hybridfree/eevblog-posts huggingface dataset:
I need help downloading from pan baidu - Page 1
Forum section: electronics / projects

author: sandy_22
author_rank: Newbie
timestamp: October 01, 2025, 11:33:30 am
content: I have a big dataset(337gb) that is hosted on baidu pan that I'd like downloaded. Can someone help me download the file for free?link:https://pan.baidu.com/s/1M9yuzS2N4XAwA6Q7_B9mJw?pwd=ednypwd=ednyThank you in advance

author: coromonadalix
author_rank: Super Contributor
timestamp: October 01, 2025, 02:14:14 pm
content: did you wrote a 337 "Giga" byte size ??

author: squadchannel
author_rank: Frequent Contributor
timestamp: October 01, 2025, 02:46:57 pm
content: I don't know which file you want.but there were plenty of hints.https://od.hessfr.fr/VMware/
I need help in using the schematic diagram - Page 1
Forum section: electronics / projects

author: K-Experiment
author_rank: Contributor
timestamp: April 11, 2019, 11:32:36 am
content: I need helpthere is an amplifier kit schematic diagram but i dont know how to connect the audio directly to the board(the switches were not included apparently)the audio input connection is unknown.

author: StillTrying
author_rank: Super Contributor
timestamp: April 11, 2019, 12:04:35 pm
content: The audio signal input looks like it's the "1" under "VOLUME".Audio ground doesn't seem to be shown, it'sprobablythe "3" under "VOLUME".

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 11, 2019, 12:19:32 pm
content: Quote from: StillTrying on April 11, 2019, 12:04:35 pmI'd say it's missing from the diagram. At first I had the same thought, the audio goes to the leftmost MON switch but from there it only goes to the LINE OUT.And don't forget it is pretending to be stereo...

author: StillTrying
author_rank: Super Contributor
timestamp: April 11, 2019, 12:26:07 pm
content: "At first I had the same thought, the audio goes to the leftmost MON switch but from there it only goes to the LINE OUT. And don't forget it is pretending to be stereo..."And me. The 4 rightmost switches seem to have small hard to see connections to the MON's "looped around" connection.

author: james_s
author_rank: Super Contributor
timestamp: April 12, 2019, 10:12:46 pm
content: It sure would be nice if they'd provide a proper schematic, I hate these drawings that show wires connecting to pins on drawings of actual components, it's very difficult to follow where anything goes, especially if you don't have exactly the same components.

author: Nusa
author_rank: Super Contributor
timestamp: April 13, 2019, 01:19:52 am
content: Looks like only one channel is shown connected to the board via what are obviously two-gang pots. You're presumably supposed to intuit the other channel.An actual picture of the board would be revealing on that subject, if there're connections for both channels. Or perhaps there are two copies of the board, one for each channel?
ı need help sg3525 phase difference - Page 1
Forum section: electronics / projects

author: Hypsjw61
author_rank: Newbie
timestamp: November 12, 2024, 04:13:14 am
content: I'm trying to get a 150 degree phase difference from sg3525, but I need help with the values ​​of resistors and capacitors.

author: Andy Chee
author_rank: Super Contributor
timestamp: November 12, 2024, 04:25:58 am
content: Did you mean phase margin?Please post the complete sg3525 schematic.

author: Simon
author_rank: Unknown
timestamp: November 12, 2024, 08:48:22 am
content: I'm assuming this relates to this topic:https://www.eevblog.com/forum/projects/sg3525-fiber-splice-termination-device/msg5710363/#msg5710363It would be best to keep all discussion in one place. From both threads no actual questions are obvious.
I need help to find a product for a project. - Page 1
Forum section: electronics / projects

author: Hammerheadr
author_rank: Newbie
timestamp: February 29, 2016, 01:39:42 am
content: I am making a project for myself. I am wanting this product to move with me. So it needs to track somthing either that I carry or have on me.is there anything on the market that would track like that within 20-30 feet. I want to attach this to a motor on a 360 degree pivot so that the motor turns to me where ever i am in the room and then follow me when I move. I know i can do this with remote control either wireless or wired. But I want this to be automated. so it needs to follow my bluetooth in my phone. or IR or somthing that i wear on me or to that effect. I have no idea where to look. any help would be apreciated. this will run on 110v circuit. I will have a board in the unit so I can power down to different powers. so it can be 110 or less.

author: Rerouter
author_rank: Super Contributor
timestamp: February 29, 2016, 06:32:58 am
content: weak RF transmitter in your pocket, 2 antennas on your device, turn the device until the phases match, note this can result in it being 180 degrees out, but its a start for a concept,
I need help understanding missing pins: BGA vs HTQFP - Page 1
Forum section: electronics / projects

author: shrykullgod
author_rank: Newbie
timestamp: May 17, 2024, 12:11:11 pm
content: I'm trying to make this:https://github.com/Nitrokey/nitrokey-3c-nfc-lpc55-hardwareThis project uses the LPC55s69JEV98K, in BGA format, with 98 pads.I have this part, but in QFP format, with 64 leads. LPC55s69JBD64K. HTQFP.Please, here is the datasheet:https://www.nxp.com/docs/en/data-sheet/LPC55S6x.pdfStarting at page 11, you will see the pin assignments.I see a daunting task to overcome, given my limited understanding.I must understand why these pins are missing from the QFP package, and if this difference is significant enough to render my effort useless:VSS_PMU, VSS, VREFN.I am using Kicad 8. I can replace footprints and symbols. I can Reroute tracks and update the project. I can learn those things. But the pin difference worries me.Can someone help me move forward. Sorry to bother.

author: pcprogrammer
author_rank: Super Contributor
timestamp: May 17, 2024, 01:43:51 pm
content: Hi, most of the missing pins will be GPIO and might need software changes to remap peripheral in/outputs to some other GPIO pins.The VSS you state missing on the pins is actually on the chip as an exposed pad underneath. You will have to make provisions for it on the PCB. Soldering this is a bit harder then normal SMD leads soldering.The VREFN pin, negative ADC reference voltage, most likely is internally tied to VSS on the smaller pin count packages.For the VSS_PMU pin it is most likely the same.I would not worry about these and just make a layout with the smaller package.Edit: look at page 124 of 138 for information about the exposed pad underneath the package.

author: shrykullgod
author_rank: Newbie
timestamp: May 17, 2024, 02:56:04 pm
content: thank you!!!!! i have a heat gun for the pad under. thanks a bunch.and now off to another giant effort to examine and adjust the firmware....eh
I need help with one power supply!!!  HP DPS-1200fb-1 a - Page 1
Forum section: electronics / projects

author: anton bostandzhiev
author_rank: Newbie
timestamp: February 28, 2023, 09:38:49 pm
content: Hello everyone, I'm new to the forum. I want to ask you, I have a HP dps-1200fb-1 power supply, how can I raise the voltage, now it is 12.50 V, I want to raise it to 13.80 V. Thanks

author: DavidAlfa
author_rank: Super Contributor
timestamp: February 28, 2023, 10:35:55 pm
content: There's an adjustment inside which lets you adjust the output between 11 and 13.8V.More useful info:https://blog.seidel-philipp.de/hp-dps-1200fb-power-supply-hack-for-charging-lipos/#OptionalVoltage_adjustmentshttps://github.com/raplin/DPS-1200FB/blob/master/readme.md

author: anton bostandzhiev
author_rank: Newbie
timestamp: March 01, 2023, 08:54:26 pm
content: Hello, thank you for your help, but my power supply is not the same as the one you set as an example.This is my power supply HP DPS-1200fb-1a
I need help with with buck/flyback converther that does not use any controllers - Page 1
Forum section: electronics / projects

author: NikKot
author_rank: Newbie
timestamp: August 23, 2020, 06:35:36 pm
content: I want to make a 32V to 16V converter but I do not have access to microcontrollers and other specialized components. I'm looking for for a circuit that only requires base components like pnp/npn transistors and etc. It doesn't have to be "beefy", I only need 100-200mA from it and I don't really care about efficiency. Any help and ideas or circuits will be appreciated. I'm using LTSpice so the ideal option would be some kind for circuit for that.I'm sorry if this kind of topic isn't accepthed here, but it seems to me like a good place to post this.upd. Forgot to mention that I have ferrite cores and I can wind them with the amount for turns needed.

author: Buriedcode
author_rank: Super Contributor
timestamp: August 23, 2020, 07:10:32 pm
content: The MC34063A is pretty widely available - even if you can't order form any distributor, they are so ubiquitous you can find them in almost any USB car cigarette power adapter. It's old, less than stellar efficiency, low frequency, but it does the job, and will work fine for your application.It's Vmax is 40V so should be fine for 32V in, and should just about handle the output current.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 23, 2020, 07:51:22 pm
content: This is a pretty reasonable approach, having current-mode behavior similar to UC3842, but with variable frequency as well. Multiple outputs are shown, you may not need those.Tim

author: langwadt
author_rank: Super Contributor
timestamp: August 23, 2020, 08:45:45 pm
content: why a switcher if you don't care about efficiency ?

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: August 23, 2020, 09:04:06 pm
content: my last smps was llc and used a pic micro.was easy to develop and worked well.even had oc detect.

author: NikKot
author_rank: Newbie
timestamp: August 26, 2020, 12:58:03 pm
content: Quote from: T3sl4co1l on August 23, 2020, 07:51:22 pmThank you very much! I'll look into it and modify to my needs when I'll have time and update on how it turned out. Sorry for not replying quickly i was too busy too check this thread.
I need some help finding the right connectors for some ribbon cable. - Page 1
Forum section: electronics / projects

author: dabombplace
author_rank: Newbie
timestamp: January 16, 2017, 07:51:56 am
content: I'm working on a project with an Alpine x108u head unit. I could go on about that for an hour, but in short I need to extend (or get a longer) Flex cable; and I need to get some sort of break out for a different flex.The white Flex Labeled "Sumiromo - G 20861" Goes to the front buttons, and I need to have that break out so I can solder my own buttons (that's a massively simple explanation for what I need to do.)The Brown/Dark Flex goes to the screen, and I need a longer version of that (~8" or so)Problem is, I have no clue where to get any of the information from either of these. The Dark flex has no markings, and I'm not knowledgeable enough in the types of flex cables to know what type of board side connector to use on the white cable.Can anyone here help me figure this out?

author: capt bullshot
author_rank: Super Contributor
timestamp: January 16, 2017, 08:39:38 am
content: Hithe white one looks pretty much standard, you should be able to buy somewhere a matching connector. Most of these connectors sell in MOQ of thousands.Maybe a solution is desoldering the matching connector from the PCB and building the extender using single wiresthe other one looks custum designed for this product, so you won't be able to buy a longer version of it. Apparently there's some high speed routing done there, you might be able to extend its length by carfully building an extender using twisted pair wires and proper grounding ...

author: Cyril.Anthony
author_rank: Contributor
timestamp: January 17, 2017, 12:26:45 pm
content: the brown cable looks like standard 0.5mm pitch 50pin FPC and the white one is 1mm pitch FPCsorry couldn't count the number of pinsBrown - FH12-50S-0.5SHwhite - FH12 - 40S - 1SH

author: bktemp
author_rank: Super Contributor
timestamp: January 17, 2017, 12:39:02 pm
content: It looks similar to cables used with Iriso connectors (locking type FFC):http://www.iriso.de/en/products/category/fpcffc-connector/product/9686sIf you want to use normal FFCs, it needs some cutting, otherwise the cables won't fit.

author: amyk
author_rank: Super Contributor
timestamp: January 18, 2017, 03:32:54 am
content: Quote from: Cyril.Anthony on January 17, 2017, 12:26:45 pmLook carefully at the traces of the brown one near the exposed end... that's not standard.

author: dabombplace
author_rank: Newbie
timestamp: January 21, 2017, 07:43:53 am
content: Quote from: Cyril.Anthony on January 17, 2017, 12:26:45 pmI'm going to go ahead and order some connectors and let you guys know if anyone's right.If it helps at all, the brown cable carries Touch screen data and display data + power.
I need some major help !  - Page 1
Forum section: electronics / projects

author: Charlie91
author_rank: Newbie
timestamp: February 03, 2012, 07:35:08 pm
content: Hey guys ! Basically, I've got a small project idea in which I'm going to integrate a Bluetooth device into a car radio circuit... And I'm looking for advice on how to supply a constant charge to the Bluetooth device with constant power without using a supply that's too high... Will I need to use a step down transformer or ? The Bluetooth device uses a 3.5mm aux cable to take charge usually but I'm not sure how to go about this at all....I know I'm an idiot but I need some help !Cheers, Charlie.Ps. I will upload photos of the device and my progress when I can.

author: Jimmy
author_rank: Regular Contributor
timestamp: February 04, 2012, 06:37:11 am
content: What is the device's model number?what power does it need?What are you trying to do?Need as much info as you can give

author: amspire
author_rank: Super Contributor
timestamp: February 04, 2012, 07:09:41 am
content: Are you talking about some kind of Bluetooth device with an inbuilt lithium battery? If you are going to build it into the radio, you will not want a battery power Bluetooth device. You do not want to have to pull out your radio every 2 years to change the lithium battery, especially as it will be powered by the car battery anyway.I am not sure how well you can integrate a bluetooth device into a radio anyway. You need to be able to ask the bluetooth device to make itself discoverable so you can pair to it. You definitely do not want to have it permanently discoverable.I assume you have given up on the FM transmitters as a way of getting music into your car radio, and so now you want to find a bluetooth device that you can connect directly to the radio's audio circuit. It may be possible, but you can get great bluetooth radios with handsfree phone support for about $150. Is it worth trying to make a non-integrated bluetooth device work?It would be much easier adding an audio input lead that you can plug into a standard earphone socket.Richard

author: Rerouter
author_rank: Super Contributor
timestamp: February 04, 2012, 07:20:50 am
content: being how it would be fittied into the radio, you would power it off the accesory wire, i am going to guess this device runs off 5V and uses bugger all current, if so deadbug a lm7805 with some capacitors, and power the device off accesory,or if the thing really draws some power, then one of these might be better (albiet pricier)http://au.element14.com/recom-power/r-78c5-0-1-0/switching-regulator-5v-1a/dp/1903040I work with automotive tracking systems and instruments, and that 1 regulator so far has never failed on me,
I need to choose capacitive proximity sensor for measuring the distance - Page 1
Forum section: electronics / projects

author: FilipCichowski
author_rank: Newbie
timestamp: July 21, 2025, 12:05:25 pm
content: I need to build simple, ESP32-based project for research purpose.I'm looking for right proximity sensor.Requirements:- capacitive- easy integration with ESP32 (existing library would be huge advantage)- I need to get value from it in order to calibrate the device and be able to recognize size & distance to the objects. It should detect metal blocks and phones close to it.- low power, but no strict current consumption requirementI'm considering IQS231 - I need to write custom library for it. Documentation for dev board is somehow cryptic, but I think the integration through I2C is doable.Do you know any board with sensor useful for this purpose? I need to build prototype quickly, I want to save time spent for writing the library from scratch.

author: TimFox
author_rank: Super Contributor
timestamp: July 21, 2025, 02:04:26 pm
content: You should specify the range of distances you need to measure.Different position sensors are used for microscopic and macroscopic distances.
I Need WFM sample file produced by DS2000,4000,6000 Rigol DSO - Page 1
Forum section: electronics / projects

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 12, 2016, 03:47:58 pm
content: I Need WFM sample file produced by DS2000,4000,6000 Rigol DSO. anybody care to help?

author: danadak
author_rank: Super Contributor
timestamp: March 12, 2016, 04:14:51 pm
content: This should help -https://www.eevblog.com/forum/testgear/rigol-ds1000z200040006000-waveform-capture-utility/Regards, Dana.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 12, 2016, 08:22:55 pm
content: Quote from: danadak on March 12, 2016, 04:14:51 pmsorry but i think you dont understand. what i need is wfm file from another scope. i dont have DS2000,4000,6000 so i cannot produce them. the purpose is to understand the format. i've looked into my scope DS1000Z wfm format and now i understand some small portion of it. but since DS2000,4000,6000 (which i dont have) have different graticule ie 8 x 14 instead of 8 X 12 for DS1000Z. so i need to look where the value is stored. i checked my ds1000Z wfm, the value 12 is all over the place, its broad place to search. so i hope i can find value 14 (graticule value) in DS2000,4000,6000 wfm format with hope i can narrow down the location. not another rigol download capture utility, just a wfm file fresh out of a DS2000,4000,6000. thanks.edit: in case you ask why. i'm currently building a software that hopefully can mimic (compatible with) the 8 x 14 DS2000,4000,6000's graticule gracefully.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 20, 2016, 11:42:22 am
content: the project has moved to phase 2: beta testing...http://www.soasystem.com/download/visadso/
I need your technical help on pcb  - Page 1
Forum section: electronics / projects

author: Md Mubdiul Hasan
author_rank: Regular Contributor
timestamp: January 18, 2018, 01:29:26 am
content: Hello there,I am attaching a very simple design of LED driver here in PADS 9.5.At this setting "No error" has been found in verify design.Kindly, talk about this design for further improvement.1. Via patterns.2. layer definition3. Routing4. Add drafting5. Mounting hole.6. pour manager

author: ogden
author_rank: Super Contributor
timestamp: January 18, 2018, 11:36:34 am
content: Quote from: Md Mubdiul Hasan on January 18, 2018, 01:29:26 amCan't you show it (also) as .png or .jpeg? I did not even know PADS software before your post- If too much effort needed to even read your question, most likely you will not get answer.
i scored some old DIY ham radio equipment 80m band - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: January 23, 2023, 09:19:50 am
content: sometimes i score all sorts of cool equipmenti really enjoy looking at other peoples diy stuffsince i am a very active diy dude my self :-)this set consist of a 80m band receiver, and a 80m band tube transmitteryou will find a few of the design solutions quite cool.I had so much fun playing with this set for a few days, so i will be happy to share the video outcome with youreceiver :https://youtu.be/AYFj3EgD3Iotransmitter :https://youtu.be/ENL1uPUnd7I

author: bidrohini
author_rank: Regular Contributor
timestamp: January 23, 2023, 10:34:05 am
content: Thanks for the detailed videos.

author: Bud
author_rank: Super Contributor
timestamp: January 23, 2023, 09:17:11 pm
content: Have you scored a 80m antenna with it?Without one that equipment (transmitter at least) would be of little use.

author: james_s
author_rank: Super Contributor
timestamp: January 23, 2023, 09:27:37 pm
content: You can buy one for 60 bucks.https://www.amateurradiosupplies.com/80m-Antennas-s/44.htmOr just build one yourself.

author: TimFox
author_rank: Super Contributor
timestamp: January 23, 2023, 09:49:00 pm
content: Approximately 40 meters of wire, center-fed through an appropriate balun, should work fine.

author: oz2cpu
author_rank: Frequent Contributor
timestamp: January 25, 2023, 11:18:33 am
content: thanks for the comments : i got a roof full of antennas, and dummyloads too,the problem with this transmitter here was the missing powersupply,sometimes i am not able to go all the way with full features test of productsbut that is not needed to enjoy the level of DIYand to be able to understand how much fun one had making this.
I think I need to learn a bit about signal conditioning, or buffering? - Page 1
Forum section: electronics / projects

author: jwhitmore
author_rank: Regular Contributor
timestamp: December 17, 2019, 06:10:41 pm
content: I'm experimenting with dimming mains lights using a H11AA1 chip to detect the zero crossing of the Mains input power. I'm having some difficulty with the output from the H11AA1 when connected to the micro controller, which is going to be doing the intelligent switching. I'll attach two images, one is of the output from the H11AA1 opto-coupler zero crossing detection chip, WITHOUT the micro controller soldered onto the PCB. In this image the spikes are very responsive, for what of a better word. So without the uC it all looks great. The problem is when I move the H11AA1 chip from the PCB without a UC to a board with the uC soldered onto the PCB it all goes a bit pear shaped. The spikes are no longer instantaneous but rather ramp up, relatively slowly and die away equally slowly.All that might not be a problem, but I think if nothing else I'm not sure the zero crossing will be detected in the correct place.On top of that I'm using an interrupt on change pin in the micro controller and I'm not getting a nice clean 100Hz of zero crossing.I have a physical copy of 'The Art of Electronics', second edition, but not at present. I should maybe get the 3rd edition on my Kindle so I always have it handy. Is this just a case of putting a logic gate between the H11AA1 chip and the uC to buffer the signal and remove stray capacitance, if that is the problem.Thanks in advance for any advice on this one...

author: jhpadjustable
author_rank: Frequent Contributor
timestamp: December 17, 2019, 10:17:19 pm
content: As the old robot said, "Need more input!" Post full details of all connections to the phototransistor side of the opto.

author: wraper
author_rank: Unknown
timestamp: December 17, 2019, 10:21:50 pm
content: Looks as if there is capacitor attached to MCU pin. Or pin configured as output and set high. Please provide at least partial schematic.

author: jwhitmore
author_rank: Regular Contributor
timestamp: December 19, 2019, 11:13:39 am
content: Thanks a million for your responses. I'm sorry I didn't provide enough information, but the output pin of the H11AA1 was connected directly to the uC. You did however have me smacking my head as I'd just soldered on the uC without programming anything into it. I never even thought of it having an electronic effect depending on the configuration of it's pins. So thanks a million for that. School boy error on my part.I think that's helping me to get this moving. Thanks again.
I think I've made one of the best RGB propeller clocks out there - Page 1
Forum section: electronics / projects

author: allanw
author_rank: Frequent Contributor
timestamp: January 19, 2012, 08:45:56 pm
content: I'm sure you guys have all seen this video from over two years ago:However it's a bit limited - it can only do 8 colors (3 bits color resolution, each RGB on/off).For my school's week-long hack-a-thon session calledBuild18, I've finally decided to spin the TLC5947-basedRGB stickI designed two years ago. These feature RGB LED's with 36-bits of color resolution (12-bits per color). We found a MechE to join our team which *really* helped out a ton.Since we didn't have time to mess around with figuring out how to transfer power through a motor, we decided to just spin some AA batteries instead. 4x NiMH batteries have the perfect discharge curve for what I need, 4.0 - 5.5V unregulated voltage for the LED's. Two sets of batteries are paralleled for more current.And everything works perfectly! The spinning MCU is very dumb and just writes out raw image data via SPI. We can get the update rate to be about 600 Hz on the ARM Cortex-M3 based mbed platform. We're still working on getting animations working, which involves sending raw image data over a wireless link. We also have the 4x400MHz XMOS chip just in case the ARM doesn't cut it in terms of compute power, but it's pretty hard to set up and we only have 24 hours until final demos!Enough talk, here's pictures, video coming soonhttp://imgur.com/a/89tqy

author: ndictu
author_rank: Regular Contributor
timestamp: January 19, 2012, 10:00:59 pm
content: Well that's pretty hugeGood work.BTW, make the base a little more blade shaped, turn the motor 90degrees and you have an awesome fan. Might be too big though ... Ceiling fan maybe?

author: Short Circuit
author_rank: Frequent Contributor
timestamp: January 19, 2012, 11:17:11 pm
content: At that size, it reminds me of this rotor LED application.Too bad it requires quite some skills to fly such toys at night.

author: allanw
author_rank: Frequent Contributor
timestamp: January 20, 2012, 03:06:07 pm
content: Video! Will post more details soonStill working on sending image data wirelessly.Don't forget the obligatory Jimmy Wales face:
I Thought I Saw a "Transmission Line" (for the first time :P) - Page 1
Forum section: electronics / projects

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 22, 2011, 03:22:33 am
content: Fiddling with op-amp earlier and feed them with some MHz signal through BNC cables. I got some nasty signal attenuation, even if i disconnected the cable from the op-amp circuit, particularly at 50MHz sine signal. So i curious, stop my op-amp fiddling and try to figure out whats going on. I thought there is some sort of shorting inside the BNC/coax cable that i DIY'ed earlier, measuring continuty check showing my DIY cable is fine (no short), but still, the shit happened. So just as Dave's video on Tektronix probe shock (that i voted everyday), i come to the conclusion that my cable is acting as a transmission line (antenna) to my signal generator. Here is the setup:My BNC/Coax Cable Length =77.5cm(from end to end or tip to tip of BNC connectors) i have 2 of this DIY cable.Resonance frequency =60MHzfrom FG (wavelength somewhere at 500cm), not the exact resonance i think, but to demonstrate it best here.1.jpg = using one of the cable to read the signal, i suspect there is already attenuation along the line. (but i cannot prove it)2.jpg = adding another cable through the T-junction (was meant to go to the op-amp circuit) note how nasty the attenuation on the DSO.3.jpg = adding a terminator at the end of cable solve the problem (attenuation) adding impedance to it to avoid power loss.4.jpg = adding more BNC cable instead of a terminator will solve the issue as well.Calculating it, the resonance occured at 1/3 of wavelength (500cm/3=167cm), maybe including the T-junction length and accessories etc.So watch out newbies (me included), you could just tossing your FG good bye by just connecting a proper length'ed antenna (cable) to it.

author: Rufus
author_rank: Super Contributor
timestamp: April 22, 2011, 04:29:29 am
content: You saw a transmission line the first time you saw some coax. What you saw today was a standing wave. google it.Signals propagate in coax about 0.6 or 0.7 times the speed of light, you might find a figure in the coax specifications. Remember than when you work out wavelengths.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 22, 2011, 05:30:36 am
content: ok. what i saw is a standing wave with near infinite SWR right? but still damaging to the source. but no electromagnetic energy is transmitted whatsoever, right?

author: jahonen
author_rank: Super Contributor
timestamp: April 22, 2011, 07:44:11 am
content: Quote from: Mechatrommer on April 22, 2011, 03:22:33 amNo, ordinary test equipment is not damaged since they are usually designed (I think that is a reasonable requirement!) to withstand ordinary impedance mismatches at their outputs. Furthermore, the power level is usually low.Regards,Janne

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 22, 2011, 07:51:13 am
content: Quote from: Rufus on April 22, 2011, 04:29:29 am0.66667 x 500cm = 333cm... 155cm ~ wl / 2, sounds more reasonable now.
I took one of those Halloween Jumping Spiders apart... - Page 1
Forum section: electronics / projects

author: parabuzzle
author_rank: Contributor
timestamp: November 03, 2014, 01:54:23 pm
content: I'm a halloween nut and I usually build my own elaborate props but sometimes we buy filler props like those cheesy jumping spider props (http://www.spirithalloween.com/product/tt-jumping-spider1/) as filler for our charity haunted house.. well, one of them stopped working this year and I decided to take it apart to try and fix it.. needless to say, I abandoned the idea when I saw how it was made. Its doomed to fail from the start. I can't believe that someone would approve this for a production product, let alone sell it for $80! I have prototypes that look cleaner than this.Here are some pictures of the inside:

author: Kjelt
author_rank: Super Contributor
timestamp: November 03, 2014, 02:07:37 pm
content: Quote from: parabuzzle on November 03, 2014, 01:54:23 pmYeah this looks like standard Chinese chopshop quality not much different from the Sony products in the 70's I must say.As long as the ic under the blob is still ok, this should be an easy repair, I have seen much worse when half of the components were soldered together above the pcbConcerning the price, my guess is that the chinese chopshop received $10 for it, the shipper another $5, the importer $20 and the seller took the rest, so don't blame the chinese chopshop to make this product for $10 but the american enterpreneur (aka scam artist) that took the most of your money

author: parabuzzle
author_rank: Contributor
timestamp: November 03, 2014, 03:16:22 pm
content: It appears that one of the "solder pads" lifted off the board.. I just added another bodge wire... sad.

author: mariush
author_rank: Super Contributor
timestamp: November 03, 2014, 03:43:25 pm
content: Here's a copy of the images he attached, because they either load extremely slow or not at all for me:

author: Richard Head
author_rank: Frequent Contributor
timestamp: November 03, 2014, 07:00:34 pm
content: Looks like someone had a bad sneeze when working on that PC board!

author: Zero999
author_rank: Super Contributor
timestamp: November 03, 2014, 09:21:02 pm
content: It's very cheap and nasty so it's surprising they've bothered with two speakers: a very cheap piezo transducer and a not so cheap moving coil speaker.Anyone know why this might be?

author: parabuzzle
author_rank: Contributor
timestamp: November 03, 2014, 11:53:55 pm
content: I think one is a speaker and one is for sensing vibration as the prop trigger. I came to this conclusion because I can trigger it by touching it
I turned a cheap CV PSU to a CC LED driver - Page 1
Forum section: electronics / projects

author: ElectronSurf
author_rank: Regular Contributor
timestamp: January 08, 2024, 07:27:16 pm
content: It's a 1$ chinese 12V-2A PSU with a common design using CSC7203, the one I got instead of TL431 in the feedback loop using just a zener diode to regulate output voltage.My plan was to inject a circuitry to the feedback loop to bypass the zener and by doing so I can regulate output voltage/current. The picture from Falstad simulator is showing the concept.Note that I'm using BC556 transistor to bypass the zener and not shown in the schematic. it's soldered directly on the zener. The box was just big enough to fit the PCB and potentiometer.
I want to add more time to this relay delay - Page 1
Forum section: electronics / projects

author: Shaydzmi
author_rank: Regular Contributor
timestamp: June 15, 2020, 07:21:57 am
content: The maximum is 3 seconds, I want it to be 5 minutes or even 10 minutes if possible.What should I do in terms of changing capacitors or resistors etc?Thamk you.This is the circuit:http://tinyurl.com/yb4xq2kyPhotos:

author: m3vuv
author_rank: Super Contributor
timestamp: June 15, 2020, 07:38:36 am
content: whats it for?,if it was me i would build a new pcb with a 555.

author: Shaydzmi
author_rank: Regular Contributor
timestamp: June 15, 2020, 07:54:16 am
content: Quotethank you,,I have a lot of them in hand, and I don't have the resources and knowledge to build new ones.
I want to charge capacitor with a switching regulator - Page 1
Forum section: electronics / projects

author: LM21
author_rank: Regular Contributor
timestamp: May 24, 2022, 03:10:08 am
content: I am thinking about old and familiar problem where we have two capacitors with different voltages. If those capacitors are then connected in parallell, sparks fly and some energy will be lost. But a switching regulator is able to convert voltages and currents with little losses.I am not really thinking of building any of such systems, but what kind of regulator would be best. Some simple constant current fly back perhaps.

author: Circlotron
author_rank: Super Contributor
timestamp: May 24, 2022, 03:31:35 am
content: A diode and inductor in series with one of the connections between the two capacitors will transfer energy one way with relatively low loss.

author: ajb
author_rank: Super Contributor
timestamp: May 24, 2022, 05:30:24 pm
content: It depends a lot on how different the voltages are, and what rate of charge transfer (current) you require. In that sense it's no different from selecting a switching regulator for any other kind of application. You will of course want current control, but that can be added to any converter topology.Control of the converter may be a bit different than with typical converter applications depending on what you're actually trying to do. If you have some big monster cap at a relatively high voltage and you're trying to use it to charge a smaller cap up to a defined voltage below that, then you just set the output voltage and desired current limit as normal and you're done. If you're trying to equalize the voltage on two caps or something, then you would have to use the difference between the two voltages to drive the error amp rather than the difference from a fixed setpoint.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 24, 2022, 07:44:55 pm
content: Some food for thought:The energy stored in a capacitor rises with the square of the voltage over the capacitor.This means, that if one battery starts with a higher voltage then the other, and you connect them in parallel, the end result is that the sum of the energies stored in both capacitors is less after the connection. It is a closed system, but the energy has to go somewhere. With a resistor the difference is dissipated as heat, by just connecting a wire you create the sparks. By just adding an inductor, the energy is stored in the inductor, which then starts charging the other capacitor. (With a dampened oscillation because of losses), or it stops by adding that diode.For any practical use, the size of the capacitors will have a big influence on the circuit.If it's just for your curiousity, then combining it with learning spice simulations could be a good idea.
I want to create a retro stick pad! - Page 1
Forum section: electronics / projects

author: Reef_Stevens
author_rank: Newbie
timestamp: August 29, 2015, 01:00:19 pm
content: Hey guys,My name is Reef, I've just started getting into electronics and want to create my own Retro style arcade stick for 2d style fighting games... I remember playing street fighter back in the day on the big arcade machines and I want to emulate this.I've done a touch of research into it and the "Zero Delay Arcade USB Encoder" seems to be everyone's PCB of choice.I could just buy one of them, but I really want to try and print my own as I have access to a PCB printer and some knowledge in creating PCB designs using EAGLE (pcb design software). I'm thinking I might just try and directly mimic this board and hard solder everything. I'm a little confused,,, there doesn't seem to be any logical chips on board? Any advice/tips are appreciated =D

author: BradC
author_rank: Super Contributor
timestamp: August 29, 2015, 01:09:04 pm
content: It'll be an SMD uController on the back of the board.

author: senso
author_rank: Frequent Contributor
timestamp: August 29, 2015, 01:21:39 pm
content: Probably either a micro-controller with USB, or maybe a small atmega with V-USB.
I wish to create a DIY signal generator with Readout! - Page 1
Forum section: electronics / projects

author: kingoftaurus
author_rank: Contributor
timestamp: March 27, 2014, 02:36:03 am
content: Hello all!I'mnew to the forum, but I've been watching Dave's videos for a while now and well... I've got thisproject..I just bought a brand new,straight out of the box, HP 130c. And while I stepped out of mytime machine, it suddenly aged a "few" years and is now (only) 10% out of calibration. (how do I know this without a signal generator?I plugged it into a certain known 60hz outlet..*cough*and I calculated that I was only getting 55hz)http://www.hpmemory.org/timeline/bob_devries/hp130c_01.htmSo I downloaded the user manual, and the service manual. (I uploaded the service manual so youll see what I am in need of to cal this thing)Basically, to sum it up, in order to get this thing running 100% again, I need:A signal generator "Range: 10 mv to 5 v pp at 50 kHz reference; 500 kHz."A signal generator "Range: 10 Hz to 500 kHz"A square wave generator "Range: 1 to 50 kHz Risetime: 0.175 ?sec"A test oscillator "Range: 5 Hz to 500 kHz Accuracy: ± 1%o"A time-mark generator "Range: 1 ?sec to 5 see Accuracy: -± 0.75%"All of which i'm sure can be combined into a single item that I could (possibly, maybe) DIY together.Also, some other items that i'll need that (maybe) could be DIY together:L-C meter Range: "41 ,to 49 pf at 50 kHz Accuracy: ± 3%"I'm wondering maybe that that means LCR meter? I also am curious about making one that has a better range? (for other uses, and if possible).If I must, I'll just buy something that you guys reccomend that's GOOD but not RICH.KingofTaurus,Las Vegas, Nevada(I bought the oscilloscope for 50 bucks)(can you believe this thing has tubes?)(can you believe this thing is only 10% out of cal after 51 years and that the bugger still works!?!??)(the same guy also has a tube tester that I'm going to buy from him!)(i'm seriously considering sending it to Dave to play with! since he loves those old electronics)

author: Rerouter
author_rank: Super Contributor
timestamp: March 27, 2014, 02:44:37 am
content: Though I'm probably going to be kicked in the head for suggesting it, but a micro-controller driving a AD9850 for your frequency and 3 or so op amps would give you everything you would want including output amplitude and rise time (fast comparator for fast rise time)just swapping out the crystal so it becomes a cleanly divisible fraction of a hz, (they mention in the datasheet what ones required)you can buy them in bread-board-able modules cheaper than you can get the chip and so far mine has been rock solid,
I working on different open source project (one at the time) - Page 1
Forum section: electronics / projects

author: Irilia
author_rank: Regular Contributor
timestamp: August 29, 2024, 03:19:19 am
content: I working on different open source project, they are all based on the esp32 S3I have some one for the Code in C, Lots of random problem because the compiler is still in development but the majority of things are working. I'm developing a product that do power supply, hot air, soldering iron and simple multimeter by default (can be adapted how you want if you modify the code) by default every fonction is optional, but the code will be pre made. The part will be available from different sellers as a kit, it's beginner friendly, and made to take the less space possible, 3 tier will be available, with 3 different quality (obviously you have what you pay for) everything will use the. GAN technology my goal is to get the most efficient possible, (I don't consider a linear power supply because of the inefficient and the bulkiness, but it's totally possible to add one if you need). Obviously a website for the different projects will be open with a forum.In a second time I want to do an universal PCB, for the different types of appliances, they are all controlled the same way just the numbers of Relay that changes (basically) and because it's open source everyone can adapt the Code how they want, this solution is durable, and the same PCB will be usable in 20 year. I will not implement any connectivity (no Bluetooth or WiFi) because I'm looking for a stable option no useless thing (because it's an ESP the community can add the connectivity if they want obviously.I hope you find these projects interesting 😉Ps) for now I'm looking for an open source multimeter Chip so if anyone knows one I'm interested.Thanks in advance.

author: tooki
author_rank: Super Contributor
timestamp: September 03, 2024, 06:09:13 pm
content: Quote from: Irilia on August 29, 2024, 03:19:19 amOpen-source chips? Are you seeking to fabricate your own silicon at home?So what do you actually mean by "open-source" in this case?!?There are plenty of multimeter chips out there, for example the MAX1499. But fundamentally, you need a suitable A/D converter and then design a front end around it that implements the features you want. If you think there's a chip out there that implements an entire multimeter circuit, including the front end, input protection, and other essentials, you are sorely mistaken. (And from the questions you ask, I don't think you are quite knowledgeable enough at this time to be designing an entire multimeter.)
I would like some course recommendations, to enhance my skills in board developm - Page 1
Forum section: electronics / projects

author: Velth
author_rank: Contributor
timestamp: May 23, 2023, 05:47:32 pm
content: Hi, it's been over two years since I started making my own boards, but I've never taken a proper course. I feel like I have "street knowledge," but I would really appreciate recommendations for a course that can truly help me improve. All the courses I come across are too basic and weak. I'm looking for something that can really enhance my skills in design, routing, and so on.

author: qat
author_rank: Contributor
timestamp: May 23, 2023, 10:29:03 pm
content: Have you looked intohttps://academy.fedevel.com/?That guy also has a Youtube channel with lots of good info. Then there is also Eric Bogatin's courcehttps://www.bethesignal.com/bogatin/(expensive though...)There are also many books on the subject, High Speed Digital Design, and TAOE to name two really good ones.

author: Leiothrix
author_rank: Regular Contributor
timestamp: May 23, 2023, 10:46:40 pm
content: I likehttps://www.youtube.com/@PhilsLab.He does videos with all sorts of layout tips.He also has a paid course available, but I haven't done that so no comment there.

author: Faranight
author_rank: Unknown
timestamp: May 24, 2023, 05:24:19 am
content: Search Google and Youtube for "Rick Hartley". Some very useful stuff.
I would like to build a Bluetooth audio device, please help! - Page 1
Forum section: electronics / projects

author: signal
author_rank: Regular Contributor
timestamp: May 14, 2015, 07:30:21 pm
content: I am looking to build a basic bluetooth device, that will leverage a bluetooth chip.The device will be very basic, it will be an audio client. it will do like so:1. Pair to a receiver2. Whenever audio is received (3.5mm jack or similar), transmit audio via HFP (not A2DP)3. Once audio is done transmitting it will go back to just waiting for more audio, it will not hog the channelSo it works similar to the way GPS prompts and other things work, they play on the HFP channel as needed, and then go back to waiting.I am looking at this chip (RN-52)https://www.sparkfun.com/products/11678It would seem I just need a board with a mic jack, and this chip, but am I missing something? Is there a more ideal chip I should be looking at?Thanks for your help!Signal
I would like to set up an electornics lab  - Page 1
Forum section: electronics / projects

author: ohin4ododo
author_rank: Newbie
timestamp: June 07, 2012, 02:09:04 pm
content: please guide me how to set up an electronics lab

author: PeterG
author_rank: Frequent Contributor
timestamp: June 07, 2012, 02:25:04 pm
content: What aspect of setting up a lab do you need help with?Regards

author: 500in1
author_rank: Contributor
timestamp: June 07, 2012, 02:33:20 pm
content: Try this:http://www.eevblog.com/2011/04/30/eevblog-168-how-to-set-up-an-electronics-lab/

author: obiwanjacobi
author_rank: Super Contributor
timestamp: June 08, 2012, 06:18:43 am
content: Just start simple. Buy what you need - second hand if possible. The more experience you gain the more you will know what you like and need.Anyway, that is how I am doing it. Just recently started (again) with electronics and purchased a 2nd hand (analog) scope for 50 euros. Its not the latest greatest but it works fine and it helped me fix an audio mixerYou will also learn what doesn't work for you. Like an USB scope I bought which totally sucks. No problem, just put it up for sale and move on...
I2C bus pull-up resistor sizing, is 3mA min or max ?_? - Page 1
Forum section: electronics / projects

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: May 25, 2022, 07:03:12 am
content: Hey AllFor you I2C gurus out there, can you tell me if the bus pull-up resistor (Rp) should be chosen such that the sink current is >3mA or <3mA for Standard-mode?If I dig through the NXP golden document "NXP - I²C bus specification and user manual.pdf" on I2C use it says that you need to have a sink current of at least 3mA to be within spec for Standard-mode. But then if I look at say the datasheet for TMP1075 then I am told not to exceed 3mA

author: ataradov
author_rank: Super Contributor
timestamp: May 25, 2022, 07:14:06 am
content: At a minimum device should be able to sink 3 mA to meet the spec requirements, it may do more.With this guaranteed number, when selecting the resistors your best bet is to be at or below 3 mA. This will give you the best compatibility with an abstract worst case scenario device. Most real devices are much more capable, of course.

author: Siwastaja
author_rank: Super Contributor
timestamp: May 25, 2022, 07:41:09 am
content: I think you have a perspective issue."You have to sink at least 3mA", "you" refers to thechip designer. So their I2C compatible device needs to sink at least 3mA while respecting the voltage specs.Hope this helps make sense.