hybridfree/eevblog-posts huggingface dataset:
osc optical probes - Page 1
Forum section: electronics / projects

author: Deathwish
author_rank: Unknown
timestamp: November 15, 2015, 11:54:32 pm
content: I was sat here thinking about whether anyone has ever designed or produced an optically connected probe for an oscilloscope before, possibly a pen type device with a memory built in that then transmits the memory to the main scope when say half full or such.I have some daft ideas at times but you never know.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 15, 2015, 11:58:40 pm
content: I don't know what you mean exactly, buthttp://w140.com/tekwiki/wiki/7J20

author: helius
author_rank: Super Contributor
timestamp: November 16, 2015, 12:04:15 am
content: the duplication of the DAC and memory in each probe would make them bulky and expensive

author: Deathwish
author_rank: Unknown
timestamp: November 16, 2015, 12:07:27 am
content: Quote from: blueskull on November 16, 2015, 12:00:08 amThat will do me, Sorry guys, been awake 2 days now so the brain is fried. Yep or completely free and mobile and data transmitted via bt or some such which would of course mean a lag and so not really RT .
Oscillation burst when coming out of clipping - Page 1
Forum section: electronics / projects

author: merlinb
author_rank: Contributor
timestamp: June 28, 2021, 09:15:17 am
content: I'm building a classic discrete transistor amp but using SMD transistors I happen to have. I've swapped the original through-hole transistors for the following, the rest of the circuit is unchanged:BC214 changed to BC860CBC184 changed to BC850CBC461 changed to FZT949BC441 changed to FZT869However, with a 600 ohm load, the SMD version produces oscillations when coming out of clipping, whereas the original through-hole version did not.Oscillation when exiting clipping is something I've seen a few times in other amplifiers, but never before bothered to look into. What's the actual mechanism? I tried 100R base stoppers on the output transistors, but no dice.Schem:https://www.schematicsforfree.com/archive/file/Audio/Products/Professional%20Audio/N-O/Neve/Neve%20ba338.jpgTop trace is a 1kHz sine showing oscillation around 300kHz. Bottom trace is distortion residual.

author: jonpaul
author_rank: Super Contributor
timestamp: June 28, 2021, 09:24:30 am
content: Add damping RC at output eg 50 Ohm + 1000 pFj

author: Whales
author_rank: Super Contributor
timestamp: June 28, 2021, 09:47:43 am
content: What is the step response of the amplifier normally? Try putting a square wave into it (and run it well below clipping), see if the same oscillations are present.If they are present:you're seeing the overshoot (underdamping) of your amplifier. It can be partially combated by putting a capacitor (1nF?) across the collector & base pins of TR2 (this reduces the whole amplifier's gain at higher frequencies, hiding the problem).If the ringing oscillations are not present:not sure. Perhaps TR2 is getting driven into saturation and this leads to interesting effects when it recovers?EDIT: make sure the edges of your input square wave are very sharp, eg similar speed of edge rise/fall that you get in the unwanted oscillations themselves. My cheap siggen doesn't provide very sharp edges, so it would probably not lead to as much ringing/oscillation at the amplifier output.

author: merlinb
author_rank: Contributor
timestamp: June 28, 2021, 10:08:53 am
content: Quote from: Whales on June 28, 2021, 09:47:43 amSpot on! Yes there was overshoot, and changing C3 to 470pF has trimmed that down pretty much to critical damping. Bandwith still good enough for government work, thanks!

author: merlinb
author_rank: Contributor
timestamp: June 28, 2021, 10:32:17 am
content: I'm still curious about what is causing the difference between using SMD v. through hole. The transistors appear to have basically the same transition frequency in either case?

author: Whales
author_rank: Super Contributor
timestamp: June 28, 2021, 01:16:01 pm
content: Glad that workedI'm no expert here, but I presume that the transition frequency of two different transistors can be the same even if they have completely different gains and input capacitances? That would lead to different gain & phase performance of the entire amplifier circuit, which would in turn result in different amounts of overshoot behaviour.
oscillation frequency of filter - Page 1
Forum section: electronics / projects

author: ftransform
author_rank: Frequent Contributor
timestamp: May 23, 2013, 08:09:07 pm
content: So I have a active low pass filter built infront of me, which I tested, and it seems to workHowever a filter calculator claims that this filter oscillates. What does this mean?I was unable to detect any oscillation with an oscilloscope on the output of the filter....the filter claims the oscillation happens at a low frequency, which I measure with the FFT feature on my oscope, and I can't see any peaks there ..,....

author: kg4arn
author_rank: Unknown
timestamp: May 23, 2013, 08:37:47 pm
content: What's the response to a square wave input with a fast edge look like?If it's unstable, it should ring in response.

author: ftransform
author_rank: Frequent Contributor
timestamp: May 23, 2013, 08:44:57 pm
content: Quote from: kg4arn on May 23, 2013, 08:37:47 pmthis is a filter thats filtering a DC signal, meant to clean it up for the ADC.Does this oscillation happen at a really low amplitude or something?

author: kg4arn
author_rank: Unknown
timestamp: May 23, 2013, 09:35:06 pm
content: I don't know what a filter calculator is? So maybe I am mis-understanding you.In general, it is my understanding (and limited experience) that the active filter should be stable if there is little ringing in response to an edge input. It may overshoot some, but stabilize in a few cycles.In the frequency domain, a frequency response sweep should show no significant peaking as you approach the cutoff frequency.I'm guessing you have an op amp circuit and if you post the schematic the op amp experts might comment.It does not sound to me like the circuit is oscillating, since the oscillations should build up in amplitude until they are limited by the active device current/voltage limits and I would think that you should see that on the scope.I am not an active filter expert, so I will watch for others to comment.
Oscillation of transformer primary voltage immediately before pulse in CCPS - Page 1
Forum section: electronics / projects

author: state_of_flux
author_rank: Contributor
timestamp: August 15, 2023, 12:20:04 pm
content: Hello all,I am designing a CCPS and using a phase-shifted, series-resonant bridge as the switching topology. There is a DC block capacitor in series with the transformer primary winding.After fleshing out a full simulation, I decided to validate the transformer design in the simulator. I found that, moments before the initiation of a new pulse, the transformer voltage begins to oscillate at a very low frequency of approximately 15kHz. This has happened in both my SPICE simulator and PLECS simulation software. This causes the transformer to saturate immediately, and the waveforms from here onwards get progressively worse.This does not entirely make sense to me as the PWMA-PWMD are clearly not switching. However, both SPICE and PLECS are showing this oscillation, so I must be missing something.Has anyone seen any thing similar to this and have a suggestion as to what may be causing it/potential fix or whether it is a simulation artifact?Best,SoF
Oscillations at IOs - Page 1
Forum section: electronics / projects

author: rakeshm55
author_rank: Regular Contributor
timestamp: May 21, 2014, 04:44:06 am
content: Hi,I have a scheme as shown in image.FPGA----Bi dir buffer-----bead------ external short----- bead ---- Bi dir buffer ---FPGA1. the curved line shows short external to my board ie the external connector pins are shorted.In the FPGA there is a control bit. when it is set to '1' data is transferred from A to B.....When set to '0' data is transmitted from B to A.My observation is lets say when i set control bit as one ''0'' and ""A"" driven with '1'' I observe 41.2Mhz oscillation at ""B"". When I probe on (B side) Bi directional chip input I see a high signal over which there is a oscillation of 41.2Mhz.......The oscillations persist for a long time and after a while it ceases say 15sec etc. then there wont be any.....I tried removing one bead with 0 ohms resistor.....here the oscillations ceased.... what could be the reason.What solution i would have if i do not want remove the bead??? say external component to prevent oscillation

author: rakeshm55
author_rank: Regular Contributor
timestamp: May 21, 2014, 10:28:08 am
content: Hi,I connected a 10nF capacitor to ground at the shorting point of the beads..... Still the oscillation persists.....I will try with a 22Ohms series resistance to check whether that would dampen the so called oscillation....

author: moffy
author_rank: Super Contributor
timestamp: May 22, 2014, 01:10:47 am
content: How long is the wire link? Sounds like LC oscillation with the wire and the beads. Try terminating each end of the circuit connected to the lead to ground with a load resistor.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 22, 2014, 03:12:50 am
content: Those gates are positive feedback. You made an oscillator of some sort (obviously). Lesson, don't put ferrite beads on that kind of driver?If you need signals to the outside world, it's probably better to stick with a well-proven chip, not some new, poorly specified buggy piece of junk. Hard to beat HC245s or whatever.Tim
oscillator Design - Page 1
Forum section: electronics / projects

author: yalect
author_rank: Regular Contributor
timestamp: December 03, 2020, 10:58:43 am
content: Hi,I would like to ask you that I want to build an oscillator withop-ampI am thinking to useLM358as it's showen on the attached picture but I want to ask what's the relation betweenR1andR2(on the circuit) to work the oscillator fine and must (R1>R2) or vice versa?.- what about the output form, is fine square or I can modify it?.thank you

author: Refrigerator
author_rank: Super Contributor
timestamp: December 03, 2020, 01:07:30 pm
content: First i would advise you to simulate this circuit on LTspice, this way you can play around with the resistor values and see all the voltages.

author: Zero999
author_rank: Super Contributor
timestamp: December 03, 2020, 05:48:27 pm
content: Another resistor is required between the non-inverting input and +V. The value of R1 is far too low. Look up Schmitt trigger, before going any further.

author: yalect
author_rank: Regular Contributor
timestamp: December 03, 2020, 10:46:18 pm
content: thank you for all.- why a resistor is required between the non-inverting input and +V, this will stabilize the tension of V+ in cerain range and so the current, more explain, please.- what about the output form?"is fine square or I can modify it?".

author: Zero999
author_rank: Super Contributor
timestamp: December 04, 2020, 10:53:18 pm
content: When the comparator's output is 0V, R4 is connected in parallel with R2 and when the output is 5V, R4 is in parallel with R1, giving the different voltage thresholds. Look up Schmitt trigger and potential divider.Attached are some schematics, annotated with voltages when power is first applied (top), after the capacitor has charged and after the capacitor has discharged. The plot shows the voltages on the output, inverting and non-inverting inputs. I've also attached the LTSpice file, so you can simulate it yourself.Note that the simulation uses an op-amp/comparator, with a rail-to-rail output, to simplify the calculations. If the LM358 is used, it's a bit more difficult, since the output will saturate at around 1.5V under the supply voltage.
Oscillator for AD9851 - 5V - Page 1
Forum section: electronics / projects

author: minion
author_rank: Contributor
timestamp: July 08, 2017, 11:57:12 pm
content: Hey,I am looking for an oscillator for AD9851. The problem is, that most of the oscillators nowadays are for 3.3V and AD9851 is 5V device.Preferably it should be 180MHz or 200MHz, so I don't have to use 6x built-in PLL. If that is not possible 30MHz or 33.333MHz will suffice.It should also be SMD and relatively precise (hopefully at least 25ppm).I have access to Farnell and I was not able to find something like that. What would be your recommendation?thank you

author: Zero999
author_rank: Super Contributor
timestamp: July 09, 2017, 08:14:52 am
content: Yes, all you need is a logic level shifter. If it's just one channel and inverting isn't a problem, the 74LVC1G14 will probably do.

author: minion
author_rank: Contributor
timestamp: July 09, 2017, 08:25:36 am
content: I just assumed, maybe wrongly so, that logic shifter will introduce too much jitter? So it should be ok?thank you, guys

author: minion
author_rank: Contributor
timestamp: July 09, 2017, 08:49:12 am
content: Aha, make sense, tnx
Oscillator load capacitance - Page 1
Forum section: electronics / projects

author: shadewind
author_rank: Frequent Contributor
timestamp: October 28, 2011, 11:26:42 pm
content: I know that standalone crystals need a specific load capacitance but is this also true for oscialltor chips like this one:http://se.farnell.com/txc/7c-50-000mbb-t/osc-50-000mhz-3-3v-smd-5-0x3-2/dp/1842050It has a specified load capacitance but I'm assuming this is just the maximum load that it can drive since the load is usually capacitive in nature (input FET gates). The crystal oscillator circuit must surely be buffered to minimize the effect of the load to a negligible level?

author: Balaur
author_rank: Unknown
timestamp: October 29, 2011, 12:48:39 am
content: That particular device has all the required stuff inside to generate a clock signal.The datasheet says that the maximum output load depends on the supply voltage. Ex: 5V VDD allows you to drive a load up to 50pF.As an example, a Virtex 6 FPGA has a typical input pin capacitance of 8pF, a PIC 16F676 has 5pF and so on.Cheers,Dan

author: Unknown
author_rank: Unknown
timestamp: October 29, 2011, 12:23:25 pm
content: What's the second (first) number for output load in the datasheet, eg. 15 pF for 5V?

author: Balaur
author_rank: Unknown
timestamp: October 29, 2011, 02:30:46 pm
content: Quote from: alm on October 29, 2011, 12:23:25 pmMy understanding is that the chip can drive up to 15pF @ 1.8V, up to 30pF @ 2.5V, 2.8V, 3.3V and up to 50pF @ 5V while maintaining the specified rise and fall times. What are the other numbers for, I don't know. Examples, maybe?

author: sub
author_rank: Regular Contributor
timestamp: October 30, 2011, 01:30:01 pm
content: It might be for when it is oscillating on the third overtone as given in the row below, perhaps.
Oscillator Type - Page 1
Forum section: electronics / projects

author: electosleepy
author_rank: Contributor
timestamp: May 29, 2016, 06:03:27 am
content: Hi,I would like to know is the any difference between an oscillator type? Is the difference negligible? I'm currently would like to swap a MEMS (silicon) 200MHz, 50ppm oscillator with an X0(standard) type that is also 200MHz, 50ppm.http://www.digikey.com.au/product-search/en/crystals-and-oscillators/oscillators/852334

author: lincoln
author_rank: Regular Contributor
timestamp: June 04, 2016, 06:57:05 am
content: What are you driving? We have used MEMS osc to drive gigEthernet and sgmii phys with good results. The MEMS are tiny...

author: tggzzz
author_rank: Super Contributor
timestamp: June 04, 2016, 07:10:11 am
content: The answer is application dependent, so what does the application require.The "50ppm" is ppm per what? Temperature, voltage, initial accuracy, long-term drift, and averaged over what interval (google "phase noise").
Oscillatr  self foor primary oof transformer 2pins  - Page 1
Forum section: electronics / projects

author: abishekghimire
author_rank: Newbie
timestamp: August 04, 2025, 03:56:30 pm
content: I already connected the gate (or base) through a resistor to the feedback coil, and that coil’s other end is at +V — so I was wondering: why still use a 100kΩ startup resistor from +V to the gate? Isn’t it already getting voltage?its anchannel mosfet its foe feed back coil setup and chatgpt says:the feedback coil doesn’t produce any voltage at power-on — it only works after oscillation starts. So the 100k resistor gives the gate a small startup charge to turn the MOSFET or transistor on just enough to begin flux in the transformer. Once that happens, the feedback kicks in and takes over. So yeah, even if the gate’s already “connected,” you still need that startup resistor to get things moving. Makes sense now,whats the correct way or circuit connection how for auto oscilation,please help me experts or people with sme knowledge,if anything ele need t be carified then im ready,help me!

author: CaptDon
author_rank: Super Contributor
timestamp: August 05, 2025, 12:32:25 am
content: 1. Show us your schematic so we have a clue what your circuit looks like. 2. Turn on your spell checker, the tag line in your post is almost unreadable.
oscilloscope circuit Query - Page 1
Forum section: electronics / projects

author: yalect
author_rank: Regular Contributor
timestamp: October 12, 2015, 06:53:16 pm
content: Hello,I would like to ask you if I can build simple high or medium speed PC/USB oscilloscope based on microcontrollerthank you

author: lincoln
author_rank: Regular Contributor
timestamp: October 12, 2015, 06:59:08 pm
content: This question is un-anserable with out numbers. so Yes! or no.

author: navidrct
author_rank: Regular Contributor
timestamp: October 12, 2015, 09:23:58 pm
content: Quote from: yalect on October 12, 2015, 06:53:16 pmOf course u need external ADC with high sample per second rate . u should choose which one is enough for u . go to digikeyAnd for live showing of signal u should use high speed usbSent from my HUAWEI G730-U00 using Tapatalk

author: tggzzz
author_rank: Super Contributor
timestamp: October 12, 2015, 09:47:48 pm
content: Quote from: navidrct on October 12, 2015, 09:23:58 pmNo, you don't.I've seen MHz signals displayed on mechanical XY plotters with a frequency response below 10Hz. I've also used a 40MS/s scope to measure adn characterise sub-nanosecond risetimes.

author: Fat
author_rank: Regular Contributor
timestamp: October 12, 2015, 10:01:15 pm
content: Quote from: yalect on October 12, 2015, 06:53:16 pmNot trying to be a smart a$$, but yes you can, if you are willing to throw enough money at it. The reality is, with the cost of equipment the way it is and the availability of good used equipment spending the money to create the scope is not likely to happen. Now if this is like my projects and you want to do one because you enjoy it and can live with something that is more costly than buying one and will be an under performer too (the hallmark of my projects), but you just want to do it, then, yeah, it can be done, but it's a heck of a task.

author: moffy
author_rank: Super Contributor
timestamp: October 13, 2015, 02:25:09 am
content: Quote from: tggzzz on October 12, 2015, 09:47:48 pmI assume the MHz signals were mixed down in frequency to fit within the 10Hz BW, and for the 40MS/s scope measuring sub-nanosecond risetimes I assume you need a VERY stable trigger of a repetitive waveform and lots of repetitions.

author: tggzzz
author_rank: Super Contributor
timestamp: October 13, 2015, 08:41:03 am
content: Quote from: moffy on October 13, 2015, 02:25:09 amNo, repeat yes. No, in the sense there was no traditional RF mixer. Yes, in the sense a sampler can be analyser as a mixer.QuoteYes. The trigger was derived inside the scope from the repetitive waveform. HP (and Tek) know the importance of the trigger circuit - shame many amateur 'scope reviewers don't. I rather like the practical introductionhttps://www.eevblog.com/forum/projects/which-oscilloscope-to-choose-for-libs/msg772010/#msg772010

author: yalect
author_rank: Regular Contributor
timestamp: October 13, 2015, 07:32:45 pm
content: what about 50Mhz bandwiththere are projects?
Oscilloscope demo signal board schematic - Page 1
Forum section: electronics / projects

author: ad0hg
author_rank: Newbie
timestamp: March 18, 2014, 01:49:22 am
content: Hello everyone.First post long time lurker. I do some volunteer work and was wondering if anyone had some schematics for an Oscilloscope demo board? I usually bring a power supply and several bread board'ed circuits but though it would be great if someone had already had this kind of project completed so I could cut down on my baggage. Let me know if anyone has any ideas. If I had the time and the skills I would attempt this myself but given my current real work load its out of my reach right now.ThanksSteve

author: nowlan
author_rank: Frequent Contributor
timestamp: March 18, 2014, 02:36:34 am
content: This OSCILLOSCOPE TUTOR KIT ?http://www.vellemanusa.com/products/view/?id=526181
Oscilloscope from scratch - Page 1
Forum section: electronics / projects

author: Unknown
author_rank: Unknown
timestamp: May 14, 2010, 10:50:05 am
content: Hi! I am a 24 year old experimenter from sweden that have been doing electronics since i were 6 year old.Oscilloscopes are a great too to have around the lab for checking signals for abnormalities, i used to have a Tektronix 2445B 200MHz analog scope but its been broken for some time now, then i thought: hey i have that old broken 10MHz scope just laying around, maybe i could do something with it.Said and done, i decided to try and build a scope from scrath, maybe i´d learn something in the process.This is the progress after about a week of work:

author: thedigitalprincess
author_rank: Contributor
timestamp: May 14, 2010, 11:14:51 am
content: That's a lot of wires but a cool project non the lessI hope it comes together well for you.The only issue I have is the viewing panel without the grid divisions. How do you know the period and amplitude of your waveform?

author: Unknown
author_rank: Unknown
timestamp: May 14, 2010, 12:06:12 pm
content: I just wanna see what waveforms look like. But the grid is typically in centimeters so if i wanned to i could make a grid outta some plexiglass and calibrate the input for xV/div and so on.This is a work in progress and may take several years to finish.

author: Simon
author_rank: Unknown
timestamp: May 14, 2010, 12:33:37 pm
content: hm reminds me of a similar scope my dad built from a kit long ago, it still sort of works but the screen displays a bit topsiturvy, probably needs a few parts changing like caps

author: Unknown
author_rank: Unknown
timestamp: May 15, 2010, 10:39:20 am
content: A little update. Yesterday i designed a triggered sweep generator with trig holdoff.Schematic:The holdoff works by strobing pin 6 on the LM311 as per datasheet suggestion.

author: Polossatik
author_rank: Frequent Contributor
timestamp: May 17, 2010, 01:09:37 am
content: Maybe you can get some inspiration from theWelec scope project

author: Unknown
author_rank: Unknown
timestamp: May 17, 2010, 09:10:45 am
content: Eww digital. Why would i get inspiration from that ? I cannot program FPGA's, or any mcu for that matter.

author: Polossatik
author_rank: Frequent Contributor
timestamp: May 17, 2010, 02:41:54 pm
content: sorry, was meant to be posted inhttps://www.eevblog.com/forum/index.php?topic=490.0
Oscilloscope front end - Page 1
Forum section: electronics / projects

author: theoldwizard1
author_rank: Regular Contributor
timestamp: January 16, 2023, 10:43:19 pm
content: While I did have a couple of classes in analog circuit design at university, that was 50 years ago ! Me career was in embedded digital system design and software so I never "honed" those skills.I would like a short explanation on how digital oscilloscope front ends work. Most of the low end 'scopes have a +5V or less Vref. How do they deal with voltages above that and how do they deal with negative voltages ?I assume different voltage scales are achieved by precision resistor dividers or ... ?How does the font end protect itself from over voltage ? Say you have it on a 10V scale, but accidentally feed it a 100V signal ?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 16, 2023, 11:20:03 pm
content: Nothing special about it being a digital scope, you can read the Tektronix books from the 1960s and the principles are still valid.https://www.davmar.org/concepts.html

author: Benta
author_rank: Super Contributor
timestamp: January 16, 2023, 11:31:55 pm
content: There's nothing special about a "digital 'scope", it just uses a different display technology and has memory capability.The front ends are exactly the same. Stay within the limits printed on the front panel and you're fine.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 17, 2023, 01:40:31 am
content: Oh, and I'd read this one first "Oscilloscope Probe Circuits" just so you understand the "why" of what's going on in the input of the scope, then read "Vertical Amplifier Circuits".

author: dobsonr741
author_rank: Frequent Contributor
timestamp: January 17, 2023, 02:43:47 am
content: TI has great educational resources. This one is a 50ohm 2GHz frontend:https://www.ti.com/lit/ug/tiduba4/tiduba4.pdfAnother one for 3.2GS/sec:https://www.ti.com/lit/ug/tiduda6a/tiduda6a.pdfIt mentioned this cute little input buffer, BUF802, if you are into the 1Mohm||10pF inputs:https://e2e.ti.com/blogs_/b/analogwire/posts/how-to-simplify-afe-designs-with-hi-z-buffersBUF802 data sheet shows the input protection with clamp diodes, the AC vs DC path, and applying dual rail power.https://www.ti.com/lit/ds/symlink/buf802.pdf
Oscilloscope Hameg HM205-3 20MHz 2ch Storage 1994 test teardown - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: August 08, 2022, 08:04:30 pm
content: see this cool ANALOG scope, with a special ADC MEMORY DAC = Digital part tooit is actually very genius designed, and it works super good too.Printer interface, and I also got the thermal printer workinghttps://youtu.be/5Qq4pfjk_mg
oscilloscope Model question - Page 1
Forum section: electronics / projects

author: Plasmah77
author_rank: Newbie
timestamp: May 29, 2010, 10:54:06 pm
content: Hi all I'm a newbie here.I have my first question:Whats the difference between these two models TEKTRONIX 2215 and the 2215A?I won a 2215a on ebay and just wanted to know what the A in the model# meant.ThanksJim

author: EEVblog
author_rank: Unknown
timestamp: May 29, 2010, 11:14:12 pm
content: According tohttp://www.testequipmentdepot.com/usedequipment/tektronix/oscilloscopes/2215a.htm"Same specifications as 2215 with improved CRT intensity and bandwidth limit"Often an A revision is just an upgraded model internally (new construction and BOM), with very little or no major spec differences.The 2215 is a nice and solid basic scope.Dave.

author: Plasmah77
author_rank: Newbie
timestamp: May 29, 2010, 11:29:58 pm
content: Well thanks to you sir.I actually almost bought a DSO Nano as my first scope until I watched your Youtube videoThanks so much for steering me in the right direction.Jim

author: EEVblog
author_rank: Unknown
timestamp: May 30, 2010, 12:00:20 am
content: Quote from: Plasmah77 on May 29, 2010, 11:29:58 pmA wise choice!I've gotten quite a bit of backlash from defenders of the DSO nano pointing out all sorts of niche benefits and how wonderfully cool and handy it is. They are so missing the entire point, it's rather humorous!Dave.

author: charliex
author_rank: Frequent Contributor
timestamp: May 31, 2010, 12:39:01 am
content: You're lucky the dso nano isn't open source Dave, they'd be outside your house with pitchforks

author: EEVblog
author_rank: Unknown
timestamp: May 31, 2010, 02:37:58 am
content: Quote from: charliex on May 31, 2010, 12:39:01 amThe hardware and most of the firmware for the DSO nano IS open source!I already get hate mail, it cracks me up!Dave.

author: Ferroto
author_rank: Frequent Contributor
timestamp: May 31, 2010, 02:26:21 pm
content: Quote from: EEVblog on May 31, 2010, 02:37:58 amCriticizing open source anything is like criticizing someone's child. Except this "child" has many many parents all over the world. This creates a mob mentality.If you really want pitch forks outside your home, just point out that the GPL borrows from the marxist philosophy of communal ownership. Although that would amount to trolling at the worst possible level.

author: charliex
author_rank: Frequent Contributor
timestamp: May 31, 2010, 04:54:43 pm
content: Ahh well in that case we better keep an eye on dave til it cools off, or send him more GPL'd hardware to test
Oscilloscope probe Ground Spring - Page 1
Forum section: electronics / projects

author: prasimix
author_rank: Unknown
timestamp: May 27, 2016, 05:26:24 pm
content: Any idea where to find such spring on ebay that has reasonable price. I mean 10 pcs for a dollar/euro not just for one piece.

author: jancumps
author_rank: Unknown
timestamp: May 27, 2016, 06:22:38 pm
content: I make these myself by winding stiff wire round the smooth edge of a drill that's has a slightly smaller diameter than the probe.A trick learned by looking at the videos of our member Alan Wolke here.

author: tggzzz
author_rank: Super Contributor
timestamp: May 27, 2016, 07:47:24 pm
content: Or you could 3D print something like an adaptor for an HP 1.5GHz probe,https://entertaininghacks.wordpress.com/2015/04/23/scope-probe-accessory-improves-signal-fidelity/

author: macboy
author_rank: Super Contributor
timestamp: May 27, 2016, 08:35:29 pm
content: I found a spring inside a ball point pen that was the perfect diameter to fit my 1 GHz low-Z probes. It works!

author: joeqsmith
author_rank: Super Contributor
timestamp: May 27, 2016, 10:00:27 pm
content: Same. Keep a spool of wire around just for this purpose. I wrap it around the probe 1st then take it off and give it a twist.Quote from: jancumps on May 27, 2016, 06:22:38 pm
Oscilloscope probes - Page 1
Forum section: electronics / projects

author: FreeThinker
author_rank: Frequent Contributor
timestamp: October 05, 2010, 02:04:09 pm
content: I've just aquired an IsoTech 650 scope.It's about 10 years old but in good working order.I've got some probes of uncertain parentage which work ok but decided to check out some new replacements.As it's a 50mhz scope I thought that a minimum of 100mhz was the way to go but I'm now confused as to exactly which to get.I found some p6100 going cheap (about £10 uk) but they claim DC-6Mhz at *1 and DC-100Mz at *10 is this normal? Will it be ok for my scope? Others had compensation on BOTH *1 and *10 some only on *10 and some were only *1. Techtronics had a set for $9999.99 ().What sort of spec should I be looking at, what price range, any preference or buying advice?Thanks In Advance.

author: Unknown
author_rank: Unknown
timestamp: October 05, 2010, 02:32:10 pm
content: Choosing a probe for your Tektronix scope (nothing Tek specific about it). The lower bandwidth and lack of compensation range in x1 mode is normal. The low bandwidth is the reason why an x10 is more useful 95% of the time. There's usually no stated compensation range because there's nothing to compensate (an x1 probe is basically a fancy piece of coax, although a pretty special piece if you get a good brand).I dislike cheap no-name probes, but it probably doesn't make sense to spend $25-$75 each on used brand name probes for a cheap, low-bandwidth scope. Good brands would be the Agilent(HP)/Lecroy/Tektronix trio. I believe PMK also makes some decent probes. I consider brands like Probemaster and Pomona pretty mediocre, and most other cheap brands are even worse (note that a decent probe costs $100+ each new, so $50 would qualify as cheap for a new probe). But if you don't want to spend more on probes than on the scope, you're probably limited to the cheap ones.

author: FreeThinker
author_rank: Frequent Contributor
timestamp: October 05, 2010, 03:38:25 pm
content: Thanks for the reply.Looks like the £10 ones for me then, I have no need for super accuracy etc just general work and a bit of repair.Only paid £13.50 for the scope from a guy who was closing out an Electronics repair unit.Calibration sticker was for 2006 so should be fairly accurate was just a bit worried about the bw @*1 that the probes quoted but seems about normal.As you say no point in spending a fortune on probes for a cheap scope but at the same time no point In saving a few pounds on probes to cripple a decent scope.If the cheap ones perform OK then I'm happy enough with that.££

author: sonicj
author_rank: Frequent Contributor
timestamp: October 06, 2010, 11:34:01 pm
content: i am content with my stock rigol probes. they can be had on ebay for around $60 usd. the 200mhz hantek probes look nice @ around $40 shipped per pair.-sj
Oscilloscope Problem - Page 1
Forum section: electronics / projects

author: flyingfrancisco
author_rank: Contributor
timestamp: January 12, 2012, 05:04:16 pm
content: Hello everyone.I have a Kenmore dual trace 20 Meg oscilloscope that I am having a problem with. The traces are " Quivering" which was not the case before. Does anyone have any ideas of what in the circuit could be causing this. Also I am not a tech, just a hobbyist so please keep your answers simpleFrancisco

author: Unknown
author_rank: Unknown
timestamp: January 12, 2012, 05:11:59 pm
content: My first guess would be dried out caps, resulting in increased power supply rippling coupling into the vertical or trigger circuit. Try measuring power supply voltages and ripple. Second guess would be bad switch contacts, try cycling the switches a few times. Both are fairly common in old scopes.

author: flyingfrancisco
author_rank: Contributor
timestamp: January 12, 2012, 05:20:14 pm
content: Thx for your quick reply!

author: benemorius
author_rank: Regular Contributor
timestamp: January 12, 2012, 05:20:31 pm
content: What frequency is the signal you're looking at? (Or is it every signal you've tried?) Likely causes are noise and/or a higher frequency signal mixed with the one you're trying to see. Some scopes have options to filter these from the triggering circuit.

author: w2aew
author_rank: Super Contributor
timestamp: January 12, 2012, 10:09:26 pm
content: Also, what are you using for a probe? And, what is the nature of the circuit node that you are looking at (high impedance)? Poorly shielded probes and high impedance circuit nodes are susceptible to stray pickup of 50/60 cycle noise from the mains - which can make the traces wiggle.

author: Fraser
author_rank: Super Contributor
timestamp: January 12, 2012, 10:12:21 pm
content: Place the oscilloscope in X-Y mode with no inputs. You should see a nice stable compact dot on the screen. Check focus and brightness. If the dot is oblong or quivering, you have noise in your input stages most likely caused by PSU ripple. As has been stated, failed smoothing capacitors can cause PSU rail ripple.Aurora

author: siliconmix
author_rank: Frequent Contributor
timestamp: January 23, 2012, 09:35:38 pm
content: kenmore.never heard of that make.i'd agree with whats been said about the caps.is there a 60 hz ripple on the trace also?

author: jimmc
author_rank: Frequent Contributor
timestamp: January 23, 2012, 11:11:33 pm
content: My first thought would be to check whether you have recently placed any mains powered equipment near the 'scope.The stray magnetic field from some mains transformers is quite large and can cause the trace to quiver by directly deflecting the electron beam in the CRT.Jim
oscilloscope project - Page 1
Forum section: electronics / projects

author: yalect
author_rank: Regular Contributor
timestamp: October 22, 2015, 08:10:35 am
content: Hi,I have project of oscilloscope, I would like to ask you if I can build simple two channel usb oscilloscope high speed based on FPGAthank you

author: SteveLy
author_rank: Regular Contributor
timestamp: October 22, 2015, 08:16:34 am
content: If you mean to ask if is it possible to do so, the answer is yes. But the fact that you have to ask suggests that maybe it's a project beyond your present skill levels.More precise info on what you had in mind would help others help you.

author: Kalvin
author_rank: Super Contributor
timestamp: October 22, 2015, 09:05:01 am
content: You might want to start from here:http://www.fpga4fun.com/digitalscope.html

author: nctnico
author_rank: Super Contributor
timestamp: October 22, 2015, 09:54:17 am
content: You can but you better start thinking about the firmware of your oscilloscope first. The time needed to create the firmware will be at least 100 times more than the time needed to create the hardware.
Oscilloscope Simulator - Page 1
Forum section: electronics / projects

author: TKt48
author_rank: Newbie
timestamp: December 09, 2014, 05:20:52 pm
content: Hello, I'm from Poland, but currently living in the UK.I present you my analog oscilloscope simulator. I am aware that there is a lot of similar stuff, but I hope to design something more complex. My program uses FFT and Butterworth filter so there is proper AC/DC coupling. Signal can be taken from text file - you can generate own one. As a guide i took Tektronix 465 and w2aew videos from Youtube.Please, tell me what do you think about it. The project is in very early stage (I wrote it couple of days ago). Due to the design it works more like "single shot" mode. Long time ago I designed CRT simulator with persistence, focus, brightness etc. but it is slow...Program in ZIP file as an attachment.

author: hexreader
author_rank: Frequent Contributor
timestamp: December 09, 2014, 05:53:33 pm
content: I quite like it...Has a nice feel to it and seems to work very well.How about an option to show channel two as a yellow trace? - takes away the realism, but might make dual-trace easier on the eye.... oh ... and welcome to the forum. I am new here too.

author: Dajgoro
author_rank: Frequent Contributor
timestamp: December 09, 2014, 06:04:31 pm
content: It crashes upon starting it.I have: AMD cpu, win7 64bit professional.

author: TKt48
author_rank: Newbie
timestamp: December 09, 2014, 06:46:08 pm
content: @hexreader: Sorry, it's analog scope with monochromatic crt...@Dajgoro: Try now, updated file in first post. If it still doesn't work, install .NET Framework.

author: mcinque
author_rank: Unknown
timestamp: December 09, 2014, 06:47:22 pm
content: do some people really accept to run on their personal computer a software attached from an unknown user with 1 post?

author: hexreader
author_rank: Frequent Contributor
timestamp: December 09, 2014, 08:35:56 pm
content: Quote from: mcinque on December 09, 2014, 06:47:22 pmYes, I must admit I was a bit nervous at doing so, and checked the .exe best I could before running. Would not want to guarantee that the file is harmless though...And the answer seems clear.... at least two of us took the chanceI would certainly recommend that others be more cautious. mcinque makes a good point.

author: free_electron
author_rank: Super Contributor
timestamp: December 09, 2014, 09:47:37 pm
content: nah. just get a real scope.

author: mcinque
author_rank: Unknown
timestamp: December 09, 2014, 10:15:11 pm
content: Quote from: free_electron on December 09, 2014, 09:47:37 pmDid you decompile it?

author: Stonent
author_rank: Super Contributor
timestamp: December 10, 2014, 01:18:50 pm
content: Got any source code?
Oscilloscope - Tektronix 2336 YA - Strange ringing (between 100-200 MHz) problem - Page 1
Forum section: electronics / projects

author: felixd
author_rank: Regular Contributor
timestamp: October 07, 2012, 08:50:49 pm
content: Hello.I'm seeing strange thing on my Tektronix 2336 YA. Since I've bought it oscilloscope is triggered by a pulse that is coming from "nowhere". It appears randomly in every 30s - 2 minutes.This pulse is seen on each channel (on AC/DC/GND mode), probes connected/disconnected. This pulse is also seen on probe compensation signal. This is how I've managed to record it using 2nd oscilloscope. Pulse/ ringing frequency is between 100-200 MHz.This pulse runs trigger.I've also accidentally recorder it on below video (0:36 second)Wiertolot- Silnik EMAX GT2215I've recorder this pulse also on probe compensation signal:Any ideas why this pulse appears? How can it be fixed? What to check ? ;]Thanks for replaying

author: Niklas
author_rank: Frequent Contributor
timestamp: October 08, 2012, 12:02:09 am
content: Perhaps it is not related to the oscilloscope at all. It might be something in the same building that draws a lot of power and is switched on or off periodically. Perhaps try another power outlet and see if the problem disappears?

author: felixd
author_rank: Regular Contributor
timestamp: October 08, 2012, 02:18:33 pm
content: I've connected it to UPS.Same thing.My digital scope is not affected.Can it be dirt inside old scope + very high voltage? Maybe that's a problem.

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 08, 2012, 06:10:24 pm
content: It almost looks like a burst of RF, but it seems a bit short to be useful. Any RF transmitters near that could do this?

author: xygor
author_rank: Regular Contributor
timestamp: October 08, 2012, 09:35:11 pm
content: It looks like there might be an intermittent arc inside the scope. Open the case, turn off the lights, look, listen.

author: felixd
author_rank: Regular Contributor
timestamp: October 08, 2012, 10:19:20 pm
content: Quote from: xygor on October 08, 2012, 09:35:11 pmI was talking yesterday with people from Poland. They told me that this might be the problem.I'll check that tomorrow.

author: felixd
author_rank: Regular Contributor
timestamp: December 01, 2012, 04:20:35 pm
content: Lot of time since my last post. The problem is with arc's. I can hear them, but I'm not able to see themToday I have some time to dig inside my oscilloscope.
Oscilloscope tektronix TPS 2014 - Page 1
Forum section: electronics / projects

author: zzlong94
author_rank: Contributor
timestamp: June 27, 2018, 07:34:58 am
content: Hi guys! I want to get the result directly from the oscilloscopeBt I have some problems with the oscilloscope connected to my own laptop.I connected the oscilloscope RS232 port with my usb port.I did install the hardware needed for the window but nothing came up.If there a futher configuration or setting needed to connect oscilloscope and the laptop?
Oscilloscope Tester KEYRING, my first ever product! - Page 1
Forum section: electronics / projects

author: MaxSimmonds
author_rank: Contributor
timestamp: November 16, 2020, 07:19:25 pm
content: Hey guys!I wanted to show my first ever electronic product, it's a keychain that (hopefully) looks cool and can test oscilloscopes! It's not meant to be something used for referencing testing or anything like this, more like something you can keep on your person, showing off you're an engineer, and use if (like me) you like to go around and buy/sell scopes, that usually don't come with probes.It allows you to check almost all the functions the scope as to offer, and is either battery powered (CR2032) or usb powered (diode OR'd together, so either can be used). I designed it in KiCAD, and had it fab'd at JLC.It uses the Colpitts oscillator, which was new to me before I made this. In fact, I was bored one day and randomly opened "The art of electronics" to a page on the oscillator, and I decided to breadboard it, and make a keyring out of it! Let me know what you think, and if you're interested, I'm selling the spares on Tindie (https://www.tindie.com/products/theengineeringoctopus/oscilloscope-tester-keyring-battery/early xmas present, perhaps) . I also made a website (www.theengineeringoctopus.co.uk) to explain them a bit too, I hope to keep adding anything I make to the site. Thanks for reading!PS apart from the cool way I connect my keyring to the 'scope, with a BNC pin and a ground ring (I'm pretty proud of that solution) I'm also pretty proud of how I took the photos, I used my bathtub to get a cool white background, check it out!
Oscilloscope trigger offset error? - Page 1
Forum section: electronics / projects

author: David Chamberlain
author_rank: Frequent Contributor
timestamp: April 02, 2017, 05:31:59 pm
content: Hi all,I have a rather noisy signal and am triggering it's rising edge. This is on a Rigol DS1102DThe slope of the edge is not consistent but figured if I set the trigger at a particular voltage then all rising edges should cross through that point.What I'm getting is in the image below and cannot explain it.From the image the point where the I see the least dt is always about 1.6ns after the trigger point, I would have expected all the edges to cross through the trigger but they don't.If it's important the sensitivity is set at 0.1 div.Can anyone help explain this?Thanks
oscilloscopes timers/div - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: April 20, 2014, 08:56:23 am
content: Hi guys ,In my tek 2235 100Mhz scope the least timer scale is .05us/div . So 1/0.5us is 20MHz/div. If I want to see 90MHZ signal the signal seems to too dense so that I am not able to calculate frequency. why it is limited to .05us /div and how signal greater than 20MHz can be seen clearly

author: 128er
author_rank: Regular Contributor
timestamp: April 20, 2014, 09:17:20 am
content: I dont own a Tek 2235, but a Tek 2335 150 MHz. It has a "X10 MAG" switch at the horizontal controlling section. Its a way to extend your horizontal timebase.

author: David Hess
author_rank: Super Contributor
timestamp: April 20, 2014, 06:57:17 pm
content: x10 horizontal magnification (pull the A and B sec/div variable control straight out) extends the 2235 sweep speed from 50 ns/div to 5 ns/div which will easily show a 90 MHz signal. Oscilloscopes however make very crude frequency counters.
Osram SMD LED polarity inconsistency - Page 1
Forum section: electronics / projects

author: dadler
author_rank: Unknown
timestamp: March 25, 2016, 09:01:12 pm
content: So, I bought Osram 0805 SMD LEDs in red, green, and orange.I am populating a board with them now, but thought I would test the polarity of them first.I discovered that for some reason, the Hyper red LEDs are marked with the dot on the anode, but the rest are marked with the dot on the cathode.If I wouldn't have tested, all of the red LEDs would have been populated backwards.http://www.mouser.com/Optoelectronics/LED-Emitters/Standard-LEDs-SMD/_/N-ec21j?P=1yzvlvb&Keyword=OSRAM&FS=TrueIn the Osram 0805 LEDs above on mouser, only the Hyper Red is backwards from the rest.Is there some manufacturing/logistical reason to mark LED polarity in an inverse fashion?Yes, this information is in the datasheet:

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 25, 2016, 09:55:17 pm
content: Probably to do with the bonding - you sometimes find TH LEDs with the "big" internal part as anode instead of the normal cathode.Regardless of marking, the cathode should always be towards the index holes on the tape.

author: nukie
author_rank: Frequent Contributor
timestamp: March 25, 2016, 10:55:33 pm
content: It's more reliable to determine the anode of a TH LEd by the leads. If in doubt always check with dmm in diode mode.

author: Skashkash
author_rank: Regular Contributor
timestamp: March 26, 2016, 12:21:47 am
content: I remember this coming up in a screaming circuits blog post a while ago. .http://blog.screamingcircuits.com/2013/01/how-not-to-mark-a-diode.htmlYou just really need to check the data sheets and not make any assumptions.
OT? IEEE Spectrum article  1963 cipher machine/espionage scandal/backdoor - Page 1
Forum section: electronics / projects

author: jonpaul
author_rank: Super Contributor
timestamp: September 01, 2021, 05:50:02 am
content: Bonjour a tous: Here is My IEEE Spectrum article about a 1963 cipher machine and a huge Swiss/CIA/NSA espionage case Rubicon, just went onlinehttps://spectrum.ieee.org/the-scandalous-history-of-the-last-rotor-cipher-machineThis represents about a years work.Forum members thoughts and feedback are greatly appreciated!I am happy if you enjoy this work.Bon Soiree,Jon

author: dmendesf
author_rank: Frequent Contributor
timestamp: September 04, 2021, 03:00:17 am
content: I enjoyed it a lot. Thank you!

author: richnormand
author_rank: Unknown
timestamp: September 04, 2021, 08:00:51 pm
content: Liked it very much.Nice work!Cheers and thanks for posting.

author: rstofer
author_rank: Super Contributor
timestamp: September 07, 2021, 03:49:47 pm
content: Very interesting article, thanks for posting.