what an oscilloscope recommended for a woman passionate about electronics?

[CharlotteSwiss]

what can all this teach me ?

Triggering to get a stable signal is the most important tool you have ! 

one day I will understand many things about this triggering, everything seems to be circulating around him 

[CharlotteSwiss]

If you are having trouble saving screenshots, you could try a different USB thumbdrive. I presume you have tried simply waiting --

The Rigol sometimes is balky in this same way, especially  if a complex display is in use. But using a low capacity thumb drive and a lot of patience cures it for me.

I don't remember if the problem did it only with this stick, I have 3 ... the smallest is 8GB, maybe a minor one was better .. I will investigate this problem better later

[CharlotteSwiss]

For audio work we use a much slower timebase setting usually unless we want to see distortion of a very clean sinewave.

ok, but it's just a test to see signals other than the compensation one .. among other things, I have no chance to hear how the audio jack output of the pc sounds, I don't use it and I don't have audio speakers for 3.5 jack
(the audio comes out via usb-dac-amplifier-japan speakers from mobile). Good sound for me 

[Labrat101]

Hi
sorry I did not get back about the plug had urgent stuff .
I think that you are getting too much info that is confusing you .
I notice that every one is telling you the Correct ways which are all Good but I think that you are miss understanding .
As you are a novice . and 99% of us on this site are super Nerds including myself .
 and you are not getting the entire concept.
You are trying to run before you can walk . ( not being rude)
Try connecting your plug as shown . the other end to PC / Phone / MP player etc .
 use the ground as it will make it easier for you . Yes, you can use a probe without a ground but as you are learning use the Ground
 turn on the sound music what ever. connect probe to the first connector on the scope marked yellow . press Auto and you should
see a result.

 I don't know what your electric knowledge is like . but I guess its limited as well.
 putting it simple without the maths & numbers etc .  A sine wave is alternating as it moves up & down from the centre line .
 Upper part is Positive and the down is negative the distance between the up and lower peeks are the Peek to Peek voltage. (VPP)
 Square wave is a pulse  ON or  OFF  . Like playing with a light switch the bulb goes on and off.  The vertical line on the square wave (90deg up)
Is the rise time and the other is the Fall time speed of the switch contacts opening or closing .
This also applies to the Sine slops .
So 100Hz is = 100 ON OFF's per second .  ( OK I put a Number )
The AC setting as some other have also mentioned Correctly is a little confusing to the new comer  . ( not required at this time )
stay on DC setting for now.

I hope this helped And I know to much knowledge to fast is hard .
But in a week or 2 you will laugh at how easy it was .
Time base has been mentioned very nicely by the others posts
PS keep your trigger level positive on the signal .from centre line 10% to 90%  but not above the wave.
You then need to turn the Horizontal (time base till you get a smaller more compact wave to see all )
 this will take practice and you can turn this knob from min to max to get the feel of what it does.


I use to write Manuals for Intel.

[rstofer]

Look at your compensation signal at 1us/div.  Now you will see some kind of exponential rise in the rising edge and you can shift the trace back and forth by adjusting the trigger level.  My trace breaks up when I try to get below 300 mV for the trigger point.  You will be able to see exactly where the scope triggers on that edge.

ok I set the time base to 1us (with such fast times the angle of the signal is rounded a lot).
But then I didn't understand where I should move the pointer trigger. Down until it comes out of the signal?

(Attachment Link)

sorry but it's not easy for me 

You can trigger at any level the scope can handle.  It really doesn't matter in this example but sometimes, when we're trying to actually measure risetime of a signal, we want the time between 10% and 90% and triggering at 10% might be handy.  Then we look at the time when we reach 90% and call it risetime.  THere are variations on the 10%/90% numbers but these will do for now.

The important take-away:  You got the right signal and you can move the trigger point.  That is all that's necessary right now.

[alsetalokin4017]

For audio work we use a much slower timebase setting usually unless we want to see distortion of a very clean sinewave.

ok, but it's just a test to see signals other than the compensation one .. among other things, I have no chance to hear how the audio jack output of the pc sounds, I don't use it and I don't have audio speakers for 3.5 jack
(the audio comes out via usb-dac-amplifier-japan speakers from mobile). Good sound for me 

You are not even seeing what you think or want to see, because you are using the Autoset function rather than setting up the scope yourself.

You are inputting a 4 Hz sine wave --- but your display is showing not what you are wanting to see, which presumably is a 4 Hz sine wave. Rather, the scope thinks you want to see some high frequency noise, which is probably there whether or not your 4Hz sine wave is there.

[tautech]

For audio work we use a much slower timebase setting usually unless we want to see distortion of a very clean sinewave.

ok, but it's just a test to see signals other than the compensation one .. among other things, I have no chance to hear how the audio jack output of the pc sounds, I don't use it and I don't have audio speakers for 3.5 jack
(the audio comes out via usb-dac-amplifier-japan speakers from mobile). Good sound for me 

You are not even seeing what you think or want to see, because you are using the Autoset function rather than setting up the scope yourself.

No, the Autoset return bar even if you adjust the trigger level as the OP has done.
Another front panel button must be pressed before it disappears

[alsetalokin4017]

For audio work we use a much slower timebase setting usually unless we want to see distortion of a very clean sinewave.

ok, but it's just a test to see signals other than the compensation one .. among other things, I have no chance to hear how the audio jack output of the pc sounds, I don't use it and I don't have audio speakers for 3.5 jack
(the audio comes out via usb-dac-amplifier-japan speakers from mobile). Good sound for me 

You are not even seeing what you think or want to see, because you are using the Autoset function rather than setting up the scope yourself.

No, the Autoset return bar even if you adjust the trigger level as the OP has done.
Another front panel button must be pressed before it disappears

I am talking about the sine wave she displayed up above. Please look at that screen carefully, and tell me how a 4 Hz sine wave input signal results in that display.

[alsetalokin4017]

Garbage in, garbage out. This applies to oscilloscopes as well as computers. Users need to be able to tell the difference, because the scope can't.

[tautech]

For audio work we use a much slower timebase setting usually unless we want to see distortion of a very clean sinewave.

ok, but it's just a test to see signals other than the compensation one .. among other things, I have no chance to hear how the audio jack output of the pc sounds, I don't use it and I don't have audio speakers for 3.5 jack
(the audio comes out via usb-dac-amplifier-japan speakers from mobile). Good sound for me 

You are not even seeing what you think or want to see, because you are using the Autoset function rather than setting up the scope yourself.

No, the Autoset return bar even if you adjust the trigger level as the OP has done.
Another front panel button must be pressed before it disappears

I am talking about the sine wave she displayed up above. Please look at that screen carefully, and tell me how a 4 Hz sine wave input signal results in that display.

412 Hz 

[CharlotteSwiss]

You set your sine wave at "a few Hz frequency" but the scope's automatic measurement is indicating 412.858 kiloHertz, and the rough calculation from the graticule markers and the 20 ns/div horizontal timebase setting is wildly different even from that.

This does not indicate anything wrong with the scope... rather it is an artefact of the Autoset function which is guessing what you want to see, and is zeroing in on the noise on top of your true "a few Hz" frequency, rather than the sine wave you are sending it, I think.

in fact I hadn't noticed, so wouldn't autoset be used? manual for now I am not able to do anything though ..

You miss my point. I am asking you  to _calculate_ the frequency of the displayed sine wave, based on the graticule markers and the timebase setting. You have one full cycle displayed over 9.5 divisions horizontally, at 20 nanoseconds per division. What is the frequency of the displayed wave?

1: (1.9 × 10 raised to -7) = frequency
that's what I'm missing?

[CharlotteSwiss]

Try connecting your plug as shown . the other end to PC / Phone / MP player etc .
 use the ground as it will make it easier for you . Yes, you can use a probe without a ground but as you are learning use the Ground
 turn on the sound music what ever. connect probe to the first connector on the scope marked yellow . press Auto and you should
see a result.

 I don't know what your electric knowledge is like . but I guess its limited as well.
 putting it simple without the maths & numbers etc .  A sine wave is alternating as it moves up & down from the centre line .
 Upper part is Positive and the down is negative the distance between the up and lower peeks are the Peek to Peek voltage. (VPP)

the rest I opened my discussion .. in the beginners section. 
I know the theory on AC, Vrsm, Vp Vpp (I'm not an engineer though).
I immediately connected the probe in that way, I also put the snapshot of what I see on the display
thanks 

[CharlotteSwiss]

You can trigger at any level the scope can handle.  It really doesn't matter in this example but sometimes, when we're trying to actually measure risetime of a signal, we want the time between 10% and 90% and triggering at 10% might be handy.  Then we look at the time when we reach 90% and call it risetime.  THere are variations on the 10%/90% numbers but these will do for now.

The important take-away:  You got the right signal and you can move the trigger point.  That is all that's necessary right now.

yes for now with the trigger I stop here, ok I understand that I can move the trigger point inside the signal both up and down, and this is positive (for the signal)
 

[CharlotteSwiss]

You are not even seeing what you think or want to see, because you are using the Autoset function rather than setting up the scope yourself.

You are inputting a 4 Hz sine wave --- but your display is showing not what you are wanting to see, which presumably is a 4 Hz sine wave. Rather, the scope thinks you want to see some high frequency noise, which is probably there whether or not your 4Hz sine wave is there.

I started yesterday to turn on an oscilloscope for the first time, maybe tomorrow I will understand that I can also do something without an autoset
I will try to understand how not to use autoset 

[rstofer]

1: (1.9 × 10 raised to -7) = frequency
that's what I'm missing?

1.9 x 10^-7 is the time.  The frequency is 1/time or 5.26... MHz

You think you are putting in 4 Hz and the frequency counter thinks it is 413 kHz.  Worse yet, you have 9.5 divisions at 20 ns per division so a cycle is 190 ns and the frequency is about 5 MHz (if I did the calculation correctly).  In other words, you are seeing noise at a high frequency on top of what is probably noise at a low frequency but, whatever it is, it's NOT a 4 Hz sine wave.

A 4 Hz waveform would show 1 cycle in 1 division if you could set 250 ms per division.  It would take 1/4 second to sweep 1 division and probably 3 seconds to trace the screen (assuming 12 division across the screen).

You probably can't select 250 ms per division so pick 100 ms/div and the sine wave will take 2.5 divisions.  Assuming it is actually a 4 Hz signal.  My guess is that there is some kind of scaling going on with the signal generator.  I would just about trust the frequency counter but I know for sure that 20 ns per division seems wrong for audio.

Given 20 kHz as an upper limit on audio (whether it is or not), we know that 50 us is the time per cycle.  If we want just two cycles on the screen, we have 50 us across 6 divisions or 8.33 us per division.  We can't dial that so we pick 10 us per division.  Or 5 us/div.

One thing is clear:  We need to know what we're looking for before we decide to display it.  For an audio signal, nanoseconds are out of the question.

[CharlotteSwiss]

Here once again we have the opportunity to point out that the AUTO setup button is a different thing than the Auto Sweep Mode.

The AUTO setup button causes the scope to make a "best guess" at the signal and chooses the timebase, trigger level and vertical amplitude based on this guess. It sets the scope up  "automatically" but this may not always be what the user needs to see. It can be a good starting point for probing a completely unknown signal but should not be relied upon to give the user the best data or image possible.

The Auto horizontal sweep mode tells the scope to pause unless a signal over the trigger level is detected, at which point the scope runs and displays the signal. When the signal is removed or drops below the trigger level, the scope stops running and displays a static (still picture) of the last waveform detected. The Normal horizontal sweep mode tells the scope to just keep running, no matter what the trigger level is. If the signal amplitude drops below the trigger level, the trace will just lose horizontal stability but will continue to display, and when the signal is gone you'll see a flat line. The Single Shot horizontal sweep mode (not a trigger mode!) waits for a signal amplitude greater than the trigger level and then runs One Sweep, that is one horizontal screen width, and then stops, holding the display of the waveform detected during that single horizontal sweep.

It is important at this stage to be practicing reading the actual values of traces and their frequencies using the graticule markers. The vertical scale is calibrated in volts per division and the horizontal scale is calibrated in seconds per division -- the scale factors set by the user on the vertical scale and horizontal timebase controls. So if you have vertical scale set to 1 volt per division and you see a signal that is three and a half divisions tall, you are looking at a 3.5 volt difference between the low and high. If you have the horizontal timebase set to 500 microseconds per division and your sine wave is exactly 4 divisions from peak to peak, you have a frequency of 1 cycle per 2 milliseconds or 500 Hz.  ( 1 / 0.002 = 500 ) Und so weiter.

thanks for the explanation; I know the lower part about the dividers, like the calculation of the frequency based on the times (50Hz = 50 periods in a second).
The part concerning the auto or manual settings, I have yet to understand them, for now I have been told to press the Auto key (made yesterday to calibrate the probes), and today for the first measurement of a signal other than that of cal
 

[rstofer]

You are not even seeing what you think or want to see, because you are using the Autoset function rather than setting up the scope yourself.

You are inputting a 4 Hz sine wave --- but your display is showing not what you are wanting to see, which presumably is a 4 Hz sine wave. Rather, the scope thinks you want to see some high frequency noise, which is probably there whether or not your 4Hz sine wave is there.

I started yesterday to turn on an oscilloscope for the first time, maybe tomorrow I will understand that I can also do something without an autoset
I will try to understand how not to use autoset 

Did Autoset get a trace on the screen?  Sure!  It may not be what you want in terms of V/div or t/div but it's a trace on the screen.  It is entirely possible that a scope remembers the last settings (which is itself a setting) and you could have left the scope in X-Y mode or some other bizarre set of parameters.

Autoset worked fine.  It's tweaking the display and rationalizing the settings that needs work.

If you think the signal is 4 Hz and the Frequency Counter thinks somewhere over 400 kHz and the math says somewhat over 5 MHz, something is wrong.  It isn't the fault of Autoset.

[CharlotteSwiss]

1: (1.9 × 10 raised to -7) = frequency
that's what I'm missing?

1.9 x 10^-7 is the time.  The frequency is 1/time or 5.26... MHz

You think you are putting in 4 Hz and the frequency counter thinks it is 413 kHz.  Worse yet, you have 9.5 divisions at 20 ns per division so a cycle is 190 ns and the frequency is about 5 MHz (if I did the calculation correctly).  In other words, you are seeing noise at a high frequency on top of what is probably noise at a low frequency but, whatever it is, it's NOT a 4 Hz sine wave.

A 4 Hz waveform would show 1 cycle in 1 division if you could set 250 ms per division.  It would take 1/4 second to sweep 1 division and probably 3 seconds to trace the screen (assuming 12 division across the screen).

You probably can't select 250 ms per division so pick 100 ms/div and the sine wave will take 2.5 divisions.  Assuming it is actually a 4 Hz signal.  My guess is that there is some kind of scaling going on with the signal generator.  I would just about trust the frequency counter but I know for sure that 20 ns per division seems wrong for audio.

Given 20 kHz as an upper limit on audio (whether it is or not), we know that 50 us is the time per cycle.  If we want just two cycles on the screen, we have 50 us across 6 divisions or 8.33 us per division.  We can't dial that so we pick 10 us per division.  Or 5 us/div.

One thing is clear:  We need to know what we're looking for before we decide to display it.  For an audio signal, nanoseconds are out of the question.

if you look carefully, the calculation for the frequency I wrote is right 1: (time of the period).
As I said above, I'm not sure what goes through the audio output of this PC, I can't even try if the audio comes out .. because I don't have speakers with jack, and I use the USB to exit the PC with audio
(DAC Musical Fidelity). I have to be sure to take a certified signal to learn something, I would miss trying a pc audio output ...
 

[CharlotteSwiss]

Did Autoset get a trace on the screen?  Sure!  It may not be what you want in terms of V/div or t/div but it's a trace on the screen.  It is entirely possible that a scope remembers the last settings (which is itself a setting) and you could have left the scope in X-Y mode or some other bizarre set of parameters.

Autoset worked fine.  It's tweaking the display and rationalizing the settings that needs work.

If you think the signal is 4 Hz and the Frequency Counter thinks somewhere over 400 kHz and the math says somewhat over 5 MHz, something is wrong.  It isn't the fault of Autoset.

now I want to try again: first I measure the signal of the audio cable, but without any online signal in play, in my opinion a frequency comes out of that cable ...
Then I try again with the online signal frequency still 4 Hz ...
I'll be careful how often the oscilloscope marks me at the top right
 

[CharlotteSwiss]

I start to see something sensible on the display: I generated an online sine wave at 10Hz (also the ground on the plug), and the autoset took us: on the display it indicates <10Hz, but doing the calculation with the dives of the times, 10Hz comes out precise. 1/(20msx5 in sec)=10Hz



then analyze this sine wave are not goats, but the important thing is to begin to understand what I see on the display 

[CharlotteSwiss]

I then tried to generate the sinusoidal signal online at 40Hz: with the calculation of the div it comes out right, at the top it instead marks <10Hz
1:(about 25ms ->sec)= 40Hz
therefore the time base is correct on the display, the wording of the frequency is not.



in both cases I see the trigger marker out of the wave

[rstofer]

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.

[rstofer]

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

[tkamiya]

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!

By the way....  I have never seen this kind of rapid response to a newbie question.  I think everyone has this tall blond woman with blue eyes in back of their mind....   

[alsetalokin4017]

I then tried to generate the sinusoidal signal online at 40Hz: with the calculation of the div it comes out right, at the top it instead marks <10Hz
1:(about 25ms ->sec)= 40Hz
therefore the time base is correct on the display, the wording of the frequency is not.

(Attachment Link)

in both cases I see the trigger marker out of the wave

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.