEVblog!I have bought a KSGER T12 soldering station with the black v2.05 pcb from banggood, and I have already done the grounding of the case to PE.However, I have not yet grounded the secondary circuit (the tip + controller) and I have some questions about this procedure, since I have had trouble finding a detailed tutorial for this.I have studied the schematics provided by floobydust herehttps://www.eevblog.com/forum/reviews/t12-stm32-v2-1s-soldering-station-controller-schematic-etc/msg2467236/#msg2467236and they say that "PE GND needs jumper or extra wire added!"I have measured continuity from the GND pin on the controller to these - pins on the mainboard. The first two pictures shows this.From my understanding any of these pins should be connected to PE to provide ground to the controller and the tip. Is this correct?If so, is it also correct to use any of the colored connections in the third picture?

author: Benta
author_rank: Super Contributor
timestamp: December 15, 2021, 09:52:12 pm
content: I'm a bit unsure about what you wish to achieve.A soldering tip connected to PE is not always desirable. A floating tip is in most cases the better choice.In cases where you really need a PE connected tip, a ground clip to the heating element body is usually the better solution.

author: makken
author_rank: Newbie
timestamp: December 16, 2021, 12:57:54 pm
content: Thanks for the answer!From my understanding it was a safety hazard not to ground the heating element, but maybe I was wrong. There was a ground path from PE to the tip at the V2.04 board apparently, but that was removed in V2.05 (black pcb).Some more detailed comments about this are found herehttps://www.eevblog.com/forum/dodgy-technology/dangerous-solder-station-ksger-t12/msg3852254/#msg3852254
Grounding of Pace Intelliheat Stations - Page 1
Forum section: electronics / beginners

author: Okto47
author_rank: Contributor
timestamp: November 15, 2023, 02:04:16 pm
content: Hello,Has anyone changed his Intelliheat Station to a soft grounded System ?( Ground to tip ~20kΩ - 1MΩ instead of its original <2Ω , that ESD can’t discharge too fast).Or controlled if it’s possible to do it ?Thx.
Grounding question... - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: July 16, 2014, 12:51:07 pm
content: Hi,So I've got this box I'm using for a CNC controller. It is aluminum and I've got 120V (North America) coming into via a 3 conductor plug. The chassis is connected to the AC ground. The neutral goes to a 48V switching power supply. The hot goes through a fuse then through a switch to the switching power supply. The neutral-chassis and hot-chassis are open on my meter, but the ground-chassis is short (switching power supply is mounted to the aluminum case directly). All of this is fine so far, right?The switching supply is 48V DC has a V+ and V-. With nothing connected to the V-, it is also open to the chassis, but it ends up getting tied to ground as well because the controller I am using (Geckodrive G540) is mounted directly to the aluminum chassis and obviously its metal case is grounded to the V-. Is it ok that the V- gets connected to chassis ground? Is this how DC devices in a metal chassis are normally done?Thanks,Alan

author: ejeffrey
author_rank: Super Contributor
timestamp: July 16, 2014, 03:55:08 pm
content: Yes, that is the normal way you would configure electronics in a metal chassis.
grounding schemes for portable battery powered devices - Page 1
Forum section: electronics / beginners

author: rakeshm55
author_rank: Regular Contributor
timestamp: August 17, 2018, 03:41:18 am
content: Hi,I am developing a battery powered system (28V Battery) which has RF modules and Baseband modules. The only power source is battery.As of now ground of each modules comes in contact with the enclosure.Is there any recommended schemes for portable devices?? What are the aspects to be covered for grounding to obtain better EMI/EMC performance.??Any documentation covering this aspect.

author: Zero999
author_rank: Super Contributor
timestamp: August 17, 2018, 08:01:58 am
content: The metal enclosure is often connected to the negative of the battery, to prevent a large voltage difference from occurring between the electrical system and the chassis. In some cases, the enclosure is connected to the battery via a high impedance or over voltage protection devices such as MOVs or diodes. As a general rule of thumb, it's not good design practise to use the case as a return current path.
Grounding Stepper Motor Drivers - Page 1
Forum section: electronics / beginners

author: Larsson55
author_rank: Regular Contributor
timestamp: September 10, 2022, 03:59:16 pm
content: The attached pic indicates one of the four drivers I have in my CNC machine to drive my 4 stepper motors. I have conflicting/confusing answers on how to ground the shielded cables feeding each driver. All feeding cables are 22 AWG, 4 conductors wrapped in aluminum foil with a bare grounding wire. The maximum length of a cable is about 14 feet and the minimum length about 7 feet.A = 4 conductors feeding the signal to the driver from the breakout board.B = Nothing connected as per manufacturer.C = 2 conductors (BLK/RED) feeding 48VDC power to the driver from the power supply unit.D = 4 conductors feeding power to each stepper motor.My question is what to do with the bare grounding wire. Do I take the bare grounding wire to my star point ground from all 3 cables or from only cable A, C, D or any other combination?Thank you

author: rstofer
author_rank: Super Contributor
timestamp: September 10, 2022, 05:38:14 pm
content: I would ground the shield on one end only. This will be dependent on how the connectors are made but, since the metallic jacks must be earth grounded, it should be easy to ground one end of the shield to the connector body. I would cover the other end of the shield with shrink tubing to keep it insulated. I do not want to form ground loops between the computer and the tool itself.

author: Larsson55
author_rank: Regular Contributor
timestamp: September 10, 2022, 07:25:01 pm
content: Sorry but my question is not which end of a cable to ground but rather which cable(s) to ground, There are 3 cables so which one do I ground? maybe all?Thanks

author: wraper
author_rank: Unknown
timestamp: September 10, 2022, 07:37:58 pm
content: A and B look like optically isolated inputs. If you ground them to anywhere at all, then do so from the opposite side, not at controller. No need to use shielded cables for C - power. It's advisable to ground the shield of the motor cable - D. The best way likely would be connecting the shield on both ends, to the chassis GND point on driver side and to the motor enclosure on opposite end.

author: Larsson55
author_rank: Regular Contributor
timestamp: September 10, 2022, 08:07:13 pm
content: Quote from: wraper on September 10, 2022, 07:37:58 pmThanks for your time, all is clear now
Grounding Strap - Page 1
Forum section: electronics / beginners

author: reed
author_rank: Contributor
timestamp: August 15, 2021, 05:49:42 pm
content: Hi,I was taking a microwave apart today. Around some wires I found a strap wrapped around and connected to the chassis for grounding, it had earth sheathing.Was it to prevent / cut down EMF?Would it be useful for me to use this method in places around my DIY CNC (in addition to the ferrite beads)?Sorry for daft question, but been meaning to join for a while and finally get around to learning more, need to start somewhere...Thanks

author: SeanB
author_rank: Super Contributor
timestamp: August 15, 2021, 09:17:01 pm
content: Not really, more there to manage the cables, to keep them in a neat loom and routed correctly, so they are not going to rub on the case, or on the interior of the cavity, but keep them neat and in place. The sleeve on the tab is there to provide more insulation, so the high voltage in the cable does not break down the insulation with time and arc over to the metal chassis.

author: reed
author_rank: Contributor
timestamp: August 16, 2021, 08:50:34 pm
content: There were numerous cable ties as well, also the cables still touched the body in places.No matter
Grounds... - Page 1
Forum section: electronics / beginners

author: mortos360
author_rank: Regular Contributor
timestamp: October 19, 2012, 01:25:04 pm
content: Can you always put them together or are there any conditions where you should never combine them?I am wondering if I can use my function generator to drive an transistor... the problem is, that my FG seems to have mainsGround while my power supply doesn't. The PS has a 3th yellow connector that is mainsGround, but I don't know I can just short that with the negative rail of the PS.. or can I?I remember a video of Dave where he talks about the danger of connecting oscilloscope probes (positive probe tip) to mainsGround, but I don't remember anything about him talking if I can safely connect all grounds together.If I had 3 different power sources.. like a LabPS a battery and some other device.. is it in general safe to connect all grounds together?ps: I just watched Daves video again and it seems to be OK to short negative rail of the PS with the mainsGround.

author: benemorius
author_rank: Regular Contributor
timestamp: October 19, 2012, 03:25:45 pm
content: Quote from: mortos360 on October 19, 2012, 01:25:04 pmYup. I was going to recommend watching it again with your situation in mind. I believe all the answers are there.The very reason that your power supply isn't permanently mains earth grounded (it's called floating) is so that you can hook it up to other things that are grounded. It's usually a good idea for safety reasons to have it grounded any time you don't need it to be floating, which is why it gives you an earth terminal right next to the negative supply terminal. This makes it easy to short them together. If you leave your whole circuit floating it may float to a high enough voltage (relative to earth) to harm you. For instance, this can happen if some equipment fails and shorts part of your circuit to live mains voltage. Your circuit likely won't care, but now it will be at mains potential waiting for you to touch it and get a nasty shock. Dave's video probably addresses this too. It might not be a bad idea to re-watch the video until you grasp everything he has to say.
Grouop loop isolator - how it works - Page 1
Forum section: electronics / beginners

author: amateur_25
author_rank: Regular Contributor
timestamp: May 17, 2015, 08:28:51 pm
content: I believe I have the dreaded group loop issue. My monitor's audio input is connected to my pc, there's this humming sound I can hear when there's no audio.It's not coming from my monitor because it's not there when I connect to my phone which is battery powered of course.I built up a simple circuit with an cheapo audio isolation transformer 1K:20K.Yes it's not the ideal transformer but it was all I could get my hands on. My local rip off merchant maplin isn't the finest collection of componentsSadly I only had one 56K modem I could salvage the transformer from.My question is what has the transformer done to my humming noise? Am guessing it's 20K impedance that has affected the loudness ofthe audio? Ah well you can't win. If I bought a ground loop isolator I'd probably have the same issue unless it has a proper transformer.
GRT8-B1 AC/DC Timer Relay wont turn off - Page 1
Forum section: electronics / beginners

author: Runenaldo
author_rank: Newbie
timestamp: September 11, 2021, 07:43:28 am
content: Hello everyone!I have build myself a 3dprinter (Rat Rig V-core 3) and the heated bed is 240V AC, so it it switched from the controller board (SKR pro 1.2) with a 24V DC on/off signal via an SSR. I wanted to put in a little safety as SSR's are known to fail closed, so I decided to add a GRT8-B1 AC/DC 12V ~ 240V Timer Relay. I feed A1 and A2 directly from the same power supply I also feed the controller board with and then I tried to "steal" the positive signal from the SSR to the Signal pin on the timer relay, but the relay then never turns off, it is always active. When I remove the wire to the signal pin it does its countdown and opens the relay as normal.Is there someway I can make this work, or do I have to get another relay to control the timer relay? (which I think would defeat the whole purpose)
GSM door opener - old GSM phone mod :) - Page 1
Forum section: electronics / beginners

author: mucek
author_rank: Contributor
timestamp: September 02, 2014, 07:51:45 am
content: http://www.ecat.si/2014/08/gsm-door-opener-nokia-gsm-mod/Simple project for re-use some old GSM phones into something useful ...It's as simple as can be, though if you have any questions, you are welcome!Regards,Gregor

author: Whales
author_rank: Super Contributor
timestamp: September 02, 2014, 08:34:22 am
content: Sounds like a nice idea. I'm assuming the phone provider lets it be 'receive only' if you don't bother paying for any credit/contract/etc? Otherwise it might end up being more expensive than you think.

author: mucek
author_rank: Contributor
timestamp: September 02, 2014, 08:45:00 am
content: True, we have possibility (with one operator only!) for a 1 EUR/year contract. Others and prepaid options are far more expensive ...

author: Whales
author_rank: Super Contributor
timestamp: September 02, 2014, 09:51:01 am
content: 1 euro per year sounds very nice. Hopefully nothing more complicated will crop up.Next challenge: make a receiver tuned to the EM patterns of your engine's firing sequence during idle.

author: SeanB
author_rank: Super Contributor
timestamp: September 02, 2014, 07:10:09 pm
content: Funny, I did the opposite with an old Motorola phone to make a cheap cellular alarm monitor. Simply used the phone with the car charger and no battery, powered from 12V, and a simple one shot to press the call button when the siren went off. Put a small amount of PAYG money in the phone and left it at that. It never was used other than in test, but worked each time.

author: Stonent
author_rank: Super Contributor
timestamp: September 03, 2014, 01:15:14 am
content: Good to see this circuit being used for good and not evil.

author: zapta
author_rank: Super Contributor
timestamp: September 03, 2014, 03:27:29 am
content: Quote from: Stonent on September 03, 2014, 01:15:14 amEnough said.
GSM Module + RS485 transceiver directly possible ? - Page 1
Forum section: electronics / beginners

author: andre123
author_rank: Newbie
timestamp: February 11, 2020, 06:57:02 am
content: Hello,I was wondering if someone could confirm if it is feasible to interface a GSM module for example SIM900, SIM900, Quectel's M95 or Neoway's N10 , maybe if we use the RS232 interface with HW the flow control pins RTS/DTR to the MAX485 or equivalent to talk to a master RS485 node ? or do i need to use a microcontroller to handle that ? What got me suspicious is i never saw an RS485 GSM modem without having its own microcontroller, that got me intrigued.RegardsAndre
GSM signal repeater cable - Page 1
Forum section: electronics / beginners

author: fubar.gr
author_rank: Unknown
timestamp: April 09, 2024, 07:27:00 am
content: Hello all, I have a GSM 5G repeater for bringing mobile signal to a basement with no reception.The repeater works perfectly, but I want to move the internal antenna to a different location about 5 meters away, so I will need an extension cable, but I don't know the type of the connectors used or what type of cable is needed. Please see the attached photos.Thank you.

author: srb1954
author_rank: Super Contributor
timestamp: April 09, 2024, 07:43:55 am
content: Looks like a N-type connector.

author: MarkT
author_rank: Frequent Contributor
timestamp: April 09, 2024, 10:16:16 pm
content: Secondedsearch term: "rf connector guide"

author: Vovk_Z
author_rank: Super Contributor
timestamp: April 10, 2024, 08:03:46 am
content: Yes, it must be N-type connectors (Male and female types for cable crimping).5G band that's >=2-3 GHz I guess so you have to take into cosideration low loss cable types suitable for such high frequencies.

author: radiolistener
author_rank: Super Contributor
timestamp: April 10, 2024, 08:30:15 am
content: looks like usual N connector.Note that at these frequency there is a high cable loss, so look for cable loss in datasheet and estimate if it have sense to use so long cable, because the signal will be attenuated a lot.
GU-29 829B help to identify the pinout - Page 1
Forum section: electronics / beginners

author: Ghitza
author_rank: Contributor
timestamp: July 31, 2021, 07:59:23 pm
content: Hi guys,please don't laugh. I have the datasheet but I don't get the idea of how to count the pins.By datasheet I see there are 3 pins (6.3V in paralel and 12.6V in series) for the filament but which are those?

author: TimFox
author_rank: Super Contributor
timestamp: July 31, 2021, 08:29:21 pm
content: Vacuum-tube pins are always numbered clockwise from the pin side (shown in your photo).The larger (fat) pin for the 7-pin "Septar" base is pin 4.The heater is between pins 1 and 7, with a center-tap at pin 5.You can connect 12.6 V from 1 to 7, or 6.3 V from (1&7) to (5).When buying a socket, note that there are two similar socket types: make sure the vendor specifies it for an 829, the most common type using it, along with the 4D32, the 832, and a few others. The official name is "B7A", the "B7G" is the normal 7-pin miniature (6C4, etc.). An 813 also uses a largish 7-pin socket ("Giant 7-pin A7-17"), that is not compatible. It has two fat pins at 1 and 7, instead of one at 4.The full RCA data sheet:https://frank.pocnet.net/sheets/201/8/829.pdf
Guess that part - Page 1
Forum section: electronics / beginners

author: vargoal
author_rank: Regular Contributor
timestamp: January 18, 2015, 02:36:02 am
content: Hi EEVBlog,I am currently reverse engineering my Turnigy Mega Meter 7 in 1 multimeter device. Anyway I came along this part which I believe is a voltage regulator but I can't find a datasheet for it.I tried searching it on digikey and on semiconductor's site. Do any of you know where I can find a datasheet for it?

author: Yansi
author_rank: Super Contributor
timestamp: January 18, 2015, 02:39:04 am
content: BCP56Almost sure it is, the circuit it is in is a simple voltage regulator with a zener in the base pin.

author: vargoal
author_rank: Regular Contributor
timestamp: January 18, 2015, 02:42:12 am
content: Thanks, That was quick.

author: vargoal
author_rank: Regular Contributor
timestamp: January 18, 2015, 04:23:07 am
content: Also just FYI, the way this device operates they probably should have just put in a full blown LDO but whatever. Anyway I reversed enough to make my mod before reassembling it.

author: 3roomlab
author_rank: Frequent Contributor
timestamp: January 18, 2015, 04:38:47 am
content: whoa 7 in 1 ...its totally MCU controlled ?

author: Skimask
author_rank: Super Contributor
timestamp: January 18, 2015, 04:41:50 am
content: Quote from: vargoal on January 18, 2015, 02:36:02 amhttp://www.marsport.org.uk/smd/mainframe.htm

author: vargoal
author_rank: Regular Contributor
timestamp: January 18, 2015, 04:47:53 pm
content: Here are some photos of the device for those of you who are interested but don't want to take your apart or simply don't have one.Note: Red wire soldered on the one side is not part of original design but it allows me to use the servo test feature without two power supplies/batteries hooked up. Only draw back is now if I do try and use two sources then there will be major problems because both positives and negatives will be connected instead of just negatives on both being connected like before.
Guess the pinout of toy phone schema - Page 1
Forum section: electronics / beginners

author: hotter
author_rank: Newbie
timestamp: May 18, 2015, 05:27:52 pm
content: Hi, I have this old "toy phone" schema and I would like to play with it a bit and maybe do something useful... But the problem is that schema is without any wires and I am not sure where should I solder 2 speaker wires and 2 power wires. Is it possible to trace it somehow? I was trying but no success...

author: kolbep
author_rank: Frequent Contributor
timestamp: May 18, 2015, 09:18:32 pm
content: I think top left pad will be +3v (the way it snakes through all the switches and then to the IC)2nd from the right will be the Speaker out (Probably the Transistor is an amp for the speaker?then maybe the very right hand pad will be 0v for the battery, and for the other leg of the speaker (looks like the only other pad that had a wire on it before)??

author: hotter
author_rank: Newbie
timestamp: May 19, 2015, 04:42:58 pm
content: Yes, you are almost rightIt works when connected like this: to the most left power+ and speaker wire1; to the most right power-; second from right speaker wire2. Thanks.I wanted to connect it to theIntercom phone("door phone") and make it ring, but its not that easy, the sound is noisy and quite. I need something else...Intercom phoneschematics:Maybe someone knows what input is needed for L+ and L-? If someone knows any circuits that would generate ringing sound and work with Line L+ and L- pins that would be great.
Guess who - broken component photo - Page 1
Forum section: electronics / beginners

author: gis
author_rank: Contributor
timestamp: November 13, 2013, 11:59:33 am
content: Can anybody guess what is this and its value from dimensions?Thanks, cheersGiovanni

author: Dataforensics
author_rank: Unknown
timestamp: November 13, 2013, 12:21:42 pm
content: I assume its open circuit. If so you could try and carefully unwind the wire thats left. Then measure resistance of what you can and calculate for whole length.Would have thought that even if damage has caused a change in value, you would get magnitude, and you have first two digits.

author: gis
author_rank: Contributor
timestamp: November 13, 2013, 12:29:18 pm
content: Thanks a lot!

author: dr_p
author_rank: Frequent Contributor
timestamp: November 13, 2013, 01:40:43 pm
content: that looks like heat damage on a 2W package, so I spit the table bellow:Code:5 V10 V20 V30 V40 V50 V100 V200 V22 1.1 W4.5 W18.2 W40.9 W........................2200.1 W0.5 W1.8 W4.1 W7.3 W11.4 W45.5 W......2k2............0.2 W0.4 W0.7 W1.1 W4.5 W18.2 W22k........................0.1 W0.1 W0.5 W1.8 Wwhat voltage was used in the device it came from?

author: G7PSK
author_rank: Super Contributor
timestamp: November 13, 2013, 06:36:42 pm
content: It does not look like it says 2k2 or 2.2 so you can most likely strike that one, I would bet on 22 or 220 ohms as the most probable judging by the wire thickness.

author: SeanB
author_rank: Super Contributor
timestamp: November 13, 2013, 07:45:38 pm
content: If you do not want to unwind just measure from half way to whichever end is still intact. As it is 22R or 220R you simply have to see if the resistance to the end is under 15R or under 70R. With the thick wire my guess is it is a 22R 2W glazed enamel resistor. Replace with a 22R 5W one and you will be fine.I will guess it came out of a telephone, as this is a common size and type used there.
Guessing SMD programable LED polarity - Page 1
Forum section: electronics / beginners

author: symbianas
author_rank: Regular Contributor
timestamp: January 18, 2023, 05:33:14 pm
content: Hi, I have bought unknown programmable (ws2811/ws2812...) LED strip which has 3 wires (black, blue, green).Its not very clear which is "positive" which is "negative" and which is "data in". Is there any way to guess/test without unwrapping black taped LED strip? Also not damaging it?In third image I have tested which wire is soldered to which part of LED strip.Black - negative?Blue - data in?Green - positive?

author: CountChocula
author_rank: Unknown
timestamp: January 18, 2023, 06:00:36 pm
content: The cap should be tied to VCC and GND, so I would also guess black is ground, green is VCC, and blue is data. You could check by connecting to a PSU with a very low current limit (<50mA) and then feeding in enough data to light the first LED only. If you get it wrong, there shouldn't be enough current to fry anything.

author: symbianas
author_rank: Regular Contributor
timestamp: January 18, 2023, 06:21:10 pm
content: Yes!!! We have guessed correctly! Its working! Thanks!The marking next to LED (green triangle) is not that clear though.Is there a way to guess voltage?Its working from 3.3V quite bright, I think it might be 5V driven, but not sure how to test?

author: CountChocula
author_rank: Unknown
timestamp: January 18, 2023, 07:41:23 pm
content: Excellent, glad it works! You could try cautiously raising the voltage while keeping the current limited to a small range… again, just light one LED so that you only need little current and see what happens if you raise to 5V. Then again, if it works at 3.3V, why mess with it?

author: symbianas
author_rank: Regular Contributor
timestamp: January 18, 2023, 09:07:04 pm
content: Quote from: CountChocula on January 18, 2023, 07:41:23 pmIts easier to find power supply of 5V.I think I found equivalent to my led strip:https://www.aliexpress.com/item/1005004455070681.html?spm=a2g0o.productlist.main.1.2d08246cRNofC2&algo_pvid=f31db506-cf40-4d72-ab8a-b4babed61591&algo_exp_id=f31db506-cf40-4d72-ab8a-b4babed61591-0&pdp_ext_f=%7B%22sku_id%22%3A%2212000029232572388%22%7D&pdp_npi=2%40dis%21EUR%2125.01%2117.51%21%21%21%21%21%40210219c216740757955497261d0689%2112000029232572388%21sea&curPageLogUid=XM80M8WbpCa2So it seems that its:5V110cm (148LEDs)SMD 2020 WS2812C LEDChip: San'anPower: 0.1W/LEDNow whats left is to find out how much Amps do I need drive this thing.

author: CountChocula
author_rank: Unknown
timestamp: January 19, 2023, 12:56:29 am
content: I would guess around 3A if all the LEDs are on at full brightness, plus whatever is needed to run the MPU that controls the string. (.1W / 5V = 20mA per LED). Good luck!
GUI based software to make simple android app - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: June 21, 2020, 05:20:37 am
content: 1. Is there complete GUI based software for PC to make a very simple android app.2. I have make two switch on app: one when press send data via bluetooth and other when press receive data on BTand display on small display box on screen

author: ebclr
author_rank: Super Contributor
timestamp: June 21, 2020, 11:59:16 am
content: https://www.embarcadero.com/br/products/rad-studio/create-android-apps

author: chris_leyson
author_rank: Super Contributor
timestamp: June 21, 2020, 12:27:08 pm
content: Basic4Android is now free

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: June 21, 2020, 12:42:15 pm
content: What I wanted to ask was complete GUI based software.No need to write text code, since my apps are very very simple

author: chris_leyson
author_rank: Super Contributor
timestamp: June 21, 2020, 01:10:59 pm
content: You can draw most if not all o the controls, buttons, sliders et using the B4A GUI and a minimal amount of programming. Maybe there was a MIT Scratch like extension at one time but I'm not sure.

author: Zero999
author_rank: Super Contributor
timestamp: June 21, 2020, 07:05:18 pm
content: Quote from: Vindhyachal.takniki on June 21, 2020, 12:42:15 pmPlease be more explicit. Are you talking about a fully graphical programming language?

author: filssavi
author_rank: Frequent Contributor
timestamp: June 21, 2020, 07:17:17 pm
content: I’m not an Android programmer myself, but I will go out on a limb and say that what you ask does not exist, also depending on the specifics of the other device sending Bluetooth messages might not be as straightforward as you think, especially if your device is not something standard.In essence if your device is something like a BT headset, keyboard, etc the OS will do all the complex protocol housekeeping for you, however it your developing something custom you will in all likelihood need to do it yourself which is not something you want do to in something like singlink or labview, trust meAnyway app development is not terribly complex, and you can pick it up fairly quickly

author: ebclr
author_rank: Super Contributor
timestamp: June 22, 2020, 11:30:02 am
content: Did you check the link is exactly what you want
Guidance for an AD2S1205WSTZ - Page 1
Forum section: electronics / beginners

author: Valto
author_rank: Newbie
timestamp: October 06, 2023, 02:03:15 pm
content: Here is my resolver.https://1drv.ms/i/s!Ank8chvZyxv8hMdqMOHFq-NwC8n1wQ?e=rY3BN1I a quite new to PCB design I've done some playing around in Kicad but i have not ordered a serious board yet. My question really is how should i go about designing a board for the AD2S1205 since I don't think simulating it is an option at my skill level since its not on LTspice. So should i just Copy-Paste the reference design to Kicad and cross my fingers?
Guide / resource on making relatively safe Li-ion packs? - Page 1
Forum section: electronics / beginners

author: monster_of_electronics
author_rank: Contributor
timestamp: April 21, 2015, 06:44:24 am
content: I'm looking to make some li-ion packs out of a bunch of good quality samsung li-ion cellls I have been fortunate enough to acquire cheaply. Are there any guides out there or resource outlining the critical steps for putting together relatively safe, sturdy DIY li-ion packs?Like what protection circuits are reliable/good enough, fuses, recommended packaging, insulation, pros/cons of different safety features, etc.

author: tszaboo
author_rank: Super Contributor
timestamp: April 21, 2015, 11:58:25 am
content: This can help by the electronics safety:http://www.ti.com/lit/an/slua707/slua707.pdf
Gutless Servo - Page 1
Forum section: electronics / beginners

author: The_Welding_Library_Guy
author_rank: Contributor
timestamp: February 26, 2019, 09:10:03 am
content: I was needing a 360 degree servo for a project but just had a few MG996r's in the random bits drawer. I did a bit of reading and set out to modify one to turn 360 degrees. While I was mucking around in the servo though. I had a sudden desire to mutilate this poor motor by ripping the control circuitry out and clipping the motor to my bench power supply. So I did and exclaimed EUREKA! Now I didn't need to tie up an ardiouo just to turn a servo left or right when a button is closed. The power source for this project is a 12v lead acid batt. I originally was planing on dropping the voltage down to 7v with resistors for the servo. But the more I think about it. The more that 7.2v max seems like its to protect that now lobotomized control board. What do y'all think about running the motor at 12.6v outright? Do you think the little DC motor would handle it just fine? I have tested it in short burst under load and it seems to work fine. Just wanted to see if anyone might no something I didn't before I decided to make this the permanent plan.

author: Psi
author_rank: Super Contributor
timestamp: February 26, 2019, 10:54:13 am
content: Hard to say.Run it for a while and keep an eye on the motor case temp.If it doesn't get hot it's probably fine.If it's going to fail from over voltage it will be through heat.Also keep in mind that while it may work fine at 12V it may not work fine if stalled at 12V.At its proper voltage the motor may survive a constant stall.Handling a stall maybe part of the design requirements for a servo

author: Brumby
author_rank: Unknown
timestamp: February 26, 2019, 12:57:04 pm
content: What Psi said ^ ^ ^ ^

author: tsman
author_rank: Frequent Contributor
timestamp: February 26, 2019, 01:10:27 pm
content: Sounds dubious to run it at 12.6V. The servo is designed to run off a 5 cell RC battery pack which is nominally 4.8V but may be up to 7.2V straight off the charger. I'd expect the servo manufacturer to spec a motor that operates in that range for maximum torque instead of trying to run a 12V motor from 4.8V.

author: Psi
author_rank: Super Contributor
timestamp: February 27, 2019, 11:21:22 am
content: It's not uncommon for a DC motor to have quite a wide acceptable voltage range.No real way to know what spec motor they used.
GW Instek 1054B capture SPI to PC - Page 1
Forum section: electronics / beginners

author: AlexF
author_rank: Newbie
timestamp: February 15, 2018, 01:30:28 pm
content: How I can capture SPI transfer to PC using GW Instek 1054B? Please help

author: mikerj
author_rank: Super Contributor
timestamp: February 15, 2018, 04:14:43 pm
content: Does the 1045 include serial decoding? I was pretty it didn't.
Gw instek  power supply - Page 1
Forum section: electronics / beginners

author: Shutterdial
author_rank: Newbie
timestamp: March 18, 2017, 11:13:36 pm
content: My power supply came with a short bar. I'm guessing it shorts out the negative and ground if this is correct Why?

author: w2aew
author_rank: Super Contributor
timestamp: March 19, 2017, 02:11:39 am
content: Quote from: Shutterdial on March 18, 2017, 11:13:36 pmBecause the output is floating. If you want a positive output, connect the bar between ground and the negative side of the supply. If you need a negative supply voltage, then strap the pos output to ground.I did a video on this: