hello first of all I am new at this chat.
I want to to build a basic genartor and scope using the computer with matlab .
for example using signal generator I want to signal in matlab, for this I need to connect BNC cable to my audion input using this :

https://www.amazon.com/Female-3-5mm-Mono-Plug-Adapter/dp/B00IE7UVQO

my question is simple ,how can i know the voltages of my audio input ? and the current of my input audio input in order to not ruin my audio input .

 

Is the BNC connection a necessity?

To protect your line input, use a voltage divider to reduce the input AC voltage to below 100mV.

Audio inputs are generally AC coupled via a series capacitor. This means that the input will not accept DC voltages or any signal below a low frequency, below 20Hz.

 

Is the BNC connection a necessity?

To protect your line input, use a voltage divider to reduce the input AC voltage to below 100mV.

Audio inputs are generally AC coupled via a series capacitor. This means that the input will not accept DC voltages or any signal below a low frequency, below 20Hz.

you are right !! i ment the mic input not the audio input

 

hi,
Look at this 'how to' link.
https://www.instructables.com/id/Use-Your-Laptop-as-Oscilloscope/

E

 

The Instructable shows a stereo line input on the computer, not a mono mic input.
It also shows a stereo plug but calls it a jack.

The mic input on a computer has a DC voltage on it to power an electret mic. This voltage might damage or mess up the circuit feeding it, use a coupling capacitor to block the DC voltage.

 

The Instructable shows a stereo line input on the computer, not a mono mic input.
It also shows a stereo plug but calls it a jack.

The mic input on a computer has a DC voltage on it to power an electret mic. This voltage might damage or mess up the circuit feeding it, use a coupling capacitor to block the DC voltage.

so you are saying that i cant use my laptop as an
OSCILLOSCOPE ,connecting it to my mic input ?

 

I said to use a coupling capacitor to block the DC that is fed to an electret mic, then the 'scope will not show DC levels. Make the input plug and cable mono, not stereo. Obviously you must attenuate the input signal down to a mic level.