i tried to use my musical keyboard for signal generation and to view it in WINSCOPE by taking output through headphone wire as mentioned in the experiment corner of this site...
but the voltage i am getting from the headphone is coming out to be DC instead of AC.

also its value is coming out to be very less(mV).if i use it in winscope...will i have to amplify it??? and if i do...what voltage to??/ how much voltage can a pc audio card bear???as its is said it may damage the audio card...

 

Hello,

What output are you taken for the signal?
If it is the MIDI output, there will be a digital signal with info on wich tone, wich instrument etc.

Bertus

 

The OP said a musical keyboard using the headphone jack.

i tried to use my musical keyboard for signal generation and to view it in WINSCOPE by taking output through headphone wire as mentioned in the experiment corner of this site...
but the voltage i am getting from the headphone is coming out to be DC instead of AC.

You should not be getting digital out of the headphone jack.
Do you also have a LINE OUT on the keyboard? I would use this if you have it.

The output from the line out should not exceed 20ma. You WILL fry your sound card.

Is the meter you are using auto switching? Or can you choose AC or DC? If so, select AC and see the result. If it only shows DC, see if your meter has a frequency or duty cycle meter mode. This will tell you if it is a 60hz hum or not.

You are playing a note when you are checking the meter right?

Also see if your keyboard has an infinite sustain mode. This allows the key to play as long as it is pressed. Else the sound decays like a real piano. Also, choose a instrument that has a very monotone sound. Like a flute. Piano usually has an attack in the beginning. Many newer synths play a sample of a piano rather than generating a tone that sounds piano-ish.

Ok I found the link to our eBook page on the subject:
http://www.allaboutcircuits.com/vol_6/chpt_4/12.html