Help me learn using op-amps

[izua]

Hi! I'm starting to learn to use opamps - using a soundcard as a signal generator and scope.

I'm trying to spit out a signal, feed it to a voltage follower, and then read it back. Should be pretty simple, but I realised it's not. The sound card will output an analogue value with a dual polarity, i suppose ( i don't have any electrical info on it - i believe it's somewhere around 1.1V Rms, from previous topics).

I have a +9V supply. So i powered an 741 from that, fed the output of the soundcard and read back the output of the opamp via the aux input.
Well, since I have only 9V, i thought i'd miss a phase. and that's exactly what happens.

I was thinking of splitting the supply with resistors, but that would give me a higher reference point than the ground, and I could cause a short between the soundcard's ground and the power supply's ground. So..

I'm looking for a schematic/info/etc on how to output a signal from a soundcard, power an opamp from a unipolar power supply of 9v and feed the signal back into the soundcard.

Here's what I get:
**broken link removed**

thanks!

 

[banjo]

Starting with opamps

It looks like your op-amp is clipping the input signal. You can solve this with a input bias network. Basically, it is a voltage divider that shifts the input signal up until the negative peaks do not go below ground.

However, if your real purpose is to learn about op-amps, I would suggest working with a simulator instead. Numerous simulators and op-amp models are available for free on the Internet. For example:

**broken link removed**

Simulators remove all the problems and limitations of using this sound card system.

 

[hotroy]

Re: Starting with opamps

ron mancini book on op amps

 

[izua]

Re: Starting with opamps

Thanks for the link, I'll try it!
But if i'll learn that only in theory, how can I actually apply it?

By learning I mean I want to create various audio stuff with them, at some point, not just understand their principles of operation. Or at least, be able to, hehe.

Can you draw me a simple schematic of the bias network?
Thanks!

 

[banjo]

Starting with opamps

The simulator is not really theory. You draw out the circuit just a you would wire up the real circuit. The simulator will not tell you where your mistakes are. You have to simulate, look at the waveforms and decipher it for yourself.


If you want some examples of resistor biasing, look at:

**broken link removed**

 

[Meridian]

Starting with opamps

Here is another link: "741 Op-Amp Tutorial"

**broken link removed**