hybridfree/eevblog-posts huggingface dataset:
DIY Spotwelder w/ LeadAcid Battery, Auto Solenoid, and Relay Timer (Jose's DIY) - Page 1
Forum section: electronics / projects

author: JCHaywire
author_rank: Newbie
timestamp: October 14, 2023, 02:09:40 am
content: I got interested in building a spot welder. I want to weld some LiON batteries, some LiFEPO, and it's just a fun project. This brought me to "Jose's Extreme DIY" on YouTube. His design uses a cheap millisecond mechanical relay timer to switch an old-fashioned automotive solenoid. I built it twice and got the same result: when the electrodes are not touching anything--or touching a non-conductive surface, the relay clicks ONCE properly. But when there's a conductive material nickel, or aluminum can material--anything you'd typically spot weld--it clicks open and shut cyclically without stopping. Like a chattering ratchet. And it doesn't deliver a spark. Now my manifestation of this design looks kinda weird, but it's mechanically sound and follows the "schematic" exactly. I feel like I'm really close to it working, but I don't know which direction to turn in troubleshooting. Is there a diode needed somewhere to keep it from firing repeatedly? Actually why IS it doing that? I'm tired of looking at it, but I really want this funny-looking thing to work. It's such a simple circuit that it's got me wondering if I'm crazy. Ideas?

author: JCHaywire
author_rank: Newbie
timestamp: October 14, 2023, 02:12:20 am
content: This is a drawing of what you're seeing.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 14, 2023, 02:40:59 am
content: Is it possible the electronic switch is going though a "brownout" when the leads are shorted. Then, it resets and repeats.If the electronic switch is switching a relay (the blue cubicle thing) which then switches the solenoid, try powering the electronic switch from a different supply.

author: SeanB
author_rank: Super Contributor
timestamp: October 14, 2023, 04:37:27 am
content: Simplest fix is that your timer is getting low voltage from the battery. Either power it from a separate power supply, capable of handling the contactor current, or use a diode and a large value capacitor, probably something over 4700uF 16V, to supply power to the timer board alone during this time.

author: Swake
author_rank: Frequent Contributor
timestamp: October 16, 2023, 08:09:03 am
content: yes, that it is. When the welding occurs the solenoid basically shorts the output for the battery and therefor forces it to 0V for long enough to reset the timer.
DIY STM32 flash programmer with FT232R - Page 1
Forum section: electronics / projects

author: Boscoe
author_rank: Frequent Contributor
timestamp: September 08, 2015, 11:25:31 am
content: So i'm doing a programmer to make a batch of MCUs a bit easier to program with an automated process (program). However I'm having trouble with the UART comms. I have set all the baud rates etc. to the correct values and i'm sending the commands described in the boot loader documentation from ST but I get strange or no no response. First off the baud rate the boot loader is sending seems to be faster than the max of 115200 and some times I get one, two or three bytes sent back from the boot loader when I should be getting fifteen for the command I'm sending.This is the document I've been usinghttp://www.st.com/web/en/resource/technical/document/application_note/CD00264342.pdfIf anyone who has experience doing this could give me some pointers?Thanks

author: Psi
author_rank: Super Contributor
timestamp: September 08, 2015, 11:28:59 am
content: I use this linux stm32 flashing tool to program some STM32F1 chips and it works fine.http://sourceforge.net/projects/stm32flash/You could look at the code or datalog what it sends and compare that to your app. It might give you some clues.

author: Boscoe
author_rank: Frequent Contributor
timestamp: September 08, 2015, 03:23:01 pm
content: Thanks. I found what it was. I didn't initialise the boot loader, i just started writing commands to it.
Help on N79A8211 MCU - DIY Temp Chamber / ATC-800+  - Page 1
Forum section: electronics / projects

author: pelule
author_rank: Frequent Contributor
timestamp: February 07, 2016, 08:53:46 pm
content: Hi folks,I am building a DIY Temperature Test Chamber based on an old fridge. I like to use the ATC-800+ Temperature Controller, a simple 3-point regulator (HeatOn-Off-CoolOn) with a hysteresis of +/- 1°K.I like to "tweak" that for my needs - I guess it is easier to use that ready made HW and adopt the SW, than to make a complete one.The MCU used is the Chinese N79A8211-S20R, an 8-Bit MCU with ADC, 4k FLASH, 128 Byte E2PROM and ICP (in circuit programming)See the Chinese Data Sheet (an English version I didn't find at the WWW), filesize was too big to attach so just added link.My Chinese is not that good, so I like to ask the folks here around, if one could help me answering some question.It seems based on the 8052 core, correct ?Does one of the folks here have experiance with this MCU?Does one have an english data sheet or is willing to do some short translations?Thanks for any tip already in advance.Linkt to the Chinese data sheet:https://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&sqi=2&ved=0ahUKEwjyxZ7Oo5HQAhUG8ywKHYewAL0QFggiMAE&url=http%3A%2F%2Fwww.mikrocontroller.net%2Fattachment%2F273484%2FN79A8211.pdf&usg=AFQjCNFU2w3c7SU3vZAFziaT1eo0LF-a8w&bvm=bv.137904068,d.bGg

author: pelule
author_rank: Frequent Contributor
timestamp: November 06, 2016, 04:26:06 pm
content: Updates/corrected
DIY Time-Of-Flight Mass Spectrometer Ion source - Page 1
Forum section: electronics / projects

author: ChristofferB
author_rank: Frequent Contributor
timestamp: September 25, 2021, 11:10:25 pm
content: Oh boy this is one of the more involved projects.DIY mass spectrometry is not massively popular. Aside from Ben Krasnow and two others I know of, there aren't a lot of people trying.Ben and one other, the two most successful ones, are both magnetic sector spectrometers (1940's style).I'd like to try a more modern technique, simply because it seems easier, and I had almost all the signal chain available in NIM modules (Nuclear Instrumentation)The very short story: you make an ion and time it as it flies between two detectors; as its energy is well defined, its speed is proportional to its mass.Image 1: Electron multiplier 1 generates timed electron pulses that ionizes molecules in the chamber. These are accelerated through a drift tube towards the detector, electron multiplier 2. The time differential is proportional to the ion mass m/zOk but creating ion bunches with start times is difficult. Many instruments use a high voltage pulse on a grid to let bunches through.Ingeniously, Burle made a TOF MS in the 1960's that uses a channel electron multiplier (CEM) as ion source: the collector is removed so the electrons shoot out in bunches triggered by photoelectrons through a window. The CEM/"Channeltron" then also gives a start signal for the TOF measurements.A channeltron /CEM is really just like the multiplier part of a photomultiplier, but made of a resistive material so it's a continuous voltage divider for itself.Image 2: Ionization principle detailsSo in practice, I took a standard mass spectrometer detector CEM, removed the anode cap that usually collects the electrons, mounted it in a high voltage feedthrough flange. It has an integrated resistor to make sure the output is a bit above zero potential, to make the electrons attracted to the anode. I have currently shorted this to simplify this.The feedthrough, one pole, connected to the cone of the CEM, is connected via an RC filter to a high voltage source.The other terminated to ground via 50 ohm, and a signal coupled out to a preamp/scope etc.I am not sure whether I should have a larger resistance from the CEM output to GND, to make the electrons coming out actually be attracted to something grounded, like the chamber wall opposite it. I am also considering using a higher voltage on it, so far 2800V is the highest I've tried, my new 7.5kV 1mA variable psu is in the mail.The Ion source is housed in a KF40 cross with a quartz viewport opposite the channeltron feedthrough, and one port towards a turbomolecular pump.Operating pressure around 10^-6 and 5*10^-7 Torr.So far I haven't seen an output from this setup.It is also good to note that this is not my idea; A few papers in Review of Scientific Instrumentation touched on the idea around 1969-72.I believe Burle commecerialized the CEM and was just hunting for applications, but it seems a cool concept.Hope you found this interesting! More to come as it happens!
DIY topic the next 2 weeks on my test and teardown videos - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 06, 2022, 09:28:05 am
content: I got a lot of old homebrew instruments, i had a lot of fun testing, repairing, teardown video documentall videos are going to be released the next 2 weeks, one new pr day,see the list here, feel free to commenthttps://www.youtube.com/user/alfa49alfa/videos

author: inse
author_rank: Super Contributor
timestamp: October 06, 2022, 12:32:02 pm
content: Are they made by the same person?The converter and the power supply had similar handcrafted PCBs inside

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 06, 2022, 02:40:11 pm
content: YES, almost all units are from the same person the next 2 weeks, it is explained in the video description,you are going to see A LOT of funny instruments, I tried to mix it a bit, so the tech level is spread out a bit.some of the units would have taken many month to make

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 10, 2022, 08:47:11 am
content: you might want to look againtoday it is a SPECTRUM ANALYZERvery homebrew unit :-) i actually managed to get it working

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 18, 2022, 11:10:46 am
content: today releaseDIY 2m transceiver FM 10watt 1976 80channelsyesterday it was :DIY frequency counter 0-500Mhz TTL 1975

author: bidrohini
author_rank: Regular Contributor
timestamp: October 21, 2022, 12:04:56 pm
content: Wow! all finished products. Looks like these videos cost a lot of money and time. Thank you.

author: oz2cpu
author_rank: Frequent Contributor
timestamp: October 21, 2022, 11:38:43 pm
content: thanks, yes some of my supporters had so much fun making the unitsi got a little bit more diy projects comming up the next few weeksso check the video link again soon to see more
diy USB charger - Page 1
Forum section: electronics / projects

author: hpibmx
author_rank: Regular Contributor
timestamp: December 02, 2021, 09:08:08 am
content: Hi,can anyone help me understand this basic USB charging circuit please?so I just teardown of my power bank just to confirm there's no data pin connected, I've got a female USB and would like to explement charring phone by my self.in the picture you can see data pins are not connected to anywhere at all! but when I setup the same circuit without the chip it doesn't charge phone at all! I'm powering my female USB thought my bench power supply, and have tried different setting for it non worked.I've teardown another simple USB power adapter as well, same thing nothing more thank cap and diode in at.So can anyone help me undrestand why?Thank you.

author: magic
author_rank: Super Contributor
timestamp: December 02, 2021, 09:12:30 am
content: Some brands short D+ and D- together to indicate a charger.It's clearly visible on your first picture (power bank?), not sure about the other board.

author: hpibmx
author_rank: Regular Contributor
timestamp: December 02, 2021, 09:45:38 am
content: Quote from: magic on December 02, 2021, 09:12:30 amI'm just so ashamed of my self right nowI didn't pay close attention!thank you so much for your help.It's charging now.
DIY vacuum PCB exposure box? - Page 1
Forum section: electronics / projects

author: Harvs
author_rank: Super Contributor
timestamp: September 13, 2013, 12:11:23 am
content: Anyone built a double sided PCB exposure box with vacuum clamping? I'm thinking something similar to theKinstenone.The Kinsten box looks like a nice tool, but at over $500, it's outside of what I think is reasonable to pay for exposing PCBs on an occasional basis.I've rigged up a ghetto box at the moment to try some things out, and it works pretty well, but the biggest issue is getting even pressure across the whole board. This has lead to tracks blurring a bit, which last night I was making a board which included a 12-pin 0.45mm pitch DFN and it took a couple of goes to get the results sharp enough. Once I got a clean transfer the results were perfectly fine for a quick prototype.So anyway I can see how having a vacuum clamp system would be excellent. I'm happy to pay for plans if anyone knows of a decent set...
DIY VR Headset, with VR Box headset, MIPI DSI LVDS phone screen and TrinusVR - Page 1
Forum section: electronics / projects

author: gorgamin
author_rank: Contributor
timestamp: November 09, 2016, 11:52:40 pm
content: Hi Guys,I bought one of these cheap VR BOX headsets:If you're not familiar with these, its basically a nicer google cardboard. You put your phone into the sliding tray, but it allows you to adjust the lenses. The strap is horrible though, especially the top strap, it keeps slipping off, but it might just be my big head (I've been told) so I'll have to replace it with some comfortable webbing, and make metal strengthening posts on the inside of the headset so it won't break. There's just flimsy plastic tabs holding it together from the factory.Another idea would be to make some soft foam pads to replace the cheap stock pleather ones that make your face sweat.I was wondering if there was a way to build a LVDS / MIPI DSI permanent display for these cheap headsets, using a replacement Samsung mobile phone screen which can now be bought for little.Some info on LVDS and MIPI:http://electronics.stackexchange.com/questions/118185/lvds-vs-mipi-whats-the-differenceIf you haven't tried TrinusVR yet, please do so:http://trinusvr.com/The most difficult part would be to get the lcd panel input signal converted from say HDMI or DisplayPort. This still leaves the accelerometer, and how to actually get TrinusVR to detect it.The best project on this so far is this:https://hackaday.io/project/364-mipi-dsi-display-shieldhdmi-adapterAnother idea might be to add an external power bank to a cheap previous gen galaxy phone, to say a belt clip and just use that, or just use a long USB cable and connect the phone like that.This will be miles easier, but how can we call ourselves tinkerers if we don't reinvent the wheel again, but better?If anyone is keen to collaborate on such a project, or if you have any advice or expertise, please comment.This project is already trying to do something similar:http://www.mtbs3d.com/phpBB/viewtopic.php?f=140&t=15247
DIY Wireless Thermostat & Home Sensor Network - Page 1
Forum section: electronics / projects

author: Codemonkey
author_rank: Regular Contributor
timestamp: December 29, 2016, 05:21:41 pm
content: Hi All,Had a bit too much time on my hands over xmas so had a go at a quick video to show off a project I've been working on for ages now. Feel free to tear it apart, ask questions etchttps://youtu.be/ZQLcsOjQ-I4
DIY Xbox 360 Wireless Receiver - Page 1
Forum section: electronics / projects

author: paul_g_787
author_rank: Frequent Contributor
timestamp: June 19, 2022, 06:24:35 pm
content: I have a whole bunch of Xbox 360 controllers I have acquired slowly over time. All faulty. And I did think I could test them using the USB play and charge Cable to connect them to my PC.Nope. You need to use a wireless receiver....While looking on eBay for a USB Xbox 360 Controller Receiver I came across this idea of the DIY wireless receiver, by soldering a USB cable to the RF board salvaged from a 360 console.I have a bunch of these RF boards laying about from old scrapped consoles.Have a look at this tutorial:https://www.instructables.com/DIY-Xbox-Controller-Receiver-for-PC/There is just one thing puzzling me. What exactly is the need for the 5V Zener diode in series with the USB 5V (red wire)?All of the tutorials I can find say to use a 5V or 5.1V Zener diode here (check youtube).I am familiar with using a Zener Diode in parallel reverse bias to regulate voltage, but I am not understanding this use-case. Surely it is just acting as a regular diode here?Can anyone enlighten me as to the specific need for the Zener Diode?

author: paul_g_787
author_rank: Frequent Contributor
timestamp: June 20, 2022, 08:28:01 pm
content: OK so it does not actually apparently need to be a Zener diode. The use is to simply drop the voltage from 5V to 3.3V to power the board.I used 2x 1N4007 in series to drop the voltage instead and this is working great, I am getting 3.4V (close enough).
DIY zig-zag grounding transformer? - Page 1
Forum section: electronics / projects

author: Circlotron
author_rank: Super Contributor
timestamp: September 28, 2021, 02:01:19 am
content: I just wanna mess around with a 3-phase zig-zag grounding transformer and get a feel for what they do with regard to balancing phases and effectively locking amplitude and phase separation of 3 phase-shifted sinusoids together. I'm not going to get one made but I was thinking, if I used 3 single phase transformers with double primaries and suitably cross connected these primaries would that work? (secondaries unused) I'm fiddling around on a benchtop, not speccing a power station.https://eepower.com/technical-articles/characteristics-and-uses-zig-zag--and-wye-delta-grounding-transformers/#Edit -> looks like the article answers my question.Would three single phase transformers be as effective as one 3-phase unit?
DIY/Alternative fume extractor media - Page 1
Forum section: electronics / projects

author: Mephitus
author_rank: Regular Contributor
timestamp: July 06, 2015, 02:11:28 pm
content: My wife HATES the smell of solder. To remedy this, I have bodged together a box, a couple 120mm PC fans and such. But have run into a problem of figuring out a decent material to use for the filter media. All my searches only show how to repurpose existing filters for other uses, but nothing on creating your own filter media. Mostly I am doing this because I am poor, partially because I am curious if a filter can be put together with free/scavenged materials. Existing ideas include re-using brita water filter activated carbon sandwiched between cotton and bug-netting. If anyone else has some ideas I am open to suggestions.

author: rolycat
author_rank: Super Contributor
timestamp: July 06, 2015, 02:20:13 pm
content: There's a DIY filter design here:http://www.instructables.com/id/Activated-Carbon-Air-Filter/

author: Augustus
author_rank: Regular Contributor
timestamp: July 06, 2015, 02:31:32 pm
content: Filters intended for use in kitchen range hoods are readily available (any hardware store should stock them) and relatively cheap... You can cut them down to any size needed... The better ones have a layer of activated carbon, they should be pretty effective and worth a try...

author: georges80
author_rank: Frequent Contributor
timestamp: July 06, 2015, 03:20:39 pm
content: You can buy inexpensive activated carbon filter material (looks like sponge) in large sheets on Ebay from US vendors selling US made material. Cut to fit, put a few layers together if you want thicker material.I made a filter box (1/4" mdf) with a reasonably quiet PC fan (Newegg etc) and use large diameter Locline to duct from the work bench soldering area to the filter box that sits next to a window. I can vary the fan speed (PWM controller) as needed and it does a great job of moving the flux fumes away.Can't 'smell' the fumes so it appears to function reasonably well.I posted up my project in a thread on this forum, should be easy enough to find by searching on my user id.cheers,george.

author: ajb
author_rank: Super Contributor
timestamp: July 06, 2015, 04:25:55 pm
content: You can get the media fairly inexpensively from McMaster as well. I've had a roll sitting in my office for a couple of weeks for just this purpose, one day I'll need to get around to making the filter box.http://www.mcmaster.com/#carbon-air-filters/

author: macboy
author_rank: Super Contributor
timestamp: July 07, 2015, 04:21:45 pm
content: Large inexpensive sheets of activated carbon filter media are available at aquarium supply stores. I bought a pack of two sheets each roughly 45 x 30 cm by 1 cm thick for around $6 CDN.
DL1416 STM datasheet not T ou B - Page 1
Forum section: electronics / projects

author: rvalente
author_rank: Frequent Contributor
timestamp: September 20, 2015, 05:01:40 pm
content: Hello Friends,I found a bunch of DL1416STM displays and a single DL1416B.Found datasheets for the B and T versions but not for the STM version.On breadboard the single B unit I have works like a charm but the the STM flickers and get crazy.Does anyone has the datasheet for the STM version? I neither know the manufacturer.

author: SiCarbide
author_rank: Newbie
timestamp: September 21, 2015, 07:01:19 pm
content: The company you are looking for is TSM, not STM.It seems to be the device from Three-Five Systems Inc, but the datasheet is only available as a payed service.http://www.chipdocs.com/pndecoder/datasheets/THREE/TSM1416.htmlAnyway - they look like almost 30 years old... what about scrapping 'em?Good luck,SiCjust look at the example document (1991) here, where that TSM1416 has been used for an "intelligent driver" using a 8748 (looooong ago):http://www.epanorama.net/sff/Digital/Misc/874X_CPU_Programmer.pdf

author: rvalente
author_rank: Frequent Contributor
timestamp: September 21, 2015, 08:58:36 pm
content: True, the code is TSM1416 no STM1416 (i've been using the STM32 hehe, thats why the code stick to my mind)I'll not being use this display for production, just got them around and makes such a vintage clock!Well, I'll be glad if someone had an old scan of this datasheet.
DLP - die pictures - Page 1
Forum section: electronics / projects

author: Noopy
author_rank: Super Contributor
timestamp: February 16, 2020, 08:13:30 pm
content: Hello everybody,interested in a DLP-Die?I have taken some pictures:https://www.richis-lab.de/DLP.htmYou can find better REM-pictures online but on these the mirrors don´t glow!

author: Noopy
author_rank: Super Contributor
timestamp: March 14, 2020, 12:00:51 pm
content: Update: I got some REM-pictures of a DLPhttps://richis-lab.de/DLP.htm#REM

author: Miyuki
author_rank: Frequent Contributor
timestamp: March 16, 2020, 06:46:58 pm
content: How they manufacture them ?

author: daqq
author_rank: Super Contributor
timestamp: March 16, 2020, 07:58:21 pm
content: Quote from: Miyuki on March 16, 2020, 06:46:58 pmAs with most advanced semiconductors and MEMS in particular, they use witchcraft. It's the most reasonable explanation.

author: Noopy
author_rank: Super Contributor
timestamp: March 16, 2020, 08:37:29 pm
content: Quote from: Miyuki on March 16, 2020, 06:46:58 pmWell let´s see whether my english is good enough for this.The basic technique is in theory simple: You have a "stable" layer on which you deposite a sacrificial layer and then you deposite another stable layer. Since you will have openings in the last layer you can etch the sacrificial layer away and you have a hovering layer.If you do this more than once and stack the residual parts correct you can do gears or a dlp.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 16, 2020, 09:11:51 pm
content: I took a DLP to Supercon, where Adam McCombs had set up an electron microscope

author: Miyuki
author_rank: Frequent Contributor
timestamp: March 20, 2020, 10:30:20 am
content: Quote from: Noopy on March 16, 2020, 08:37:29 pmThat makes sense, just doing it with consistent result is witchcraftSo basically very similar to UV cured resin 3D printing, layer after layer and wash out unwanted material
DLP Technology Tips and Tricks - Page 1
Forum section: electronics / projects

author: dreaquil
author_rank: Regular Contributor
timestamp: March 09, 2015, 07:41:59 pm
content: Hi,I'm about to embark on my thesis using DLP technology and I was wondering whether anyone has any tips or traps for young players to share with me. I'm going to be using them with lasers for scanning purposes.
DMM Adapters for YR1035+ and HRM-10 cables/fixtures - Page 1
Forum section: electronics / projects

author: mawyatt
author_rank: Super Contributor
timestamp: January 31, 2025, 03:25:13 pm
content: Thought posting this as a stand alone thread might be useful for folks that may have an interest.https://www.eevblog.com/forum/testgear/any-more-in-depth-info-on-the-yr1035-battery-tester-milliohm-meter/The concept originates with al777 and the RC3563 meter on post #29 mentioned above, and is about creating a simple adapter that allows the cables and fixtures from the popular Battery Test Meters like the YR1035+ and HRM-10 to be utilized on bench type lab DMMs with full 4-wire Kelvin Type measurements.We really like the Coaxial Kelvin Probes for the YR1035+, so decided to develop a simple PCB and order the proper GX12 and XS10 connectors, the GX is used by the HRM-10 and the XS by the YR1035+.Since there is required spacing behind the PCB as it mounts with 4 banana plugs into the DMM, we decided to use the cheap banana plugs for audio use. These have enough space behind the plug engaging to allow the GX or XS connectors to be wired to the PCB from the backside. We had used these type banana plugs before on a "DMM Calibrator" and R & C References, but had no spares so just measured the thread width from the DMM Calibrator and ordered from AliX that "looked" the same. From that measurement the hole size was determined for the PCB, unfortunately the banana plugs we received were slightly larger (risks of dealing with AliX) in thread diameter so the 4 holes on the PCB had to enlarged a few mm.When the PCBs arrived we quickly resized the holes and grabbed the connectors and soldering iron. Here you can see the results, and these adapters work quite well indeedThese adapters now allow 4 Wire DMM use with the nice Kelvin Clips and 4 Wire Planar Kelvin Probes from the HRM-10 and the 4 Wire Coaxial Kelvin Probes from the YR1035+, plus the other cables and fixtures for these meters.Anyway, hope some folks find these adapters usefulBest

author: mawyatt
author_rank: Super Contributor
timestamp: January 31, 2025, 03:32:19 pm
content: Higher resolution images for above.Best
DMM LoZ adapter. - Page 1
Forum section: electronics / projects

author: firewalker
author_rank: Super Contributor
timestamp: November 12, 2016, 09:32:41 am
content: In DMMs with low Z measurement capability, how low, is low Z?Also is just a resistive element? Or is there a circuit combination?Would a DMM adapter make sense for LoZ measurements (crowd founded)? Something like the adapter below, but with loZ circuitry.Alexander.

author: Dave
author_rank: Super Contributor
timestamp: November 12, 2016, 10:08:07 am
content: Low impedance on U1272A is around 1.7k, for example. I'm guessing it's a PTC or a combination of resistor+PTC so it doesn't get destroyed if the voltage you apply is too high.I don't see this being a successful crowdfunder, sorry.

author: Wytnucls
author_rank: Super Contributor
timestamp: November 12, 2016, 11:16:47 am
content: http://www.testequipmentdepot.com/fluke/accessories/batteries-chargers-adapters/sv225.htmhttp://en-us.fluke.com/products/all-accessories/fluke-sv225.html#features
DMM Wrong Probe Insert Alarm Mod. - Page 1
Forum section: electronics / projects

author: ReVl27
author_rank: Newbie
timestamp: February 14, 2017, 04:59:28 pm
content: Hello everyone,I'm using a UT61E multimeter.There's one feature that I really miss on this model is the "Wrong Probe Insert" Alarm. I mean the feature like those on some Fluke meters, the multimeter beeps if the probe and the mode selection is incorrect.I made this mistake all the time and would like to make a mod on my UT61E, too.I plan to made a separated circuit, maybe add another small buzzer to beeps independently.I just wonder is there any simple circuit to achieve this feature because I can't imagine how this feature is made???It would be great if someone could give me an idea or explain to me how it works??Thanks a lot!!!

author: Kleinstein
author_rank: Super Contributor
timestamp: February 14, 2017, 05:37:43 pm
content: It is rather difficult to add this feature later on. The difficulty is in still keeping the high voltage safety with modification at the input stage. There usually is not much space.The normal way to sense a probe in the current contact with a split contact ring, that will make two contacts. So this extra contact is used to sent a connector in the current input and warn you if the range is set to voltage.The other case of measuring current with the probe in the voltage terminal is usually less critical and more difficult to test, as there can be a high voltage at that terminal. So it would be more like a mechanical switch, like a pin in the center - this would be difficult to add.

author: ReVl27
author_rank: Newbie
timestamp: February 15, 2017, 03:07:01 am
content: Thank you Kleinstein, the split contact ring make a lot of sense.I'll consider more about this.

author: james_s
author_rank: Super Contributor
timestamp: February 15, 2017, 04:31:15 am
content: Depending on the design, an optical sensor might work.Personally I'd just buy a Fluke though.

author: PointyOintment
author_rank: Frequent Contributor
timestamp: February 19, 2017, 12:01:00 pm
content: Quote from: ReVl27 on February 14, 2017, 04:59:28 pmIf you can accept the alarm working only with shrouded-plug probes, you could use a switch to sense the presence of the shroud, which could be easier to do in a safe way.

author: _Wim_
author_rank: Super Contributor
timestamp: February 19, 2017, 08:47:10 pm
content: You could glue a plate on your selector knob that blocks the current input when voltage is selected... Ugly, but should work...
DMTD issues - Page 1
Forum section: electronics / projects

author: cncjerry
author_rank: Unknown
timestamp: January 28, 2024, 04:17:19 am
content: Every time I get a new piece of equipment I go back and try to figure out why my DMTD board has a sin wave offset riding on the phase delta. So if I have a .006ms phase difference at the start, I have 1/.006ms sine wave modulating the output. Modulating might not be the correct word, but the phase delta varies by up to 1e-11 at the rate of that frequency. I realized this evening that this board uses an sypd-1 phase detector instead of a mixer so maybe I am interpreting the output incorrectly. I'll post some pictures but was thinking the basic problem is related to the phase detector as that outputs a DC value related to the phase, right? How would the output compare to a mixer like a tuf3? I am out of the office and this just came to mind.ThanksJerry

author: cncjerry
author_rank: Unknown
timestamp: January 28, 2024, 06:27:39 am
content: Attached is an example of the phase delta I see. I've been playing around with this for years, finally thought I would figure it out. I picked up a 5370B recently and I am using that as the TIC with an offset of 1hz in this run. These aren't phase wraps, I'm missing a very basic point I think. I'm thinking of swapping in TUF3 mixers for the SYPD-1 phase detectors. I thought phase detectors and mixers behaved the same when close in frequency but have never researched it.Thanks.you can also see the subharmonics in the trace. I thought it might be a reflection, so I tried resistive as well as reactive power splitters. I also tried just a 'T' without luck. I also put directional couplers on the inputs at one point, 10Mhz filters, tried a TICC instead of the 5370, used a DDS and a 3336 and 3325 synthesized generators for the offset, changed the power and am now using lt3045s and lt3094s to feed the DMTD board. I tried QBit low noise amps ahead of the splitter (splits the reference to reference and DUT for testing) and then used connectorized attenuators to balance the signals. I brought the phase into alignment several ways but since the phase varies, that didnt help, all it did was start the curve in a different quadrant. I thought I had it when I found an opamp with excessive floating input voltage. I also thought I had it when a coupling cap was in backwards. Nope and nope.This board used transformers to couple in the signals. I had to make some changes to ensure the load was the same on all inputs (after I found the problem).I put probes on the 5370B and tested it at different points and the offset delta swing starts post phase detector. I also used an HP 4815 vector impedance meter to probe the signal path of the reference vs the DUT and they were near perfect. By the way, that is my favorite piece of test equipment, the 4815. Mine is perfect in every way. I have a parts unit as well. Bought both for $80 bucks...Thanks again.
DMX PAR light wireless control devices, question - Page 1
Forum section: electronics / projects

author: CaptDon
author_rank: Super Contributor
timestamp: September 22, 2021, 06:23:25 pm
content: So, I am new to DMX but experienced with MIDI and there seems some parallels in the thought process.I see hundreds of these "36 LED 36watt" units for sale on Ebay. More interesting is that you can easilybuy "10-packs" and they come with 10 wireless controls. What is the uniqueness of these controls? I wouldexpect at some point two DMX wireless devices responding to one handheld wireless transmitter due tohaving the same I.D. from an R.F. standpoint. Does anyone know what the limit of the R.F. I.D. is? Thousands?Millions? I am not talking about the DMX address, but the R.F. data link addressing. I assume they are runninga 2.4ghz link frequency. Anyone fooled around with this stuff? Are they using some ISO communicationsstandard. I am expecting one of my DMX wireless transmitters to start controlling other devices in my houseor vice versa? Thanks for any help/ideas/leads!!!

author: ajb
author_rank: Super Contributor
timestamp: September 22, 2021, 07:52:47 pm
content: All of those questions are really going to depend on the device. With those ebay cheapos who knows? I think the 'Donner' brand is pretty common so there's probably a fair bit of info out there about them on the internet, and a lot of the other similar looking ones will, I guess, likely have similar features.If you want something well supported and dependable, there are a number of options from established brands in the business, from Chauvet at the lower end to LumenRadio, who recently acquired Wireless Solutions and their W-DMX line, and a bunch of other ones in between. With a few exceptions, none of those are compatible with any others. The LumenRadio products are probably the closest thing to a standard going forward, since they and Wireless Solutions both produce OEM modules that get built into fixtures from several different brands, and both will be able to interoperate going forward. The general chatter I see from people I know who use this stuff seems to also indicate that LumenRadio is one of the more reliable options. Other manufacturers include Enttec, City Theatrical, and RC4.I expect most of those will be designed for one-to-many transmission, where every receiver gets the same universe worth of DMX data, so you would still need to configure each fixture with a unique DMX address if you want independent control. Actually I would expect that to be the default behavior on any system, since even when a fixture has wireless RX built in it will also have wired DMX ports, so you want consistent behavior/configuration regardless of which one you're using. Better brands will have some sort of pairing process, but the basic cheap ones might just have a few selectable channels. You'd need to look at the specs/documentation (such as you can get from ebay products, anyway) to really know more.
DO-160 protection and Infos from aerospacepal.com - Page 1
Forum section: electronics / projects

author: luky315
author_rank: Regular Contributor
timestamp: August 25, 2024, 07:23:17 pm
content: Once there was this great site aerospacepal.com with a lot of calculation tools and examples for DO-160 designs. But unfortunately the site is gone and the owner not responding anymore - so my question would be if someone still has the content. This would help me a lot!

author: Prime
author_rank: Regular Contributor
timestamp: January 07, 2025, 02:18:30 am
content: I am also looking for the information. Did you have any luck finding it?

author: luky315
author_rank: Regular Contributor
timestamp: January 07, 2025, 08:48:58 am
content: Unfortunately, no

author: Jon_S
author_rank: Contributor
timestamp: January 07, 2025, 09:06:00 am
content: Shame, seems like that could have been quite useful.There is some information available on the Wayback Machine if you go back to 2017:Wayback Machine 2017: AerospacePal
Do 3V only CAN bus transceivers with standby/wakeup exist? - Page 1
Forum section: electronics / projects

author: Yansi
author_rank: Super Contributor
timestamp: September 17, 2019, 09:27:27 am
content: Hello,I am not sure if my searching capabilities are weak, or whether there is a reason I can't find any, but do 3V3 only CAN transceivers with standby and wakeup functionality exist? So far I could not find any. Plenty of 5V Vcc transceivers with standby and wakeup, but no single 3V supply ones.I am looking for something like thisNCV7344 (datasheet), but single 3V3 supply operation. Standby current well below 100uA is appreciated, as those 100uA is the maximum the whole contraption (including PSU and MCU) may consume in standby.Thank you for any hints.Y.
Do AC Chopper need any output filtering when used with long cables? - Page 1
Forum section: electronics / projects

author: Miyuki
author_rank: Frequent Contributor
timestamp: May 20, 2023, 02:00:56 pm
content: Hi folks,I have a question about AC choppers like one built inST AN2316Input filtering is clear, it has common specs it needs to meet.But does output need any form of filtering? My use case will be single phase AC motors, fans, and pumps up to about 100W connected to a central controller with a few meters of cable.Is such cable tight enough or does it need any special filtering or shielding?
do arc snubbers increase relay DC capabilities? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: October 08, 2019, 02:09:38 am
content: if you take a AC contactor or relay, and you put a snubber across it (ARC quencher, seem that many technologies exist), can you extend the rating of the contactor when switching DC ?

author: Someone
author_rank: Super Contributor
timestamp: October 08, 2019, 02:27:56 am
content: Yes

author: coppercone2
author_rank: Super Contributor
timestamp: October 08, 2019, 02:28:34 am
content: is there a derating curve that is realistic ?and what is the best arc quencher to do this? I see good ones go for 40$ per pole!

author: MagicSmoker
author_rank: Super Contributor
timestamp: October 08, 2019, 09:33:33 am
content: Quote from: coppercone2 on October 08, 2019, 02:28:34 amThe ampacity is the same for AC or DC when the contacts are closed, so the same derating curve applies. The reason standard relays have much lower DC current (and, usually, voltage) ratings than for AC is entirely due to the nasty habit of DC arcs persisting when AC arcs automatically extinguish at the next zero crossing.An RC snubber can be placed across the contacts to improve the DC interruption capability of a relay as long as the capacitance is sufficiently high to absorb the energy of the total loop inductance without rising to a voltage that would cause air gap ionization (basically, CV² = LI²) and the resistor is sized to limit the peak current when the contacts next close.Alternatively, place strong rare earth magnets on either side of the contacts like shown below:

author: Seekonk
author_rank: Super Contributor
timestamp: October 08, 2019, 07:55:42 pm
content: If you have a NC/NO relay, placing a cap across those two contacts and a large ohmage resistor to the other polarity will give nearly the full AC rating of a relay on DC. The cap will reverse the current flow and extinguish the arc. According to James Dillon Cobine.

author: floobydust
author_rank: Super Contributor
timestamp: October 08, 2019, 09:14:48 pm
content: What voltage and current are you looking at?A snubber will only mitigate the circuit inductance, from which the back-EMF starts and maintains a DC arc greater than the relay is good for. It's all about contact air gap. I see blowout magnets used around 125V up.I haven't seen resistance verses current and gap length data for arcs. We've all seen an arc being "pulled" larger and larger.Looking atPV solar relays,2.0mm gap and 450VDC rating butFTR-K2Wis 3.2mm and 60V 30A rated
Do DC-DC converters work ok if there is a large amount of ripple on the input? - Page 1
Forum section: electronics / projects

author: e100
author_rank: Frequent Contributor
timestamp: August 19, 2019, 11:08:19 am
content: For example, if the input voltage momentarily drops below some threshold does it go into some kind of shutdown mode, or does it continue powering itself from the energy stored in the output circuit and wait for the input voltage voltage to climb back above the threshold before it resumes.

author: tszaboo
author_rank: Super Contributor
timestamp: August 19, 2019, 11:25:06 am
content: Yes. No. Maybe. Depends.
Do high current rail splitters exist? - Page 1
Forum section: electronics / projects

author: e100
author_rank: Frequent Contributor
timestamp: March 15, 2018, 10:56:01 am
content: Low distortion 10-100 w class AB audio amp modules often require a split rail power supply.Thinking aloud, would it be possible to use a single supply class D audio amp to generate a high current virtual ground to satisfy the power requirements of a class AB split rail amp? Would the RF noise leak into the class AB amp making it as bad as a class D amp?

author: dmills
author_rank: Super Contributor
timestamp: March 15, 2018, 11:23:28 am
content: Seems like a hard work alternative to a 10kuF cap in series with the speaker (The usual way to skin a single supply amp if you do not want to bridge the load, you usually want to bridge the load)!A CCM buck converter running 50% duty cycle would also probably get it done, and has the virtue of simplicity (CCM so if is effectively two quadrant).Regards, Dan.

author: e100
author_rank: Frequent Contributor
timestamp: March 15, 2018, 03:49:44 pm
content: You got me thinking, wouldn't it make sense if all class AB amps operated in bridge mode by default?Lower voltage power supply = cheaper components, or am I missing something?

author: dmills
author_rank: Super Contributor
timestamp: March 15, 2018, 04:17:20 pm
content: Lower effective load impedance, so the SOA issues are about the same, but now if you want to support a 4 ohm load you need to be able to drive into 2 ohms, and all the non ideal behaviours become a much bigger issue.Also twice the component count....Regards, Dan.

author: C
author_rank: Super Contributor
timestamp: March 15, 2018, 05:19:36 pm
content: Think of problem areas and what is effected.A differential audio input is great as it removes a lot of noise.But you have to remember that with only two connections you have equal of a PWM input if it is not a balanced signal input. A DC offset can build over time. So you need a 0 signal input to counter the building DC offset. Most times it has the bad name of ground.With a single output you are putting un-equal loads on each power rail and counting on a return path to balance the load on other rail.With differential output you are putting an equal load on each rail but need 2X circuit. By knowing that rail load is equal the circuit can better adjust to rail changes. You can save of power supplies.The PWM like DC offset of input can be easily removed using the zero signal input.The thing often forgotten is that with differential output you are not trying to make a positive output side match a negative output side with each built from different transistor types ( NPN. PNP). But are trying to make two NPN based sides match & two PNP sides match. A positive/negative side miss match becomes a common mode signal to output which is ignored.
Do I have a fake Tektronix P6137 probe ? Hows yours ? - Page 1
Forum section: electronics / projects

author: BravoV
author_rank: Super Contributor
timestamp: November 30, 2011, 05:43:48 am
content: Just bought pair of used 400 Mhz Tektronix P6137 probes from ebay, the seller is from US and here what I got.See the contact points pointed by the red arrows, it is definitely not gold plated.Another shot.While here at one of the tech surplus shop , click here ->http://www.qservice.tv/vpasp/shopexd.asp?id=8114&bc=no, click at the lower right thumb pic to zoom, and their P6137 pic like below here has the golden contact which I assume its gold plated.Anyone who own this particular model of Tek probe, could you please confirm this ?

author: amspire
author_rank: Super Contributor
timestamp: November 30, 2011, 05:52:54 am
content: I cannot confirm it, but I am pretty sure they are genuine.

author: tesla500
author_rank: Regular Contributor
timestamp: November 30, 2011, 06:16:33 am
content: Just because they're not gold plated doesn't mean they're counterfeit. Gold plating can actually be bad if both male and female are not gold plated. If the scope has tin or nickel plated BNCs, as most scopes do, using gold plated male BNCs could accelerate corrosion and lead to bad joints due to dissimilar metals, especially in harsh environments.

author: grenert
author_rank: Frequent Contributor
timestamp: November 30, 2011, 06:30:37 am
content: Those almost certainly are genuine. The production life of many of their products (like those of Agilent, Fluke, etc.) is so long that there are often revisions over time. Sometimes they designate them "A" or "B" or whatever, but I imagine that more subtle changes don't get any designation change at all.

author: wkb
author_rank: Super Contributor
timestamp: November 30, 2011, 07:25:56 am
content: Fwiw: my definitely genuine P6131 are both silver plated, as is my P3136.Not to worry I'd say.Wilko

author: BravoV
author_rank: Super Contributor
timestamp: November 30, 2011, 12:58:01 pm
content: Thanks for the feedbacks, I guess I was worrying too much.

author: lowimpedance
author_rank: Super Contributor
timestamp: November 30, 2011, 10:45:02 pm
content: BravoI have a variety of TEK probes and none of them are gold plated, all look like yours so as others have stated they should be genuine.Have fun using them!!.

author: BravoV
author_rank: Super Contributor
timestamp: December 01, 2011, 04:26:28 am
content: Quote from: lowimpedance on November 30, 2011, 10:45:02 pmThanks !