pc sound card-based oscilliscope

hi
i am new to electronics world.
i heard that i can make my pc as oscilliscope by connecting a props to my sound card's mic plug,but if i use this method for high voltages(not very high voltages only 25 volts max.) it will damage my sound card or even my pc.
so please i want a circuit diagram that protects my sound card from damage(reduces the i/p signal voltages)
thanks

Hello

You can find some Soundcard oscilloscopes software that require no hardware to be attached to the pc. You need only one sound card and some connectors to drive the signal at the input of the sound card of your pc. Check here: **broken link removed**

Additional pc oscilloscopes:

Non Commercial
**broken link removed**
http://www.geocities.com/huz_52/
http://home.planet.nl/~m.f.hajer/
http://www.discovercircuits.com/O/oscilloscopes.htm
http://www.geocities.com/tangmonster911/oscilloscope.htm (ISA bus)
http://www.dansworkshop.com/Homebuilt oscilloscope.shtml (TV based)
http://www.geocities.com/SiliconValley/Lakes/7156/articl3.htm (with LEDs)
http://www.electronic-projects.net/Electronic-Projects/projects/telescope/index.shtml (TV based)
**broken link removed** (TV based)

Commercial:
**broken link removed**
**broken link removed**
**broken link removed**
http://www.picotech.com/oscilloscope.html
**broken link removed**
**broken link removed** (USB)
**broken link removed**
**broken link removed**
http://www.bitscope.com/

Thanks very much