hybridfree/eevblog-posts huggingface dataset:
Splice in the USB cable - Page 1
Forum section: electronics / projects

author: IconicPCB
author_rank: Super Contributor
timestamp: October 15, 2019, 02:32:18 am
content: How troublesome can a splice in USB2 be?

author: IconicPCB
author_rank: Super Contributor
timestamp: October 15, 2019, 02:38:55 am
content: I am not sure how to determine the requirement.A USB 2 camera lives on the cable. It plugs directly into the PC.The cable looks like it had been either cut inadvertently and repaired or extended by 15 cm.In use the camera ( part of machine vision openCV ) is showing some instability in the form of flickering display where the flicker appears as change in size of displayed item.

author: Monkeh
author_rank: Super Contributor
timestamp: October 15, 2019, 02:44:16 am
content: Quote from: IconicPCB on October 15, 2019, 02:32:18 amVery.Replace it.

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 15, 2019, 03:24:01 am
content: Cut out the splice and replace it with a cheap hub as a repeater.

author: Pack34
author_rank: Frequent Contributor
timestamp: October 16, 2019, 10:26:43 pm
content: It could be if you're sending a lot of data. I've had some pretty dodgy splices on some USB-FS and USB-HS cabling and they worked fine. That being said, if you're noticing some odd behavior then I would replace it. Long runs of USB2 cables are pretty cheap.

author: IconicPCB
author_rank: Super Contributor
timestamp: October 16, 2019, 10:37:53 pm
content: It, the USB cable, is the camera cable; partof machine vision setup.Been experiencing some vision instability. Control processor has died now so need to repair the control processor and then address the USB cable issues.
Splice Wire to NASA Standards - Page 1
Forum section: electronics / projects

author: ebclr
author_rank: Super Contributor
timestamp: September 22, 2016, 02:29:26 am
content: http://www.hq.nasa.gov/office/codeq/doctree/NSTD87394A.pdf

author: raptor1956
author_rank: Frequent Contributor
timestamp: September 22, 2016, 03:10:23 am
content: Watching the NASA video on "soldering" reminded me of the Phil Hartman skit "The Anal Retentive Carpenter"...http://www.nbc.com/saturday-night-live/video/anal-retentive-guy/n9800Brian

author: Rerouter
author_rank: Super Contributor
timestamp: September 22, 2016, 03:34:40 am
content: That is called the lineman splice, and its simplified version is cross twisting the wires before soldering,What they show above called the lap splice i am not fond of, as any motion around the joint and the solder fails, whereas that splice atleast has mechanical support so the solder is not having to do much work, (it is soft after all)

author: calexanian
author_rank: Super Contributor
timestamp: September 22, 2016, 04:33:58 am
content: Yeah. That's a line mans splice. Its what i was taught so many years ago. It has none of the properties of a braid. May as well just twist the wires and solder them.

author: alanb
author_rank: Frequent Contributor
timestamp: September 22, 2016, 07:39:16 am
content: I am surprised that NASA permitted any type of splice. I would have expected them to insist that all wires were unjointed from end to end.

author: max_torque
author_rank: Super Contributor
timestamp: September 22, 2016, 05:58:33 pm
content: Pretty sure no one will be soldering anything these days! Carefully controlled Mechanical crimping is much, much, much more reliable, especially with an adhesive jacket/filler etc

author: Jeff_Birt
author_rank: Regular Contributor
timestamp: September 22, 2016, 06:19:45 pm
content: Quote from: Rerouter on September 22, 2016, 03:34:40 amWell that is true for any solder joint, if things move while it is cooling you have a poor solder connection. For example if a panel snags/jerks going through the wave machine all the components shake and you have problems.The lineman's splice is also called a 'Western Union' splice coming from the days of the telegraph. As one of my teachers told me "The first step to a good electrical connection is a good mechanical connection." It pains me to watch auto mechanics on TV try to solder, good lord they find more and more creative ways to do it all wrong every time.

author: dom0
author_rank: Super Contributor
timestamp: September 22, 2016, 06:23:26 pm
content: There is eutectic solder (of course only for home/hobbyist use - it's leaded) that makes it pretty much an non-issue. Quite handy for free-hand splices without a third hand or anything else to hold stuff in place.
Split bobbin CT's, and the do's and dont's of measuring AC current - Page 1
Forum section: electronics / projects

author: senso
author_rank: Frequent Contributor
timestamp: December 13, 2014, 01:06:32 am
content: Good night everybody,So, another project(or crazy idea), I have been thinkering about a measuring mains(in Portugal its 230v AC at 50Hz), I want to measure both the voltage and current, and I want to use split bobbin current transformers, but as far as I have seen they are sort of rare, and very, very expensive, Mouser and RS don't seem to carry them, and I have a preference for a legit supplier in Europe, the eBay cheapies dont convince me, the current ranges that I want to measure are 0.30A and 0-100A.Regarding the electronics I'm pondering using the ADE7816 or the ADS131E08, I'm thinking about only measuring one phase, but there might be some situations in my eletrical installation(made 20 years ago by a shoody contractor) that I don't have a neutral connection, only three phases, and I would like to still have some idea to how the mains voltage is going.Maybe it would be cheaper to use some 12-14 bits ADC's, but those chips have the advantage of the multiple converters to sample the various signals at the same time.Any input about what is in essence power metering, split bobbin CT's(or Rogowski coils) are welcome.Best regards.

author: johansen
author_rank: Super Contributor
timestamp: December 13, 2014, 01:23:17 am
content: do you mean split core?

author: senso
author_rank: Frequent Contributor
timestamp: December 13, 2014, 01:54:25 am
content: Yes, maybe thats my fail, wrong keywords.

author: SeanB
author_rank: Super Contributor
timestamp: December 13, 2014, 04:37:50 am
content: Grab the el cheapo clamp meter and use the clamp section for the current sensing, you can probably keep the signal conditioning inside and toss the COB display driver and hard wire it to give you the 200A range permanently to an output. Strip the rest out and leave the 9V battery and a switch if needed and get the 2V output via a screened lead. That gives the current measurement cheaply, and then just use a decent meter for the voltage side.
Split groundplane, why? - Page 1
Forum section: electronics / projects

author: edgelog
author_rank: Regular Contributor
timestamp: December 02, 2017, 06:22:52 pm
content: I'm fiddling around with a broken Razer Mako speaker system and one strange (to me) layout got me wondering. The ground plane is split over a part of the board with a few decoupling capacitors across the gap. I'm just wondering why they did it this way. Anyone can clue me in?Since it's a speaker system, all signals are in the audio range, nothing RF here.

author: elal1862
author_rank: Newbie
timestamp: December 02, 2017, 09:01:58 pm
content: So you've heard about ground plane inductance, but you forgot about ground plane resistance - which isn't negligible if you're dealing with a couple of amps of return current (from the speakers back to the power amp, when playing at full blast). You don't want that current to take a shortcut across the input stage!

author: edgelog
author_rank: Regular Contributor
timestamp: December 02, 2017, 09:06:02 pm
content: Quote from: elal1862 on December 02, 2017, 09:01:58 pmYes, that makes sense. Thx.

author: cat87
author_rank: Regular Contributor
timestamp: December 03, 2017, 10:11:50 am
content: If you look at it, the planes are not actually split. They have continuity. It's more like they just branch out. This split is done to keep dirty noisy ground currents from the power section away fron the input ground.

author: janekm
author_rank: Unknown
timestamp: December 03, 2017, 10:21:47 am
content: I'm curious about those speaker terminals, could you post some pictures of those? Seems like an unusual footprint!

author: edgelog
author_rank: Regular Contributor
timestamp: December 03, 2017, 11:07:41 am
content: Quote from: janekm on December 03, 2017, 10:21:47 amThe main unit contains the woofer, connected by leads soldered to the middle of the main board. Two satellite speakers each contain a midrange and a tweeter. The connection between the main unit and the satellites is with RJ45 connectors and pretty heavy flat cables. I took apart one of the satellites which showed me that the midrange and the tweeter have their own connections to the main unit, so the frequency filters are in the main unit.

author: Specmaster
author_rank: Super Contributor
timestamp: December 03, 2017, 11:18:09 am
content: Quote from: cat87 on December 03, 2017, 10:11:50 amDave has done blog on current paths on a pcb and while the ground plane is connected further down the pcb, the large speaker current will not find its way back the input stages to cause noise problems. Remember electricity will always take the shortest route if it can and that is why the ground is split but has decoupling caps across the divide to allow access signals across but block out the high power dc currents.Sent from my SM-J510FN using Tapatalk
Split rail Power supply using coupled inductor - Page 1
Forum section: electronics / projects

author: tip29
author_rank: Newbie
timestamp: December 18, 2019, 04:19:15 pm
content: Hello guys,So I recently built a split rail power supply using TPS560430 fixed frequency switcher and a coupled inductor following the topology as shown below. (TPS560430 doesn't require a catch diode)I designed it to output +6V -6V. The result I got was an uneven split from the ground. Like +9V -3V. More positive than negative.If I load + and - terminals the split starts improving. And, across the + and - terminals the switcher IC regulates the output of 12V perfectly.If I increase the input voltage to the IC the split starts getting worse (uneven).Is there anything I can do to get close to even split without loading the power supply?Thank you.

author: capt bullshot
author_rank: Super Contributor
timestamp: December 18, 2019, 04:49:47 pm
content: The positive side rectifies the coupled inductor ringing if unloaded, and the negative side is loaded by the switcher IC, so this circuit can't produce evenly split output if unloaded.This circuit requires some substantial and best case evenly distributed load to produce an even split. There's some other tricky circuits available that regulate the positive side and provide the negative side unregulated, using an AC coupling capacitor and an additional (non-coupled) inductor. It's similar to the SEPIC auxiliary described here:https://www.maximintegrated.com/en/design/technical-documents/tutorials/3/3740.htmlbut the inductors don't need to be coupled.Here's an example for the "charge pump" method:https://www.analog.com/media/en/reference-design-documentation/design-notes/dn47f.pdfEdit: If you simply want to split your supply to half (midpoint @ 1/2 Vin), use a synchronous half bridge buck converter driven by a 50% duty signal, and its output as the virtual GND.

author: David Hess
author_rank: Super Contributor
timestamp: December 19, 2019, 01:08:49 am
content: Good tracking between the supplies requires the switching regulator to be in continuous conduction mode which requires a minimum load on the main output.

author: tip29
author_rank: Newbie
timestamp: December 19, 2019, 10:35:55 pm
content: Thanks for the links.
Sporadic interference on an open collector bus, at 2.5MHz? - Page 1
Forum section: electronics / projects

author: Artlav
author_rank: Frequent Contributor
timestamp: July 05, 2020, 03:05:12 am
content: I got a single wire UART bus spanning dozens of meters, and things on it tend to glitch and lock up a few times a week.I've tried adding clamp and TVS diodes and series resistors, to little effect.Eventually i sat there staring at a scope for a few hours, and was able to capture several bursts at 2.5MHz, about 4 times an hour. They vary in duration and intensity, but are fairly consistent in frequency.What is it, where can it be coming from and how to protect from it?I suspect weather might have something to do with it, since it's much rarer in the winter than in the summer, but i don't see where the frequency comes from.I'm also near an airport with planes flying over, but the bursts are there even at night when no one is flying and don't seem to coincide with the planes in any obvious way.EDIT: Fixed images

author: minifloat
author_rank: Contributor
timestamp: July 05, 2020, 10:15:45 am
content: You're saying single line uart... Did you use some kind of screen to protect it against EMI?Multiple times an hour, I think it could be• ripple control signal• CCFL or FL start• something else regularly occurringSummer more than winter, maybe a starter device of some aircon or exhaust ventilation?Do you have some galvanic isolation on the line TRX of the bus nodes?br, mf

author: tggzzz
author_rank: Super Contributor
timestamp: July 05, 2020, 03:18:38 pm
content: An open collector connection usually means relatively high impedance, so a small amount of interference energy can produce a larger voltage. Try reducing the pull-up resistor.You don't say what the transmitter and receiver and cable are, so we can't assess whether that is sensible. However a series resistor at the source seems odd with an open collector bus.Dozens of metres long. The ground/neutral potentials at each end could be changing, e.g. if a motor or heater switches on. Isolate the grount/neutrals by using optical fibre or an optocoupler at the receiver.

author: David Hess
author_rank: Super Contributor
timestamp: July 05, 2020, 05:43:46 pm
content: If it cannot be screened and there is no ground loop, then the easiest solution may be to limit the bandwidth at the receive end to a level commensurate with the baud rate.
Spot the fake CAN transceiver - Page 1
Forum section: electronics / projects

author: e100
author_rank: Frequent Contributor
timestamp: August 29, 2022, 07:56:56 am
content: Both claiming to be SN65HVD230 3.3v transceivers.It kind of surprises me that the fake is so different.(120 Ohm terminator, nothing else connected)

author: voltsandjolts
author_rank: Unknown
timestamp: August 29, 2022, 08:32:24 am
content: Well, at least it's easily spotted.Worse would be if it functioned fine for a month then crapped out. But it might do that too

author: AndersJ
author_rank: Frequent Contributor
timestamp: August 31, 2022, 08:04:49 am
content: From my point of view,the fake one is the on the right, with a recessive idle voltage of 2V.Is that the correct answer?Both are however asymmetric,which I often see, but I have not been able to figure out why that happens.Any ideas on that?Finally,concerning idle voltage levels,is it a bad idea to mix 5 and 3.3V tranceivers on the same bus?

author: AndyC_772
author_rank: Super Contributor
timestamp: August 31, 2022, 09:24:33 am
content: It's just because in the recessive state, CANH is simply not pulled high, and CANL is not pulled low.The active drivers in the CAN transceiver are disabled, and the bus goes high impedance. It's the 120 Ohm terminating resistors that pull CANH and CANL to the same voltage as each other, but no device on the bus sets what that voltage acutally is. It's floating.This is why the common mode voltage slowly decays after each dominant bit, and why it's not a problem. As soon as the bus is allowed to go recessive, the terminating resistors ensure that (CANH - CANL) drops to 0V in a very short space of time, but the absolute voltages on CANH and CANL decay exponentially because stray capacitance slowly discharges.I'm not 100% sure which device is which either, though it seems likely that the one on the right is genuine just because it has the higher signal level. Neither trace is 'wrong', though.Tip: 3.3V CAN transceiver are virtually unobtainable from any legitimate source right now, but 5V ones are if you look hard. Your microcontroller may have 5V tolerant inputs, so if you have 5V available in your design, this might be a solution that doesn't actually require any additional logic or level translators.

author: e100
author_rank: Frequent Contributor
timestamp: August 31, 2022, 03:05:01 pm
content: Quoting the datasheet"The SN65HVD23x family has the recessive bias voltage set higher than 0.5*VCC to comply with the ISO 11898-2 CAN standard which states that the recessive bias voltage must be between 2 V and 3 V"So the one on the left isn't compliant, and the differential voltage is down 30% compared to the one on the right.
Spot welding: Theory of Operation? - Page 1
Forum section: electronics / projects

author: BurnedResistor
author_rank: Regular Contributor
timestamp: July 16, 2017, 10:14:43 pm
content: Hello All,I know this forum has had it's fair share of microwave-transformer-battery-pack spot welder projects. I am not interested in building one. I am simply fascinated by such high current devices: Therefore I wanted to learn more about how they work. I wanted to know if anyone has any kind of technical resources on more proffesional spot welders. I have not been able to find much. What kind of parameters can you control? Current? Pulse Length? Number of Pulses? Pulse spacing? What affect do these have on the weld and on the materials that the welder can opperate on?What kind of ranges for the above paramters are typical?What kind of architecture do industrial spot welders use? I have seen two common ones:Charging a bank of capacitors and then discharging them through the weld or using a high ratio and high current transformer to turn a high voltage signal/spike into a high current for welding. I have also seen the combination, where a high voltage is stored in a capacitor bank and then discharged through a transformer.Just intuitively the latter seems like a better architecture:No huge current to the capacitor bank (comparatively)That should get a better lifetime? Don't know about that. Enlighten me.It is probably easier to control the length and spacing of the high voltage pulses than the high current ones. Again, is that right?What kind of switching device is used when switching the welding current in the first kind of architecture? What kind of switching device is used for the high voltage?What are the biggest design considerations? Biggest issues to overcome? Most common technologies?I know this seems rather open-ended but I simply am having a hard time starting to dig into this topic and am hoping for some spot-welding experts!Thanks

author: BurnedResistor
author_rank: Regular Contributor
timestamp: July 16, 2017, 10:27:40 pm
content: Quote from: blueskull on July 16, 2017, 10:17:43 pm'As I understand this design simply shorts the rc battery accross the terminal using some mosfets? So essentially a discharge welder?Is this architecture also used for larger, industrial welders?
Spring finger contact relay, like Printact relay - Page 1
Forum section: electronics / projects

author: ezalys
author_rank: Frequent Contributor
timestamp: June 21, 2018, 04:13:11 pm
content: Hey all,I was taking apart an old Tek 576 curve tracer and it had some relays in it that have little spring loaded fingers that make contact with the PCB. There's no wires which are soldered to the PCB, just gold plated pads that the spring fingers touch, and plated through holes for the coil supply that pins make contact with. These relays were made by Printact. Does anyone know if relays like this are still made? They're seem really robust and easy to clean.
Spring Loadet Pin for USB Connection? - Page 1
Forum section: electronics / projects

author: Lord of nothing
author_rank: Super Contributor
timestamp: July 30, 2019, 03:48:35 pm
content: HiA Product who should have a Cradle have 5 Flat Pads who maybe USB could be tapped off.The Product have an normal USB Connector to. So I guess the 5 Pads are an USB Doc Connector.Nowerdays its "easy" to let something 3D Printing. The only Problem is I would need some Spring loaded Pins to get a propper connetion.Are some maybe with an USB Connector on the other Side ready for sale?Thanks
Spring Plunger Component Name? - Page 1
Forum section: electronics / projects

author: mbush91
author_rank: Newbie
timestamp: June 02, 2017, 02:33:57 pm
content: Hello All,I have been googling for hours to no avail. I am looking the name of a mechanical component which I have seen used before. The component will be used on a production test rig to depress a tactile switch. The component consists of a spring loaded metal cylinder nested inside another cylinder. The inner cylinder sticks out of both ends so when the outer cylinder is mounted it allows the entire inner cylinder to be pushed downward then springs back to the normal position. The whole thing is maybe 3mm-5mm in diameter and maybe 15mm - 20mm long?I have attached an image that I quickly modeled of what I am attempting to describe. It shows the component in the uncompressed (normal) position. When the top is pushed down the entire inner cylinder moves with it.If anyone knows what to call this thing to find it for sale I would really appreciate it!

author: MagicSmoker
author_rank: Super Contributor
timestamp: June 02, 2017, 02:37:11 pm
content: The informal name is a pogo pin.See, for example, this selection at DigiKey:https://www.digikey.com/products/en/connectors-interconnects/contacts-spring-loaded-and-pressure/311?k=pogo+pin&k=&pkeyword=pogo+pin&pv1989=0&FV=ffe00137&mnonly=0&newproducts=0&ColumnSort=0&page=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25

author: mbush91
author_rank: Newbie
timestamp: June 02, 2017, 02:57:13 pm
content: Sadly, pogo pins are not what I'm looking for as only one end moves and they are make for electrical connections. I am looking for something where the spring loaded inner cylinder comes out of both ends so when I press on the top the bottom moves down

author: mjkuwp
author_rank: Unknown
timestamp: June 02, 2017, 05:38:09 pm
content: perhaps these terms:spring plungerindex plungerCheck:http://www.essentracomponents.com/en-us/tooling-positioning-components/locating-positioning-components/ball-spring-plungers-accessories/index-plungershttps://www.carrlane.com/en-us/http://www.vlier.com/mcmaster.com

author: ajb
author_rank: Super Contributor
timestamp: June 02, 2017, 05:43:31 pm
content: If all else fails, sounds like the sort of thing that could be made relatively easily from a piece of brass rod, brass tubing (or perhaps an externally threaded bushing), and a couple of shaft collars.

author: calexanian
author_rank: Super Contributor
timestamp: June 04, 2017, 04:16:08 pm
content: You want a solenoid. Or a solenoid mechanical actuator. Search with solenoid and it should get you closer to what you want.
Spurious Frequency - Page 1
Forum section: electronics / projects

author: Unknown
author_rank: Unknown
timestamp: February 12, 2010, 05:33:43 am
content: dear all..I want to ask about spurious frequency, I've used AppCAD to find RF and koeficient where spurious frequency happen but I still don't know how to determine their spurious frequency and spurious rejection...

author: nsrmagazin
author_rank: Regular Contributor
timestamp: February 07, 2019, 10:22:22 am
content: This can help you:https://www.keysight.com/upload/cmc_upload/All/21October2014WebcastSlides.pdf
SPWM hardware - Page 1
Forum section: electronics / projects

author: Achu
author_rank: Contributor
timestamp: May 30, 2019, 03:28:07 am
content: Hi,Could any one guide me on how to create a hardware to make spwm alternating on two two outputs for each half cycle.I indent not to use a micro-controller.(Though using an u-Controller is easy)

author: Psi
author_rank: Super Contributor
timestamp: May 30, 2019, 03:31:36 am
content: You need to explain more about what you are after.What signals are the inputs and what are the outputs?If not using a micro controller then you are going to need compactors and latches/flipflops

author: Achu
author_rank: Contributor
timestamp: May 30, 2019, 03:37:01 am
content: My aim is to create alternating spwm signals corresponding to each half cycle by comparing sine and ramp/triangular wave.I believe it is evident from the picture.Yes I'm willing to do it the hard way by not using programming.I might use it to drive an H bridge to make a crude inverter.

author: pwlps
author_rank: Frequent Contributor
timestamp: May 30, 2019, 07:23:48 am
content: Quote from: Achu on May 30, 2019, 03:37:01 amIt is not evident from the picture because there is an inconsistency: comparing sine and ramp/triangular wave from the top picture would yield a 50% duty cycle near zero voltage (single pulse PWM) but this is not the case for the bottom picture signal where you would you need a multiple-pulse pwm. Figure 5.4 in the following link shows how to modify your triangular reference.https://shodhganga.inflibnet.ac.in/bitstream/10603/33606/10/10_chapter5.pdf

author: Achu
author_rank: Contributor
timestamp: May 31, 2019, 01:22:56 am
content: My sincere apologies.I am a noobie.But do you understand what I am trying to communicate?

author: Etesla
author_rank: Regular Contributor
timestamp: May 31, 2019, 02:08:22 am
content: The way you turn the triangle wave, sin wave combo into a square wave is with a comparator. The best way to get the PWM square wave output, and its complement, is to use another comparator with the inputs flipped. This gives you control of the dead time (important for H bridge circuits).
SPWM Switching frequency - Page 1
Forum section: electronics / projects

author: Dmeads
author_rank: Regular Contributor
timestamp: September 17, 2020, 02:07:15 am
content: Hullo!Im coding an SPWM block. The last one I did had a switching frequency of 3 KHz, but I would like to make one with faster PWM.I did some research, and it seems most inverter H-bridge ICs like 6-20 KHz, but I have seen some at 40 KHz and 100 KHz switching frequency.Yes, I know faster switching means more efficiency, and that you need high speed MOSFETs or other transistors, but what is a good switching frequency to use? Do you just kind of match it to the MOSFETs you are using? Lets say for something like an IRFZ44N. Does anyone have experience designing inverters or have some papers on switching frequency vs efficiency? What is bad about too high of a switching frquency?I am playing around with driving a motor, so it would have variable speed like 0-200Hz or so @120VAC.Thanks, Dom

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 17, 2020, 02:28:32 am
content: Look up "VFD carrier frequency" for details. Typically IGBTs operate at 20kHz or less while MOSFET inverters are typically in the 40kHz range.
SQD-643 backlight inverter - Page 1
Forum section: electronics / projects

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 16, 2023, 06:14:26 am
content: Going to use a TFT panel that comes with a SQD-643 backlight inverter.Does anyone know/have any experience with this inverter? The pinout is marked on it - Vcc, GND, ENA and ADJ. I know it works with a Vcc of 12V.ENA is an enable pin, 3V min for enabling as far as I got.My question is really about the ADJ pin. It's supposed to be usable to adjust the backlight "brightness", but I don't know how or what it does exactly. In particular, I don't know if it adjusts the current or the output voltage. I guess the current would make more sense. Also, I don't know how it's supposed to be used. Is it a logic input taking PWM? Or an analog input? I don't want to try things blindly and fry something.If anyone knows...
Square inch challenge - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 06, 2020, 03:42:35 am
content: Just wondering if you've ever tried to cram something into a square inch of PCB just because you can, and what did you end up with?I found a VCO module (Crystek CVCO55CL-0600-0880) in my stuff and decided to mount it on a board so I can have two SMA outputs and a manual trimmer. This isn't some fancy calibration-grade thing, just so I can sweep the VCO manually through its 600-880MHz range so I can test my antique spectrum analyzer plug-in.http://w140.com/tekwiki/wiki/1L20On my board I am trying to put a resistive splitter so I can put my counter in the loop, a trimpot and a linear regulator. Nothing extraordinary. Yes I can buy the VCO eval board but these days I have no pocket money for a 35$ US board, the 5$ OSH Park deal is fine for me.

author: greenpossum
author_rank: Frequent Contributor
timestamp: May 06, 2020, 03:57:13 am
content: Hackaday ran square inch challenges, the most recent two are:https://hackaday.io/contest/160135-the-return-of-the-square-inch-projecthttps://hackaday.io/project/7813-the-square-inch-projectPlenty of impressive entries there.
Square Pegs and Round Holes: SOIC Adapter - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: August 01, 2020, 04:46:11 pm
content: I have recently bought someand I have an adapter based on OTS-28-1.27-04 ZIF Adapter like this...https://www.waveshare.com/ots-28-1.27-04.htm

author: NivagSwerdna
author_rank: Super Contributor
timestamp: August 01, 2020, 04:50:46 pm
content: but... the IC is too wide to fit in the adapter (and too big for my PCB footprint) so something has gone wrong somewhere...The datasheethttps://www.cypress.com/file/43841/downloaddescribes the package as "28-pin SNC (300 Mils) SN28.3 (Narrow Body) Package Outline, 51-85092" with width (edge of pin to far side pin edge of 0.463/0.477 = 11.76/12.12mm)I'm confused now because at the top of the datasheet it says... "Available in Pb-free and non Pb-free 28-pin (600-mil) PDIP, 28-pin (300-mil) narrow SOIC, 28-pin TSOP I, and 28-pinreverse TSOP I packages" and I thought I had opted for "28-pin (300-mil) narrow SOIC"But the IC doesn't fit in the adapter it is too wide! What sort of adapter would I need for these?I found this...https://www.cypress.com/file/117446/downloadwhich calls it SNC 28.300 rather than SOIC-28... but I don't find much when I google SNC... is it a non-standard footprint? Is it basically too wide for all standard ZIF sockets??Thanks in advance

author: OM222O
author_rank: Frequent Contributor
timestamp: August 01, 2020, 08:18:52 pm
content: sounds like you have the 600 mil version (CY62256NLL-70PXC check the package marking), which is twice as wide. I'm not sure how much they cost, but easiest solution: order new chips with the correct footprint.If you bought a huge reel and don't have production PCBs, then redesign the PCB. If you have bought a reel AND have the production PCBs, just put them aside, redesign the PCB so it fits both footprints, then use them for the later revisions which accommodate the larger footprint as well. this way no chips are unused.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: August 01, 2020, 09:00:56 pm
content: They are 300 mil body but very wide pins... must be a wide SOIC 28 version that I wasn't aware of... I have found some 11.9mm wide adapters... which is close.. (although they seem to be unobtainium...https://www.waveshare.com/ots-28-1.27-23.htm
Square Wave voltammetry - Page 1
Forum section: electronics / projects

author: Aswin94
author_rank: Newbie
timestamp: August 24, 2021, 06:56:03 pm
content: I am doing an electrochemical analysis using square wave voltammetry. I want to test on an electrochemical cell equivalent circuit such as Randles circuit.Therefore, does anybody have any suggestions or advice on this? The factors to be considered while choosing various circuit element parameters.

author: Zero999
author_rank: Super Contributor
timestamp: August 27, 2021, 12:13:01 pm
content: Sorry, I've no idea. I've never heard of it before. I just Googled it now.It looks like the easiest way to do this is with a DAC a buffer amplifier, a current shunt and sense amplifier and an ADC.
Square/Round female single pin connectors - Page 1
Forum section: electronics / projects

author: lukier
author_rank: Unknown
timestamp: July 28, 2017, 11:14:43 am
content: Hi,this was bugging me for a while. Where to get the nice square-round female single pin connectors, the same that are used on HP or Tektronix logic probes or some probe adapters? I would like to DIY some logic analyser lead sets or probe adapters. Tektronix ones cost an arm and a leg, even on eBay, and these things are pretty much just these female pin connectors with 100-150 Ohm resistors and normal 0.1" two row pin header connector on the other end.The common solution is to use the standard Dupont pin headers (Picture 1), but these are IMHO rather crappy.Another option that came to my mind is removing the metal part somehow from the precision turned sockets (Picture 2) and putting these in a heat shrink tube. But do Keysight or Tek resort to this kind of handcraft?I've checked Farnell and Digikey, googled for images but nothing comes up. Is there an off the shelf part - precision wire to female pin header connector?

author: tablatronix
author_rank: Regular Contributor
timestamp: July 28, 2017, 01:55:26 pm
content: I wonder if they are using pcb or crimp style pin sockets, surely they exist as crimpable or just use pcb sockets.https://www.google.com/search?rlz=1C1CHZL_enUS748US748&biw=1164&bih=768&tbm=isch&sa=1&q=machined+pin+socket&oq=machined+pin+socket&gs_l=img.3...0.0.0.8997.0.0.0.0.0.0.0.0..0.0....0...1..64.img..0.0.0.xbGy8eMgis8https://www.mill-max.com/pin receptacle ?

author: lukier
author_rank: Unknown
timestamp: July 28, 2017, 02:20:16 pm
content: Quote from: tablatronix on July 28, 2017, 01:55:26 pmDidn't know about Mill-Max, they have some other cool things I was looking for (spring loaded pin headers), thanks!That's probably it, something like 1134-0-18-15-47-27-10-0 or 0740-0-18-80-34-27-10-0 (solder cup in this case):https://www.mill-max.com/products/rec/1134https://www.mill-max.com/products/rec/0740Not extremely cheap, but I could probably buy 50 ($23-$25). I wonder how much better this is than just DIYing things out of cheap machined pin socket headers.

author: Benta
author_rank: Super Contributor
timestamp: July 28, 2017, 06:47:31 pm
content: A main supplier of this type of connectors/sockets is the Swiss company Preci-Dip.Looking at "tek_nice_2.gif" I could imagine that the connectors you are looking for is either type 65007 or 65009:http://www.precidip.com/en/Products/Contacts.html
squares for tonner transfer to copperclad board - Page 1
Forum section: electronics / projects

author: m3vuv
author_rank: Super Contributor
timestamp: April 10, 2020, 12:24:41 pm
content: Hi alll,i build a lot of things manhattan style,ie glueing bits of copperclad to another board,just thinking is there a downloadable pattern for tonner transfer to create copper islands onto a pcb,sort of like a bunch of say 5mm squares with a 2mm gap?

author: m3vuv
author_rank: Super Contributor
timestamp: April 10, 2020, 01:27:06 pm
content: i know that i wanted something to print and iron on,thats the whole point of this post,cheers anyway.

author: coppercone2
author_rank: Super Contributor
timestamp: April 11, 2020, 04:42:06 pm
content: for something that simple you might be able to use a sharpie and ruler

author: Wimberleytech
author_rank: Super Contributor
timestamp: April 11, 2020, 05:48:36 pm
content: Quote from: m3vuv on April 10, 2020, 12:24:41 pmGo here and download this free software:https://www.expresspcb.com/Download the "classic" version.It is super super easy to use...learning curve maybe 10 minutes...prolly less.I have been using it for years to make toner transfer PCBs.The tool is designed to allow you to upload to their PCB mfg service, but it also lets you print to your laserjet, dimensionally accurate.This example shows double sided, but I do not make double-sided pcbs, so these are done with wires.
SRAM: 6C6264 vs 6C62256 - Page 1
Forum section: electronics / projects

author: smbaker
author_rank: Regular Contributor
timestamp: October 25, 2020, 03:37:31 am
content: I have a project that I designed to use either a AS6C6264 or a AS6C62256. I'm only using 4K of the RAM, with the expectation it wouldn't matter which IC is installed.In my circuit, the following pins differ between the two ICs and this is how I connected them to ensure equivalent behavior:26 (CE2 on 6264, A13 on 62256): High1 (NC on 6264, A14 on 62256): HighEverything else (!CE, !OE, !WE, address bits, data bits, etc) is as you would expect for an 8-bit CPU.Looking at the datasheets (https://www.alliancememory.com/wp-content/uploads/pdf/Alliance%20Memory_64K_AS6C6264v2.0July2017.pdf,https://www.alliancememory.com/wp-content/uploads/pdf/AS6C62256.pdf), my belief is that it should make absolutely no difference which SRAM is used. Both parts are the same speed. Yet it's the case that the 62256 works fine, but the 6264 causes the MCU to sporadically reset, the LEDs to flicker, and general chaos ensues.Could someone be so kind as to look at the datasheets and see if I have somehow obviously gone wrong?Thanks,Scott

author: greenpossum
author_rank: Frequent Contributor
timestamp: October 25, 2020, 03:58:36 am
content: Maybe just a faulty specimen? Do you have any other means to test it?

author: smbaker
author_rank: Regular Contributor
timestamp: October 25, 2020, 04:00:14 am
content: I tested it in a mini pro programmer and it tested out good (I have no idea how through this test is)

author: greenpossum
author_rank: Frequent Contributor
timestamp: October 25, 2020, 04:09:32 am
content: Can you disconnect that NC? I know it should mean there is nothing connected to this pin but sometimes it can mean don't use this pin.

author: smbaker
author_rank: Regular Contributor
timestamp: October 25, 2020, 04:31:17 am
content: Quote from: greenpossum on October 25, 2020, 04:09:32 amYeah, I already tried that... of course, I suppose the IC could have become damaged while it was connected.

author: m k
author_rank: Super Contributor
timestamp: October 25, 2020, 08:07:16 pm
content: My first guess is that your CE2 is not very high all the time.

author: smbaker
author_rank: Regular Contributor
timestamp: October 26, 2020, 03:32:00 am
content: Quote from: m k on October 25, 2020, 08:07:16 pmI will put the scope on it and find out for sure.Scott
SRS PS350 or PS310 Schematics - Page 1
Forum section: electronics / projects

author: ion599
author_rank: Newbie
timestamp: January 30, 2013, 09:14:57 am
content: I recently got a SRS PS350 and a PS310, but they aren't functional. I was wondering if anyone here has the user manual with the schematics. The user guidehere:http://www.thinksrs.com/downloads/PDFs/Manuals/PS300m.pdfomits the schematic, which would be very helpful in trouble shooting these devices.Thanks,LD

author: Betawi
author_rank: Newbie
timestamp: February 25, 2013, 09:35:05 pm
content: Hi,I have the same issue; have a broken PS350. Were you able to locate schematics?
SS495A Miniature Ratiometric Linear sensor with supply voltage 3.3V ? - Page 1
Forum section: electronics / projects

author: beduino
author_rank: Regular Contributor
timestamp: March 28, 2019, 06:15:02 pm
content: Hello,For some reason I'd like to apply supply voltage 3.3V to magnetic field radiometric sensor SS495A instead of recomended minimum 4.5V in its datasheethttps://eu.mouser.com/datasheet/2/187/honeywell-sensing-sensors-linear-hall-effect-ics-s-947420.pdfto detect strong neodynium magnet passing nearby but a few centimeters away, so no need to make any kind of precise magnetic fields measurement, just detect magnet magnetic fields N/S direction.It seams that after supplying such lower voltage 3.3V this SS495A sensor responds quite well, as well as null offset is in dthe middle of 3.3vcc, but since it looks like this sensor have built in amplifier, is it fine to power this thing with voltage ~1V less than its specs for radiometric output?According to datasheet:"Miniature Ratiometric Linear sensors have a ratiometric output voltage, set by the supply voltage. It varies in proportion to the strength of the magnetic field."It will not be used in any life critical application, just to estimate wheel rotation speed with magnets glued to its ring.I'm considering also other option - maybe instead of SS495A sensor use a loop of wire connected to opamp inputs and detect changing magnetic flux, but in this case I might be limited by minimum wheel speed, since electromagnetic pulse will depend on how fast wheel rotates - magnet speed, so it looks like Hall effect sensors like SS495A seams to be more usefull at low speeds aka minimum as low as 1km/h I expect?What do you think?
SSD1963 based display - Page 1
Forum section: electronics / projects

author: Dajgoro
author_rank: Frequent Contributor
timestamp: February 19, 2017, 12:03:54 am
content: Hi.I've been looking to use a SSD1963 based 4.3" LCD display module such as this one:http://www.ebay.com/itm/4-3-4-3-inch-480-272-TFT-LCD-Module-Display-Touch-Panel-SSD1963-51-AVR-STM32-/111669867497?hash=item1a000af3e9:g:5aQAAOSw6BtVUyCxThe issue is that it has no manual/datasheet. There is the datasheet for the SSD1963 IC itself.Did anyone try to use it with anything else except an arduino or raspberry?I was thinking about using it with a PIC18F, but it seems there are no libraries.I found some but they are all for different mcu-s. There is also the issue with the 16 bit bus, as I see libraries work with 8 bit bus?Its a mess, does anyone have any experience using it?

author: Dajgoro
author_rank: Frequent Contributor
timestamp: February 19, 2017, 01:08:39 pm
content: For anyone who is also interested in this display, I found a video on youtube explaining it a bit:

author: fki82
author_rank: Contributor
timestamp: February 19, 2017, 03:26:24 pm
content: you could also have a look tohttps://git.ugfx.io/CorentinB/uGFX/src/a171f917d373f3ff527976c9c34725c0faaf6716/drivers/gdisp/SSD1963

author: Dajgoro
author_rank: Frequent Contributor
timestamp: February 26, 2017, 03:35:03 am
content: Thanks for the link!

author: cyberfish
author_rank: Regular Contributor
timestamp: February 27, 2017, 01:48:08 pm
content: It's a simple SRAM-like interface (without address lines). Should be pretty easy to port another library to your microcontroller? All you have to do is replace the very low level GPIO functions.It can work with a 8-bit bus, but if you want any reasonable frame rate (ie, not just a static display), you'll probably need 16-bit bus attached to a microcontroller's external memory interface (eg. STM32F4 or F7).

author: bson
author_rank: Unknown
timestamp: February 28, 2017, 10:24:10 am
content: Command 0xf0 configures the pixel data interface. If you set it to 8 bits you can use an 8 bit parallel bus with either 8080 or 6800 style timing. Commands only use D7:D0 and ignore the top 16 bits; only pixel data seems to use the additional width, if you configure it to. (Power-on default is to use the full 24 bits.)This looks pretty neat actually, so I ordered one for use with MSP430 and ARM...
SSR and Holding Current - Page 1
Forum section: electronics / projects

author: kolbep
author_rank: Frequent Contributor
timestamp: November 25, 2021, 07:03:40 pm
content: Hi All.Just a quick one.I have several led string lights (230v 7w per 20m string) = 0.031mAIIRC the strings have 160 leds in Series with a resistor, which is in parallel with another 60 leds with their resistor.I am trying to run them with Omron G3MB-202P Solid State Relays (1 solid state relay per string). The SSR's are controlled with Shift Registers on an Arduino.I am having a problem where the LED strings where they are running dim, sometimes don't light up, or light up, then go dim immediately afterwardsThe Omron SSR's are rated for 0.1A to 2A current. I presume the 0.1A is the minimum (holding) current.My Arduino program does not pulse the SSR's, instead it keeps the power on to the SSR the whole time the light chain is meant to be on (i.e any time from 250ms upwards). Does that mean that I do not need to worry about the 0.1A holding current (because the SSR does not need to self latch)?If I need to worry about the holding current, then I will need to put a dummy load equivalent to 2300R, 23W (that will probably need to be normal lightbulbs, because large resistors will get a bit hot.If it is not the Holding Current causing the problems, then could it be that I am trying to run the LED strings with a Triac (and as there is no rectifier, the LEDS are only drawing on the forward cycle). If that is the case, then I will probably need a bridge rectifier on each string.It also seems to be more problems with the White-Flash Strings. They are similar construction, but every 5th LED flashes at it's own rate.Thanks for any suggestions.P

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 26, 2021, 01:31:42 am
content: Try using a series combination of a resistor and capacitor as the minimum load, good starting point would be X rated 1uF and 100 ohm, 2W.

author: kolbep
author_rank: Frequent Contributor
timestamp: November 26, 2021, 05:55:31 am
content: Thanks,Let me scrounge through my boards, and see if I can find some to try that out.P

author: kolbep
author_rank: Frequent Contributor
timestamp: November 27, 2021, 06:57:56 am
content: Just another question,the voltage for the 1uF Class X Capacitor,What voltage should that be, with our Voltage in South Africa being RMS 240v or should it be based on the peak of 340v?,

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 27, 2021, 12:46:31 pm
content: Every X rated capacitor I have seen is rated to at least 250V RMS, that's a nominal rating and will work on 240V.

author: kolbep
author_rank: Frequent Contributor
timestamp: November 27, 2021, 01:03:46 pm
content: Thanks,Will give it a shot

author: kolbep
author_rank: Frequent Contributor
timestamp: January 01, 2022, 03:49:36 pm
content: Well, it Worked.Thanks NiHaoMikeHere is the project in its huge gloryhttps://youtu.be/_u6RM6NwyWw
aaaaaaaaaaaaa - Page 1
Forum section: electronics / projects

author: smd32
author_rank: Newbie
timestamp: September 15, 2020, 08:49:46 pm
content: aaaaaaaaaaa

author: ledtester
author_rank: Super Contributor
timestamp: September 15, 2020, 11:25:15 pm
content: For a heating application here's an idea to control the power of the heater -- e.g. for 50% power just turn the heater on for 5 seconds and then off for 5 seconds; for 20% power turn it on for 2 seconds and off for 8, etc.

author: TheMG
author_rank: Frequent Contributor
timestamp: September 16, 2020, 12:26:20 am
content: Any specific reason you want to control the heater this way? The usual way to do this sort of thing is PWM with a standard on/off SSR. With a PID control you can actually achieve very precise temperature control using this method, provided the pulse frequency is high enough relative to the overall thermal mass of the system.

author: ledtester
author_rank: Super Contributor
timestamp: September 16, 2020, 03:58:17 am
content: You might be interested in this Wikipedia article on "bang-bang control":https://en.wikipedia.org/wiki/Bang%E2%80%93bang_control

author: ledtester
author_rank: Super Contributor
timestamp: October 20, 2020, 05:53:42 pm
content: You might find these videos on the design of a temperature controlled lab water bath helpful:Laboratory Water Bath (12): Software, Chapter 3 (Heater Model-Based Control)https://youtu.be/HK1JmZx7Swg