Any PC works on 5v logic voltage. So you have to make sure the input amplitude should not cross 5v. If you are working on circuit with high voltage, use a high value resistors of 1K to 1M ohm, as required. A high value potentiometer can help you to adjust the amplitude.
Yes. Mic-in is only needed... Make sure you have the audio drivers installed in your PC and it detects the mic port.
They have mentioned in their site to use 1 volt as input. Please go through these FAQ... http://www.zelscope.com/faq.html
Picoscope is another option. However, as bandwidth requirements rise, price does too and as far as I know the delta with 'discrete' scopes becomes smaller...
Picoscope is another option. However, as bandwidth requirements rise, price does too and as far as I know the delta with 'discrete' scopes becomes smaller...