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Why can't I see bouncing of a switch on an oscilloscope?
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Why can't I see bouncing of a switch on an oscilloscope?
Can't observe DC offset in a simple RC circuit with an oscilloscopeWhy I cannot see SPI signal properly with oscilloscope?See if signal is amplified without an oscilloscopeTiming diagram of circuit involving switch debouncingMy “audio oscilloscope” can't measure static/constant voltages but only changesHow to add bouncing to a switch in LTspice?Oscilloscope saving data unexpectedlyWhy do I see multiple waveforms on my oscilloscope in normal trigger mode?Bouncing at some points in square waveFrequency of contact bouncing
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$begingroup$
I'm trying to view the bouncing of a simple switch on an oscilloscope.
I have prepared a simple breadboard circuit (power->switch->resistor->ground). The problem is, it is displayed as a perfect square/rectangle on the scope. I have attached a photo of the scope screen and the circuit.
Please help me understand why I can't catch the bouncing of the switch on the scope. I don't think it this is a non-bouncing switch.
Edit: Here is a photo showing a zoomed-in time scale (50us/div). As you can see it is rising from 0V to 9V within 150us and staying there. I have tried a few different switches. The resistor in the picture is 220-Ohm, 0.5-Watt.
switches oscilloscope debounce
New contributor
$endgroup$
|
show 16 more comments
$begingroup$
I'm trying to view the bouncing of a simple switch on an oscilloscope.
I have prepared a simple breadboard circuit (power->switch->resistor->ground). The problem is, it is displayed as a perfect square/rectangle on the scope. I have attached a photo of the scope screen and the circuit.
Please help me understand why I can't catch the bouncing of the switch on the scope. I don't think it this is a non-bouncing switch.
Edit: Here is a photo showing a zoomed-in time scale (50us/div). As you can see it is rising from 0V to 9V within 150us and staying there. I have tried a few different switches. The resistor in the picture is 220-Ohm, 0.5-Watt.
switches oscilloscope debounce
New contributor
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10
$begingroup$
Have you tried adjusting the time base / horizontal scale?
$endgroup$
– NMF
9 hours ago
1
$begingroup$
If you don't succeed on the first try, try again.
$endgroup$
– StainlessSteelRat
9 hours ago
9
$begingroup$
I have a hard time believing that your zoomed in version is actually a new trig. Nothing would look like that except the scope's internal interpolation. An clean break with an RC-filter created by the scope would show an exponential clean rise - nothing linear. I bet that you just zoomed in on the stored waveform.
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– pipe
8 hours ago
2
$begingroup$
My zoomed photo is from another capture with battery instead of power supply. But as @pipe sait I have captured on zoomed out view and then zoomed on the rising edge after that. Now I understand that changing time scale before the capture and after the capture is different things? I didn't know that. I will need to figure out how to capture when time scale is set to uSec range.
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– Deniz
8 hours ago
2
$begingroup$
@Deniz Set the time base reasonably fast (maybe 1ms), the scope trigger to "single" and "rising edge", then press the button. That should be OK. You might also want to look at the display settings, and either change the points to just show dots for each point, or to step to each point (giving a ”staircase" effect). That'll stop you getting fooled when you zoom in too far.
$endgroup$
– Graham
7 hours ago
|
show 16 more comments
$begingroup$
I'm trying to view the bouncing of a simple switch on an oscilloscope.
I have prepared a simple breadboard circuit (power->switch->resistor->ground). The problem is, it is displayed as a perfect square/rectangle on the scope. I have attached a photo of the scope screen and the circuit.
Please help me understand why I can't catch the bouncing of the switch on the scope. I don't think it this is a non-bouncing switch.
Edit: Here is a photo showing a zoomed-in time scale (50us/div). As you can see it is rising from 0V to 9V within 150us and staying there. I have tried a few different switches. The resistor in the picture is 220-Ohm, 0.5-Watt.
switches oscilloscope debounce
New contributor
$endgroup$
I'm trying to view the bouncing of a simple switch on an oscilloscope.
I have prepared a simple breadboard circuit (power->switch->resistor->ground). The problem is, it is displayed as a perfect square/rectangle on the scope. I have attached a photo of the scope screen and the circuit.
Please help me understand why I can't catch the bouncing of the switch on the scope. I don't think it this is a non-bouncing switch.
Edit: Here is a photo showing a zoomed-in time scale (50us/div). As you can see it is rising from 0V to 9V within 150us and staying there. I have tried a few different switches. The resistor in the picture is 220-Ohm, 0.5-Watt.
switches oscilloscope debounce
switches oscilloscope debounce
New contributor
New contributor
edited 2 hours ago
bitsmack
11.9k73677
11.9k73677
New contributor
asked 9 hours ago
DenizDeniz
1364
1364
New contributor
New contributor
10
$begingroup$
Have you tried adjusting the time base / horizontal scale?
$endgroup$
– NMF
9 hours ago
1
$begingroup$
If you don't succeed on the first try, try again.
$endgroup$
– StainlessSteelRat
9 hours ago
9
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I have a hard time believing that your zoomed in version is actually a new trig. Nothing would look like that except the scope's internal interpolation. An clean break with an RC-filter created by the scope would show an exponential clean rise - nothing linear. I bet that you just zoomed in on the stored waveform.
$endgroup$
– pipe
8 hours ago
2
$begingroup$
My zoomed photo is from another capture with battery instead of power supply. But as @pipe sait I have captured on zoomed out view and then zoomed on the rising edge after that. Now I understand that changing time scale before the capture and after the capture is different things? I didn't know that. I will need to figure out how to capture when time scale is set to uSec range.
$endgroup$
– Deniz
8 hours ago
2
$begingroup$
@Deniz Set the time base reasonably fast (maybe 1ms), the scope trigger to "single" and "rising edge", then press the button. That should be OK. You might also want to look at the display settings, and either change the points to just show dots for each point, or to step to each point (giving a ”staircase" effect). That'll stop you getting fooled when you zoom in too far.
$endgroup$
– Graham
7 hours ago
|
show 16 more comments
10
$begingroup$
Have you tried adjusting the time base / horizontal scale?
$endgroup$
– NMF
9 hours ago
1
$begingroup$
If you don't succeed on the first try, try again.
$endgroup$
– StainlessSteelRat
9 hours ago
9
$begingroup$
I have a hard time believing that your zoomed in version is actually a new trig. Nothing would look like that except the scope's internal interpolation. An clean break with an RC-filter created by the scope would show an exponential clean rise - nothing linear. I bet that you just zoomed in on the stored waveform.
$endgroup$
– pipe
8 hours ago
2
$begingroup$
My zoomed photo is from another capture with battery instead of power supply. But as @pipe sait I have captured on zoomed out view and then zoomed on the rising edge after that. Now I understand that changing time scale before the capture and after the capture is different things? I didn't know that. I will need to figure out how to capture when time scale is set to uSec range.
$endgroup$
– Deniz
8 hours ago
2
$begingroup$
@Deniz Set the time base reasonably fast (maybe 1ms), the scope trigger to "single" and "rising edge", then press the button. That should be OK. You might also want to look at the display settings, and either change the points to just show dots for each point, or to step to each point (giving a ”staircase" effect). That'll stop you getting fooled when you zoom in too far.
$endgroup$
– Graham
7 hours ago
10
10
$begingroup$
Have you tried adjusting the time base / horizontal scale?
$endgroup$
– NMF
9 hours ago
$begingroup$
Have you tried adjusting the time base / horizontal scale?
$endgroup$
– NMF
9 hours ago
1
1
$begingroup$
If you don't succeed on the first try, try again.
$endgroup$
– StainlessSteelRat
9 hours ago
$begingroup$
If you don't succeed on the first try, try again.
$endgroup$
– StainlessSteelRat
9 hours ago
9
9
$begingroup$
I have a hard time believing that your zoomed in version is actually a new trig. Nothing would look like that except the scope's internal interpolation. An clean break with an RC-filter created by the scope would show an exponential clean rise - nothing linear. I bet that you just zoomed in on the stored waveform.
$endgroup$
– pipe
8 hours ago
$begingroup$
I have a hard time believing that your zoomed in version is actually a new trig. Nothing would look like that except the scope's internal interpolation. An clean break with an RC-filter created by the scope would show an exponential clean rise - nothing linear. I bet that you just zoomed in on the stored waveform.
$endgroup$
– pipe
8 hours ago
2
2
$begingroup$
My zoomed photo is from another capture with battery instead of power supply. But as @pipe sait I have captured on zoomed out view and then zoomed on the rising edge after that. Now I understand that changing time scale before the capture and after the capture is different things? I didn't know that. I will need to figure out how to capture when time scale is set to uSec range.
$endgroup$
– Deniz
8 hours ago
$begingroup$
My zoomed photo is from another capture with battery instead of power supply. But as @pipe sait I have captured on zoomed out view and then zoomed on the rising edge after that. Now I understand that changing time scale before the capture and after the capture is different things? I didn't know that. I will need to figure out how to capture when time scale is set to uSec range.
$endgroup$
– Deniz
8 hours ago
2
2
$begingroup$
@Deniz Set the time base reasonably fast (maybe 1ms), the scope trigger to "single" and "rising edge", then press the button. That should be OK. You might also want to look at the display settings, and either change the points to just show dots for each point, or to step to each point (giving a ”staircase" effect). That'll stop you getting fooled when you zoom in too far.
$endgroup$
– Graham
7 hours ago
$begingroup$
@Deniz Set the time base reasonably fast (maybe 1ms), the scope trigger to "single" and "rising edge", then press the button. That should be OK. You might also want to look at the display settings, and either change the points to just show dots for each point, or to step to each point (giving a ”staircase" effect). That'll stop you getting fooled when you zoom in too far.
$endgroup$
– Graham
7 hours ago
|
show 16 more comments
7 Answers
7
active
oldest
votes
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First, "zoom in" to that rising edge by adjusting the time base. When you start getting close, you will start to see the rising slope of the signal.
As you do this, you will start to lose resolution on your captured signal. You can capture new samples of that rising edge using the scope's triggering mechanism.
Once you can see the rising slope, capture a new sample. Any bouncing/overshoot/noise should become apparent.
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I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
7
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If you zoom a stored waveform it may not have intermediate samples and just interpolate. You may see the edge sharper if you store a new sample at the higher timebase setting. As mentioned, good or new switches may have very little detectable bounce.
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– KalleMP
8 hours ago
4
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@Deniz no switch closure is going to result in a piecewise linear pulse -- that has to be a zoom-in of something sampled at a lower rate (probably 150$mu$s, because that's how long it's taking to rise up).
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– TimWescott
8 hours ago
1
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@Deniz To convince oneself, switch the scope display mode to points if possible
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– crasic
2 hours ago
add a comment |
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This is an issue with scope setup and misunderstanding of how to interpret scope captures. You must capture the rising edge of a single pulse at a reasonably small resolution by using a single trigger. Good news is that this is exactly what oscilloscopes are designed to do
The generic procedure is:
- Set trigger to edge (up) and trigger level at approximately half scale of your button voltage
- (Optional) Move the trigger (horizontal) offset to the left hand of screen to maximize the portion of capture after trigger
- Switch trigger to "normal" and "single mode" to arm the trigger for a single capture
- Press your button
- If you use continuous trigger you will get a new capture with every button press
- If you don't use normal mode you may lose the captured signal due to preview refresh (typically triggered at 60 Hz to have a simulated "live signal" mode), "single-normal" mode freezes the scope after capture
Most digital capture scopes record a fixed number of points at all time base, so the sample rate is determined by a combination of time base and capture depth (which may be configured) and limited by the maximum sampling rate. On my Tektronix oscilloscope the scope displays both the time per div and effective sample rate.
What is displayed may also be "windowed" depending on the mode, so it may not always be clear what your sample rate actually is. For example, 100K points into 1-second timebase with 10 divisions on screen would be 10 kS/sec. 100k points into a 10 µs timebase with 10 divisions on screen would be 1 GS/sec. Typically this is near the limit for common digital scopes, so time bases below 10 µs are often "zoomed in" divisions at 10 µs (e.g. 100k points into 10 divisions at 10 µs, but display one division with 1 µs time base on the screen).
Also note that analog bandwidth (for example, "100 MHz") does not directly relate to the digital sample rate.
An additional quirk, triggering is not done on the (digital) sampled signal, but directly on the input through a dedicated trigger system. This means that you can trigger (sometimes) on a pulse that is too short to be resolved in the digital signal. Or you can add a trigger delay much much longer than the sample depth (for example, display the capture at 10 µs resolution, but 1 second after the trigger). This is also why there is often an "aux" or "external trigger" port that can be used to trigger, but never displayed or captured.
The scope is effectively sampling continuously into a ring buffer and the trigger comes along and tells the sampling systems to store the buffer. This is a large amount of data, so it requires some time to store the data and to rearm the sample system. The electronics and suitable memory to process a gigabit stream continuously is very expensive so scopes are designed to make use of limited storage depth and digital bandwidth through triggering schemes.
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+1! Much more informative than my answer :)
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– bitsmack
3 hours ago
add a comment |
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Figure 1. The guys down at photo-forensics found this.
There are several factors:
- You have a nice new clean switch that bounces very little.
- Your scope is loading the circuit and the 15 pF is enough to help. This is unlikely, though, with what appears to be a resistor with a value in the hundreds of ohms. (The colour rendition of your photo is poor.)
- Timebase is too fast - but your comments say you've checked this.
I'd go with the first and second option.
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I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
3
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So you think the 15pF is loading the 220 Ohms with a 3.3ns RC asymptote resulting in a 150us linear ramp? Ask the forensic guys to check again. My forensic guy said it smelt like 220 ohm i.stack.imgur.com/xEwUo.png
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– Sunnyskyguy EE75
8 hours ago
add a comment |
$begingroup$
Assuming that the pull-down resistor is a reasonable value (1k - 10k), the very next thing that I would check is to see if there is a filter active on that channel. I wouldn't be looking for signal averaging - this is a single-event occurrence and the trace shows that single event. But it is entirely possible that there is a very-low frequency low-pass filter that is turned ON in the scope.
Another way to find out if it is a scope problem is to simply plug a pair of wires into the busses for the switch contacts. Then brush the two switch wires together and look at the noise (or lack thereof). Noise means scope is probably okay. Smooth ramp says that the scope isn't displaying the full bandwidth of the input signal.
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add a comment |
$begingroup$
Here is a test I did with my 200MHz Tek scope. You should be able to get similar results with the Rigol, this is an older scope with a modest 2Gs/s capture frequency.
My circuit is just a standard 10:1 probe connected across a 6mm tact switch with a 1K pullup to +5V supply.
Not all the captures were this messy, some were pretty ideal looking. Pushing it hard seemed to lead to more messiness. There's a bit of ringing despite a bypass across the power supply- that falling edge due to the switch contacts closing is very fast.
If I set the sweep too slow (and then expand) I just get interpolation between samples, which might be misleading. There's no information there so the scope fakes it.
Capture was single event, triggered by falling edge on the active channel, set relatively close to the 5V level (the yellow arrow on the right indicates the trigger level of 3.68V). The center of the screen is at -96ns (moved to view a bit more of the pre-trigger data since most of the action is pre-trigger).
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add a comment |
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Use an old switch or store your new switch in a mixture of salt water and vinegar for a few hours. That will corrode the contacts and increase the bounce.
New contributor
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add a comment |
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I have gone thru the answers mentioned above.
But First, please change your oscilloscope.
The scope you are using would have a shallow memory.(Acquisition Memory ...may be 1K or a few K memory).
Try with Deep Memory Scopes.Tektronix TDS 3000 or 4000 series , Keysight DSOx 3000 to 6000 series or many more brands and models are available.
You will definitely get a beautiful contact bounce ringing at the top the vertical rising/ falling edges.
The number of ringing edges is proportional to the length of your grounding wire length.Less the length, less ringing.The more the length, more ringing.
The Deep Memory scopes will contain record length or Acquisition memory in terms of Mb ....say 2Mb , 4Mb, 8Mb etc......Don't worry about Sampling rates. Deep memory will control to sustain the sampling rate.
I have captured enough time these switching circuits,in Deep memory scopes.
Try ...
Best Regards
A Senthil
New contributor
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10
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The instrument in use is orders or magnitude more than sufficient if used properly. Recommending the purchase of new gear over learning to use the ordinary and suitable gear at hand is the mark of those who do not know what they are doing. There exists a capture rate, within the capability of that scope where the bouncing of the actual contacts is easily represented on the screen alone, nevermind any off-screen memory.
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– Chris Stratton
3 hours ago
add a comment |
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7 Answers
7
active
oldest
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7 Answers
7
active
oldest
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active
oldest
votes
active
oldest
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$begingroup$
First, "zoom in" to that rising edge by adjusting the time base. When you start getting close, you will start to see the rising slope of the signal.
As you do this, you will start to lose resolution on your captured signal. You can capture new samples of that rising edge using the scope's triggering mechanism.
Once you can see the rising slope, capture a new sample. Any bouncing/overshoot/noise should become apparent.
$endgroup$
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
7
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If you zoom a stored waveform it may not have intermediate samples and just interpolate. You may see the edge sharper if you store a new sample at the higher timebase setting. As mentioned, good or new switches may have very little detectable bounce.
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– KalleMP
8 hours ago
4
$begingroup$
@Deniz no switch closure is going to result in a piecewise linear pulse -- that has to be a zoom-in of something sampled at a lower rate (probably 150$mu$s, because that's how long it's taking to rise up).
$endgroup$
– TimWescott
8 hours ago
1
$begingroup$
@Deniz To convince oneself, switch the scope display mode to points if possible
$endgroup$
– crasic
2 hours ago
add a comment |
$begingroup$
First, "zoom in" to that rising edge by adjusting the time base. When you start getting close, you will start to see the rising slope of the signal.
As you do this, you will start to lose resolution on your captured signal. You can capture new samples of that rising edge using the scope's triggering mechanism.
Once you can see the rising slope, capture a new sample. Any bouncing/overshoot/noise should become apparent.
$endgroup$
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
7
$begingroup$
If you zoom a stored waveform it may not have intermediate samples and just interpolate. You may see the edge sharper if you store a new sample at the higher timebase setting. As mentioned, good or new switches may have very little detectable bounce.
$endgroup$
– KalleMP
8 hours ago
4
$begingroup$
@Deniz no switch closure is going to result in a piecewise linear pulse -- that has to be a zoom-in of something sampled at a lower rate (probably 150$mu$s, because that's how long it's taking to rise up).
$endgroup$
– TimWescott
8 hours ago
1
$begingroup$
@Deniz To convince oneself, switch the scope display mode to points if possible
$endgroup$
– crasic
2 hours ago
add a comment |
$begingroup$
First, "zoom in" to that rising edge by adjusting the time base. When you start getting close, you will start to see the rising slope of the signal.
As you do this, you will start to lose resolution on your captured signal. You can capture new samples of that rising edge using the scope's triggering mechanism.
Once you can see the rising slope, capture a new sample. Any bouncing/overshoot/noise should become apparent.
$endgroup$
First, "zoom in" to that rising edge by adjusting the time base. When you start getting close, you will start to see the rising slope of the signal.
As you do this, you will start to lose resolution on your captured signal. You can capture new samples of that rising edge using the scope's triggering mechanism.
Once you can see the rising slope, capture a new sample. Any bouncing/overshoot/noise should become apparent.
edited 8 hours ago
answered 9 hours ago
bitsmackbitsmack
11.9k73677
11.9k73677
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
7
$begingroup$
If you zoom a stored waveform it may not have intermediate samples and just interpolate. You may see the edge sharper if you store a new sample at the higher timebase setting. As mentioned, good or new switches may have very little detectable bounce.
$endgroup$
– KalleMP
8 hours ago
4
$begingroup$
@Deniz no switch closure is going to result in a piecewise linear pulse -- that has to be a zoom-in of something sampled at a lower rate (probably 150$mu$s, because that's how long it's taking to rise up).
$endgroup$
– TimWescott
8 hours ago
1
$begingroup$
@Deniz To convince oneself, switch the scope display mode to points if possible
$endgroup$
– crasic
2 hours ago
add a comment |
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
7
$begingroup$
If you zoom a stored waveform it may not have intermediate samples and just interpolate. You may see the edge sharper if you store a new sample at the higher timebase setting. As mentioned, good or new switches may have very little detectable bounce.
$endgroup$
– KalleMP
8 hours ago
4
$begingroup$
@Deniz no switch closure is going to result in a piecewise linear pulse -- that has to be a zoom-in of something sampled at a lower rate (probably 150$mu$s, because that's how long it's taking to rise up).
$endgroup$
– TimWescott
8 hours ago
1
$begingroup$
@Deniz To convince oneself, switch the scope display mode to points if possible
$endgroup$
– crasic
2 hours ago
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
7
7
$begingroup$
If you zoom a stored waveform it may not have intermediate samples and just interpolate. You may see the edge sharper if you store a new sample at the higher timebase setting. As mentioned, good or new switches may have very little detectable bounce.
$endgroup$
– KalleMP
8 hours ago
$begingroup$
If you zoom a stored waveform it may not have intermediate samples and just interpolate. You may see the edge sharper if you store a new sample at the higher timebase setting. As mentioned, good or new switches may have very little detectable bounce.
$endgroup$
– KalleMP
8 hours ago
4
4
$begingroup$
@Deniz no switch closure is going to result in a piecewise linear pulse -- that has to be a zoom-in of something sampled at a lower rate (probably 150$mu$s, because that's how long it's taking to rise up).
$endgroup$
– TimWescott
8 hours ago
$begingroup$
@Deniz no switch closure is going to result in a piecewise linear pulse -- that has to be a zoom-in of something sampled at a lower rate (probably 150$mu$s, because that's how long it's taking to rise up).
$endgroup$
– TimWescott
8 hours ago
1
1
$begingroup$
@Deniz To convince oneself, switch the scope display mode to points if possible
$endgroup$
– crasic
2 hours ago
$begingroup$
@Deniz To convince oneself, switch the scope display mode to points if possible
$endgroup$
– crasic
2 hours ago
add a comment |
$begingroup$
This is an issue with scope setup and misunderstanding of how to interpret scope captures. You must capture the rising edge of a single pulse at a reasonably small resolution by using a single trigger. Good news is that this is exactly what oscilloscopes are designed to do
The generic procedure is:
- Set trigger to edge (up) and trigger level at approximately half scale of your button voltage
- (Optional) Move the trigger (horizontal) offset to the left hand of screen to maximize the portion of capture after trigger
- Switch trigger to "normal" and "single mode" to arm the trigger for a single capture
- Press your button
- If you use continuous trigger you will get a new capture with every button press
- If you don't use normal mode you may lose the captured signal due to preview refresh (typically triggered at 60 Hz to have a simulated "live signal" mode), "single-normal" mode freezes the scope after capture
Most digital capture scopes record a fixed number of points at all time base, so the sample rate is determined by a combination of time base and capture depth (which may be configured) and limited by the maximum sampling rate. On my Tektronix oscilloscope the scope displays both the time per div and effective sample rate.
What is displayed may also be "windowed" depending on the mode, so it may not always be clear what your sample rate actually is. For example, 100K points into 1-second timebase with 10 divisions on screen would be 10 kS/sec. 100k points into a 10 µs timebase with 10 divisions on screen would be 1 GS/sec. Typically this is near the limit for common digital scopes, so time bases below 10 µs are often "zoomed in" divisions at 10 µs (e.g. 100k points into 10 divisions at 10 µs, but display one division with 1 µs time base on the screen).
Also note that analog bandwidth (for example, "100 MHz") does not directly relate to the digital sample rate.
An additional quirk, triggering is not done on the (digital) sampled signal, but directly on the input through a dedicated trigger system. This means that you can trigger (sometimes) on a pulse that is too short to be resolved in the digital signal. Or you can add a trigger delay much much longer than the sample depth (for example, display the capture at 10 µs resolution, but 1 second after the trigger). This is also why there is often an "aux" or "external trigger" port that can be used to trigger, but never displayed or captured.
The scope is effectively sampling continuously into a ring buffer and the trigger comes along and tells the sampling systems to store the buffer. This is a large amount of data, so it requires some time to store the data and to rearm the sample system. The electronics and suitable memory to process a gigabit stream continuously is very expensive so scopes are designed to make use of limited storage depth and digital bandwidth through triggering schemes.
$endgroup$
$begingroup$
+1! Much more informative than my answer :)
$endgroup$
– bitsmack
3 hours ago
add a comment |
$begingroup$
This is an issue with scope setup and misunderstanding of how to interpret scope captures. You must capture the rising edge of a single pulse at a reasonably small resolution by using a single trigger. Good news is that this is exactly what oscilloscopes are designed to do
The generic procedure is:
- Set trigger to edge (up) and trigger level at approximately half scale of your button voltage
- (Optional) Move the trigger (horizontal) offset to the left hand of screen to maximize the portion of capture after trigger
- Switch trigger to "normal" and "single mode" to arm the trigger for a single capture
- Press your button
- If you use continuous trigger you will get a new capture with every button press
- If you don't use normal mode you may lose the captured signal due to preview refresh (typically triggered at 60 Hz to have a simulated "live signal" mode), "single-normal" mode freezes the scope after capture
Most digital capture scopes record a fixed number of points at all time base, so the sample rate is determined by a combination of time base and capture depth (which may be configured) and limited by the maximum sampling rate. On my Tektronix oscilloscope the scope displays both the time per div and effective sample rate.
What is displayed may also be "windowed" depending on the mode, so it may not always be clear what your sample rate actually is. For example, 100K points into 1-second timebase with 10 divisions on screen would be 10 kS/sec. 100k points into a 10 µs timebase with 10 divisions on screen would be 1 GS/sec. Typically this is near the limit for common digital scopes, so time bases below 10 µs are often "zoomed in" divisions at 10 µs (e.g. 100k points into 10 divisions at 10 µs, but display one division with 1 µs time base on the screen).
Also note that analog bandwidth (for example, "100 MHz") does not directly relate to the digital sample rate.
An additional quirk, triggering is not done on the (digital) sampled signal, but directly on the input through a dedicated trigger system. This means that you can trigger (sometimes) on a pulse that is too short to be resolved in the digital signal. Or you can add a trigger delay much much longer than the sample depth (for example, display the capture at 10 µs resolution, but 1 second after the trigger). This is also why there is often an "aux" or "external trigger" port that can be used to trigger, but never displayed or captured.
The scope is effectively sampling continuously into a ring buffer and the trigger comes along and tells the sampling systems to store the buffer. This is a large amount of data, so it requires some time to store the data and to rearm the sample system. The electronics and suitable memory to process a gigabit stream continuously is very expensive so scopes are designed to make use of limited storage depth and digital bandwidth through triggering schemes.
$endgroup$
$begingroup$
+1! Much more informative than my answer :)
$endgroup$
– bitsmack
3 hours ago
add a comment |
$begingroup$
This is an issue with scope setup and misunderstanding of how to interpret scope captures. You must capture the rising edge of a single pulse at a reasonably small resolution by using a single trigger. Good news is that this is exactly what oscilloscopes are designed to do
The generic procedure is:
- Set trigger to edge (up) and trigger level at approximately half scale of your button voltage
- (Optional) Move the trigger (horizontal) offset to the left hand of screen to maximize the portion of capture after trigger
- Switch trigger to "normal" and "single mode" to arm the trigger for a single capture
- Press your button
- If you use continuous trigger you will get a new capture with every button press
- If you don't use normal mode you may lose the captured signal due to preview refresh (typically triggered at 60 Hz to have a simulated "live signal" mode), "single-normal" mode freezes the scope after capture
Most digital capture scopes record a fixed number of points at all time base, so the sample rate is determined by a combination of time base and capture depth (which may be configured) and limited by the maximum sampling rate. On my Tektronix oscilloscope the scope displays both the time per div and effective sample rate.
What is displayed may also be "windowed" depending on the mode, so it may not always be clear what your sample rate actually is. For example, 100K points into 1-second timebase with 10 divisions on screen would be 10 kS/sec. 100k points into a 10 µs timebase with 10 divisions on screen would be 1 GS/sec. Typically this is near the limit for common digital scopes, so time bases below 10 µs are often "zoomed in" divisions at 10 µs (e.g. 100k points into 10 divisions at 10 µs, but display one division with 1 µs time base on the screen).
Also note that analog bandwidth (for example, "100 MHz") does not directly relate to the digital sample rate.
An additional quirk, triggering is not done on the (digital) sampled signal, but directly on the input through a dedicated trigger system. This means that you can trigger (sometimes) on a pulse that is too short to be resolved in the digital signal. Or you can add a trigger delay much much longer than the sample depth (for example, display the capture at 10 µs resolution, but 1 second after the trigger). This is also why there is often an "aux" or "external trigger" port that can be used to trigger, but never displayed or captured.
The scope is effectively sampling continuously into a ring buffer and the trigger comes along and tells the sampling systems to store the buffer. This is a large amount of data, so it requires some time to store the data and to rearm the sample system. The electronics and suitable memory to process a gigabit stream continuously is very expensive so scopes are designed to make use of limited storage depth and digital bandwidth through triggering schemes.
$endgroup$
This is an issue with scope setup and misunderstanding of how to interpret scope captures. You must capture the rising edge of a single pulse at a reasonably small resolution by using a single trigger. Good news is that this is exactly what oscilloscopes are designed to do
The generic procedure is:
- Set trigger to edge (up) and trigger level at approximately half scale of your button voltage
- (Optional) Move the trigger (horizontal) offset to the left hand of screen to maximize the portion of capture after trigger
- Switch trigger to "normal" and "single mode" to arm the trigger for a single capture
- Press your button
- If you use continuous trigger you will get a new capture with every button press
- If you don't use normal mode you may lose the captured signal due to preview refresh (typically triggered at 60 Hz to have a simulated "live signal" mode), "single-normal" mode freezes the scope after capture
Most digital capture scopes record a fixed number of points at all time base, so the sample rate is determined by a combination of time base and capture depth (which may be configured) and limited by the maximum sampling rate. On my Tektronix oscilloscope the scope displays both the time per div and effective sample rate.
What is displayed may also be "windowed" depending on the mode, so it may not always be clear what your sample rate actually is. For example, 100K points into 1-second timebase with 10 divisions on screen would be 10 kS/sec. 100k points into a 10 µs timebase with 10 divisions on screen would be 1 GS/sec. Typically this is near the limit for common digital scopes, so time bases below 10 µs are often "zoomed in" divisions at 10 µs (e.g. 100k points into 10 divisions at 10 µs, but display one division with 1 µs time base on the screen).
Also note that analog bandwidth (for example, "100 MHz") does not directly relate to the digital sample rate.
An additional quirk, triggering is not done on the (digital) sampled signal, but directly on the input through a dedicated trigger system. This means that you can trigger (sometimes) on a pulse that is too short to be resolved in the digital signal. Or you can add a trigger delay much much longer than the sample depth (for example, display the capture at 10 µs resolution, but 1 second after the trigger). This is also why there is often an "aux" or "external trigger" port that can be used to trigger, but never displayed or captured.
The scope is effectively sampling continuously into a ring buffer and the trigger comes along and tells the sampling systems to store the buffer. This is a large amount of data, so it requires some time to store the data and to rearm the sample system. The electronics and suitable memory to process a gigabit stream continuously is very expensive so scopes are designed to make use of limited storage depth and digital bandwidth through triggering schemes.
edited 7 mins ago
Peter Mortensen
1,60031422
1,60031422
answered 6 hours ago
crasiccrasic
3,094926
3,094926
$begingroup$
+1! Much more informative than my answer :)
$endgroup$
– bitsmack
3 hours ago
add a comment |
$begingroup$
+1! Much more informative than my answer :)
$endgroup$
– bitsmack
3 hours ago
$begingroup$
+1! Much more informative than my answer :)
$endgroup$
– bitsmack
3 hours ago
$begingroup$
+1! Much more informative than my answer :)
$endgroup$
– bitsmack
3 hours ago
add a comment |
$begingroup$
Figure 1. The guys down at photo-forensics found this.
There are several factors:
- You have a nice new clean switch that bounces very little.
- Your scope is loading the circuit and the 15 pF is enough to help. This is unlikely, though, with what appears to be a resistor with a value in the hundreds of ohms. (The colour rendition of your photo is poor.)
- Timebase is too fast - but your comments say you've checked this.
I'd go with the first and second option.
$endgroup$
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
3
$begingroup$
So you think the 15pF is loading the 220 Ohms with a 3.3ns RC asymptote resulting in a 150us linear ramp? Ask the forensic guys to check again. My forensic guy said it smelt like 220 ohm i.stack.imgur.com/xEwUo.png
$endgroup$
– Sunnyskyguy EE75
8 hours ago
add a comment |
$begingroup$
Figure 1. The guys down at photo-forensics found this.
There are several factors:
- You have a nice new clean switch that bounces very little.
- Your scope is loading the circuit and the 15 pF is enough to help. This is unlikely, though, with what appears to be a resistor with a value in the hundreds of ohms. (The colour rendition of your photo is poor.)
- Timebase is too fast - but your comments say you've checked this.
I'd go with the first and second option.
$endgroup$
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
3
$begingroup$
So you think the 15pF is loading the 220 Ohms with a 3.3ns RC asymptote resulting in a 150us linear ramp? Ask the forensic guys to check again. My forensic guy said it smelt like 220 ohm i.stack.imgur.com/xEwUo.png
$endgroup$
– Sunnyskyguy EE75
8 hours ago
add a comment |
$begingroup$
Figure 1. The guys down at photo-forensics found this.
There are several factors:
- You have a nice new clean switch that bounces very little.
- Your scope is loading the circuit and the 15 pF is enough to help. This is unlikely, though, with what appears to be a resistor with a value in the hundreds of ohms. (The colour rendition of your photo is poor.)
- Timebase is too fast - but your comments say you've checked this.
I'd go with the first and second option.
$endgroup$
Figure 1. The guys down at photo-forensics found this.
There are several factors:
- You have a nice new clean switch that bounces very little.
- Your scope is loading the circuit and the 15 pF is enough to help. This is unlikely, though, with what appears to be a resistor with a value in the hundreds of ohms. (The colour rendition of your photo is poor.)
- Timebase is too fast - but your comments say you've checked this.
I'd go with the first and second option.
answered 9 hours ago
TransistorTransistor
88.2k785189
88.2k785189
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
3
$begingroup$
So you think the 15pF is loading the 220 Ohms with a 3.3ns RC asymptote resulting in a 150us linear ramp? Ask the forensic guys to check again. My forensic guy said it smelt like 220 ohm i.stack.imgur.com/xEwUo.png
$endgroup$
– Sunnyskyguy EE75
8 hours ago
add a comment |
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
3
$begingroup$
So you think the 15pF is loading the 220 Ohms with a 3.3ns RC asymptote resulting in a 150us linear ramp? Ask the forensic guys to check again. My forensic guy said it smelt like 220 ohm i.stack.imgur.com/xEwUo.png
$endgroup$
– Sunnyskyguy EE75
8 hours ago
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
$begingroup$
I have added 50uSec zoomed time scale photo. As you can see no bounce. I will also try to read button with a micro controller to see whether it is actually bouncing or not.
$endgroup$
– Deniz
8 hours ago
3
3
$begingroup$
So you think the 15pF is loading the 220 Ohms with a 3.3ns RC asymptote resulting in a 150us linear ramp? Ask the forensic guys to check again. My forensic guy said it smelt like 220 ohm i.stack.imgur.com/xEwUo.png
$endgroup$
– Sunnyskyguy EE75
8 hours ago
$begingroup$
So you think the 15pF is loading the 220 Ohms with a 3.3ns RC asymptote resulting in a 150us linear ramp? Ask the forensic guys to check again. My forensic guy said it smelt like 220 ohm i.stack.imgur.com/xEwUo.png
$endgroup$
– Sunnyskyguy EE75
8 hours ago
add a comment |
$begingroup$
Assuming that the pull-down resistor is a reasonable value (1k - 10k), the very next thing that I would check is to see if there is a filter active on that channel. I wouldn't be looking for signal averaging - this is a single-event occurrence and the trace shows that single event. But it is entirely possible that there is a very-low frequency low-pass filter that is turned ON in the scope.
Another way to find out if it is a scope problem is to simply plug a pair of wires into the busses for the switch contacts. Then brush the two switch wires together and look at the noise (or lack thereof). Noise means scope is probably okay. Smooth ramp says that the scope isn't displaying the full bandwidth of the input signal.
$endgroup$
add a comment |
$begingroup$
Assuming that the pull-down resistor is a reasonable value (1k - 10k), the very next thing that I would check is to see if there is a filter active on that channel. I wouldn't be looking for signal averaging - this is a single-event occurrence and the trace shows that single event. But it is entirely possible that there is a very-low frequency low-pass filter that is turned ON in the scope.
Another way to find out if it is a scope problem is to simply plug a pair of wires into the busses for the switch contacts. Then brush the two switch wires together and look at the noise (or lack thereof). Noise means scope is probably okay. Smooth ramp says that the scope isn't displaying the full bandwidth of the input signal.
$endgroup$
add a comment |
$begingroup$
Assuming that the pull-down resistor is a reasonable value (1k - 10k), the very next thing that I would check is to see if there is a filter active on that channel. I wouldn't be looking for signal averaging - this is a single-event occurrence and the trace shows that single event. But it is entirely possible that there is a very-low frequency low-pass filter that is turned ON in the scope.
Another way to find out if it is a scope problem is to simply plug a pair of wires into the busses for the switch contacts. Then brush the two switch wires together and look at the noise (or lack thereof). Noise means scope is probably okay. Smooth ramp says that the scope isn't displaying the full bandwidth of the input signal.
$endgroup$
Assuming that the pull-down resistor is a reasonable value (1k - 10k), the very next thing that I would check is to see if there is a filter active on that channel. I wouldn't be looking for signal averaging - this is a single-event occurrence and the trace shows that single event. But it is entirely possible that there is a very-low frequency low-pass filter that is turned ON in the scope.
Another way to find out if it is a scope problem is to simply plug a pair of wires into the busses for the switch contacts. Then brush the two switch wires together and look at the noise (or lack thereof). Noise means scope is probably okay. Smooth ramp says that the scope isn't displaying the full bandwidth of the input signal.
answered 5 hours ago
Dwayne ReidDwayne Reid
18.2k21949
18.2k21949
add a comment |
add a comment |
$begingroup$
Here is a test I did with my 200MHz Tek scope. You should be able to get similar results with the Rigol, this is an older scope with a modest 2Gs/s capture frequency.
My circuit is just a standard 10:1 probe connected across a 6mm tact switch with a 1K pullup to +5V supply.
Not all the captures were this messy, some were pretty ideal looking. Pushing it hard seemed to lead to more messiness. There's a bit of ringing despite a bypass across the power supply- that falling edge due to the switch contacts closing is very fast.
If I set the sweep too slow (and then expand) I just get interpolation between samples, which might be misleading. There's no information there so the scope fakes it.
Capture was single event, triggered by falling edge on the active channel, set relatively close to the 5V level (the yellow arrow on the right indicates the trigger level of 3.68V). The center of the screen is at -96ns (moved to view a bit more of the pre-trigger data since most of the action is pre-trigger).
$endgroup$
add a comment |
$begingroup$
Here is a test I did with my 200MHz Tek scope. You should be able to get similar results with the Rigol, this is an older scope with a modest 2Gs/s capture frequency.
My circuit is just a standard 10:1 probe connected across a 6mm tact switch with a 1K pullup to +5V supply.
Not all the captures were this messy, some were pretty ideal looking. Pushing it hard seemed to lead to more messiness. There's a bit of ringing despite a bypass across the power supply- that falling edge due to the switch contacts closing is very fast.
If I set the sweep too slow (and then expand) I just get interpolation between samples, which might be misleading. There's no information there so the scope fakes it.
Capture was single event, triggered by falling edge on the active channel, set relatively close to the 5V level (the yellow arrow on the right indicates the trigger level of 3.68V). The center of the screen is at -96ns (moved to view a bit more of the pre-trigger data since most of the action is pre-trigger).
$endgroup$
add a comment |
$begingroup$
Here is a test I did with my 200MHz Tek scope. You should be able to get similar results with the Rigol, this is an older scope with a modest 2Gs/s capture frequency.
My circuit is just a standard 10:1 probe connected across a 6mm tact switch with a 1K pullup to +5V supply.
Not all the captures were this messy, some were pretty ideal looking. Pushing it hard seemed to lead to more messiness. There's a bit of ringing despite a bypass across the power supply- that falling edge due to the switch contacts closing is very fast.
If I set the sweep too slow (and then expand) I just get interpolation between samples, which might be misleading. There's no information there so the scope fakes it.
Capture was single event, triggered by falling edge on the active channel, set relatively close to the 5V level (the yellow arrow on the right indicates the trigger level of 3.68V). The center of the screen is at -96ns (moved to view a bit more of the pre-trigger data since most of the action is pre-trigger).
$endgroup$
Here is a test I did with my 200MHz Tek scope. You should be able to get similar results with the Rigol, this is an older scope with a modest 2Gs/s capture frequency.
My circuit is just a standard 10:1 probe connected across a 6mm tact switch with a 1K pullup to +5V supply.
Not all the captures were this messy, some were pretty ideal looking. Pushing it hard seemed to lead to more messiness. There's a bit of ringing despite a bypass across the power supply- that falling edge due to the switch contacts closing is very fast.
If I set the sweep too slow (and then expand) I just get interpolation between samples, which might be misleading. There's no information there so the scope fakes it.
Capture was single event, triggered by falling edge on the active channel, set relatively close to the 5V level (the yellow arrow on the right indicates the trigger level of 3.68V). The center of the screen is at -96ns (moved to view a bit more of the pre-trigger data since most of the action is pre-trigger).
answered 58 mins ago
Spehro PefhanySpehro Pefhany
213k5162429
213k5162429
add a comment |
add a comment |
$begingroup$
Use an old switch or store your new switch in a mixture of salt water and vinegar for a few hours. That will corrode the contacts and increase the bounce.
New contributor
$endgroup$
add a comment |
$begingroup$
Use an old switch or store your new switch in a mixture of salt water and vinegar for a few hours. That will corrode the contacts and increase the bounce.
New contributor
$endgroup$
add a comment |
$begingroup$
Use an old switch or store your new switch in a mixture of salt water and vinegar for a few hours. That will corrode the contacts and increase the bounce.
New contributor
$endgroup$
Use an old switch or store your new switch in a mixture of salt water and vinegar for a few hours. That will corrode the contacts and increase the bounce.
New contributor
edited 1 hour ago
Peter Mortensen
1,60031422
1,60031422
New contributor
answered 3 hours ago
ronron
1
1
New contributor
New contributor
add a comment |
add a comment |
$begingroup$
I have gone thru the answers mentioned above.
But First, please change your oscilloscope.
The scope you are using would have a shallow memory.(Acquisition Memory ...may be 1K or a few K memory).
Try with Deep Memory Scopes.Tektronix TDS 3000 or 4000 series , Keysight DSOx 3000 to 6000 series or many more brands and models are available.
You will definitely get a beautiful contact bounce ringing at the top the vertical rising/ falling edges.
The number of ringing edges is proportional to the length of your grounding wire length.Less the length, less ringing.The more the length, more ringing.
The Deep Memory scopes will contain record length or Acquisition memory in terms of Mb ....say 2Mb , 4Mb, 8Mb etc......Don't worry about Sampling rates. Deep memory will control to sustain the sampling rate.
I have captured enough time these switching circuits,in Deep memory scopes.
Try ...
Best Regards
A Senthil
New contributor
$endgroup$
10
$begingroup$
The instrument in use is orders or magnitude more than sufficient if used properly. Recommending the purchase of new gear over learning to use the ordinary and suitable gear at hand is the mark of those who do not know what they are doing. There exists a capture rate, within the capability of that scope where the bouncing of the actual contacts is easily represented on the screen alone, nevermind any off-screen memory.
$endgroup$
– Chris Stratton
3 hours ago
add a comment |
$begingroup$
I have gone thru the answers mentioned above.
But First, please change your oscilloscope.
The scope you are using would have a shallow memory.(Acquisition Memory ...may be 1K or a few K memory).
Try with Deep Memory Scopes.Tektronix TDS 3000 or 4000 series , Keysight DSOx 3000 to 6000 series or many more brands and models are available.
You will definitely get a beautiful contact bounce ringing at the top the vertical rising/ falling edges.
The number of ringing edges is proportional to the length of your grounding wire length.Less the length, less ringing.The more the length, more ringing.
The Deep Memory scopes will contain record length or Acquisition memory in terms of Mb ....say 2Mb , 4Mb, 8Mb etc......Don't worry about Sampling rates. Deep memory will control to sustain the sampling rate.
I have captured enough time these switching circuits,in Deep memory scopes.
Try ...
Best Regards
A Senthil
New contributor
$endgroup$
10
$begingroup$
The instrument in use is orders or magnitude more than sufficient if used properly. Recommending the purchase of new gear over learning to use the ordinary and suitable gear at hand is the mark of those who do not know what they are doing. There exists a capture rate, within the capability of that scope where the bouncing of the actual contacts is easily represented on the screen alone, nevermind any off-screen memory.
$endgroup$
– Chris Stratton
3 hours ago
add a comment |
$begingroup$
I have gone thru the answers mentioned above.
But First, please change your oscilloscope.
The scope you are using would have a shallow memory.(Acquisition Memory ...may be 1K or a few K memory).
Try with Deep Memory Scopes.Tektronix TDS 3000 or 4000 series , Keysight DSOx 3000 to 6000 series or many more brands and models are available.
You will definitely get a beautiful contact bounce ringing at the top the vertical rising/ falling edges.
The number of ringing edges is proportional to the length of your grounding wire length.Less the length, less ringing.The more the length, more ringing.
The Deep Memory scopes will contain record length or Acquisition memory in terms of Mb ....say 2Mb , 4Mb, 8Mb etc......Don't worry about Sampling rates. Deep memory will control to sustain the sampling rate.
I have captured enough time these switching circuits,in Deep memory scopes.
Try ...
Best Regards
A Senthil
New contributor
$endgroup$
I have gone thru the answers mentioned above.
But First, please change your oscilloscope.
The scope you are using would have a shallow memory.(Acquisition Memory ...may be 1K or a few K memory).
Try with Deep Memory Scopes.Tektronix TDS 3000 or 4000 series , Keysight DSOx 3000 to 6000 series or many more brands and models are available.
You will definitely get a beautiful contact bounce ringing at the top the vertical rising/ falling edges.
The number of ringing edges is proportional to the length of your grounding wire length.Less the length, less ringing.The more the length, more ringing.
The Deep Memory scopes will contain record length or Acquisition memory in terms of Mb ....say 2Mb , 4Mb, 8Mb etc......Don't worry about Sampling rates. Deep memory will control to sustain the sampling rate.
I have captured enough time these switching circuits,in Deep memory scopes.
Try ...
Best Regards
A Senthil
New contributor
New contributor
answered 4 hours ago
A SenthilA Senthil
1
1
New contributor
New contributor
10
$begingroup$
The instrument in use is orders or magnitude more than sufficient if used properly. Recommending the purchase of new gear over learning to use the ordinary and suitable gear at hand is the mark of those who do not know what they are doing. There exists a capture rate, within the capability of that scope where the bouncing of the actual contacts is easily represented on the screen alone, nevermind any off-screen memory.
$endgroup$
– Chris Stratton
3 hours ago
add a comment |
10
$begingroup$
The instrument in use is orders or magnitude more than sufficient if used properly. Recommending the purchase of new gear over learning to use the ordinary and suitable gear at hand is the mark of those who do not know what they are doing. There exists a capture rate, within the capability of that scope where the bouncing of the actual contacts is easily represented on the screen alone, nevermind any off-screen memory.
$endgroup$
– Chris Stratton
3 hours ago
10
10
$begingroup$
The instrument in use is orders or magnitude more than sufficient if used properly. Recommending the purchase of new gear over learning to use the ordinary and suitable gear at hand is the mark of those who do not know what they are doing. There exists a capture rate, within the capability of that scope where the bouncing of the actual contacts is easily represented on the screen alone, nevermind any off-screen memory.
$endgroup$
– Chris Stratton
3 hours ago
$begingroup$
The instrument in use is orders or magnitude more than sufficient if used properly. Recommending the purchase of new gear over learning to use the ordinary and suitable gear at hand is the mark of those who do not know what they are doing. There exists a capture rate, within the capability of that scope where the bouncing of the actual contacts is easily represented on the screen alone, nevermind any off-screen memory.
$endgroup$
– Chris Stratton
3 hours ago
add a comment |
protected by Nick Alexeev♦ 1 hour ago
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Have you tried adjusting the time base / horizontal scale?
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– NMF
9 hours ago
1
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If you don't succeed on the first try, try again.
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– StainlessSteelRat
9 hours ago
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I have a hard time believing that your zoomed in version is actually a new trig. Nothing would look like that except the scope's internal interpolation. An clean break with an RC-filter created by the scope would show an exponential clean rise - nothing linear. I bet that you just zoomed in on the stored waveform.
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– pipe
8 hours ago
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My zoomed photo is from another capture with battery instead of power supply. But as @pipe sait I have captured on zoomed out view and then zoomed on the rising edge after that. Now I understand that changing time scale before the capture and after the capture is different things? I didn't know that. I will need to figure out how to capture when time scale is set to uSec range.
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– Deniz
8 hours ago
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@Deniz Set the time base reasonably fast (maybe 1ms), the scope trigger to "single" and "rising edge", then press the button. That should be OK. You might also want to look at the display settings, and either change the points to just show dots for each point, or to step to each point (giving a ”staircase" effect). That'll stop you getting fooled when you zoom in too far.
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– Graham
7 hours ago