what is DC and AC coupling?

[cheesent]

ac coupling vs dc coupling

To what I know, DC coupling can be used for both AC and DC.
AC coupling is used for AC only.
how is the circuit look like when DC or AC coupling was used?

 

[Awarapunshee]

ac coupling dc coupling

As you said DC coupling allows both DC and AC signals through, while AC coupling accepts only AC signals.
Fig1a shows a waveform containing both AC and DC. If the oscilloscope is DC coupled, then the waveform is displayed as drawn in Fig1a. If the oscilloscope is AC coupled, then the DC portion of the waveform is blocked and only the AC portion is displayed as shown in Fig1b.

 

[cheesent]

ac coupled dc coupled

Hi,

Thanks for your answer.
For AC coupling, capasitor is necessary while DC coupling is direct conncetion (need nothing?).
Then, why we call coupling?

 

[Awarapunshee]

dc coupling vs ac coupling

One meaning of coupling is linking, thats why.