hybridfree/eevblog-posts huggingface dataset:
Video buffer IC quesiton... - Page 1
Forum section: electronics / beginners

author: donsql
author_rank: Newbie
timestamp: March 24, 2021, 08:57:58 pm
content: So I need some advice. I am trying to put together a circuit to split a video signal between two 80s CRTs.I found an IC that should do the job, but all the example circuits use a 75 ohm resistor because most applications where for standard TV sets and devices using VGA which specify an impedance of 75 ohms.The CRTs I am trying to use are not television sets and specify an input impedance of 1k-5k depending on model of the CRT.I am only sending the signal probably 6 to 20 feet and have several sets of CRTs so one of my issues would prefer to just make a circuit that is exactly the same if possible.Should I just leave them at 75 ohms?Use an exact matching resistor to that monitors specifications (could get complex with all the different monitor models)?Something say in the middle (ex 2.7k) might work?

author: Manul
author_rank: Super Contributor
timestamp: March 24, 2021, 10:24:51 pm
content: Not sure if I understand question correctly, but idealy the cable should have source and destination termination both matching cable's impedance, usually 75 ohms for video lines.Generally, if you have mismatched destination termination (you said your CRT is 1-5K), but you have proper source termination it will still be ok, reflections will be absorbed by source almost 100% and will not be seen by destination (just one reflection happens). Except that voltage levels at destination will be double. If you have both ends terminated, then reflections does not happen at all (idealy), so this is preferred. Also voltage levels will be what they should be (because usually the driver is made for destination termination to be present). If you have both ends badly terminated, then all kinds of funny business can happen with your signal.So source should be 75, cable 75 and you probably need 75 on the CRT inputs (load termination).

author: Benta
author_rank: Super Contributor
timestamp: March 24, 2021, 10:47:33 pm
content: You should terminate with 75 ohms at the CRT end. Otherwise your picture quality will suffer, especially at 20 feet cable.Either make an adapter for the CRT end or solder in the resistors directly.

author: donsql
author_rank: Newbie
timestamp: March 24, 2021, 11:03:53 pm
content: So here is the specs for the signal needed.INPUT SIGNALS• Video: RGB analog, 1 v to 5v peak-to-peak (adjustable with contrast control), 4. 7k ohm input impedance, 40 usec to 50 usec active video.I am basically taking a 1980s arcade game PCB and instead of having it just drive one monitor I need it to drive two monitors. If i just split the signal the monitors go dim so they need to be buffered.More info I found researching:Quote
Video: complete eagle board layout start to finish.  - Page 1
Forum section: electronics / beginners

author: vini_i
author_rank: Regular Contributor
timestamp: August 17, 2015, 06:47:37 pm
content: I captured and narrated a video of a complete board design from start to finish using Eagle. The video is not an outright tutorial but it hits every major step that i can think of. It a bit long and i apologize for that. Any comments or critiques would be appreciated.The video includes; Schematic capture, converting to a board, board layout, uploading to OSHpark and generating Gerber files.

author: lutkeveld
author_rank: Regular Contributor
timestamp: August 17, 2015, 07:20:35 pm
content: Nice, thanks for that! I was thinking about doing this with DipTrace. Easy to make, easy to watch and much more informative than short tutorials.

author: oodavid
author_rank: Contributor
timestamp: October 01, 2015, 10:09:35 am
content: Thanks @vini_i - am learning on Eagle and want to try out Altium next. nice video

author: Cliff Matthews
author_rank: Unknown
timestamp: October 01, 2015, 12:40:32 pm
content: Thank you very much, well done.Subscribed. You seem to leave no stone unturned.

author: JoeB83
author_rank: Regular Contributor
timestamp: October 01, 2015, 09:24:59 pm
content: Very nice! OSH Park is my favorite too.

author: Wilksey
author_rank: Super Contributor
timestamp: October 02, 2015, 12:09:53 am
content: Nice intro video into EagleAudio went out of sync towards the end of the video for me, but it was quite easy to follow regardless.I use Eagle every day, so I was more interested in quality of content rather than learning from it, and you have done a good job, not many videos go from start to finish (would be good as a follow up video to show the finished board if you ever had it fabbed).
Video Difference Amplifier (LT6552) power supply - Page 1
Forum section: electronics / beginners

author: ohhorob
author_rank: Newbie
timestamp: November 03, 2020, 03:48:02 am
content: Video application for taking a signal and sending it a significant distance (~50m) over twisted pair.This article provides what looks could be good circuits for transmit & receive –https://www.analog.com/en/technical-articles/twisted-pair-transmission-of-closed-circuit-video-made-easy.html#https://www.analog.com/media/en/technical-documentation/data-sheets/6552f.pdfIs it correct that this application needs to give the LT6552 a split rail (+/- up to 5V) to get this working? If so, what are some practical options to take a 12-ish volt DC battery and provide a +/- 5V for this amplifier?

author: bob91343
author_rank: Super Contributor
timestamp: November 03, 2020, 04:00:05 am
content: You can get +5V with a regulator. The -5V is another story. Or vice versa. It would be easier with a pair of 6V batteries.

author: rstofer
author_rank: Super Contributor
timestamp: November 03, 2020, 05:10:07 am
content: These Power Bricks will run off USB 5V or any other 5V source and provide +-5V at up to 200 mAhttps://store.digilentinc.com/powerbricks-breadboardable-dual-output-usb-power-supplies/The chip will only drive 70 mA so it seems like this brick might work fine. A 5V 2A wall wart for a power source should do it. I don't know why it couldn't be 1A...Murata makes an entire product line of dual output DC->DC converters. I have used the 12V input +-15V output module and it works well. Digikey carries them.
Video distribution amplifier - Page 1
Forum section: electronics / beginners

author: sergeymkl
author_rank: Newbie
timestamp: March 16, 2011, 12:13:55 am
content: Hi,can anyone propose me a simple way/circuit to amplify a CVBS video signal (i think normal 75R from RCA jack) so that i can split it to a disassembled chinese video TFT module (i think those must have termination resistors) and to a character insertor device i built with a PIC so that the signal will not become weaker when splitted and thus degraded.Thanks

author: scrat
author_rank: Frequent Contributor
timestamp: March 16, 2011, 12:58:16 am
content: Although I'm not an expert, what you need is one (or more) buffer(s) working up to some MHz. Among the opamps there are some specifically designed for video applications. I think the best way should be to use two opamps connected to the terminated input, each with its output resistance added.Take a look here, maybe you can find some typical circuits and can order samples, too.http://www.analog.com/en/amplifiers-and-comparators/video-ampsbuffersfilters/products/index.html#Video_Buffers
Video: Intro to Simple Electric Circuits (new version) - Page 1
Forum section: electronics / beginners

author: TimNJ
author_rank: Super Contributor
timestamp: March 15, 2014, 05:38:23 pm
content: So about a year ago I did a video called "An Introduction to Simple Electric Circuits". For a small content producer like me, it did pretty well, got about 10k views and good reviews...but I knew I could have produced a better video so I re-recorded it and added in a slide or two. It's a little shorter, and hopefully more informative.I'm sure there's very few people on this site who need to learn what ohm's law is, but I thought I'd just put it out there.Thanks!
Video: Introduction to decibels - Page 1
Forum section: electronics / beginners

author: apelly
author_rank: Unknown
timestamp: August 25, 2016, 08:06:16 pm
content: The most interesting Michael Ossmann, of Great Scott Gadgets and HackRF fame, and occasional Amp Hour guest, has a pretty cool decibel introduction video:http://greatscottgadgets.com/sdr/3I stumbled across it doing the HackRF/GUU Radio tutorials. I think you'll find it useful and interesting if you haven't quite got your head around the concept yet.

author: Cliff Matthews
author_rank: Unknown
timestamp: August 26, 2016, 12:39:27 pm
content: Perhaps belongs in sticky?https://www.eevblog.com/forum/beginners/electronics-primers-course-material-and-books/
Video logic signals in thesaurus - Page 1
Forum section: electronics / beginners

author: Tymo890
author_rank: Newbie
timestamp: July 09, 2023, 01:54:50 pm
content: Hi,I am not beginner, but must to ask for little help with video signals.I have few good chips for RGB port and RF port from Composite Video signals. Now I have to separate them. In docs like PDF datasheet few signals have different names but can mean the same signals. List of them below:VIDEO SIGNALS THESAURUSCOMPOSITE BLANKING=VERTICAL BLNK+HORIZONTAL BLNKCHROMINANCE BLANKING=FIELD BLANKINGFIELD BLANKING =CLAMP PULSEFIELD ODD/EVEN=COLOR SWITCHINGPHASE DETECTOR=A.C.C.PAL IDENTIFICATION =4.433.619 HzRAMP=min. 7,5 V+BURST COLOR GATESANDCASTLE =BURST KEY [COLOR RGB]+CHROMINANCE BLNKCHROMINANCE Subcarrier=FIELD BLANKINGCHROMINANCE Subcarrier=RF CHROMINANCE OSCALL TAGS list:CHROMINANCE BLANKINGCOMPOSITE BLANKING [Vertical Blanking+Horizontal Blanking]FIELD BLANKING [BLACK COLOR =330mV]FIELD ODD/EVENCOLOR SWITCHINGCLAMP PULSEBURST COLOR GATEBURST KEYRAMP min. 7.5 V+ [OP AMP interface]PAL COLOR IDENTIFICATION 4.43 MHzPHASE DETECTORA.C.C. Automatic Chrominance CorectorCHROMINANCE SubcarierCHROMINANCE OSC oscilatorSANDCASTLENot necessary to explain it:LUMINANCECHROMINANCER-YG-YB-YVERTICAL SYNCVERTICAL BLNKHORIZONTAL SYNCHORIZONTAL BLNKCOMPOSITE SYNCCOMPOSITE BLNKIf somebody can explain equivalent names as electronic thesaurus?Maybe good link will be possible.

author: m k
author_rank: Super Contributor
timestamp: July 15, 2023, 11:41:04 am
content: Sync is a pulse telling when the thing must start.Blanking is a period when beam is not visible.Luminance is Y, brightness.Chrominance is U+V, (B-Y)+(R-Y), color.RGB is a color space, so is YUV.https://en.wikipedia.org/wiki/YCbCrInterlaced picture has two fields, odd and even.http://martin.hinner.info/vga/pal.htmlCan't find chrominance blanking, S-video signaling is also hiding.Chip can use blanking for other means.For Y/C cabling it could be any part of composite blanking.Field blanking indicates separation of fields 1 and 2.Color field blanking then is closer to vertical blanking.Color switching can be anything.Subcarrier is present in colors of combined signal.Sandcastle pulse is internally used multilevel pulse.Usually for different timing things.

author: Terry Bites
author_rank: Super Contributor
timestamp: July 15, 2023, 04:22:40 pm
content: Chrominance blanking occurs between the end of H-sync and the end of H-blank, ie inside the backporch. The colour burst occurs inside Chrominance-Blanking. My guess is that this quiet period to ensure the integrity of the colour burst can do its thing. Isn't analog video dead yet?
video multiplexing - Page 1
Forum section: electronics / beginners

author: jeffro
author_rank: Newbie
timestamp: August 01, 2013, 07:37:46 am
content: I am having trouble sourcing any meaningfull information on video mux formats , outside of the standard google search, is there a resource for learning the formats and hardware required to build a mux unit ?or at least to observe the the transmission stream on a fiber or copper link etc. I understand that different methods are used ( FDM,TDM WDM )and differnt test equipment would have to be usedany help would be much appreciatedI

author: vismund624
author_rank: Newbie
timestamp: August 02, 2013, 01:11:20 am
content: What are you trying to do. Like a 3D film shoot or a home surveillance system ect...?

author: jeffro
author_rank: Newbie
timestamp: August 02, 2013, 02:19:35 am
content: HiA home CCTV as a project , to output to a Recorder , I guess I could buy 1 cheap enuff , it was more about the project,cheers
Video output question - Page 1
Forum section: electronics / beginners

author: Matster Chief
author_rank: Contributor
timestamp: October 06, 2015, 07:24:50 pm
content: Hey all, so I've decided to start a little (not so little actually) project and require some assistance. Despite my relatively young age, I've always been enthralled with vintage computers and gaming systems. I'm recreating the Nintendo Gameboy as a console rather than portable. I have the necessary schematics, but one of the area's I have yet to figure out is the video. The Gameboy has a native 160 x 144 pixel LCD display. I am wanting in the end for the console to have AV RCA out. This raises several flags in my mind.1.) If the resolution the system and games were designed for is 160 x 144, will I have to implement some sort of video scaling?2.) The LCD uses a driver IC, and my question is, do I even have to use it? I'm very new so I'm here to learn.Here is the LCD schematic:Here is the CPU schematic for reference:What I'd really like to know is what pins I need to connect my RCA video jack. HDMI is a possibility, but as the project is complex enough, I don't really want to add anything else to it. However, If it is the easiest option, I'm open.Anyway, thanks for the help =)

author: German_EE
author_rank: Super Contributor
timestamp: October 06, 2015, 08:01:08 pm
content: This could be a problem. The normal way of doing things is that the CPU of the device talks to an LCD controller chip (which also contains some memory) and then the LCD controller talks to the LCD panel. What we see in your diagram are the connections between the controller and the panel. An exception to this arrangement are the intelligent displays that use SPI or I2C to talk to the CPU directly.Your project will require replacing the LCD controller with a video controller chip, and rewriting the software so that it can be interfaced. This will be a considerable task and. probably, not one for a beginner.

author: Matster Chief
author_rank: Contributor
timestamp: October 06, 2015, 08:17:21 pm
content: That is quite unfortunate... Ah well. I shall place this project on the shelf for now, and shall return to it when my knowledge and experience allows me to do so. Thanks for the help =)

author: The Magic Rabbit
author_rank: Regular Contributor
timestamp: October 06, 2015, 09:31:46 pm
content: You can actually solve this easily, you don't mind a bit of a fudge. Create your design with a backlit LCD display, and mount it inside the case. There are many cheap CCD cameras that have short focal length of a few cm, and run from 12V, and have a standard composite video output. Set one inside your box pointed at the LCD, focus it, and just feed the camera output to the TV. Ignore the camera audio and just use the audio from your project.Unconventional, but highly effective.Sent from my XT1039 using Tapatalk
Video sender PA - Page 1
Forum section: electronics / beginners

author: @rt
author_rank: Super Contributor
timestamp: May 27, 2017, 01:06:09 am
content: Hi GuysI was hoping for some tips with regard to a simple VHF video sender PA part.There are schematics out there, but I'm starting with an already working universal modulator.The first I've tried is a 2N3904.It appears the RF from the modulator cannot switch the transistor.My scope backlight shat itself last night, so I can't even look at it.I only want to use a low power amplifier for a range of a few meters.CheersEdit, Changing the 2N3904 to 2N2222, this is the first time I’ve got a signal out of the antenna end.I still have to touch the antenna to it or be very close though. Far from a transmitter.
video signal testing - Page 1
Forum section: electronics / beginners

author: MMR
author_rank: Newbie
timestamp: August 04, 2014, 02:06:14 pm
content: Friends i had a doubt regarding the video signals, i am struggling with one of the issue and please help me to solve this. I had a signal like (i attached pictures with this post) from my instrument which produces video signal. I can see the status of instrument only via CRT. But CRT displays only hrizontal lines, so i cant able to judge the problem is with the video controller or with the CRT. If i can judge the problem with the oscilloscope signal. it would be useful to me. Please guide me weather these signals are good enough to judge or else guide me how to justify this video signal.CRT controller used in this instrument is 6845.
Video Signals HELP - Page 1
Forum section: electronics / beginners

author: Vitasset
author_rank: Newbie
timestamp: January 31, 2016, 09:58:12 pm
content: Hi everyone.I want to learn video signals basically ,how to create them,basic TV concepts,simple projects like Arduino vga. I have no prior knowledge.There are a lot of information on the internet but I don't know where to start.Do you know any good website that has tutorials and what are your other recommendations ? Thanks.

author: uncle_bob
author_rank: Unknown
timestamp: January 31, 2016, 10:23:10 pm
content: HiOk, let's start by seeing if we can divide the area down a bit:Back when video first came out, a "video signal" was an analog gizmo that often was used to modulate an RF carrier. The days of putting that sort of signal on the air are drawing to a close in the commercial end of things. If that is your area of interest, they divide down into several major groups (generally by country) and get a bit more complex when color (yes I'm from the US) gets added to the signal.Once things like PC's came along, the signals began to get less "one waveform does it all" and more oriented to signals for each color (there's that spelling again) plus possibly signals for sync. The stuff was still analog and shared a lot with the earlier signals. Your VGA (and many of its predecessors) fall into this category.The digital age ultimately caught up with video and the whole idea of analog signals pretty much went away. The "modern" approach is to send data over a serial bus. It may be a multi wire serial bus, but it's still moving data. It's no different than a RS-232 or USB signal in that it's all ones and zeros. HDMI is a good example of this. The interface to a flat panel display is a very different example.So why does this matter?Well, once it's "just data" your analysis is a bit different than when it's a bunch of analog this and that. Data protocols are a more general topic (that you dig into first) and video specific stuff is a sub-section of that. If your intent is to learn for the world of the future, skip to the page on digital and go from there.If the "old stuff" (as an old guy I can say that) has interest, by all means dig into it. Pick *one* of the sections and dive into that. Don't try to learn all of them at once. Get familiar with one system and then add to that.So, which way do you want to go?Bob

author: miguelvp
author_rank: Super Contributor
timestamp: January 31, 2016, 10:27:41 pm
content: Quote from: Vitasset on January 31, 2016, 09:58:12 pmI did this tutorial just last month.https://www.eevblog.com/forum/projects/no-bitbanging-necessary-or-how-to-drive-a-vga-monitor-on-a-psoc-5lp-programmabl/Edit: but analog is dead or dying, HDMI is where is at, but I think the old stuff helps visualize things as well.Edit: An example of VGA to HDMI and HDMI to VGA:http://www.analog.com/library/analogDialogue/archives/47-02/HDMI_VGA.html
Video: Sweep Generator Basics - Page 1
Forum section: electronics / beginners

author: w2aew
author_rank: Super Contributor
timestamp: May 20, 2012, 03:47:20 am
content: I put this video together for a friend, and thought I'd share it here. It discusses what a sweep generator is, and how it can be used to visualize the "shape" of a filter (or in this case, and IF transformer), which can help in visually seeing what is happening during alignment of a radio receiver. It starts off with a bit an intro to an IF transformer, and then moves into the sweep gen.Enjoy!

author: kaptain_zero
author_rank: Regular Contributor
timestamp: May 20, 2012, 04:44:38 am
content: Thanks for the videos, I must say you have a knack for explaining things in such a way that even an old guy like me can understand it..... well, I think I understand it?!?!?73 de Christian VE4SET

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 20, 2012, 10:04:46 am
content: as usual.... NUMBER ONE!

author: vk6zgo
author_rank: Super Contributor
timestamp: May 21, 2012, 05:06:33 am
content: Quote from: kaptain_zero on May 20, 2012, 04:44:38 amIn a world full of phoneys,w2aew,like Dave, is the real deal!He not only knows his stuff,but can communicate it in a straightforward manner!His videos are like standing in a friend's workshop,being shown a new trick.When he talks to you,it is as if you are on the same level,but hadn't run into the particular method before,--not a hint of a superior attitude!.73,VK6ZGO(secret handshake to you non-hams)

author: robrenz
author_rank: Super Contributor
timestamp: May 21, 2012, 10:55:07 am
content: Quote from: kaptain_zero on May 20, 2012, 04:44:38 amI second that ! Excellent!Regards, robrenz

author: w2aew
author_rank: Super Contributor
timestamp: May 21, 2012, 02:47:40 pm
content: Quote from: vk6zgo on May 21, 2012, 05:06:33 amThank you for the very kind words, OM!73 es GL de W2AEW
Video training - Advanced SMD soldering techniques - Page 1
Forum section: electronics / beginners

author: ablacon64
author_rank: Frequent Contributor
timestamp: November 26, 2011, 08:13:08 pm
content: Didn't know where to post this. Admins feel free to move to an appropriate forum.1 hour and 17 minutes of good information. One of the best demonstrations I've seen on the web.By author's choice, the video can not be incorporated, watch on youtube:Everything you wanted to know about soldering and desoldering but were afraid to askDo you use a technique that was not covered on the video? Have a different equipment? Created some tool or modification to make your life easier when soldering? Share with us. Comment, show your opinion.

author: phil_jp1
author_rank: Regular Contributor
timestamp: November 26, 2011, 09:39:49 pm
content: Nice tutorial! Thank you!When this video was filmed?

author: ablacon64
author_rank: Frequent Contributor
timestamp: November 26, 2011, 11:58:50 pm
content: I don't know, it's not mine but it seems rather old. But very up to date in my opinion.
Video: Trap for young players!  The "hidden" danger of trimmers / trimpots - Page 1
Forum section: electronics / beginners

author: w2aew
author_rank: Super Contributor
timestamp: November 06, 2019, 10:17:05 pm
content: In this video, I review the obvious, and not-so-obvious differences between potentiometers rated as "controls" vs. those known as trimmers or trimpots. There is at least one critical parameter that can wreak havoc...

author: nez
author_rank: Regular Contributor
timestamp: November 07, 2019, 08:37:37 am
content: Thanks for that video, I was unaware of the pitfall!

author: BravoV
author_rank: Super Contributor
timestamp: November 07, 2019, 08:49:08 am
content: Thanks Alan.Ahh .. topic of pots, one of my weird fetish ...Wonder whats the endurance/operating life of this "thingy".Size comparisons.More details ->HERE

author: Electro Detective
author_rank: Super Contributor
timestamp: November 07, 2019, 09:35:34 am
content: If space permits, a better deal at the same price, is to go the bigger, repetition friendly pot,carefully chop the top of the shaft if height is a drama,and or Dremel/hacksaw in a screwdriver buddy slot on the top as wellI am assuming the bigger pots with bigger/thicker track/s can take a lot more current than the whimpy plastic trimmers,less dust, crust ingress and physical distortion over time,and reduces the chances of mystery issuesand Lab RAGE!!!..
Video Tutorial, Analysis and Simulation of a Input Filter; Part 10, Input Filter - Page 1
Forum section: electronics / beginners

author: rbola35618
author_rank: Frequent Contributor
timestamp: March 16, 2015, 09:18:54 pm
content: In this video, I discuss why an input filter is needed in a power supply and discuss what common mode and differential mode inductor do and how to analyze, and simulate its performance in attenuating differential mode noise. Comments, questions, and request for SPICE files can be sent to rbola35618@aol.com?
Video Tutorial: Basics of an RF Comb Generator... - Page 1
Forum section: electronics / beginners

author: w2aew
author_rank: Super Contributor
timestamp: November 01, 2014, 04:36:11 am
content: ...what it is, how it works, and some basic applications and uses for it...

author: awallin
author_rank: Frequent Contributor
timestamp: November 01, 2014, 09:07:55 am
content: nice video. +1 and thumbs up!questions:1. in optical frequency combs (with which I am more familiar) there are two parameters, an offset-frequency, and the repetition rate. the comb teeth are at:f_out = f_offset + n * f_repAre you saying that the offset-frequency of an RF-comb-generator is always zero? i.e. the teeth are exactly at:f_out = n*f_rep ?2. If you put a narrow-band filter around the n:th harmonic of the output, you'll get more or less a sine-wave at n*f_rep.Is this n*f_rep sine-wave always phase-coherent with the input? i.e. there are no cycle-slips and there will always be n cycles of the harmonic for each cycle of the input waveform, and the relative phase will not drift?This has to do with my first question, since in optical frequency combs you need to use phase locked loops to stabilize both f_offset and f_rep in order to get phase-coherent output.AW

author: w2aew
author_rank: Super Contributor
timestamp: November 01, 2014, 03:26:47 pm
content: Quote from: awallin on November 01, 2014, 09:07:55 amFor a simple SRD based comb generator, yes. For more theory on the SRD based comb generator, check out the HP Frequency Counter Teardown and Repair video by TheSignalPathBlog.QuoteIt will be reasonably stable with respect to the input, but you have to remember that the phase noise gets multiplied up with the harmonic, so you'll probably need to clean it up.

author: German_EE
author_rank: Super Contributor
timestamp: November 01, 2014, 08:31:37 pm
content: From some research this afternoon step recovery diodes appear to be very rare and expensive devices, I therefore went looking for an alternative and I found the following:http://www.ke5fx.com/cg.htmThis RF Comb Generator uses reasonably easy to obtain components with a pulse width of about 1nS and output beyond 2,5GHz.
Video Tutorial, Flyback Part 12 (input filter), 13 (How a PWM works) - Page 1
Forum section: electronics / beginners

author: rbola35618
author_rank: Frequent Contributor
timestamp: January 05, 2016, 02:41:15 am
content: This tutorial shows how a common and differential mode input filter interact and work. In the second video, I discuss how an integrated PWM works. I use a simple model to explain the cycle by cycle process of what happens in an integrated PWM.Part 12 How a input practical input filter works. This video is 38:57 in lengthPart 13 How a Pulse Width Modulator (PWM) works. This video is 44:18 in length
Tutorial Video on Loop compensation and Simulation of a Flyback Part 1 - Page 1
Forum section: electronics / beginners

author: rbola35618
author_rank: Frequent Contributor
timestamp: December 01, 2012, 01:57:55 pm
content: Hi EEbloggers,Here is a tutorial video on how to model and set the feeback loop using a very simplified average model.I go step by step to show and demonstrate a method taught to me by my mentor Jack Alexander.I hope you find the video usefull.Robert
Video tutorials - about using an Oscilloscope  - Page 1
Forum section: electronics / beginners

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: September 13, 2010, 12:03:46 pm
content: Found this page , of an new brand of Oscilloscopes ,has lots of educational videos ..If you have free time , take a look.http://www.acta.com.gr/products/waveacevids.html

author: Unknown
author_rank: Unknown
timestamp: September 13, 2010, 03:09:28 pm
content: Lecroy is not actually that new, they have been a high-end scope vendor for a long time (they were founded in 1964, not sure if they made scopes back then). Their entry in entry-level scopes is somewhat recent (five years?). But thanks for the link, will check them out later.

author: Bored@Work
author_rank: Super Contributor
timestamp: September 13, 2010, 06:18:13 pm
content: Quote from: alm on September 13, 2010, 03:09:28 pmI think even later. Rumor is LeCroy's entry level oscilloscopes are rebadged Atten/Siglent. If this is true it is IMHO a severe laps of judgment from a company like LeCroy.

author: Unknown
author_rank: Unknown
timestamp: September 13, 2010, 10:00:36 pm
content: The new (even more) entry level scopes may be more recent, but I had the Waverunner 6000 series in mind, which was launched in2003, but admittedly is slightly above entry level (350MHz/$10k in 2003).

author: L-Charlotte
author_rank: Newbie
timestamp: September 16, 2010, 09:01:48 am
content: good share !!!

author: Mambo
author_rank: Contributor
timestamp: September 16, 2010, 09:44:11 am
content: Good work Kiriakos-GR. A guy asked for help recently, and you seemed to think his questions were not worthy of a answer. Refer -https://www.eevblog.com/forum/index.php?topic=1170.0I personally did not like that...but this is a very good thread...so thanks "good guy"I will confirm that LeCroy are not new. In fact they are the best Oscilloscopes on the market if you simply what "very very very fast rise time / pulse measurements". They are one of the top 4 Oscilloscope makers in the world.1. Tektronix2. Agilent3. LeCroy4. YokogawaThis is based on market acceptance, and does not consider entry level units such as Fluke Scopemeters & lesser brands like Rigol etc etc.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: September 16, 2010, 05:34:15 pm
content: Quote from: Mambo on September 16, 2010, 09:44:11 amYou should thanks the people who did those videos ...There is some things , that you can not learn in forums , there is no quick answers for them.And there is also times, that the text on the board by it self , it does not help , no matter how much it will be used .That's why I had reacted that way.One well made video , its an more effective way so to distribute knowledge over complex subjects .

author: PeterG
author_rank: Frequent Contributor
timestamp: September 17, 2010, 09:02:32 am
content: I tend to agree with Kiriakos-GR regarding the use of videos. There are some topics/people that no amount of talking/typing will relay the answer to there question. In such cases it is best to simply "Show" them the answer on video.
View how many times a link is clicked at? - Page 1
Forum section: electronics / beginners

author: electrolux
author_rank: Regular Contributor
timestamp: May 06, 2014, 09:04:07 am
content: When you add a link of you website to the bottom of every post is there any way to view how many people clicked on it.

author: keithu
author_rank: Contributor
timestamp: May 06, 2014, 09:24:01 am
content: Instead of adding a direct link to your website you could add a shortened one created athttp://goo.gl/That would give you a click count.

author: mariush
author_rank: Super Contributor
timestamp: May 06, 2014, 06:55:56 pm
content: You can use a service like Google Analytics, you add it in the footer of every page of your website and it will keep track which pages are accessed, what links people click to leave your website and so on.Alternatively, write a small php script that tracks the clicks in a database. For example, create a table with 3 columns : unique url id, click count, url ... optionally you can also add the logged in user id or the ip of the user.Add the url in the table and it will get a unique ID, for example 12345. Then, instead of writing the url in the post, simply say yourwebsite.com / yourscript.php?link=12345 or yourwebsite.com/redirect/12345 (a configuration setting in apache will change redirect/12345 to yourscript.php?link=12345, see mod_rewrite for example)When user clicks on link, script loads, retrieves the url from table, increments the count and then redirect user to that url.

author: tszaboo
author_rank: Super Contributor
timestamp: May 06, 2014, 07:59:41 pm
content: I have a wordpress site, and I can tell where the traffic came from or what search engine term lead to my site. This month two times someone searched for "rm-8?" before coming to my site.Google analytics also helps. You need to put code in the html file, or plugins can do this for you.
Viewing Generator Output With an Oscilloscope - Page 1
Forum section: electronics / beginners

author: tvl
author_rank: Newbie
timestamp: January 02, 2019, 03:40:18 am
content: Remove

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: January 02, 2019, 04:37:28 am
content: I have used low voltage (120Vac - 6.3Vac) power step down transformers as audio output transformers in small amplifiers. Testing them has taught me that they make pretty good wide BW transformers. They will respond from below 50 Hz to beyond 40 KHz and are pretty linear. As long as you do not saturate the core of the transformer then the output should show a pretty good rendition of the waveshape of the 120V source. And the isolation provided, alone, makes it worth trying.

author: David Hess
author_rank: Super Contributor
timestamp: January 02, 2019, 11:09:19 am
content: Quote from: tvl on January 02, 2019, 03:40:18 amThe sine wave is not very distorted but has residual high frequency noise from the inverter function. Monitoring it through a small power transformer will work fine.

author: soldar
author_rank: Super Contributor
timestamp: January 02, 2019, 03:37:20 pm
content: IMHO, if what you want to see is the actual waveshape then I would avoid a transformer because by introducing it you are introducing all sorts of unknowns. I think there is a much easier way.Your scope has one of the leads grounded to earth (or you can ground it). Right?You generator has one side of the output grounded (or you can ground it) . Right?So you already have a common reference. Now you have 120 V rms on the generator's live wire and you do not want to stick the scope probe in there directly. Well, you can use two resistors to make a voltage divider and bring it down to a lower voltage.My 'scope has a x10 (1:10) dividing probe.

author: Zero999
author_rank: Super Contributor
timestamp: January 02, 2019, 04:21:30 pm
content: Quote from: soldar on January 02, 2019, 03:37:20 pmOnly connect the x10 probe to the live wire. Don't connect the oscilloscope's chassis to the neutral or there's a risk a large current could flow through it, as the neutral voltage will be a bit higher than the earth voltage.

author: rstofer
author_rank: Super Contributor
timestamp: January 02, 2019, 04:30:06 pm
content: Don't overlook loading the generator. I would expect the waveform to change as a function of load. I could be wrong (probably am).If I were doing this, and I'm not, I would ask myself what I was going to do about it if the waveform is trash. I probably wouldn't be thinking in terms of fixing it with a power conditioner so why bother to scope it?

author: soldar
author_rank: Super Contributor
timestamp: January 02, 2019, 06:36:48 pm
content: Quote from: Zero999 on January 02, 2019, 04:21:30 pmEvery generator I have seen has either the output totally floating or one side grounded. And same thing with the scope probes so I can't see any problem.In any case, connecting only the probe of the scope without connecting the grnd reference is useless and will not give any useful info. The scope shows voltage differential between two points so you need to connect to two points.
Vintage DMM picking up phantom voltage (video) - Page 1
Forum section: electronics / beginners

author: vutt
author_rank: Contributor
timestamp: March 07, 2021, 04:20:00 pm
content: Trying to identify problem with old DMM. It keeps showing "phantom" voltage after disconnecting from power source. Goes slowly down, but it never goes below few hundred mV and it keeps jumping around.Short 30s demonstration:https://youtu.be/DnozavvCiIUHowever as you can see from clip if I just switch power supply off probes still connected voltage drops immediately as it should.Both DMM and PSU are properly grounded. I'm using 230v->110v transformer, but it's proper 3 prong one with ground pin connection.Any ideas where to start?

author: Gyro
author_rank: Super Contributor
timestamp: March 07, 2021, 05:26:53 pm
content: Bench DMMs like that have very high input resistance on their lower voltage ranges (up to 20V on the best ones) - something in the order of 10G, compared to 10Mon a handheld one.This is to provide very minimal circuit loading, but it does mean that the input floats when disconnected, governed by the input bias current of the meter. The input bias current is normally a few 10s of pA, which stops it settling to zero.Relax and enjoy.EDIT: The manual can be found here...https://www.opweb.de/english/company/Advantest_Corporation/R6551The input resistance is actually specified as greater than 100Mon the DC mV ranges, it drops to 10Mon the higher ranges.

author: Per Hansson
author_rank: Unknown
timestamp: March 07, 2021, 07:31:44 pm
content: Watch "EEVblog 1379 - What's all this NPLC Stuff Anyhow?" it is only released to Patreons so far but it should answer your questions when it gets released.Before then you can play with the "rate/line" key on the instrument and also make sure to set it to the correct line frequency of 50 or 60Hz.Basically the instrument works as intended, edit: attached excerpts from the manual linked above by Gyro.

author: vutt
author_rank: Contributor
timestamp: March 07, 2021, 08:51:28 pm
content: Thanks guys. It was my first vintage bench DMM purchase so I thought something is wrong.And I have that manual. So LF is set correctly. I just didn't connect the dots regarding input resistance ... ...well due to lack of knowledge.Also thanks Per for Patreon tip. I have been lurking around Dave's YT channel for years. This would be as good as any excuse to support his effort with slightly more than just words

author: Per Hansson
author_rank: Unknown
timestamp: March 08, 2021, 04:20:02 pm
content: Now the video has been released, I am sure it will answer your questions better than I could
Vintage Electronics Identification - Page 1
Forum section: electronics / beginners

author: sysgenss
author_rank: Newbie
timestamp: June 18, 2020, 12:11:28 pm
content: Which is the best Section to post a mystery electronic item in for identification?

author: ArthurDent
author_rank: Super Contributor
timestamp: June 18, 2020, 03:38:12 pm
content: Weird. It looks like there is a high voltage D.C. supply that charges a large gray capacitor through some series resistors covered with black tape. The charged capacitor goes to the parts on top. The larger part has plumbing connections for water or something else to flow through and there is a yellow button you can push apparently to start or stop the flow. Between the two parts on top there appears to be a lucite piece that may be where you can attach a piece of the small wire from the spool of fine wire in the holder on one side. NOTE: this could be very dangerous if it does produce a high voltage.Maybe if the water is pure there is no current flow in the white chamber but if there are impurities in the water it starts getting conductive and if it can pass enough current it can burn open the fine wire used as a fuse. Or maybe it's a homemade sodastream device.

author: sysgenss
author_rank: Newbie
timestamp: June 18, 2020, 04:02:55 pm
content: Thanks for your input, it is much appreciated.
Vintage Heathkit AD-1013 Audio Oscilloscope, test points way off - Page 1
Forum section: electronics / beginners

author: cincin
author_rank: Regular Contributor
timestamp: March 11, 2023, 06:17:09 am
content: I'm troubleshooting an old Heathkit AD-1013 Audio Oscilloscope that's behaving oddly. It's a pretty simple circuit and I have the Assembly Manual, which is very thorough, still I'm such a beginner I can't quite figure out what's happening...In the attached schematics for the Vertical Amplifier part of the scope, test point 3 (TP3) at the collector of Q107 should be at +130V.It's connected to the +200V rail (actually +193V) through R115 (15K) which is known good.TP3 reads +193V, how can that be?thanks!

author: WattsThat
author_rank: Frequent Contributor
timestamp: March 11, 2023, 06:28:46 am
content: No current in Q107? It was common for those output transistors to fail open and the beam to be hard off center.Visually check everything first. Soldering especially so. Then the resistors, the old carbon comps rise in value with age.
Vintage HP 456A current probe/clamp battery problems - Page 1
Forum section: electronics / beginners

author: Maviday
author_rank: Newbie
timestamp: January 21, 2018, 02:03:45 am
content: Hey guys. I inherited this wonderful little HP 456A current clamp a while back and I have been trying to find batteries for it with no avail. I have looked at the manual which states that it requires TWO TR 233, and ONE TR 234 Mallory mercury (stable discharge voltage) batteries. the problem is I don't know anything else about these batteries. I have found that the TR233's are supposedly 4-4.2 Volts, and the TR234 is supposedly 5.33 Volts. Now my plan is to use two or three 18650 or 26650 batteries in series and two separate voltage regulator to supply individual voltages, however I still don't know which of these battery holders takes what. In other words I don't want to assume that the larger battery holder takes two batteries in series and the smaller takes the single battery. Since I have no actual information on the battery sizes it is impossible for me to know for sure. My guess is that the smaller holder takes the single TR234 and the larger takes the two TR233's in series...? Does anybody here have any ideas or advice?I've attached pictures for reference. I decided to post here as this old conversation is one of the older ones regarding vintage gear per this forum.Thanks

author: stevebyan
author_rank: Contributor
timestamp: January 30, 2018, 07:34:57 am
content: QuoteIf you look at the schematic, the -8 volt rail is the pink wire, the 0 volt common is the violet-white wire, and the +5 volt rail is the red wire. It also shows the -8 volt rail is the one with two batteries.So, your supposition is correct. The larger battery holder is for two TR233's.

author: Ferisoda
author_rank: Newbie
timestamp: January 30, 2018, 08:00:16 am
content: If I take this information to publish, can I share my knowledge?

author: Maviday
author_rank: Newbie
timestamp: May 03, 2018, 03:59:31 pm
content: Thank you, I hadn't noticed.

author: Maviday
author_rank: Newbie
timestamp: May 03, 2018, 04:00:24 pm
content: Quote from: Ferisoda on January 30, 2018, 08:00:16 amOkay with me...
Vintage Kenwood Amp Mains Wiring - Page 1
Forum section: electronics / beginners

author: reddish75
author_rank: Regular Contributor
timestamp: January 16, 2023, 12:21:34 pm
content: I'm repairing a Kenwood Model 500 amplifier finally after buying it 5 years ago, part of that sale was to take the aftermarket 'audiophile mains cable off' for the seller, however now I've come to put a new one in I'm not sure its wired correctly?Neutral is fused not live, not sure this is the way it was from factory? Should this be changed? Please see rough drawn diagram of how it was and the factory schematic, I'm assuming its the UMX type as its the only one with a 4 amp fuse. I'm in the UK so 230v.

author: themadhippy
author_rank: Super Contributor
timestamp: January 16, 2023, 12:28:38 pm
content: If your in the uk then yes the fuse should be in the live,was the cable a kimber/russ andrews by any chance?as he often spout shite about how reversing live and neutral can improve the sound,but always runs away asked for proof or questioned about the safety of such advice

author: reddish75
author_rank: Regular Contributor
timestamp: January 16, 2023, 01:31:59 pm
content: Kimber cable does ring a bell, it was unnecessarily thick and poorly soldered.So going off what I can see using the schematic and where the wires were connected pic one shows how it was connected, so live was being switched and neutral was fused. Again could be original as this will have had a two pin power cable from factory.So to make this safe? I would move the fuse to live before it goes to the power switch and connect all the wires on the neutral side so both white wires. going to the transformers and wires going to the voltage select switch together. See pic two.

author: themadhippy
author_rank: Super Contributor
timestamp: January 16, 2023, 02:26:40 pm
content: Whilst putting the switch (unless its double pole ) and fuse on the live is how things are meant to be done in the uk you've then introduced the problem of the wiring colours as the blue will be live and white neutral,bit of a minefield realy.
Vintage power supply suitability - Page 1
Forum section: electronics / beginners

author: Bzonic
author_rank: Contributor
timestamp: August 04, 2016, 12:47:23 pm
content: I picked up a HP 6921a 40v variable DC power supply off Craig’s for pennies and I’m wondering a few things about it. It appears to be from the late 60's and it seems to operate 100% properly but how would one validate that? Would it be a measure of the output ripple? Are those big electrolytic caps likely to be ok? I always hear about ESR measurements being conducted on smaller caps from vintage gear so I wonder if it relates to the big caps too.ThanksBrian

author: lapm
author_rank: Frequent Contributor
timestamp: August 04, 2016, 02:33:37 pm
content: Multimeter should give you some idea if regulation is working. I would change old electrolytic capasitors just to be safe side..

author: Paul Price
author_rank: Super Contributor
timestamp: August 04, 2016, 02:33:55 pm
content: Test with a load at max. output voltage and rated current and measure the ripple and noise with a scope or even a DVM.If it meets the output current and ripple/noise specs then you've answered your question.You can make a suitable load from low-voltage incandescent bulbs if you don't have the desired high-wattage resistors laying around.Contrary to some advice given above, if it works well with the test, it would be a fool's task to fix something that works well.Don't waste your time and money changing any capacitors when any equipment tested is working properly.

author: Bzonic
author_rank: Contributor
timestamp: August 04, 2016, 02:45:08 pm
content: Thanks Paul - that is definitely the direction I'd like to take. I will do some testing for peace of mind.

author: David Hess
author_rank: Super Contributor
timestamp: August 04, 2016, 02:46:53 pm
content: Quote from: Bzonic on August 04, 2016, 12:47:23 pmMeasure the ripple on the regulated output at maximum current and maximum output voltage; if the bulk input capacitors are worn out, then ripple will be present. You can also make this measurement across the bulk input capacitors directly with a maximum current load to make sure the minimum input voltage will not cause the regulator to drop out.The output capacitors should be checked for capacitance and ESR because they are part of the regulator's frequency compensation.

author: nfmax
author_rank: Super Contributor
timestamp: August 04, 2016, 03:10:50 pm
content: Download a copy of the operator's manual fromhttp://literature.cdn.keysight.com/litweb/pdf/06291-90001.pdf?id=735104, and run the 'performance tests' from section 5 (you will need to substitute modern equivalents for the recommended test equipment). If everything passes, and an internal visual inspection shows nothing amiss, run an extended soak test for maybe 24 hours on 80% load, and if it's still OK, use it!

author: Bzonic
author_rank: Contributor
timestamp: August 04, 2016, 05:18:02 pm
content: Thanks everybody! Appreciate the basic checks suggested.