Re: soundcard as oscilloscope

Could you give us your real name? First name would be nice.


I can control the amplitude of the wave form pretty easy by controlling either a variable resistor or the variac... the problem is that that the wave form looks like crap and I can't rectify it in any way(I put a rectifier as the first component).

Heres a shot of the oscilloscope:

http://www.geocities.com/abstract_dissonance/osc.JPG


Doesn't look too bad except for some clipping and a wee distortion.


I've used several resistor ratios from 10M's down to 50k but nothing seems to work. I'm not sure if it has something to do with the sound card(it should have no problem sampling 60hz mcuh better than it is?) or if its just the wave form is crap cause of the variac or what ;/

Anyone have any ideas?


AFAIK the impedance of some sound cards is pretty low, in the tens of kohm range or so. Also, there may be a bias voltage for an electret microphone on its input. Best would be to post a schematic of what you have wired up so far.

Regards, Joerg

http://www.analogconsultants.com
.

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