What is a coupling capacitor?

Discussion in 'Electrical | Electronics | Communications' started by kran, Dec 1, 2008.

1. kran Newbie

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.

#1
2. silverscorpion Ace

Engineering Discipline:
Electronics & Telecommunications
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.

#2
3. sauravgoswami Rookie

Engineering Discipline:
Electrical & Electronics
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!!!

#3
4. SHARATH0007

hi, coupling capacitors are used in circuits to filter noise signals from passing on to the next stage. for example, a coupling capacitor is used in the input of an R-C coupled amplifier to filter dc noise. As u may know, the reactance offered by a capacitor Xc= 1/(2*pi*f*C) where f is freuency, c is capacitance. as d.c has 0 freq, so the reactance offered to dc by a capacitor is very very large.:smile:

#4
5. r6rammy Newbie

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????

#5

7. augustin87r Newbie

Engineering Discipline:
Aerospace
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

#7
8. akshay04907 Apprentice

Engineering Discipline:
Electronics & Telecommunications
but sharat why it is necessary to block the dc component?why they r source of noise only?

#8
9. cranky Apprentice

Engineering Discipline:
Electronics
hey i guess the noise here refers to the dc component silver mentioned

#9
10. cranky Apprentice

Engineering Discipline:
Electronics
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

#10
11. shreyasm89 Apprentice

Engineering Discipline:
Electronics & Telecommunications
you are absolutely right

#11
12. cranky Apprentice

Engineering Discipline:
Electronics
@shreyas89:thumbs up

#12
13. Bags003 Apprentice

Engineering Discipline:
Electronics & Telecommunications
It helps to isolate the DC bias settings of the two coupled circuits.

#13
14. electronics12 Newbie

Engineering Discipline:
Electrical & Electronics
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:

#14
15. larry80 Newbie

Engineering Discipline:
Ceramic
#15
16. naveee Rookie

Engineering Discipline:
Electrical & Electronics
if both AC an DC are separated wat component will through the remaining circuit ?????

#16
17. Jeffrey Samuel Knight

Engineering Discipline:
Electronics
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

#17
18. Jeffrey Samuel Knight

Engineering Discipline:
Electronics
my post #17 answers your qn also i guess

• Like x 1
#18
19. Jeffrey Samuel Knight

Engineering Discipline:
Electronics

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

#19
20. naman2511 Enthusiast

Engineering Discipline:
Electrical & Electronics
a simple capacitor can do blocking of dc...then whats is the need of coupling capacitor??

#20
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