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 Post subject: PC Sound card Oscilloscope
PostPosted: Oct Wed 25, 2017 11:46 pm 
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Joined: Feb Mon 20, 2017 7:21 pm
Posts: 145
Today any one can use a old PC as Oscilloscope and Function generator
I have this drawing on interface for PC use as simple Oscilloscope

Looks it will work

What do you think using a PC :?: :?: :?:

Dave



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 Post subject: Re: PC Sound card Oscilloscope
PostPosted: Oct Thu 26, 2017 12:36 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: S. Dartmouth MA 02748-1225 USA
The PC's audio input has a finite maximum input voltage. Exceed it and the internal audio on the mobo is fried.

Using a USB external sound input would be safer for the P.C.

An older PC with a replaceable PCI sound card would be somewhat safer.

I don't see this a viable device to examine vibrator kickback to determine appropriate buffer cap, nor do I see it as a means to discover peak signal voltage at tube audio output. Piff~


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 Post subject: Re: PC Sound card Oscilloscope
PostPosted: Oct Thu 26, 2017 3:15 pm 
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Joined: Feb Mon 20, 2017 7:21 pm
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It is not like a real Oscilloscope and have use this for Frequency counting and testing camera shutter speed on low voltage only less than 1 1/2 v.
Still looking for some safe even for the old PC

Dave

Chas wrote:
The PC's audio input has a finite maximum input voltage. Exceed it and the internal audio on the mobo is fried.

Using a USB external sound input would be safer for the P.C.

An older PC with a replaceable PCI sound card would be somewhat safer.

I don't see this a viable device to examine vibrator kickback to determine appropriate buffer cap, nor do I see it as a means to discover peak signal voltage at tube audio output. Piff~


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 Post subject: Re: PC Sound card Oscilloscope
PostPosted: Oct Thu 26, 2017 5:01 pm 
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Location: S. Dartmouth MA 02748-1225 USA
smithdoor wrote:
It is not like a real Oscilloscope and have use this for Frequency counting and testing camera shutter speed on low voltage only less than 1 1/2 v.
Still looking for some safe even for the old PC

Dave

Chas wrote:
The PC's audio input has a finite maximum input voltage. Exceed it and the internal audio on the mobo is fried.

Using a USB external sound input would be safer for the P.C.

An older PC with a replaceable PCI sound card would be somewhat safer.

I don't see this a viable device to examine vibrator kickback to determine appropriate buffer cap, nor do I see it as a means to discover peak signal voltage at tube audio output. Piff~
Then there would be no problem using a PC based add on "audio" scope for logic up to 15 volts. I would be optimistic at using it for serial pot measurements at +-25 volts...

Even a common 'audio scope service scope of the 50's-60 is at risk if measurements got careless in a TV chassis in the vertical and horizontal sections. That is what x10, x100, low capacity and hv probes are for.

If one realizes the limitations of the measuring device it is unlikely to be ruined all but accidentally.

Best scopes I ever used were Tektronics, well suited for my lab at work. I had to add an extreme high voltage probe to solve an elusive pulse problem. Only regret the models I had could not talk directly to a computer, but through a GPIB interface. Of which was very difficult to configure. Therefore my prints were made to a desktop HP plotter. Good enough evidence that engineering had fudged the design...

At my home bench I use much older service audio scopes. Very suited for the slow, analog work. I don't do any digital work at home nor do I need to see an RF envelope above 20 khz. I no longer service industrial strobes so pico second pulses are a non-issue.

I don't believe in overkill in instrumentation, my experience is the bells and whistles are the first to fail, more often than not crippling the instrument.

I DO admit it was those scopes that supported me and my lab. So much so I had them set up for portability. I often would go into the factory environment and troubleshoot equipment and systems for noise, intermittents and electrostatic (lightning) failures.

There are many OLD scope books around that explain how to setup the early "audio" scopes for all sorts of obscure yet meaningful tests... These same setups could be applied with due caution for the "TTL" limitations of a "PC" 'scope...

YMMV

Chas


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 Post subject: Re: PC Sound card Oscilloscope
PostPosted: Oct Thu 26, 2017 8:01 pm 
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Joined: Jun Mon 01, 2015 7:58 pm
Posts: 237
Location: Vancouver, WA
The sound card is AC coupled and has a very limited bandwidth.

I wrote a program to use the sound card as the input for the roller sensor on a homemade motorcycle dyno. When I tried using a similar setup for the dynamic balance program it would not work because the frequency of the vibration sensor fell below the minimum bandwidth. Ended up using a USB data logger which could be DC coupled to the sensor.

If you want to digitally capture a signal then I would recommend getting a USB scope/logger rather than mess around trying to make one out of a sound card.


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 Post subject: Re: PC Sound card Oscilloscope
PostPosted: Oct Fri 27, 2017 7:48 pm 
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Joined: Feb Mon 20, 2017 7:21 pm
Posts: 145
I making as a low budget scope
What is the cost of USB data logger

Dave

mrriggs wrote:
The sound card is AC coupled and has a very limited bandwidth.

I wrote a program to use the sound card as the input for the roller sensor on a homemade motorcycle dyno. When I tried using a similar setup for the dynamic balance program it would not work because the frequency of the vibration sensor fell below the minimum bandwidth. Ended up using a USB data logger which could be DC coupled to the sensor.

If you want to digitally capture a signal then I would recommend getting a USB scope/logger rather than mess around trying to make one out of a sound card.


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