hybridfree/eevblog-posts huggingface dataset:
Oscilations in digital uCurrent source - Page 1
Forum section: electronics / beginners

author: Melon
author_rank: Newbie
timestamp: June 26, 2019, 06:09:47 pm
content: Hello, I've been lurking for a while but I have finally decided to make an account since I have a question myself. I'm quite a beginner so yeah, feel free to point out any dumb stuff. Anyway, to the point.I'm designing a digitally controlled current source in the range of 0 to 100uA (see first attachment). Basically I use a digital potentiometer (100kohm total resistance) as a voltage divider for a reference voltage of 3.3V coming from a regulator. The OpAmp is powered by [5,-5]V voltage regulators. The jumpers are just for measuring the current when the target chip is not placed so I can connect the transistor to GND and have a path for the current. The circuit works, but when I measure the negative pin of the OpAmp with an oscilloscope I can see small oscillations at a frequency of 300kHz (or 600kHz, I can't remember exactly right now). On the other hand I don't see anything if I measure the amplifier output. Furthermore, when I use a better probe (not just the crappy coaxial) the oscillations aren't there either. I assume this might be due to the capacitance of the probe that filters them out but can't confirm.The 3.3V reference is clean (at least at that frequency, I have some other small oscillations at 12MHz due to bad bypassing in an oscillator but thats another matter). I have also attached what I think is the relevant information from the datasheets regarding stability. So.. what's wrong here?

author: Gyro
author_rank: Super Contributor
timestamp: June 26, 2019, 07:58:35 pm
content: The first thing to try is a series resistor mounted close the to MOSFET gate. If that doesn't work then it may be necessary to put a capacitive feedback network around the opamp to improve its HF stability.At the moment the opamp is directly driving a capacitive load.

author: Kleinstein
author_rank: Super Contributor
timestamp: June 26, 2019, 08:39:44 pm
content: The BSS84 is a rather small FET. So gate capacitance may not be so bad. Still a series resistor is a good idea.If the oscillation is only seen with a poor probe - it could be in parts be due to the probe. A longer cable could add a resonance and make decoupling worse. If critical it could help to have additional series resistors (e.g. 10 ohms) where the supply to the OP comes in.With some inductance on the drain side the FET stage can add some phase shift and the usual extra RC may be needed to slow down the OP.
Oscilator circuit won't play ball - Page 1
Forum section: electronics / beginners

author: wedgetail
author_rank: Contributor
timestamp: July 13, 2020, 01:44:11 pm
content: For various reasons I have a very bad time getting this little circuit to work, now at least I believe I have the DC situation working but I must have missed a point because I can't get a sqeek out of it.I have a soldered breadboard version. As a training exercise I have used kiCAD to make a form of layout, I will attach plot of the schema with some measurements.Because I have two function generators gone on strike, BWD minilab and hp208A both dead output, at the same time I needed to check some pot cores so I made a quick check on the internet. Stumbled on the simple circuit here:http://www.discovercircuits.com/DJ-Circuits/DAJ-List-Titles-circuits.htmAny comment would be most welcome.

author: Manul
author_rank: Super Contributor
timestamp: July 13, 2020, 03:09:06 pm
content: Try to increase R1 to 1k. If nothing, try to increase supply voltage a little. It should work, if no, maybe there is some mistake.

author: wedgetail
author_rank: Contributor
timestamp: July 14, 2020, 10:32:13 am
content: ManulThanks for posting.First you were correct, I made a mistake. The output resistor and the drain resistor had been exchanged. I had only a 1k ohm in the drain. Each time I turned the board over to check the component side I failed to notice the values on the resistors.Second I also found on the internet a short youtube video dealing with exactly this same circuit, this made me believe too that my circuit should work. It worked ok as an amplifier just not oscillating. Here is the link:I have inserted a 6k8 ohm resistor and it works from 9V to 19V on most of my coils, got some ferrite material (ring cores) which I can not get to run but depends on the inductance. I think they were from old equipment used as suppressor coils on mains leads.I have also increased the source resistor to 1k ohm and it works fine with that as well, left the 10k ohm resistor in the output.All well for the time being.
Oscillating voltage (0-400mV) from a closed relay - Page 1
Forum section: electronics / beginners

author: analogo
author_rank: Regular Contributor
timestamp: August 03, 2017, 05:36:33 am
content: My MCU controls a 5 V Songle relay. The input to the relay is a 9 V battery. The NO output is connected to a LED, the NC output is disconnected. Everything works fine, but I have noticed something peculiar (peculiar only to a beginner like me, probably).If I measure the voltate from NO and ground while the coil is unpowered, I get an oscillating voltage. It starts from 0 V and ramps up to 400 mV. Then it drops down to 0 V. A sawtooth shaped waveform. If the coil has been energized and de-energized in the last 5 minutes then the voltage will go up to 400 mV in about 5 seconds. After 30 minutes it need 4 minutes to go up to 400 mV.What causes this oscillation?Is it normal? Is there a capacitor inside the relay? Has it to do with the coil?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 03, 2017, 05:39:11 am
content: Could it be that your meter changes from "Hi-Z" mode to 10Mohm mode when it switches range around 400mV?Tim

author: MK14
author_rank: Super Contributor
timestamp: August 03, 2017, 06:03:42 am
content: LEDs can make small amounts of electricity when they are in light. A bit like some photo devices, such as solar cells.Does covering the LED stop it from happening ?http://sciencewithkids.com/Experiments/Energy-Electricity-Experiments/LED-generate-electricity-experiment.htmlQuote
Oscillation frequency is too high - Page 1
Forum section: electronics / beginners

author: r00n
author_rank: Contributor
timestamp: July 31, 2024, 04:40:40 am
content: Hello EEvBloggers,I have built 6 x VCO depicted in the schematic. 5 of them are working perfectly and I have these tuned to the correct pitches and Volt/octave tracking is working wonderfully, within 1% over 8 octaves.The last one, doesn't want to behave. It is oscillating at a high pitch that is not even audible for most of its range, for my old ears. I have checked all the components and matched them with the other 5 working circuits and everything is ok. I have done some voltage measuring at various points around the switch when its open and closed, and the tuning pots comparing again to the working VCO's, but this had not led me to finding the fault.Any ideas on what component to check would be helpful. My trouble shooting skills are obviously useless.Thanks so much. Appreciated

author: Whales
author_rank: Super Contributor
timestamp: July 31, 2024, 08:09:49 am
content: If it's running, but at the wrong freq, then I'd suspect (in this order):- bad timing capacitor (C7 on pin 11)- unexpected shorts or miswiring- bad timing resistorsI bought a mixed pack of ceramic capacitors years ago and it turns out a lot of them were mislabelled or bad by a few magnitudesI wouldn't recommend using bulk/standard ceramics for the timing in this circuit, but you might be.Some photos of the units you have built would be very useful. Are you building them deadbug, manhattan, copper tape, on a PCB, solderless breadboard, ...?

author: r00n
author_rank: Contributor
timestamp: August 01, 2024, 01:15:01 am
content: building on a PCB. I had to google dead bug and Manhattani shall desolder the cap in C7 and measured it. It is a styrene one.May i just clarify please, the timing resistors are R14 AND R15?

author: Whales
author_rank: Super Contributor
timestamp: August 01, 2024, 09:23:06 pm
content: Those, but also (at a minimum) the resistors on pin 15 too. There might be others in there, I tried to look at the datasheet for the AS3340 but it doesn't seem to give any nice and simple explanations.

author: kevin.gibbs
author_rank: Regular Contributor
timestamp: May 28, 2025, 02:51:16 pm
content: Did you check the capacitance of the capacitors too?

author: coromonadalix
author_rank: Super Contributor
timestamp: May 28, 2025, 04:13:03 pm
content: i would verify all parts on pin 1 and pin 2 and crtl parts on pin15and pin 7 trimmerpin 14 is the scale, do check it too
oscillator circuit - Page 1
Forum section: electronics / beginners

author: dfox416
author_rank: Contributor
timestamp: March 15, 2014, 12:20:28 am
content: Hi,I attached a picture of an oscillator circuit. Does anyone know what is it called and how it works? Any input is greatly appreciated.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 15, 2014, 12:23:12 am
content: Phase shift oscillator.Tim

author: kg4arn
author_rank: Unknown
timestamp: March 15, 2014, 12:24:49 am
content: phase shift oscillator. Each RC section can give almost 90 deg of phase shift, so you need 3 to give 180 degrees for sure. The drain is 180 deg out of phase with the gate. 180 + 180 = 360 and you have oscillation.

author: dfox416
author_rank: Contributor
timestamp: March 15, 2014, 12:36:15 am
content: Thanks. I built it in simulation but I can't get it to oscillate. Is there some sort of excitation it needs to start oscillating?

author: kg4arn
author_rank: Unknown
timestamp: March 15, 2014, 01:01:05 am
content: build it for real and play with the RC values and it will oscillate. Sorry can't help you with simulation. The excitation is thermal noise.I have built phase shift oscillators with BJTs not FETs but I don't see why it wouldn't just fine.

author: dfox416
author_rank: Contributor
timestamp: March 15, 2014, 04:20:49 am
content: I got it working with a BJT but I cannot seem to make it work with a FET. Are there any special considerations for component values that need to be made when using a FET vs a BJT?

author: Rerouter
author_rank: Super Contributor
timestamp: March 15, 2014, 04:43:22 am
content: Not sure if this is still classed as a phase shift oscillator or an LC tank, but it happily works in simulation as a 10Khz Oscillator
oscillator issue, I am confused... - Page 1
Forum section: electronics / beginners

author: antenna
author_rank: Frequent Contributor
timestamp: October 15, 2022, 06:48:19 am
content: I have been trying to make the micro tracking transmitter on the talking electronics site herehttps://www.talkingelectronics.com/projects/MicroBug%20Tracker/MicroBugTracker-P1.htmland each time I try, the oscillation (and LED) is on steady. It is supposed to chirp, but it just creates a carrier and stays on. This latest attempt was an expensive one as I ordered RF quality C0G capacitors and dollar a piece thin film resistors. The transistors I am using are BC848 and BC858. Anyone have any ideas why that circuit might just stay on??

author: pcprogrammer
author_rank: Super Contributor
timestamp: October 15, 2022, 06:55:57 am
content: Did you read the part where it says that the LED is one of the flashing kind?This type has an oscillator in it to make the LED flash, and it is this component that turns the BC858 on and off, which in turn enables and disables the BC848 RF stage.

author: antenna
author_rank: Frequent Contributor
timestamp: October 15, 2022, 07:14:50 am
content: I blew right past that part. I never knew a "blinking LED" was a thing all by itself, I always figured it needed a circuit to make it blink. That explains why staring at that schematic for half the day offered no hints as to how it blinks lol. Thanks!
Oscillator with 4060 counter - Page 1
Forum section: electronics / beginners

author: michaelym
author_rank: Regular Contributor
timestamp: June 24, 2013, 06:25:03 am
content: Hi,I first built this circuit (Attached) with HEF4060BP and it worked perfectly.When I built it with a SN74HC4060 it doesn't work and I cannot figure out why.Michael

author: Unknown
author_rank: Unknown
timestamp: June 24, 2013, 06:39:33 am
content: What is your supply voltage?

author: michaelym
author_rank: Regular Contributor
timestamp: June 24, 2013, 07:06:45 am
content: 3.6-4.2V

author: Unknown
author_rank: Unknown
timestamp: June 24, 2013, 07:15:01 am
content: I would check the specifications of each. A cursory look tells me they have slightly different characteristics and the HC might react differently to that voltage then the HEF.

author: michaelym
author_rank: Regular Contributor
timestamp: June 24, 2013, 08:07:27 am
content: Weird, I just tried it with a 4MHz oscillator and it works.

author: thesgoat
author_rank: Contributor
timestamp: June 24, 2013, 08:51:40 am
content: I had exactly the same issue with a 32kHz crystal, ended up making a separate oscillator out of a spare inverter.

author: Alana
author_rank: Frequent Contributor
timestamp: June 24, 2013, 09:22:39 am
content: Tried wihout resistors?

author: michaelym
author_rank: Regular Contributor
timestamp: June 24, 2013, 09:32:22 am
content: Yes, I tried it without resistors and also with lower value resistors 2.2k & 100k.

author: Alana
author_rank: Frequent Contributor
timestamp: June 24, 2013, 11:50:28 am
content: Is there any reason not to use 4000b series chip instead of 74hc series? 4000b chip works and with same Vcc it should be compatible with rest of circuit if you use 74HC chips there.

author: michaelym
author_rank: Regular Contributor
timestamp: June 24, 2013, 03:07:57 pm
content: I tried it with CD74HC and it works.If I can figure out why it's not working with the SN74HC, maybe I can find a solution that only involves replacing passives, and avoid throwing out all the chips.

author: michaelym
author_rank: Regular Contributor
timestamp: June 25, 2013, 11:52:47 am
content: I mixed up the part numbers in the last reply, now it's correct.
Oscillator works when I touch it? - Page 1
Forum section: electronics / beginners

author: booyeah
author_rank: Contributor
timestamp: July 08, 2019, 12:21:32 am
content: Hi.Maybe this is obvious for others but I'm a bit stumped.I have a circuit consisting of a charge pump / voltage doubler which is connected to three LC tank circuits (two have trimmer caps) in series,It is then modulated via a dual transistor pair and subsequently capacitively coupled to a high voltage DC bias circuit which drives an avalanche photodiode transimpedance amplifier circut.Whilst probing the circuit I found that touching the coupling capacitor and/or ground, that the circuit would generate the correct signal and the device would fully function, (don't have schematics / part specs etc.)I figured it must be a grounding issue and tried adding all manner of capacitors but none of them helped, seemingly the opposite, adjusting the trimmers also doesn't help.Any thoughts appreciated

author: alsetalokin4017
author_rank: Super Contributor
timestamp: July 08, 2019, 01:40:57 am
content: Clean, inspect under microscope, reflow junctions in suspect circuit segment...

author: thedoc298
author_rank: Contributor
timestamp: July 08, 2019, 01:55:10 am
content: Masure your meter and add the same value to your circuit.

author: booyeah
author_rank: Contributor
timestamp: July 11, 2019, 12:49:11 am
content: I used that old photo just to save me fiddling about making a new one, but I have already tinned all the solder joints, and cleaned the nasty flux residue.The circuit doesn't start working when probed with an oscilloscope probe.It's only when I touch the NPN transistor collector with a metal tweezers that it functions.I don't have a good enough grasp on how these transistor oscillators work to know is it my body capacitance or resistance that's affecting the LC circuit or is it that I'm injecting mains hum by touching it?Adding small values of capacitance to ground just seems to attenuate the collector voltage to nothing.The first image is the standard non - functional behavior,Channel 2(pink) is a square wave coupled to the transistor baseChannel 4(green) is the resulting collector voltage that gets coupled to a subsequent circutChannel 1(yellow) is the non-functional result of the subsequent circuitsThe second image is when I touch the collector with a metal tweezersThe ac amplitude of the collector voltage is much reduced and the device initiates a change in frequency from ~14.5MHz to ~500kHzThe device also functions correctly

author: ArthurDent
author_rank: Super Contributor
timestamp: July 11, 2019, 02:12:40 pm
content: You may have accidentally created the equivalence of a 'THEREMIN' where changing some value changes the circuit. Here's a video showing how one works and what happens sounds something like what you describe.

author: capt bullshot
author_rank: Super Contributor
timestamp: July 11, 2019, 02:57:10 pm
content: Works when touching a pad of the capacitor - this might be an indication of a broken (literally) capacitor.
Oscillators in motherboards and dividers - Page 1
Forum section: electronics / beginners

author: tellusregio
author_rank: Newbie
timestamp: January 08, 2021, 02:17:58 am
content: I was watching the Amiga 500 video by EEV and in it he said something like "the clock is divided by 4 of course", but I do not know why that is obvious.I was wondering if there is a simple explanation for why we divide frequencies of clocks.

author: ataradov
author_rank: Super Contributor
timestamp: January 08, 2021, 02:47:09 am
content: I'm not familiar specifically with Amiga and its CPU, but it is indeed common to divide the clock this way. There are a number of reasons to do that:1. Commonly and cheaply available crystals at the time are much faster than the CPUs.2. It is common to use the same clock source to generate video pixel clock. In this case the frequency of the crystal is defined by the video standard.3. Many CPUs require 2 or more phase clock, and the easiest way to derive this is to generate high speed clock and divide.4. Divided clock would have 50 duty cycle, even if the source clock was uneven, as often would happen.

author: srb1954
author_rank: Super Contributor
timestamp: January 08, 2021, 02:58:40 am
content: Quote from: tellusregio on January 08, 2021, 02:17:58 amThe operation of the Amiga video circuitry is very closely tied to the main CPU so they can both access the portion of memory set aside as video memory without mutual interference. This requires the CPU clock to be locked in a fixed ratio to the video clock and this is achieved by deriving the CPU clock from the video clock using a simple divider.The video clock in an Amiga is around 28MHz whereas the maximum permissible clock for the MC68000 CPU is only 8MHz. Hence the video clock was divided by 4 to give a suitable 7MHz clock for the CPU.

author: tellusregio
author_rank: Newbie
timestamp: January 08, 2021, 03:27:59 am
content: Thanks both. So we can use 1 clock for many ICs that require a clock and we generally choose a clock that gives a frequency that can be divided in a "nice way" to those different ICs using "clock dividers".For the Amiga, since the video is 28MHz then we need a clock of at least that (or a higher one that could be "nicely" divided) frequency. It would not make sense to have a separate clock for the CPU because it would cost more and maybe not only that but cause possible synchronization issues if we introduced another clock anyway.

author: ataradov
author_rank: Super Contributor
timestamp: January 08, 2021, 03:54:44 am
content: This dividing is mostly a thing of the past where things were tightly coupled together. With most modern devices clock selection is much more flexible. We are not tied to some video frequencies, since everything that needs specific clock would have a PLL inside and will generate its clock internally.
Oscilliscope ground split ring clip - Page 1
Forum section: electronics / beginners

author: Maksnav
author_rank: Newbie
timestamp: March 29, 2024, 01:00:29 pm
content: Not sure where to post this, I hope its not too out of place.Ive been fruitlessly searching for a place to buy the split ring ground connector for my probe. Does anyone have a source for these? I've searched for just about every keyword combination i can think of with no success any help would be much appreciated. I could buy ground cables and tear the connector off but id prefer to just buy the clips if possible. TIA.

author: tszaboo
author_rank: Super Contributor
timestamp: March 29, 2024, 01:07:32 pm
content: Are you buying as a private person, or company?For former:https://www.amazon.com/s?k=oscilloscope+ground+clip&crid=3MNGQL7HX0RIT&sprefix=oscilloscope+gro%2Caps%2C158&ref=nb_sb_ss_ts-doa-p_2_16Same search term would work on Aliexpress ie. Mouser, Newark or others I'm sure have a "Oscilloscpe accessory kit"Carefult buying it, the ground connection exists in different diameters.

author: ebastler
author_rank: Super Contributor
timestamp: March 29, 2024, 01:11:41 pm
content: Sorry, I am not aware of a source for just the clips. Just a word of caution that you should not connect long ground wires to the probe anyway: The impedance of a long wire will distort your signals, and the large loop area formed by the probe tip and ground wire will act as a pretty effective antenna for unwanted background noise.I would not go beyond the length of a typical ground strap (as provided with the probes) -- shorter is better. So the good news is that, if you buy complete ground straps, you can use the C clip + cable and only have to discard the crocodile clip.
Oscilloshroom Question - Page 1
Forum section: electronics / beginners

author: Electro Fan
author_rank: Super Contributor
timestamp: April 04, 2015, 03:10:10 am
content: At about 1:55 into this video two sets of mushrooms become 4 sets of mushrooms. I've tried to get this to render on a couple scopes but for some reason the tops of the mushrooms in the 4 set of mushrooms don't render. I obviously don't care about oscillofun mushrooms per se, but I'm wondering what it is about either the signal from my source (I've tried both a PC and a phone with a browser - and I've tried a couple patch cables and sets of connectors) or possibly the settings on my scopes that keep the tops of the mushrooms (and the tops of some other "scenes" in the video) from rendering properly? Just want to make sure that I'm measuring X and Y properly. ThxOn the PC the video looks pretty horizontal (16:9 ish); on the scope it's more square (4:3 ish).... ?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 04, 2015, 05:55:04 am
content: I'd have to look at the waveform, but you can bet it has to do with the audio device's bandwidth and settling. Usually a near-brick wall at 20kHz, with lots of ringing.Tim
Oscilloscope - Page 1
Forum section: electronics / beginners

author: karderis
author_rank: Newbie
timestamp: April 04, 2013, 02:49:57 pm
content: Hello everybodyI want to buy a decent oscilloscope for now and for future work. I intend to go for 100Mhz. I 've read somewhere I don't remember that in order to see ripple in power supply you must have an osc illoscope with 50Mhz and further. I have seen Agilent DSO1102B and for its characteristics it' s fair enough. Should I go for Tektronix ? I don't know really. On the other hand Rigol are very cheap and I am afraid the risk. Any help is appreciated

author: PetaVolt
author_rank: Contributor
timestamp: April 04, 2013, 04:29:25 pm
content: It really depends on how much you are willing to spend. I recently bought a Rigol DS1102E and I am very happy with it. If I had more to spend I probably would have gone with a low end Agilent.Spencer

author: grego
author_rank: Frequent Contributor
timestamp: April 04, 2013, 07:45:54 pm
content: It depends as PetaVolt says. If you go into the Test Equipment forum there are lively discussions on a bunch of manufacturers across a bunch of price ranges.

author: ivan747
author_rank: Super Contributor
timestamp: April 05, 2013, 01:29:19 am
content: Tell us more about yourself, do you need a long warranty? Is support critical for you? How much money are you planning to spend? These are very useful questions for us all.Now, remember Tektronix doesn't have a very deep sampling memory, but support is on par with Agilent, I think. Agilent is a good choice, but it will cost you a lot of money. The Agilent DSO1102B is actually a rebranded Rigol oscilloscope no longer being sold by Rigol. You will get superior support, of course, compared to Rigol. The DS1102E is the cheapest option and it is very well known by this community.

author: Randall W. Lott
author_rank: Regular Contributor
timestamp: April 05, 2013, 01:42:18 am
content: I have a Rigol DS1052E and it's worked very well for me so far. If you plan on doing RF work, you may want something with a higher bandwidth.

author: megahz
author_rank: Regular Contributor
timestamp: April 05, 2013, 01:46:30 am
content: Since im 15 I don't see any point in getting an oscilloscope just yet, but my school just got 2 rigol oscilloscopes, and they seem pretty good

author: Randall W. Lott
author_rank: Regular Contributor
timestamp: April 05, 2013, 01:22:18 pm
content: Quote from: megahz on April 05, 2013, 01:46:30 amThat's awesome! My high school didn't even have an oscilloscope. Most other students my age weren't seriously interested in electronics though.

author: dr.diesel
author_rank: Super Contributor
timestamp: April 05, 2013, 01:24:16 pm
content: Quote from: megahz on April 05, 2013, 01:46:30 amYour never too young to have a Scope! They are absolutely indispensable, ask for one for X-Mas next year.

author: megahz
author_rank: Regular Contributor
timestamp: April 05, 2013, 09:34:33 pm
content: Nope next years birthday, I already got my 16th birthday present which is a good watch, swiss card (the knife), and a new soldering station
Oscilloscope Acquisition & Signal Parameter Calculator (Excel) - Page 1
Forum section: electronics / beginners

author: crysti
author_rank: Regular Contributor
timestamp: August 06, 2025, 09:04:32 pm
content: Sample rate v2.xlsx(119.93 kB - downloaded 22 times.)I am sharing an Excel-based calculator designed to assist with manual oscilloscope setup and a better understanding of acquisition and signal parameters.While most modern oscilloscopes now feature an "Auto" button, this tool is useful if you want to:Manually configure acquisition parameters (timebase, sample rate, memory depth, etc.)Understand how effective memory depth and record length are calculatedCalculate acquisition time, displayed periods, required sampling rate, and moreThe calculator was created in Excel 365 and includes regional settings (decimal, thousand separators, and list separator) that can be adjusted in the "Regional" sheet.How to use:Enter your signal and acquisition parameters (input frequency, divisions, memory, etc.) in the highlighted fields. The sheet will automatically calculate key parameters like accurate and minimum sampling rates, rise time (Gaussian), input period, effective memory depth, and total record duration.Note:This tool can be particularly helpful for users working with oscilloscopes that allow manual configuration, or for anyone wanting to understand the underlying calculations performed by their instrument.Feedback, suggestions, or requests for new features are welcome!

author: SteveThackery
author_rank: Super Contributor
timestamp: August 06, 2025, 09:19:21 pm
content: Thanks! I need to think it through, but it looks useful. Thanks again.

author: crysti
author_rank: Regular Contributor
timestamp: August 09, 2025, 02:15:09 pm
content: This is an updated version, tested on Excel 2021.

author: crysti
author_rank: Regular Contributor
timestamp: August 13, 2025, 01:42:00 pm
content: This is a new version

author: crysti
author_rank: Regular Contributor
timestamp: August 21, 2025, 04:24:06 pm
content: Updated Excel spreadsheet version, without password restrictions
Oscilloscope and Spectrum Analyzer Trigger - Page 1
Forum section: electronics / beginners

author: staticshock
author_rank: Contributor
timestamp: September 07, 2022, 08:50:17 pm
content: I have an RF instrument that has 3 outputs of 10MHz and 4 outputs of 500MHz. The instrument doesn't need an input to output the signals, but it does take a 10MHz input as a reference signal so the output signals are phase locked. The outputs are connected to signal generators (500MHz) and spectrum analyzers (10MHz) and all are in good working condition. My system was intermittently failing and it was determined that the RF instrument was the issue. I took this bad RF instrument and installed it in another system. It was performing just fine, but overnight when I returned the signal generators and spectrum analyzers connected to the outputs of the RF instrument had failed self tests. This proved that the RF instrument was bad. I've been looking at the outputs of the RF instrument on an oscilloscope and spectrum analyzer, but I don't see anything that looks out of place. The 10MHz signal does have a bit of distortion, see attached image, not entirely sure if it is the cause of failure. I'm not sure how to find a solution with proof that there is something wrong with the RF instrument. I've wondered if the signals ever dropout or if there's a spike somewhere. I don't know how to setup a trigger (and what type of trigger) to capture it on the oscilloscope or on the spectrum analyzer.

author: CaptDon
author_rank: Super Contributor
timestamp: September 08, 2022, 01:43:21 am
content: What is the 'R.F. Instrument', you haven't specified. Your 'system' was failing, what does your system consist of? What will cause a failure on your 'system'? One cycle missing from any of the references? Lost phase lock? Lots of jitter? Maybe paint a better picture of what your system does or what you do with it.

author: staticshock
author_rank: Contributor
timestamp: September 08, 2022, 12:05:48 pm
content: The RF Instrument is just a reference distribution chassis. Just like I mentioned, all it does is receives a 10MHz sine wave reference signal and distributes reference signals (10MHz) to 2 spectrum analyzers and (500MHz) to 3 signal generators. I would say the system doesn't need attention because I know that the spectrum analyzers and signal generators are in good working order. The help I need is I'm not sure of how to determine the reference distribution chassis is bad either by using an oscilloscope or spectrum analyzer to capture some kind of data.
Oscilloscope basic - Page 1
Forum section: electronics / beginners

author: Deathwish
author_rank: Unknown
timestamp: May 10, 2015, 01:56:26 am
content: I don't know if this belongs here or is helpful, but I found this earlier and thought it to be quite interesting if you want to know how an Oscilloscope works etc.http://www.amplicon.com/docs/white-papers/xyz-oscilloscopes.pdfhttp://www.cbtricks.com/miscellaneous/tech_publications/scope/abcs_of_probes.pdf

author: ez24
author_rank: Super Contributor
timestamp: May 10, 2015, 05:05:21 am
content: Looks good - I am printing it and going to read it - thanksmaybe it should be posted at this sticky post? :[url=https://www.eevblog.com/forum/beginners/oscilloscope-training-class-%28long%29/]https://www.eevblog.com/forum/beginners/oscilloscope-training-class-%28long%29/so it does not get buried in a few weeks
Oscilloscope calibration NEED HELP - Page 1
Forum section: electronics / beginners

author: ht2ht
author_rank: Newbie
timestamp: August 12, 2010, 01:48:45 am
content: Hi,I just bought a second hand oscilloscope Leader 100Mhz 8100. Think it bargain but I found a problem.When I turned it ON (very first time) after setting all switches to default as instructed in manual, it worked. However, the bright straight line appeared on the screen but not completely horizontal. It is slightly diagonal down at lower left corner and up at upper right corner.I think the line must be horizontal, right? Then what actually happened? Can I calibrate this scope?All knobs can be rotated properly.Anyone knows about this, PLEASE HELP!Thanks a lot!

author: DavidDLC
author_rank: Frequent Contributor
timestamp: August 12, 2010, 02:27:11 am
content: Is this a CRT scope ?Probably you need to move the horizontal deflection coils.But I have never done this, let's see what the people with experience on this have to say.

author: Matt
author_rank: Contributor
timestamp: August 12, 2010, 02:41:25 am
content: Look for a trace rotation adjustment. Doing a quick search,http://www.electro-tech-online.com/electronic-theory/212-using-oscilloscopes.htmlshows what this looks like and how to fix it.-Matt

author: ht2ht
author_rank: Newbie
timestamp: August 12, 2010, 02:49:58 am
content: It's CRT.I am thinking about a knob or switch that will do adjusting the trace beam back to horizontal. Opening the scope's box and turning some switch are OK to me. But if you suggested to rotate/move the deflection coils seems a really big challenge.Thanks anyway.

author: ht2ht
author_rank: Newbie
timestamp: August 12, 2010, 02:54:10 am
content: Quote from: Matt on August 12, 2010, 02:41:25 amVery useful, Matt. I've already bookmark it. Fig. 2 describes exactly what happens to my scope. Let's see if I can fix it.Thank you very much, Matt

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 12, 2010, 08:33:39 am
content: Quote from: ht2ht on August 12, 2010, 02:49:58 amWell it would be a challenge as scopes use electrostatic deflection, and so don't have deflection coils.....There is sometimes a coil wound around the face of the screen, which I believe is used to provide the rotation adjustment - not sure if it's driven with DC or a waveform derived from the X sweep, but if you can't find a trace rotate control, look for this coil and follow the leads back.

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 12, 2010, 12:14:40 pm
content: rotate the whole CRT until its horizontal!funny but seriously will fix it ok!

author: ht2ht
author_rank: Newbie
timestamp: August 13, 2010, 01:03:54 pm
content: All solved. I amnow.Thanks everyone for commenting.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 13, 2010, 01:21:39 pm
content: Quote from: shafri on August 12, 2010, 12:14:40 pmNot if it's a rectangular screen
Oscilloscope Connection Question - Page 1
Forum section: electronics / beginners

author: EmeraldPawn
author_rank: Newbie
timestamp: July 13, 2016, 12:39:18 am
content: Got a Newbie question here. I bought a old Knight KG-687 Sweep/Marker Generator which has two outputs to go to the oscilloscope. The connection at the marker generator is a simple RCA type jack, one for horizontal the other for vertical. So the question is how to connect it to my Digital Siglent SDS 1052Dl BNC input/s ? The manual says Unshielded cable with pin plug goes to scope H jack, The Red shielded cable with pin plug goes to the scope V jack on oscilloscope. Thanks for the help.

author: rstofer
author_rank: Super Contributor
timestamp: July 13, 2016, 01:44:43 am
content: I think you want to put the scope in X-Y mode and then run the Horizontal signal into Channel 1 and the Vertical into Channel 2.None of which I can verify because I have none of the pieces of gear. I can say that I use X-Y mode on my DS1054Z and also on my Tek 485 and that's the way I do it.
Oscilloscope CRT magnetic interference from nearby power transformer - Page 1
Forum section: electronics / beginners

author: Victorman222
author_rank: Regular Contributor
timestamp: November 11, 2023, 03:56:30 am
content: Hello,I have just got a new scope and after placing an hp3478A on it i noticed strange 50hz ripple on the oscilloscope. Some troubleshooting later i figured out that it is the magnetic fields from the transformer of the hp3478A that cause the interference. The previous oscilloscope didn't have this behaviour. I think the previous one behaved well because it had CRT completely in shield. This one doesn't have a shield on the CRT funnel.I'm thinking to try to bodge a shield from some scrapped scope onto this tube. Not sure if that would work and how that would impact the magnetic rotation coil.Maybe the magnetism is getting coupled through the metal chassis of the instruments, is there any way to decouple it?Are there any more obvious solutions that i missed?Thanks for any help!

author: srb1954
author_rank: Super Contributor
timestamp: November 11, 2023, 06:52:46 am
content: Quote from: Victorman222 on November 11, 2023, 03:56:30 amThe best fix is to just get more physical separation between the scope and the 3478A.You could try putting a steel sheet between the two items to provide some magnet shielding.Lastly, you can put a copper shield around the power transformer in the 3478A. This helps to contain any stray magnetic field from the power transformer. Look up "flux strap" or "flux band" for details.

author: Victorman222
author_rank: Regular Contributor
timestamp: November 11, 2023, 09:00:59 pm
content: Thanks srb1954, somehow when reading your reply something clicked in my head and while searching for source of steel sheet i remembered that i had a steel enclosure from some scrapped test equipment that would also provide more separation. I put it inbetween the oscilloscope and 3478a and the interference is almost gone (good enough). As a bonus now there is a constant reminder that something should be built in that enclosure.
Oscilloscope current probe choice - Page 1
Forum section: electronics / beginners

author: YIG_OSCILLATOR
author_rank: Newbie
timestamp: February 20, 2020, 05:31:36 am
content: I am trying to purchase a current probe for my siglent sds2304x oscilloscope. I am looking at either pintek PT 350 (50Mhz 60A$1170 ) or the instrance ICP 5150 (50Mhz 40A $1045) from AliExpress. I intend to use siglent deskew fixture. I have looked at their respective specification. Which will the house advise I go for. This is the best I can afford. Thanks
Oscilloscope Decision - Page 1
Forum section: electronics / beginners

author: Zerocool5878
author_rank: Newbie
timestamp: March 25, 2012, 03:09:02 pm
content: Hi all,I found 2 scopes on craigslist for $50 each I am not sure which would be the better one for a newbie to start with.LBO 508 is what it says on the front. It does not have a letter after it or anything and I cant any specs on that exact model because they all have a letter after it.orHitachi 50MHZ 2chan I do not know the model numberAny help with this decision would be appreciatedThanksMike

author: w2aew
author_rank: Super Contributor
timestamp: March 25, 2012, 04:04:41 pm
content: The LBO-508 is made my Leader, and is a 2-channel 20MHz BW scope.So, all things being equal, assuming they both work fine, I'd go with the wider BW Hitachi model.

author: david77
author_rank: Frequent Contributor
timestamp: March 25, 2012, 04:23:09 pm
content: I've got the Hitachi V550B CRO and it's never let me down. So judging from that I'd also go with the Hitachi.

author: wkb
author_rank: Super Contributor
timestamp: March 25, 2012, 04:38:11 pm
content: Assuming both work properly go for the higher bandwith one, the Hitachi. I am not overly fond of Leader anyway, bit of a B-brand if you ask me.

author: Zerocool5878
author_rank: Newbie
timestamp: March 25, 2012, 07:33:31 pm
content: Thanks for all the replies. I got the Hitachi one as suggested.It did not come with any probes and the seller suggested that I get them from Deal Extreme as thats where he got the last pair he had. I have bought few china made items from there, that i was happy with however im not sure when it comes to something like scope probes.Here are the ones I saw on there.https://www.dealextreme.com/p/p6100-x1-x10-100mhz-oscilloscope-probes-pair-120cm-length-114330https://www.dealextreme.com/p/60mhz-oscilloscope-probe-with-x1-x10-switch-max-600v-34220Would these be ok for me or should i get a specific brand on amazon or something? Also I imagine that the 1x/10x switching probes would be handy but would having 1x and separate 10x be better?Thanks again for any helpMike

author: Spawn
author_rank: Frequent Contributor
timestamp: March 25, 2012, 08:13:52 pm
content: Check this topic hereabout cheap probes, these are same as on DE and it's great deal for the price, buy from ebay it is cheaper than DE.And a 1x/10x will do just fine, you don't need each of them.

author: Zerocool5878
author_rank: Newbie
timestamp: March 26, 2012, 12:12:16 am
content: Quote from: Spawn on March 25, 2012, 08:13:52 pmThanks for infoWill check ebay

author: Psi
author_rank: Super Contributor
timestamp: March 26, 2012, 12:20:45 am
content: The DX probes should work fine at 50mhz.But i wouldn't get the cheapest probs DX sell, they will skimp on the wire quality and break easy.ebay will get you your probs quicker than DX.Nothing worse than a scope sitting on your bench that you cant use for 2 months while DX ship your probes.
Oscilloscope: Different offset per channel? - Page 1
Forum section: electronics / beginners

author: int2str
author_rank: Regular Contributor
timestamp: January 15, 2016, 07:16:46 am
content: If I have two channels displayed, is there a way I can offset one left/right to make it overlap the other? If I turn the horizontal offset dial, both channels move, of course. How can I only move 1?(DS1054Z here)Thanks@

author: Jeroen3
author_rank: Super Contributor
timestamp: January 15, 2016, 08:01:17 am
content: First store it as a reference?

author: SebG
author_rank: Regular Contributor
timestamp: January 15, 2016, 08:06:36 am
content: HiYou can't shift signals in time since when the scope is triggered it captures both signals at the same time. There is a way to compute the phase shift between signals if that is needed. If you want to compare a signal to another that is delayed what you can do is capture one of the signals that you triggered and then display it as a reference while you trigger the other signal, then they should line up.

author: tooki
author_rank: Super Contributor
timestamp: January 15, 2016, 06:23:50 pm
content: This does beg the question, though: Whycan'tDSOs have different horizontal offsets per channel? Since we have pre- and post-trigger memory, I don't see any reason you couldn't do it, since the horizontal offset is inherently arbitrary on a DSO.

author: dom0
author_rank: Super Contributor
timestamp: January 15, 2016, 06:31:30 pm
content: I think the Lecroy 9300 series can do that in segmented mode, so later models should be able to, too.

author: w2aew
author_rank: Super Contributor
timestamp: January 16, 2016, 05:25:07 am
content: Old analog scopes with delayed timebases allowed you to do this.

author: Simon
author_rank: Unknown
timestamp: January 16, 2016, 05:45:53 pm
content: Quote from: tooki on January 15, 2016, 06:23:50 pmProcessing speed, memory speed, memory quantity. Remember that all speeds and memory capacities at total and get divided by the amount of channels.

author: MarkL
author_rank: Unknown
timestamp: January 16, 2016, 06:19:21 pm
content: On most DSOs you *can* delay each channel by a variable amount (also known as "skew"). But the amount is usually small, on the order of +/-100ns, and is used to adjust for differences in probe and cable delays.
Oscilloscope digital channel - Page 1
Forum section: electronics / beginners

author: shadowless
author_rank: Regular Contributor
timestamp: April 26, 2011, 04:58:19 am
content: Very basic question, can i use the digital channel on the oscilloscope to measure pulse from a SG3524 chip or a picaxe output? Is analogue channel or digital channel more appropriate for this purpose?Thanks

author: scrat
author_rank: Frequent Contributor
timestamp: April 26, 2011, 08:45:59 am
content: If you're already sure that voltage levels and transitions are correct (and you can check them once and every time anything doesn't seem to be right), then the digital channel could be more comfortable for the purpose, especially because it leaves the other analogue channels free for further measurements.
Oscilloscope donate request - Page 1
Forum section: electronics / beginners

author: little_carlos
author_rank: Regular Contributor
timestamp: March 21, 2014, 04:02:00 pm
content: Hello, My name is Carlos, Im 16 years old, Im from Mexico and Im studying a Mechatronics technician degree in my highschool.Im getting all into electronics, I have some projects to make for my assignatures, for example, digital electronics and electronic sensors, and I need a oscilloscope, but, i have no money for buying one, and im almost all day in the school so i have no time left for work.Im asking, if someone have a old analog oscilloscope, that works and is no longer usefull for you, would you like to help me with my develop in my career? I really need it, it would be so nice from you guys, i would be very grateful, and i really need it for my overcoming projects.If you are interested, please send me an email to: moss.alpedo@gmail.comSincerely thanks for all of you who are interested in help. thank you so much.By the way, sorry for my bad english.
Oscilloscope for hobbyists and educational use - Page 1
Forum section: electronics / beginners

author: TheIronToSolderThemAll
author_rank: Newbie
timestamp: January 06, 2025, 08:51:08 am
content: Dear EEVblogI am currently attending advanced training in power electronics and need a 4-channel oscilloscope with decent resolution and analysis tools for various measurements on semiconductors. My old Hantek handheld oscilloscope lacks the necessary performance. Currently, there are many models and brands on the market, and I find it challenging to strike an optimal balance between price and performance.Here are three models I am considering for purchase:Rigol DH804, 70 MHzhttps://www.batronix.com/shop/oscilloscopes/Rigol-DHO804.htmlRigol DH914, 125 MHzhttps://www.batronix.com/shop/oscilloscopes/Rigol-DHO914.htmlSiglent SDS1104X-E, 100 MHzhttps://www.batronix.com/shop/oscilloscopes/Siglent-SDS1104X-E.htmlDoes anyone own one of these devices? I often see Rigol devices on YouTube but can’t really get a clear impression of how good they are.As I understand it, the math functions on Siglent devices (especially FFT) are better than those on Rigol.Additionally, the power supply is integrated into the Siglent device, which makes it my preferred option.Can anyone provide recommendations or suggest entirely different devices?Best regards

author: Aldo22
author_rank: Super Contributor
timestamp: January 06, 2025, 10:24:39 am
content: Why not this one?12bit, 2 GSa/s, 50 Mpts etc...https://www.batronix.com/shop/oscilloscopes/Siglent-SDS804X-hd.htmlhttps://www.eevblog.com/forum/testgear/sds800x-hd-review-demonstration-thread/

author: Old Printer
author_rank: Frequent Contributor
timestamp: January 06, 2025, 10:07:39 pm
content: I have the SDS 1104X-E and like it. Five years ago it was considered best in it's class, but 12 bit scopes are out now. All of this class of equipment goes through growing pains and takes a while to get the kinks worked out through firmware updates. The new scopes will still have some of that to go through, it's just the way the market is.

author: RoGeorge
author_rank: Super Contributor
timestamp: January 07, 2025, 10:11:29 am
content: You may want to look at the recent 12bits Siglent oscilloscopes, too.My personal opinion is that Siglent are slightly better than Rigol (when comparing the same new 12bits generation of scopes), but I didn't test them side by side. Thinking so because of this:https://www.eevblog.com/forum/testgear/sds800x-hd-review-demonstration-thread/