Coffee Room
Discuss anything here - everything that you wish to discuss with fellow engineers.
12829 Members
Join this group to post and comment.
kran • Dec 1, 2008

# What is a coupling capacitor?

Hello all , I want to know what is meant by a coupling capacitor? I googled up to find that In analog circuits, a coupling capacitor is used to connect two circuits such that only the AC signal from the first circuit can pass through to the next while DC is blocked. Can someone here explain this in detail? Please help.
silverscorpion • Dec 2, 2008
A coupling capacitor is a capacitor used to separate the various stages in a circuit, for example, to separate the stages of a multistaged amplifier. It separates the dc and ac components and 'couples' the output of one stage to the input of the next stage.
watever silver said is correct,but the basic function of coupling capacitors is too remove noise or other disturbances and make sure the output of previous stage is compatible with one were it is inputted!!!
r6rammy • Dec 7, 2008
do i use it for adding dc to an ac signal???
I am planning to do differential conductance measurement and i need to add the sine out from the lock in amplifier to a dc sourcemeter, how do i go about adding both together? Just join them????
augustin87r • Dec 7, 2010
Hello,

I have going through theoretic details about coupling capacitance. I have to exercise somehow. On this schematic, what are the coupling capacitors? I know a few , especially the electrolitic ones, but can somebody tell me all of them so that i can check my guesses...BEst regards, Augustin

the picture is larger on the host site
akshay04907 • Dec 7, 2010
but sharat why it is necessary to block the dc component?why they r source of noise only?
cranky • Dec 10, 2010
sauravgoswami
watever silver said is correct,but the basic function of coupling capacitors is too remove noise or other disturbances and make sure the output of previous stage is compatible with one were it is inputted!!!
hey i guess the noise here refers to the dc component silver mentioned
cranky • Dec 10, 2010
akshay04907
but sharat why it is necessary to block the dc component?why they r source of noise only?
It becomes necessary to block dc components cause-for one,you want your signal with zero as reference,as in no offset...secondly,you do analysis about the operating point and hence,you don't want to disturb the bias

* if Someone could say if this is right
shreyasm89 • Dec 21, 2010
you are absolutely right
cranky
It becomes necessary to block dc components cause-for one,you want your signal with zero as reference,as in no offset...secondly,you do analysis about the operating point and hence,you don't want to disturb the bias

* if Someone could say if this is right
cranky • Dec 29, 2010
@shreyas89:thumbs up 😀
Bags003 • Dec 31, 2010
It helps to isolate the DC bias settings of the two coupled circuits.
electronics12 • Apr 6, 2012
A coupling capacitor is a capacitor that allows AC signals to go through but not DC. DC signals are blocked. This is useful for many applications such as when biasing microphones. The DC is needed just for power but should not be transferred to the second half of the circuit.

A good article for reference on coupling capacitors is:
larry80 • Sep 11, 2012
A single capacitor that is used to link one amplifier stage to another is often called a coupling capacitor.

_____
electronic contract manufacturer
naveee • Sep 12, 2012
silverscorpion
A coupling capacitor is a capacitor used to separate the various stages in a circuit, for example, to separate the stages of a multistaged amplifier. It separates the dc and ac components and 'couples' the output of one stage to the input of the next stage.
if both AC an DC are separated wat component will through the remaining circuit ?????
Jeffrey Arulraj • Sep 12, 2012
r6rammy
do i use it for adding dc to an ac signal???
I am planning to do differential conductance measurement and i need to add the sine out from the lock in amplifier to a dc sourcemeter, how do i go about adding both together? Just join them????
not possible to add a DC signal to AC signal using a coupling capacitor it prevents the DC component completely and passes the AC component furthur
Jeffrey Arulraj • Sep 12, 2012
naveee
if both AC an DC are separated wat component will through the remaining circuit ?????
Jeffrey Arulraj • Sep 12, 2012
cranky
It becomes necessary to block dc components cause-for one,you want your signal with zero as reference,as in no offset...secondly,you do analysis about the operating point and hence,you don't want to disturb the bias

* if Someone could say if this is right

dc component is not the only source of noise any where

in multi stage if DC passes further there is a possibility of shifting the bias and also to cause signal loss

this can be avoided if we use a coupling capacitor
Naman Agarwal • Sep 13, 2012
a simple capacitor can do blocking of dc...then whats is the need of coupling capacitor??
Jeffrey Arulraj • Sep 14, 2012
coupling capacitor is used for coupling AC signal from one point to another

what is that you can't understand in it ?