Author Topic: what an oscilloscope recommended for a woman passionate about electronics?  (Read 144258 times)

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Offline coppercone2

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This has been discussed to death. Gender is irrelevant, I can think of no reason to recommend a different scope for a woman than I would for a man, or somebody who is non-binary or whatever.

Anyway ask 10 people what scope to get and you'll likely get 10 different answers. The Rigol and Siglent models are some of the most popular in the hobbyist community. A friend of mine recently picked up a DS1054Z after I suggested it and he's been raving about it. Previously he had an old Tek 465B analog scope which was a fantastic instrument in its day but I can't think of a reason to recommend one to someone now other than nostalgia or if they need XY mode.

women may be less tolerant of a noisy boat anchor/heater (especially if married to one)
 

Offline alsetalokin4017

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Lol... you are right, I am only allowed to run my RM503 in winter....

The easiest person to fool is yourself. -- Richard Feynman
 
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Offline CharlotteSwissTopic starter

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Put the trigger marker inside the waveform and see what happens to the frequency counter.
For fun, move the trigger position all the way to the left.  Like an analog scope.  I’m not always interested in what happened before the trigger.

now I'm in bed, in a few hours I try to insert the trigger into the wave and see how the frequency counter behaves.
But to move everything left, what do you mean? did you mean top or bottom trigger level? or do you mean the blue marker?

It may turn out that the frequency counter doesn’t like very low frequencies.  Try 1 kHz

I thought so too, but then we see inserting the trigger into the wave that happens ... I also imagine that it is difficult to have signals with such low frequencies?
thanks  ;)

About removing DC from signal....
Let's say you have a 12 volt power supply.  But when you use it, you hear hum on speaker.  You'd think, there GOT TO BE some noise coming through this power supply.....
So you set it to DC and measure 12 volt.  It looks clean.  You scratch your head and go get some dinner.
You'd come back and remember the discussion.  Switch to AC.  You see NOTHING.  Then you'd use AUTO button or start to lower the vertical sensitivity.  All the sudden 60Hz, or 50Hz, depending on what your country use for mains show up.  Aha....
What is happening here is, SMALL (like 100 millivolt) signal was super imposed on 12 volt.  So if you are seeing 12 volt DC, you won't really see anything.  You may notice your trace is a bit fatter than usual.  But that's it.  (noise is about 1% of 12 volt!)  When you remove your DC components, you get to focus on the noise.  Sure, you'd have to increase the sensitivity, but by doing so, you'll see the cause of the problem.  Very small, relative to DC, AC noise! ^-^ ^-^ ^-^
thanks for the explanation, I haven't understood much for now: did you mean that if I measure in DC I don't see the noise problems on the signal? and therefore it would be useful to set AC coupling in the oscilloscope to analyze this signal?  ;)

Great progress! I am very happy to see that you are crosschecking the "numbers in boxes" with what you actually see (and calculate) on the screen.

Note that you have 42 mV of vertical offset. If you move the trace down so that you have zero offset, the trigger would then be within the waveform, leaving the trigger setting where it is now. This may affect the triggering, which may in turn affect the accuracy of the builtin frequency counter.

now that you have warned me, of course I also do the calculations and observe the divisions; initially I had not taken them into consideration.
Yes, the trigger level is 42mv lower, when I get up then I try to bring it into the wave...
 ;)



 

Offline rstofer

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The frequency counter on my Rigol goes nuts when the trigger level isn't within the waveform.  Good to know!

Associated with the time/division control is a horizontal position knob just above the Ch2 input that moves the waveform left or right on the screen.  In many digital situations, we care about what  happens after the trigger and want as much trace to the right of the trigger point as possible.  Things before the trigger may not be important.
« Last Edit: June 30, 2020, 07:06:34 am by rstofer »
 

Offline CharlotteSwissTopic starter

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The frequency counter on my Rigol goes nuts when the trigger level isn't within the waveform.  Good to know!

Associated with the time/division control is a horizontal position knob just above the Ch2 input that moves the waveform left or right on the screen.  In many digital situations, we care about what  happens after the trigger and want as much trace to the right of the trigger point as possible.  Things before the trigger may not be important.

I reported with a sine wave at 15Hz. In autoset it sets a fast horizontal time and does not distinguish sinusoid, then setting it to about 20ms it distinguishes itself. I tried to move the trigger up and down in the wave, but the frequency on the upper right display is never right (alternates from a few khz to 200khz ...).
As you can see from the pictures, counting with the div is instead correct, that is about 15Hz.
Also tried channel 2, same thing.
The automatic frequency counter is fooled by something, perhaps by the type of signal I don't know.

I have moved the wave to see everything to the right of the trigger point, so the signal that interests us most is usually what I have marked in white right? while the left side of the trigger point has little interest?





thanks
 ;)
 

Offline StillTrying

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There's 2 simple things to stop the trigger triggering on the high frequency noise and displaying the wrong frequency, HF Reject Page 59, and Noise Reject Page 61. Often using just one of them is enough.
.  That took much longer than I thought it would.
 

Offline borjam

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one day I will understand many things about this triggering, everything seems to be circulating around him  ;)
It's easy.

Imagine that you want to shoot a photograph of a bullet exiting a gun. How do you achieve that?

You will use a photo camera but you need to decide when to activate the camera. If you activate it too early or too late you will not catch the bullet in your photo.

That is the trigger.  The oscilloscope is like that photo camera. ¡The difference is that it is showing you a photograph of time instead of space!

That is why how you trigger is so important.
 

Offline temperance

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Offline CharlotteSwissTopic starter

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one day I will understand many things about this triggering, everything seems to be circulating around him  ;)
It's easy.

Imagine that you want to shoot a photograph of a bullet exiting a gun. How do you achieve that?

You will use a photo camera but you need to decide when to activate the camera. If you activate it too early or too late you will not catch the bullet in your photo.

That is the trigger.  The oscilloscope is like that photo camera. ¡The difference is that it is showing you a photograph of time instead of space!

That is why how you trigger is so important.

thanks for the example, very useful. So the trigger would be like that input that triggers the shutter release at the right time. If the trigger triggers right, we will have the signal on the display, otherwise not.
Basically default the center of the display is the trigger point, and there the signal is born which we will then see on the display
I think I should have understood these things before, it would have been easier. Now I must also understand how long the signal trace is: only the length of the display? infinity? this is another thing that I don't have in mind, and it is not a beautiful thing ..

thanks borjam  ^-^
 

Offline CharlotteSwissTopic starter

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Perhaps this might help:

https://www.tek.com/learning/oscilloscope-tutorial

my english is a disaster, but it seems very useful to me. I will certainly look at it
 :-+ thanks
 

Offline CharlotteSwissTopic starter

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There's 2 simple things to stop the trigger triggering on the high frequency noise and displaying the wrong frequency, HF Reject Page 59, and Noise Reject Page 61. Often using just one of them is enough.

great suggestion: reject noise does not solve anything, but HF reject works well, I had set the sinusoidal signal generator online at 15Hz, now also the frequency counter on the display shows the right signal.
I'm happy

 

Offline borjam

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thanks for the example, very useful. So the trigger would be like that input that triggers the shutter release at the right time. If the trigger triggers right, we will have the signal on the display, otherwise not.
Exactly. You might end up with a spaguetti of overlapping signals if you make a poor decision for the trigger.

For example (seeing actual operational errors helps a lot!) use the reference signal from the scope to test different trigger voltage values.

If the trigger is +- 1 V (I don't remember) and you try to trigger at 1 V it won't be able to draw the square wave accurately. You don't want it to trigger on a "flat" part of the signal of interest. Instead, try triggering on an edge, for example on 0.5 V, and you will see a clear representation.


Quote
Basically default the center of the display is the trigger point, and there the signal is born which we will then see on the display
I think I should have understood these things before, it would have been easier. Now I must also understand how long the signal trace is: only the length of the display? infinity? this is another thing that I don't have in mind, and it is not a beautiful thing ..
You can move the triggering point on the screen as well. Maybe there is a triggering event but you want to see what happened before the that event. Remember, the oscilloscope is a camera to take pictures of time, while a photo camera takes pictures of space.

To do that, use the "position" control below the horizontal knob.

And this is a really useful trick you can't do with an analog scope. You can capture a single event, freeze it on screen, and "zoom" into the horizontal range using the horizontal control.

To do that, use the "Single" triggering button.

(Unfortunately that "zooming" is not possible in the vertical axis due to limitations in the input electronics). The resolution of that "horizontal zoom" will be limited by the memory capture size you configure.

 

Offline CharlotteSwissTopic starter

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Exactly. You might end up with a spaguetti of overlapping signals if you make a poor decision for the trigger.
For example (seeing actual operational errors helps a lot!) use the reference signal from the scope to test different trigger voltage values.
If the trigger is +- 1 V (I don't remember) and you try to trigger at 1 V it won't be able to draw the square wave accurately. You don't want it to trigger on a "flat" part of the signal of interest. Instead, try triggering on an edge, for example on 0.5 V, and you will see a clear representation.



Basically default the center of the display is the trigger point, and there the signal is born which we will then see on the display
I think I should have understood these things before, it would have been easier. Now I must also understand how long the signal trace is: only the length of the display? infinity? this is another thing that I don't have in mind, and it is not a beautiful thing ..

To do that, use the "position" control below the horizontal knob.
And this is a really useful trick you can't do with an analog scope. You can capture a single event, freeze it on screen, and "zoom" into the horizontal range using the horizontal control.
To do that, use the "Single" triggering button.
(Unfortunately that "zooming" is not possible in the vertical axis due to limitations in the input electronics). The resolution of that "horizontal zoom" will be limited by the memory capture size you configure.

thanks borjan, then I carry out these two experiments; every exercise done in the field teaches a lot to those who have to learn. Then I'll let you know if I understand
 ^-^
 

Offline rstofer

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It has been apparent for some replies now that your signal has a lot of noise.  At first I thought it was regrettable but now I think it has been helpful because you have had to explore triggering problems that I don't recall ever having.  Your examples have been more realistic.
 

Offline CharlotteSwissTopic starter

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It has been apparent for some replies now that your signal has a lot of noise.  At first I thought it was regrettable but now I think it has been helpful because you have had to explore triggering problems that I don't recall ever having.  Your examples have been more realistic.

a new thing for me, will be to learn slowly to evaluate the waveform I see. For me it's a new thing.
If I look at the output waveform from my green pc audio jack, I see it fairly uniform, but chubby (I guess it's the noise).
I deduce that the top would be a lean sinusoid perhaps ..
But with a signal like this the music is listened to, I think it is a limit of the basic audio outputs of the motherboards (poor quality)
I have to get my bones to evaluate a waveform ...

 ;)
 

Offline CharlotteSwissTopic starter

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Exactly. You might end up with a spaguetti of overlapping signals if you make a poor decision for the trigger.

For example (seeing actual operational errors helps a lot!) use the reference signal from the scope to test different trigger voltage values.

If the trigger is +- 1 V (I don't remember) and you try to trigger at 1 V it won't be able to draw the square wave accurately. You don't want it to trigger on a "flat" part of the signal of interest. Instead, try triggering on an edge, for example on 0.5 V, and you will see a clear representation.

I started with this exercise, using the square wave of cal.
I didn't quite understand the 1v or 0.5v talk of the trigger level.
The amplitude of the square signal is about 3v.
To have a stable square wave on the display, I can vary the trigger level with an offset (referred to the 0v of the signal, left pointer) that goes from 130mv at the bottom, up to 2.97v at the top. Outside this range the signal is not stable on the display!
Within this range it seems to me that the signal ramp is almost the same with both triggers.
Did you mean something different?





thanks
 ;)
 

Offline Mechatrommer

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my english is a disaster, but it seems very useful to me. I will certainly look at it
you english is fine, except too much pinky terms imho like few people around here used too much than it should be naturally... such as...
now I'm in bed, in a few hours I try to insert the trigger into the wave...
we dont "insert" a "trigger" into the wave, though i think i understand what you meant...

As others have said, stay away from mains voltage and you are orders of magnitude safer already.
come on now let the girl do her stuff.. may i suggest to insert this to the collection...

http://en.pintech.com.cn/bls_html/ighvoltageprobeblsarticlelist/zhighvoltageprobeblsarticlearticle52.html


much more pleasurable to grip and safer... though the brand name like Fluke maybe more forgiving and cheaper, except lower rating.
https://sydneytools.com.au/product/fluke-80k6-6000v-high-voltage-probe

ps: you can ignore the but (ground) plug/clip unless you know where to put it appropriately (advanced users)... ;) have fun.
« Last Edit: June 30, 2020, 03:43:16 pm by Mechatrommer »
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Offline CharlotteSwissTopic starter

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you english is fine, except too much pinky terms imho like few people around here used too much than it should be naturally... such

much more pleasurable to grip and safer... though the brand name like Fluke maybe more forgiving and cheaper, except lower rating.
https://sydneytools.com.au/product/fluke-80k6-6000v-high-voltage-probe

ps: you can ignore the but (ground) plug/clip unless you know where to put it appropriately (advanced users)... ;) have fun.

I don't always know if the translator does his job well  ;)
but what should I need probes for 6000v? :o
cost as half oscilloscope, better to turn away from the mains voltage  ;)
thanks for the suggestion  :-+
 

Offline StillTrying

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I tried the tone generator page  www.szynalski.com/tone-generator  and the Signal Generator on Soundcard Oscilloscope  www.zeitnitz.eu/scope_en

By highering the PC's volume I could easily get up to 3V peak to peak noise free sines, the square, triangle and sawtooth weren't very good, steps, overshoots and jittery, and by 9kHz they're all just sine like. So then I tried some XY shapes, they weren't very good either. :)
« Last Edit: July 11, 2020, 12:52:54 pm by StillTrying »
.  That took much longer than I thought it would.
 

Offline CharlotteSwissTopic starter

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By highering the PC's volume I could easily get up to 3V peak to peak noise free sines, the square, triangle and sawtooth weren't very good, steps, overshoots and jittery, and by 9kHz they're all just sine like. So then I tried some XY shapes, they weren't very good either. :)

for me the important thing was to have a signal feedback and that the frequency was right
thanks for the tip on that setting  ;)
 

Online tautech

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Experiment with the timebase setting and the frequency readout.
You ideally need a few waveform cycles on the display for the frequency readout to be correct.
Just using the probe compensation output will be OK to see what's happening.


While you're at it another small exercise:
Trigger Setup, select Falling or Alternate and see what they each do.  ;)
Avid Rabid Hobbyist.
Some stuff seen @ Siglent HQ cannot be shared.
 

Offline CharlotteSwissTopic starter

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Experiment with the timebase setting and the frequency readout.
You ideally need a few waveform cycles on the display for the frequency readout to be correct.
Just using the probe compensation output will be OK to see what's happening.


While you're at it another small exercise:
Trigger Setup, select Falling or Alternate and see what they each do.  ;)

now I have the table occupied by an audio system to be fixed (since the card is 12v and isolated from the mains voltage, I could also start using the oscilloscope for some checks)
As soon as I free everything, I go back to studying the siglent: I wrote down the exercises to do
thanks  ;)
 

Offline alsetalokin4017

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Just as any (working!) oscilloscope is better than no oscilloscope at all, it is also true that just about any working signal generator or function generator is better than no signal generator at all. The two instruments are born companions and are lonely without one another.

They are great fun to play with while exploring the oscilloscope, and are even very useful in the audio repair lab. Inject an audio signal of known parameters into the input of an audio circuit, use the oscilloscope to follow it through the circuitry node by node until it gets wonky or disappears -- and you have located your fault!

For under 5 USD you can build a 555-based signal generator that will produce sine (nearly), square with variable duty cycle, triangle ramp waveforms. Even such a little toy is useful in many ways.

examples: https://www.instructables.com/id/Oscillator-circuits-for-the-555-timer/

I would not use my cellphone or computer for troubleshooting faults in circuits. Better to use a standalone signal generator; even a cheap one will be better in many ways than using a general purpose and expensive gadget like a phone or computer.
« Last Edit: July 01, 2020, 01:59:55 am by alsetalokin4017 »
The easiest person to fool is yourself. -- Richard Feynman
 

Offline 0culus

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A good function generator and a good pulse generator are both useful to have around. With a reasonably fast pulser, and a tee connector, you can do crude TDR with your scope to measure the length of a piece of coax, find a fault in a coax, etc.
 

Offline borjam

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I started with this exercise, using the square wave of cal.
I didn't quite understand the 1v or 0.5v talk of the trigger level.
The amplitude of the square signal is about 3v.
To have a stable square wave on the display, I can vary the trigger level with an offset (referred to the 0v of the signal, left pointer) that goes from 130mv at the bottom, up to 2.97v at the top. Outside this range the signal is not stable on the display!
Within this range it seems to me that the signal ramp is almost the same with both triggers.
Did you mean something different?

Perfect. That's what I meant but I didn't remember the actual values involved.

So you see you can't obtain a useful trigger outside of that interval in this particular case. Setting the trigger level to, say, 1 V means "trigger when the voltage hits 1 V and it is raising". If you try to trigger on a mostly "horizontal" part of the signal you won't obtain a clear image, as you just saw :)
 


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