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What are DC-couple and AC-couple??

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nemolee

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ac couple dc couple

Dear Sirs,

Anyone can tell me what are DC-couple and AC-couple?
What different are them?
Thanks a lot.
 

sunking

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ac couple need a cap, which only ac signal can pass.
dc couple need not a cap. there is a dc bias
 

mitgrace

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IN the AC couple . always the chip can change the Bias (operation point) , IN the DC couple ,.. SOme part like ferrie beer ..The DC can pass .and reject ac noise
 

Davood Amerion

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I like to add:
In AC couple, some unwanted DC voltage blocked.
and pure original AC signal passed.
On the other hand, DC couple used in cases, where
we need to pass signal with DC voltage.
it means original signal include DC voltage.
For example composite video signal.

Regards
Davood
 

suria3

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DC couple and AC couple are applied on the necessity of signal transmission. As Davood mentioned, AC couple is to block the DC voltage and just allow AC signal. Let say one block circuit operate with dc 1.2V and the next stage operate with dc 1.5V, so here you have to block the 1.2V and pass AC only, thus you can you use resistive biasing to have 1.5V to next stage operation. As for DC couple, if between stages, the same dc voltage are applied, then there is no cap to block any dc within them.
 

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