hybridfree/eevblog-posts huggingface dataset:
Questions on Making High Voltage Circuits - Page 1
Forum section: electronics / projects

author: nshin31302
author_rank: Contributor
timestamp: February 07, 2016, 06:40:50 pm
content: So, for the past few years, i've been trying to make several high voltage circuits (started with a van de graaff and attempted to make flyback drivers and Tesla coils) but I err... Keep failing. My van de graaffs worked well, so I decided to move onto making bigger sparks. I tried making a flyback driver and it worked perfectly!..... But only on breadboard. My attempts to make it more permanent on perfboard failed. All l I got was a smoking transistor and sometimes an extremely small arc output. I tried many more Flyback circuits, but they all ended up the same way. Then I attempted a slayer exciter Tesla coil, which worked perfectly on breadboard but (not surprisingly), failed on perfboard. I just ended up redoing then circuit on breadboard, then pouring hot glue to secure the connections. Ultimately, all I've ended up with in the past 3 years are some half-working flyback drivers, a not-so -exciting Slayer exciter Tesla Coil, and less money than I would have liked.So here's my question(s).1. What am I doing wrong with the circuit? I read somewhere that the flux of the solder could act as a conductor, and could explain why the Transistor keeps heating up. Also what type of perfboard should I use? Pad per hole, Breadboard style perfboard, or something else? Also, What soldering technique should I use?Thanks in advance

author: alsetalokin4017
author_rank: Super Contributor
timestamp: February 07, 2016, 07:03:11 pm
content: Well.... it's hard to diagnose your particular problem at a distance.... but I have some opinions, fwiw...Personally, I hate pad-per-hole stuff. It's ugly and error-prone. For the kind of projects you are talking about I prefer point-to-point wiring using my own particular semi-breadboard system. For power transistors in TO-220 or TO-247 I use a couple of different types of "sockets", which greatly simplifies matters. The transistors will heat up, so proper heatsinking and ventilation is important.I don't know what you mean by "what soldering technique" to use. There is only one technique, unless you are talking about PCBs where you might use hot-air, oven reflow, wave or vaporphase soldering.I've never had problems with flux causing leakage but it's good practice to clean excess flux anyway. Use isopropyl alcohol and q-tips, pipe cleaners, etc. if you are worried about it. In the kinds of circuits you mention there isn't really any "high voltage" on your boards themselves anyway, is there? I mean in excess of 500-600 V....
Questions on points of circuit design in the BWD604 Mini-Lab - Page 1
Forum section: electronics / projects

author: intabits
author_rank: Frequent Contributor
timestamp: August 25, 2018, 11:53:24 am
content: I recently bought a few toroidal tranformers from Rockby Electronics, which they appear to have acquired as a job lot.They were originally custom made for use in the "BWD604 Mini-Lab", which is "a combination of eleven versatile instruments and facilities in a stylish compact cabinet". It's primary market seems to have been for educational lab use.They certainly packed a lot of function into this unit, and I'm planning to use a couple of the transformers to reproduce some of those functions, probably basing it on the original circuits. The maintenance manual is quite good, with schematics and circuit description:-https://www.kevinchant.com/uploads/7/1/0/8/7108231/minilab_604_v2_maintenance_manual.pdfBut after studying the schematics, I'm not clear on a number of points, and hoping others can shed some light on the them.The internal power supply (p71 top):-Q1: What is the purpose of R1/R6/R7/R11, 1W resistors strapped from input to output of the fixed voltage regulators?The Variable +/-15V power supply (P71 bot):-Q2: What is the purpose of R118/R119, resistors strapped from +/- outputs to the opposite -/+ raw filtered supplies?The Power Amplifier/Variable Supply (p77)Q3: The connections to front panel pot RV18B are faded and not clear. (Not helped by the use of dashed lines for 3 different purposes in this area!)a: Would the wiper be connected via GREEN to "GAIN" lug (to RV16), as well as via another GREEN to "GAINI" lug (to RV15)If so, why two green wires and two lugs? RV16 & RV15 are right near each other on the same PCB - one lug can go to both.(or is this wiring something to do with joining up to SW16, which also appears to be on the front panel?)b: Where do the ends of RV18B go? Are they just paralleled across to +/-15VD on the other ganged pot, RV18A?Q4: There is no connection to the collectors of Q16 & Q17 (BD139s). I assume this is using the BE junction voltages as some sort of temperature compensation, with these transistors bolted onto the same heatsink as the amplifier output transistors. Is that correct?I have more questions, but let's see how we go with these.Thanks in advance for any help on this...
AC Coupling Placement in DisplayPort Redriver Design - Page 1
Forum section: electronics / projects

author: electronx
author_rank: Regular Contributor
timestamp: June 20, 2025, 03:05:21 pm
content: Hi everyone,I'm working on a system based on the NVIDIA AGX Orin module, and I have some questions regarding the proper placement of AC coupling capacitors in a DisplayPort redriver design. Here's a quick summary of the setup:* The AGX Orin module outputs 4-lane DisplayPort differential pairs and an AUX channel to the AGX Carrier Board.* The video lanes pass through AC coupling capacitors on the carrier board and then go to a connector.* The AUX channel passes through a PI3AUX221ZTAEX switch, which supports both DC and AC coupling. Since we are using a DisplayPort sink, we chose AC coupling here.From the connector, the signals go through an FFC cable (about 60 cm long) to an extension board.On the extension board, I'm using a DisplayPort redriver: PI3DPX1203BZLEX.PI3DPX1203BZLEX datasheet(page25-26)In the PI3DPX1203 reference design shown in the datasheet, there are two sets of AC coupling capacitors:*Block1 (Orange): Pre-redriver AC coupling (directly from the GPU).*Block2 (Blue): Post-redriver AC coupling (before the sink/display).* AC coupling is also suggested for the AUX channel.In my case, the signals come not directly from the GPU but from the carrier board through an FFC cable. So I'm a bit uncertain about some points:1. Should I include the Block1 (orange) pre-redriver AC coupling capacitors on the extension board again?The signals have already passed through AC capacitors on the carrier board.2. Are Block2 (blue) post-redriver AC coupling capacitors required on the extension board?Or is it acceptable to continue with DC coupling at this stage?3. Should I include additional AC coupling capacitors for the AUX channel on the extension board?The PI3AUX221 switch on the carrier side already performs AC coupling.I’d really appreciate any insights or recommendations based on your experience. Thanks in advance!

author: electronx
author_rank: Regular Contributor
timestamp: June 22, 2025, 11:07:59 am
content: I'm thinking of getting rid of the orange and purple blocks
Questions regarding voltage divider for micro controller sensing? - Page 1
Forum section: electronics / projects

author: farukhkhanugi
author_rank: Newbie
timestamp: October 11, 2019, 06:42:13 am
content: Hello Guys,I am beginner trying to develop two voltage sensors for attiny85 microcontroller. I have two separate voltage levels that I want to sense using the attiny. One of the voltage supply is 0V-5.5V and is fluctuating very often within that range, and I want to detect the voltage every second or so through attiny85 analogread function and record it inside a log. I want to use the VS1 sense line from the schematic and connect it directly to any analog pin of the attiny85. And the SIN is directly connected to the supply voltage. On the other supply, I have linear 0V-2.7V which is connected directly to the CVP pin. And the VS2 is connected directly to another analog pin of the attiny85.The attiny85 is being powered by a separate 3.3V supply. And the reference voltage I want to use is 1.35V inside the software. So, 0V-1.35V inside the attiny analogread to detect this 0V-5.5V fluctuating range and 0V-2.7V linear range.Now, the questions:1. Is my voltage divider circuits feasible and a good approach for these two types of voltage measurements?2. Is it possible to improve the voltage sense circuitry, to get better accurate readings?3. What high quality good brand SMD components I could use for these voltage sense circuits and their eagle library parts suggestions?Any suggestions and tips would be highly appreciated. Thank You.

author: MosherIV
author_rank: Super Contributor
timestamp: October 11, 2019, 06:57:10 am
content: HiI would not put the capacitors in, they would have to be charged/discharged by the voltage being measured. If you must have them, use nF not uF.I do not think you need a voltage divider for a 1:1 No point.You may want to think about input protection, after the voltage divider, on the lower resistor put a 3.3V zener to stop any accidental over volt to the micro input.

author: farukhkhanugi
author_rank: Newbie
timestamp: October 11, 2019, 07:05:34 am
content: What if I use 3.3uF @ 50V caps? Or can you please suggest a capacitor type for this application. what nF and what voltage value caps I should use here. And should I use ceramic type non polar caps or electrolytic or cermamic polarized ones. I just want to keep the voltage reading consistent and detectable through the micro.I did not understand what you meant by 1:1 no point.the supply voltage I am using cannot possibly overshoot voltages more than 5.5V. Even though can you please show me an schematic example which will add the zener to the circuit? I am not sure how to implement a zener for this circuit. Wouldn't I need another resistor for the zener?

author: farukhkhanugi
author_rank: Newbie
timestamp: October 11, 2019, 10:49:18 am
content: The supply voltage 1 in this case is couple of 5V rated solar panels in parallel and the supply voltage 2 is a supercapacitor bank. And the solarcaps are being charged through a buck from the solar. Is it really possible for these two supplies to generate voltage spikes?
Queston about power supply! I appreciate any help,thanks in advance! - Page 1
Forum section: electronics / projects

author: RTFM
author_rank: Newbie
timestamp: May 05, 2016, 04:50:07 pm
content: I have a question I order this form ebayhttp://www.ebay.com/itm/172154742432?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AITit says that max u can get 3A from it. Is there a problem if my transformer can output 4,1A for example? Will it damge the board...it have same input ac voltage and so on,but is it problem or I'll just have 3A max form my power supply?

author: ZeTeX
author_rank: Frequent Contributor
timestamp: May 05, 2016, 05:21:36 pm
content: Quote from: RTFM on May 05, 2016, 04:50:07 pmYour transformer can output 4.1A RMS Max, if you will draw less then 4A~ it will be fine, so no, nothing will be damaged.You should put a fuse on the secondary of the transformer just in case.also you will need very big heatsink with a fan, do not try to run it at full load at low output voltage without an heatsink or else the transistor will go into thermal shutdown.(heat sink with a fan will cost more then the board itself)

author: danadak
author_rank: Super Contributor
timestamp: May 05, 2016, 05:26:03 pm
content: This looks light a straight linear supply, so its load that determines the thermal limitsin the supply. Fact that transformer could support a higher current supply not ofmaterial concern. Note I do not see a heatsink on what appears to be pass transistor,would advise you add one in any event.So in short if you limit your load to its 3A rating all should be good. If your transformeris also putting out a higher V than recommended, that would be of concern. You would haveto examine limitations of 7824 input.Regards, Dana.

author: RTFM
author_rank: Newbie
timestamp: May 05, 2016, 05:27:45 pm
content: Thanks for quick responce.That's all I need to know...good day sir!Sure I'll put fuse no doubts about that fan and heatsink too I know I need them too much heat to dissipate...You are awesome man,thanks! U may close the thread..
Quick and dirty teardowns - Two old Wheatstone Bridges - Page 1
Forum section: electronics / projects

author: intabits
author_rank: Frequent Contributor
timestamp: December 26, 2018, 03:57:24 pm
content: A couple of quick and dirty teardowns of two old Wheatstone bridges, picked up recently at a garage sale.The first is a model WB4 from Victorian Measurement Laboratory (now defunct it seems) from circa 1959. A nice unit that might scrub up very nicely with some TLC. Unfortunately, it appears that the galvanometer is cactus, but further investigation is required to be sure.It can also be used simply as a decade resistance box, and is reasonably accurate at about 0.1%.Video:The second is a "Portable Resistance Measurement Bridge" aka a "Post Office Box" (for testing telephone lines), possibly from around 1941. The resistance adjustment is performed by inserting pegs to short out fixed resistances. I'm not sure what is the best way to ensure good contact with the pegs or how best to clean the contact surfaces. Any ideas?Video:There is another, but with knobs missing and some disconnected internal wiring. Could be made into a good decade resistance box.(no video for this one, maybe later if there's any interest)
Quick-Charge Auto-Fire Capacitor Charger - Page 1
Forum section: electronics / projects

author: 4beowulf7
author_rank: Newbie
timestamp: July 31, 2015, 07:42:02 am
content: Hi guys,The circuit I like to share with you charges a PhotoFlash Capacitor several times per sec. So it's a fast charger.https://tr.scribd.com/doc/272550571/QuickCharge-AutoFire-Flash-CircuitGreetings
Quick check on a DFPlayer Mini circuit - Page 1
Forum section: electronics / projects

author: Youkai
author_rank: Regular Contributor
timestamp: May 08, 2020, 03:50:03 am
content: Planning a project that will use an Arduino to run a night-light. I want there to be a button that will play a random sound effect. I did a little research and found that a DFPlayer Mini and a PAM8403 can be used. Can you please check my schematic to see if I made any mistakes. Obviously there are missing items that I'll add in later as I work on the project (buttons, etc)One of the Youtube videos mentioned using a voltage divider in the place of the 1K resistor. What's the difference? I know that the RX pin is supposed to have 3v instead of 5v. Is a voltage divider better/worse/different than a resistor?

author: OwO
author_rank: Super Contributor
timestamp: May 08, 2020, 03:57:45 am
content: The speaker outputs of the DFplayer are driven by a built in PA, so there is no need for another PA.

author: Youkai
author_rank: Regular Contributor
timestamp: May 08, 2020, 04:59:47 am
content: Quote from: OwO on May 08, 2020, 03:57:45 amOh interesting. So I can probably take the PAM8403 out of the circuit? Cool beans.

author: OwO
author_rank: Super Contributor
timestamp: May 08, 2020, 05:14:15 pm
content: Yes, the dfplayer already has a PAM8403 or equivalent chip built in; the speaker outputs can drive a speaker up to 3W directly according to this:https://wiki.dfrobot.com/DFPlayer_Mini_SKU_DFR0299
Quick circuit: low voltage inrush limiter (USB?) - Page 1
Forum section: electronics / projects

author: c4757p
author_rank: Super Contributor
timestamp: November 23, 2015, 06:15:51 pm
content: A lot of the circuits I see floating around online for doing inrush current limiting, perhaps for a finicky interface like USB, are eitherovercomplicatedorstupid. Some even in manufacturers' app notesdon't really work. Thought I'd write up and share a circuit I've been using a lot lately that works about perfectly for this:FET Inrush ProtectionIt's fairly simple, so I'm sure I'm not the first to do it quite like this, but hopefully I can post this and bring up the SNR on this particular topic a bit

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 23, 2015, 08:28:36 pm
content: Well, one of those USB power switch thingers does everything: active current limit (if imprecise), hiccup or latched fault mode, thermal limit, the works.Neither of the discrete examples are actually "current limiting", they just fake it by being slow. I don't think FTDI has much in the way of analog engineers, and EDN...what did you expect?Tim

author: c4757p
author_rank: Super Contributor
timestamp: November 23, 2015, 08:42:16 pm
content: Fair enough

author: Jeroen3
author_rank: Super Contributor
timestamp: November 23, 2015, 09:03:50 pm
content: I've found the MIC20XX family to look promising. Not expensive and they have a lot of different configs.Unfortunately, I never got around to use one since the specs of the project did change.

author: c4757p
author_rank: Super Contributor
timestamp: November 23, 2015, 09:23:40 pm
content: Yeah, that's a nice-looking chip - definitely will put that on my list

author: Howardlong
author_rank: Super Contributor
timestamp: November 23, 2015, 09:35:21 pm
content: Depending on what you're doing, the USB3751-1 might be a solution.This offers a ton of features particularly for USB devices with rechargeable batteries, including charging port identification and capabilities, under- and over-voltage protection and ESD protection. It also offers 100mA current limit until configured otherwise.They're not cheap ($0.44 1ku) but depending on the application, once you've added up the cost of all the other paraphernalia using discrete devices, it might be an economically viable solution.

author: BravoV
author_rank: Super Contributor
timestamp: November 23, 2015, 11:49:45 pm
content: Perfect for my need with the excess of fets lying around, and appreciate the writing, thanks !

author: dadler
author_rank: Unknown
timestamp: November 24, 2015, 12:19:36 am
content: Clever, and very professionally presented. Archived for later reference. Thanks!
quick connect terminals - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: January 22, 2018, 10:48:52 am
content: I'm trying to set some stuff up for testing so want to connect things like fans to some sort of quick connect terminal so that they can be moved around etc. I'm sure there is something out there but don't know what to call it. something sprung would be good like speaker terminals but able to take 20A

author: AllTheGearNoIdea
author_rank: Unknown
timestamp: January 22, 2018, 12:21:49 pm
content: Look at Wago these are original and the best. several manufacturers make something similiar including Wiedmullerhttps://uk.rs-online.com/web/p/pcb-terminal-blocks/8919918/

author: stj
author_rank: Super Contributor
timestamp: January 22, 2018, 12:29:42 pm
content: 20A??what voltage and what termination on the other side?

author: Simon
author_rank: Unknown
timestamp: January 22, 2018, 05:42:02 pm
content: Quote from: stj on January 22, 2018, 12:29:42 pm24V, I have things like fans with their own plugs, I can use a mating half, cut the plug off.

author: Fludo
author_rank: Regular Contributor
timestamp: January 22, 2018, 07:35:00 pm
content: https://www.amazon.com/Battery-Connect-Disconnect-Connector-Recovery/dp/B01KHQR0K4/ref=sr_1_4?s=automotive&ie=UTF8&qid=1516649531&sr=1-4&keywords=battery+quick+connectThe battery quick disconnects work fairly well for DC connections, I've seen panel mount types too.

author: stj
author_rank: Super Contributor
timestamp: January 22, 2018, 09:02:58 pm
content: these are good - WAGO 221 series.

author: David Hess
author_rank: Super Contributor
timestamp: January 23, 2018, 12:07:44 am
content: I use 0.062" Molex connectors for low currents and Anderson Powerpole connectors for high currents.
Quick & Dirty teardowns: Danish Delights - more Brüel & Kjær - Page 1
Forum section: electronics / projects

author: intabits
author_rank: Frequent Contributor
timestamp: October 01, 2018, 02:31:40 pm
content: A few videos where I have a quick look at the rest of some Brüel & Kjær test gear that I saved from the dumpster over a decade ago.Type 2760 Power AmplifierPrimarily intended to drive a "shaker" for vibration measurement, but is general purpose and can also drive a speaker.Type 1902 Distortion Measurement Control UnitReceives a reference frequency signal from another piece of test gear, and produces two tones of nearby frequencies that can be used to measure several types of distortion.Type 4416 Response Test UnitFor testing the frequency response of turntable pickups, but can also be used for tape recorders.Type 4440 Gating SystemAllows for the testing of loudspeakers without the need for an anechoic chamber.Type 6202 Phase Delay UnitAlso for loudspeaker testing. Used with a phase meter, it compensates for the time taken for a signal to travel from the speaker to the testing microphone.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: October 01, 2018, 09:34:35 pm
content: I've got a 2706 power amp I use as a test amp on the bench. Really handy little thing. I machined up a custom input plug for it with a barrel and (I think) a banana plug.

author: intabits
author_rank: Frequent Contributor
timestamp: October 02, 2018, 08:19:05 am
content: Quote from: Conrad Hoffman on October 01, 2018, 09:34:35 pmI'll try to do something similar. The 2706's would come in handy as you say, and they are probably the only items from this lot that I'll ever use.
Quick & dirty Teardowns, Euro edition: Schlumberger + Brüel & Kjær - Page 1
Forum section: electronics / projects

author: intabits
author_rank: Frequent Contributor
timestamp: September 13, 2018, 07:48:09 am
content: A couple of short teardowns:-Schlumberger VB6601 Voltmeter - Nixies!Brüel & Kjær - ZR0005 Logarithmic Potentiometer - Unexpected contents
Quick dual rail portable powered breadboard hack/bodge - Page 1
Forum section: electronics / projects

author: MrSlack
author_rank: Frequent Contributor
timestamp: February 02, 2016, 10:26:56 pm
content: Tonight's hack.Needed a breadboard for doing some low frequency analogue audio stuff on. As I'm confined to the dining table to work and working out of boxes while my house is being ripped out, I knocked up a quick breadboard hack so I can play without too many trailing cables and keep all connections 100% static when I have to clear it.Base is a Wisher WBU-502L. These are great for analogue and discrete stuff. The bracket is a chunk of alu stock recovered from a blown up Chinese switch mode bend with some mole grips, drilled and deburred, then "brushed" with a scourer. Holes at top are pot sized, middle ones are 3.5 jack/pushbutton sized and the bottom three are toggle switch sized. This was glued on the front with epoxy. Binding posts were not installed and two PP3s are cable tied on with a small power cable assembly bodged up to turn the +9v and -9v rails on and off.Fugly but it works!

author: ChristofferB
author_rank: Frequent Contributor
timestamp: February 02, 2016, 11:44:07 pm
content: Nice! I'm a great fan of having a connector/switch panel on my breadboards myself. I use some L bracket pre-drilled with M3 threaded holes to mount one corner of Dsub connectors and coax flange connectors. Might not be pretty but it's way prettier than the alternative!--Christoffer

author: MrSlack
author_rank: Frequent Contributor
timestamp: February 03, 2016, 06:43:52 am
content: Good idea with the d-sub. Will bear that in mind in the future.
Quick question about PCB design - Page 1
Forum section: electronics / projects

author: Myasnik
author_rank: Newbie
timestamp: August 22, 2013, 04:44:00 pm
content: Just a really quick question.Let's suppose I would like to build something like this:http://s49.radikal.ru/i125/1112/6d/41c6684a0c56.jpg- it is not my design, I found it on arduino forum. But anyway.So, let's say I would like to get something like that, but ask some professional to design the pcb for me. Do you know how much such a thing could cost? I can imagine it is not too difficult build. Still, I would rather find a more professional guy rather than creating crap myselfAny ideas?

author: c4757p
author_rank: Super Contributor
timestamp: August 22, 2013, 04:44:44 pm
content: Quote from: Myasnik on August 22, 2013, 04:44:00 pmYour dignity.

author: Myasnik
author_rank: Newbie
timestamp: August 22, 2013, 04:47:10 pm
content: Quote from: c4757p on August 22, 2013, 04:44:44 pmHaha, it is a good answer and I see your point, but I would appreciate anactualanswerupd: let me explain though. I can slap it all together on a breaboard and it would work, but to design for actual use is anoter. I had an idea of building a kit for a very simple handheld powered by AVR and I am just exploring possibilities nowWhich is the reason I am asking.

author: KJDS
author_rank: Super Contributor
timestamp: August 22, 2013, 06:01:02 pm
content: Typically between £20 and £50 an hour for a layout agency. A straightforward digital board like that should only take a couple of days at most if there aren't too many new components that need making in the library.What is vital is that you define the board criteria before you start. Size, layer count, track and gap limits, power planes, connector locations, fixing points, IPC class, soldering method, resist, silk screen etc. You also need to know what they're going to deliver, ie gerber for all layers, some DXF to import into your mechanical system, component position and angles to program the pick and place machine, etc etc.and how much tweaking they'll accept between showing you what they think is a good layout and you adjusting it so you think it will really work.Then, just when they've spent half a day generating all the manufacturing information and archived the job you will spot a mistake that needs a modification.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: August 22, 2013, 09:45:20 pm
content: If you can put it together on a breadboard then you can layout a PCB. It's not that difficult. Download the DipTrace demo and learn how to use it.

author: johnnyfp
author_rank: Frequent Contributor
timestamp: August 23, 2013, 04:37:22 am
content: Something likethis?

author: pilogger
author_rank: Newbie
timestamp: October 07, 2013, 05:42:56 pm
content: You can try Eagle also, it worked for me very fast.

author: Smokey
author_rank: Super Contributor
timestamp: October 07, 2013, 09:37:54 pm
content: Quote from: johnnyfp on August 23, 2013, 04:37:22 amSo the short answer is:$18.00 USD
Quick question about ripple - Page 1
Forum section: electronics / projects

author: MatCat
author_rank: Frequent Contributor
timestamp: October 15, 2013, 11:40:06 pm
content: Quick question about ripple, lets say a switching reg for example is rated for 30mv of ripple, now does that mean up to 30mv above and below the regulated output voltage? Or a total, I.E. up to 15mv above and below?

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: October 16, 2013, 12:02:13 am
content: Hi,Generally it is assumed to be peak to peak. You also need to look to see if they specify bandwidth. Traditionally 20 MHz was used for ripple measurements. There may be noise that extends beyond 20MHz so watch out.Jay_Diddy_B

author: Andreas
author_rank: Super Contributor
timestamp: October 16, 2013, 09:08:05 pm
content: Quote from: MatCat on October 15, 2013, 11:40:06 pmIf nothing further is specified I would use RMS voltage. This makes "monster spikes" with high crest factor look nice within the datasheet.And further it can be read out easily with a true RMS voltmeter in the AC+DC range.With best regardsAndreas
Quick question -- what is this extra device in a 1W white LED package? - Page 1
Forum section: electronics / projects

author: dmacfarland
author_rank: Contributor
timestamp: January 04, 2017, 03:35:31 pm
content: Hey guys, I was just looking at this generic 1W white LED and noticed a separate device outside of the white die area (lower right in my photo). After some research, I've seen a similar arrangement in Cree LEDs but no mention of what it is in the datasheets.All three bonding wires you can see coming from the right are on the same terminal and so are at the same potential. The other terminal is blurred out on the left side.I'm sure it's something obvious but I can't think of what it would be.

author: Audioguru
author_rank: Super Contributor
timestamp: January 04, 2017, 03:40:05 pm
content: It is the mounting base connection. Maybe to allow you to prevent damage from static electricity.

author: GreggD
author_rank: Regular Contributor
timestamp: January 04, 2017, 04:25:56 pm
content: It is a zener diode for ESD.

author: dmacfarland
author_rank: Contributor
timestamp: January 04, 2017, 04:29:20 pm
content: Quote from: GreggD on January 04, 2017, 04:25:56 pmThanks, that is what it seemed like to me in my rudimentary testing, but I wasn't sure and didn't want to push it too far.

author: edavid
author_rank: Super Contributor
timestamp: January 04, 2017, 04:34:22 pm
content: Quote from: GreggD on January 04, 2017, 04:25:56 pmDoes that mean these LEDs conduct in the reverse direction? Or is there also a blocking diode?

author: GreggD
author_rank: Regular Contributor
timestamp: January 04, 2017, 05:51:28 pm
content: No blocking diode. Short wavelength leds (blue) are very sensitive to esd. So this zener is across the led, zeners just above the leds normal voltage and clamps at about 0.6v when reverse voltage is applied.

author: dmacfarland
author_rank: Contributor
timestamp: January 04, 2017, 05:57:58 pm
content: Quote from: GreggD on January 04, 2017, 05:51:28 pmI was measuring 0.75v, but I was being very ginger with it. In any case, that's pretty much exactly what it looked it
Quick self-introduction of Rohde_TestWalker to EEVblog community - Page 1
Forum section: electronics / projects

author: Rohde_TestWalker
author_rank: Newbie
timestamp: October 09, 2018, 08:23:36 pm
content: Hi everyone, Rohde_TestWalker here.You may already know my colleague Rich (Rich@RohdeScopesUSA) who's been a regular contributor on EEVblog on topics and questions related to test & measurement in general, with technical support for Rohde & Schwarz systems and software in particular.My goal as "Rohde_TestWalker" is to continue Rich's legacy and help guide you as much as I can on any T&M topic and answer any questions as they come up. If I can't answer them myself, I'll work with Rich and others on the R&S team to find the answers you need.So, with that said, I look forward to working with you and to answering any pesky questions that inevitably pop up, from probing and basic measurement techniques through to the latest in power integrity, power distribution networks, protocol test, wireless (and 5G, of course) as well as EMI/EMC (of course). Any questions? Just holler!Thanks! - Rohde_TestWalker

author: 2N3055
author_rank: Super Contributor
timestamp: October 09, 2018, 08:25:09 pm
content: Welcome!!

author: Rich@RohdeScopesUSA
author_rank: Frequent Contributor
timestamp: October 11, 2018, 05:36:07 pm
content: Super excited to have some additional help on the forum now! As many of you know I've been doing this on the side because I enjoy this forum. Now we (R&S) have someone more dedicated to spending time on the forums and helping out (and beyond just scopes!). Like me, they are based here in the US, so we may not be able to help on everything worldwide, but we'll give it our best shot.Welcome Rohde_TestWalker - very excited to have you onboard!-Rich

author: nctnico
author_rank: Super Contributor
timestamp: October 11, 2018, 06:06:49 pm
content: May we get a name? Or is there a team of people behind this?

author: maginnovision
author_rank: Super Contributor
timestamp: October 12, 2018, 02:53:04 am
content: Nice to see another R&S rep here. I have a question... Do you have or can you get the service manual and/or user manual for NGPV 40/3 supply?
Quick signal generator with ADF5355, PIC32 suitable? - Page 1
Forum section: electronics / projects

author: pratiken
author_rank: Contributor
timestamp: November 24, 2015, 01:07:10 am
content: Hi guysWould a PIC32 be suitable for simple SPI control of an ADF5355 signal synthesizer? From what I gather, the ADF5355 requires 32 bits programmed via SPI. The PIC32 should have no problem handling that, right?ADF5355http://www.analog.com/en/products/rf-microwave/pll-synth/adf5355.htmlPIC32http://www.microchip.com/wwwproducts/Devices.aspx?product=PIC32MX795F512HThanksPratiken

author: Paul Price
author_rank: Super Contributor
timestamp: November 24, 2015, 02:00:12 am
content: Almost any MCU could be used to do this, even any 8-bit without SPI with a little code, maybe easier if the MCU has SPI, the PIC32 is fine, overkill. The most important consideration is to match MCU Vdd operating voltage with this synth chip.

author: KE5FX
author_rank: Super Contributor
timestamp: November 24, 2015, 02:36:55 am
content: QuoteI don't mean to sound discouraging (quite the contrary!) but the fact that you're asking this question means that you've got at least two big learning curves ahead of you. The project is doable, but it isn't going to be "quick," as your subject line suggests.Budget for a least a few days spent reading data sheets and programming manuals.If you can find a similar project that someone else has already undertaken -- and you probably can, as these SPI-controlled synthesizer chips are all very similar underneath -- it could put you ahead of the game.

author: pratiken
author_rank: Contributor
timestamp: November 24, 2015, 02:48:05 am
content: Thanks for the confirmation guys!!Thankfully, I'm just following the RF engineer's directions. I've worked a lot with PIC32's in the past and when a request for controlling something with SPI first came to me, PIC32 was the first thing that came to mind. I'll definitely have to look into how the 5355 works. It seems pretty intricate, but very doable.Thanks again!

author: analogNewbie
author_rank: Regular Contributor
timestamp: November 24, 2015, 08:03:18 am
content: I would start with ADF4351.

author: VE2UM
author_rank: Contributor
timestamp: July 19, 2018, 02:55:20 am
content: I easily made it in assembly on an 8bit PIC16LF1847 and the code is compact enough to transert it on the 8-pin PIC12LF1840...I only have some tweaks to do (large frequency changes).

author: JS
author_rank: Frequent Contributor
timestamp: July 19, 2018, 05:03:06 am
content: Quote from: Paul Price on November 24, 2015, 02:00:12 amSeems to be compatible with 1.8V logic, so probably fine with anything from there up to 3.3VJS
Quick Simpson 422 bodge fixes - oscillating amplifier - Page 1
Forum section: electronics / projects

author: c4757p
author_rank: Super Contributor
timestamp: January 25, 2014, 05:16:09 pm
content: Anyone have a Simpson 420 or 422 function generator with an output amp that oscillates above a certain amplitude? I finally fixed mine...100pF capacitor added between the anode of D15 and the unpopulated trimmer capacitor. It does make the falling edge overshoot a bit worse; that could possibly be corrected by trimming the value or adding a bit of series resistance, but I don't really care.There's also a bodge that was added before I came to own this generator. 100pF in series with 51 ohms between the outer side of R120 and the outer side of R73 cuts some of the nasty ringing on the square waves.Just in case this is useful to anyone.By the way, it's no wonder this thing is crap. I think it has more bodges than non-bodges, and many look original...Edit: Bodge #1 removes the need for bodge #2.If anyone can find a schematic for the 422, that would be great. The 420 differs significantly (though the output amp is the same) and that is the only one I can find.. There are a few other problems I'd like to try to fix...
QuickCharge 3.0 (or similar) device side solution - Page 1
Forum section: electronics / projects

author: poorchava
author_rank: Super Contributor
timestamp: September 09, 2017, 11:45:04 am
content: Hey, so my company is working on a product, where we'd like to use USB-C for charging. The battery is rather large (2S3P 7600mAh Lithium-Ion pack) so we figured, we need something like QuickCharge technology to deliver more power to the device and to be able to use chargers that are already on the market.While there is a wide choice of charger-side solutions from usual suspects (PI, ON, LT, TI and such) there doesn't seem to be any for the device side. As far as I know, some parts of the protocol for HV charging are implemented inside mobile SoCs (eg. Snapdragon), but I found some vague references to chips like SMB1350, which apparently could work as a standalone solution. I also wasn;t able to find any complete specification for the communication protocol.The product is 100% commercial, but it's a specialist-oriented device with production volumes os single hundreds per year, so it seems that getting the technology directly from Qualcomm is not really an option.Has anyone here implemented some fast usb charging on the device side and could share some details as to how to approach the problem? Ideally we'd want a single- or two- chip solution for the device side, or some guidance on how to implement the necessary communication protocol inside a powerful microcontroller (eg. STM32F4 or F7).

author: stmdude
author_rank: Frequent Contributor
timestamp: September 09, 2017, 12:10:51 pm
content: You don't need QuickCharge. All that fancy "high-voltage" stuff is part of the USB-C PowerDelivery specs, which would allow you to negotiate for up to 100W of power.Since you're using ST parts, I'd start here:http://www.st.com/en/interfaces-and-transceivers/usb-type-c-and-power-delivery.html?querycriteria=productId=SC2071

author: krho
author_rank: Regular Contributor
timestamp: September 09, 2017, 04:45:34 pm
content: I'd also say that you should utilize usb-c and power delivery standard.
Altium QWAVE CM4 - Strange footprint / BOM - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: September 29, 2021, 07:06:44 pm
content: Hi,a lot of people using Altium and making a Compute Module 4 project, seem to be using this library from QWAVE:https://github.com/QWaveSystems/QWAVE_Raspberry-Pi-CM4-Altium-LibraryBut... because the CM4 has 2 connectors, I don't get how a single library component can:- have two footprints in the BOM (one for each of the connectors). I only see 1 in mine.- in the pick-and-place file have two separate coordinates (one for each connector) from a single footprint (which does have the pads for 2 connectors).Looking at all the PCBs made in that repository and other online projects there must be a way/solution to both of the above points. Can anybody explain how that works for that specific library?Thank you
QWIIC cables, 'same side' or 'reverse side' connectors? - Page 1
Forum section: electronics / projects

author: zapta
author_rank: Super Contributor
timestamp: December 15, 2023, 07:22:45 pm
content: I would like to order QWIIC (Sparkfun's I2C) cables from the link below. Do I need 'same side' or 'reverse side' ?https://www.aliexpress.us/item/3256804152933323.html

author: MLXXXp
author_rank: Frequent Contributor
timestamp: December 15, 2023, 09:38:38 pm
content: They should be "1-to-1", which appears to be what they call "reverse direction" in the diagram.
QX9920 LED driver circuit improving possibility - Page 1
Forum section: electronics / projects

author: Krotow
author_rank: Regular Contributor
timestamp: January 18, 2023, 12:11:23 pm
content: Friend gave me LED flashlight. As he said, it arrived dead so he don't need it. Thing look exactly likethis eBay lotwith 3 LEDs connected in series, supposedly Cree XM-L2. Have slider switch for dimmer control. Dissection revealed another variant of QX9920 LED driver circuit:Dimmer is based on AH49E Hall sensor and PIC with removed markings. I believe that it is PIC12C508A. Flashlight is "OFF" when Hall sensor output is 2V or less. And fully "ON" when Hall sensor output is 3.3V.LEDs are regulated with MOSFET (RU3020H) which is controlled by QX9920 LED driver. QX9920 CS resistor value is around 4.4 Ohm. LED inductor - 220 nH.Both Hall sensor, PIC and QX9920 are powered by 5V via 78L05 LDO.Two causes of failure:Obvious lack of quality control. Inside driver case was few long aluminium slivers, seems leftovers from CNC process. Slivers shorted QX9920 CS pin to ground and probably something else, destroying QX9920 and MOSFET during that.The second failure was rather hilarious. Look like someone in logistic chain by error supplied AMS L78L05L LDOs to assembly line. They also are low power 5V LDO in SOT-89 package, but with a catch - intended L78L05 have output on pin 1 and input on pin 3 where AMS L78L05L have them vice versa. So this driver board couldn't work in either wayInstalled LDO itself was fully functional.So I replaced LDO to ST L78L05ABU (it have correct pin order) and fried QX9920 and RU3020H. Played a little with RCSvalue for QX9920 and found that brightest possible light output is when Rcs value is between 4.4 and 4.5 Ohm. Which kinda match to resistors installed on R1 and R2 place.The problem - brightest light output is still pretty dim. Some 50-60% from possible light output. Checked LED assembly separately with different LED driver on 8.4V, LEDs are fine. Are it is possible to run them brighter by utilizing this same driver board? I guess that low light is caused by PWM in driver output. QX9920 datasheet claim about constant current mode support, however seems it is not working like that.
R2R self-contained DAC - Page 1
Forum section: electronics / projects

author: old gregg
author_rank: Regular Contributor
timestamp: August 28, 2014, 07:26:48 pm
content: Hi,i'm looking for a self contained R2R dac, something easy to manipulate with just the necessary pin connection. I don't want internal management with CS or DACLOAD and so on...just the stupid passive DIP8 or SIL8 R2R ladder.i've try to find it on serveral manufacters websites but I always end up with more complext chip that I don't want. I've managed to find a bourns references but not really easy to get.Do you have any references to give ? if a buffer is included nice, otherwise is not a big deal.thank you.

author: German_EE
author_rank: Super Contributor
timestamp: August 28, 2014, 07:29:51 pm
content: http://www.mouser.de/Passive-Components/Resistors/Resistor-Networks-Arrays/_/N-e89l?Keyword=R2R&FS=TrueEasy

author: Andreas
author_rank: Super Contributor
timestamp: August 28, 2014, 09:06:03 pm
content: Hello,you can use a AD7524 (grounding the CS and WR lines).With best regardsAndreas

author: casinada
author_rank: Frequent Contributor
timestamp: August 28, 2014, 09:26:52 pm
content: This video from Alan "w2aew" might be of interest to you

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 28, 2014, 09:42:14 pm
content: They still make the DAC1408?

author: w2aew
author_rank: Super Contributor
timestamp: August 29, 2014, 01:31:19 am
content: Quote from: casinada on August 28, 2014, 09:26:52 pmBourns still make R2R networks. I bought some from a few months ago. I used them on another XY oscilloscope graphics mini-project. It makes an appearance in this video:

author: Bored@Work
author_rank: Super Contributor
timestamp: August 29, 2014, 05:20:21 am
content: Quote from: Alex Eisenhut on August 28, 2014, 09:42:14 pmI knew the discussion would sooner or later come to these dinosaurs. I don't think they make the MC1408 any more, but you can still get the DAC0808 (direct replacement) and its dinosaur cousins like the DAC08, DAC0800, etc.

author: dannyf
author_rank: Super Contributor
timestamp: August 29, 2014, 01:44:31 pm
content: QuoteThere are ready-made r2r networks (not of high precision); and you can also make them yourself.There are also onboard DACs (in a mcu) or digital pots...The choices are endless.
Radial Capacitor Lead Bending Jig - Page 1
Forum section: electronics / projects

author: Evan.Cornell
author_rank: Regular Contributor
timestamp: July 30, 2022, 12:09:44 am
content: Does anyone have any tips on buying/designing radial capacitor lead bending jig? The intent is to mount radial caps laying down on a PCB.

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: July 30, 2022, 12:33:36 am
content: I have used a dull exacto knife many, many, many times.Use the back of the blade.Jeff

author: coppercone2
author_rank: Super Contributor
timestamp: July 30, 2022, 12:42:22 am
content: for a radial cap I would take a sheet of brass that is the correct thickness and file two small notches in it for the leads, press the capacitor into it and push down, if I really wanted a jig. The benefit of having the correct thickness is that you can adjust the curvature of the bend with careful filing so its not sharp, if you are inclined to do so with a diamond file.Some kind of really thin parallel pliers might be nice too for this if you really wanna be professional and not 'yank' on them during the bend. Like a very thin vise.Grind a flat on a pair of knipex parallel jaw pliers and then attach two thin gauge blocks on adjustable mounting holes so they close flush then file the correct geometry under a microscope (200$ solution). Might need an additional alignment cam because they have wobble, but if you really wanna bend a wire gripped tight....

author: tooki
author_rank: Super Contributor
timestamp: July 30, 2022, 02:16:58 pm
content: Quote from: Evan.Cornell on July 30, 2022, 12:09:44 amPiergiacomi, an Italian tool manufacturer, makes various lead forming tools:https://www.piergiacomi.com/en/catalogue/forming-pliers/For THT mounting, the 90° forming pliers might work.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: July 30, 2022, 04:15:59 pm
content: Lots of ways to do it, but the big rule is never stress the seal. Grab leads at cap and bend from there. Don't just use a support and lever against the rubber seal.
Radiant charger / desulfator for Pb battery ? - Page 1
Forum section: electronics / projects

author: smile
author_rank: Regular Contributor
timestamp: February 11, 2017, 09:36:17 pm
content: Radiant charger / desulfator for Pb battery ?There seems to be 3 versions. single. double. triple.I wonder if the pulses would help to revive UPS batteries, this circuit seems better than some desulfators.But so many diodes hmmm..... the dual version has 2 pots, I wonder how they should be adjusted. wouldn't one interfere with the other.I don't have a scope and would not want to build something for nothing, also the specified inductor is in Ohms? What about proper units, how many would that be? I could not find converter.I also wonder if they are similar to "teslachargers.com/products/battery-chargers-rejuvenators"There are not schematics, images etc. of what is inside. Typical for snake oil products. Did they even been able to sell them. All I read are probably fake testimonials.sources:http://www.thetruthdenied.com/news/2014/03/12/radiant-a-suppressed-fast-battery-charger/https://www.rcgroups.com/forums/showthread.php?1108392-Radiant-charger-HV-spike-charging-for-NiCd-NiMh-Lead-Acid/page5