Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

difference between common mode and differential mode

Status
Not open for further replies.

mdkmahesh

Member level 1
Joined
Apr 6, 2011
Messages
40
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Location
chennai
Activity points
1,558
what is the difference between common mode and differential mode and what are the possible values of inputs for the amplifier operating in the two modes?
 

ckshivaram

Advanced Member level 5
Joined
Apr 21, 2008
Messages
5,070
Helped
2,149
Reputation
4,304
Reaction score
2,089
Trophy points
1,393
Location
villingen (Germany) / Bangalore
Activity points
30,094
Common Mode gain is the response of a circuit where the input changes relative to some common point, such as ground. A single transistor amplifier is an example. An op-amp can also be an example, if one input is grounded.

Differential Mode gain is the response of a circuit where the input is measured across two pins, and the difference between those two pins controls the output, rather than the common mode value of those pins relative to ground. An op-amp in balanced or bridge mode is an example.

One way to verify/understand this is to take a properly designed op-amp, connect the two inputs together, and drive them together relative to ground. A properly balanced system will exhibit little or no response on the output. Note: This is also true for AC, so a typical test includes both DC and AC response. In the AC test, imbalance often results from unequal capacitance, whereas DC imbalance results from unequal resistance.

Differential Amplifier: Common-Mode Input - Circuit Simulator
Differential Mode and Common Mode Gain of Differential Amplifier
 

mdkmahesh

Member level 1
Joined
Apr 6, 2011
Messages
40
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Location
chennai
Activity points
1,558
Its k. Can you explain by taking some values as inputs for both common mode and differential mode amplifiers
 

samba007

Banned
Joined
Dec 4, 2010
Messages
66
Helped
10
Reputation
20
Reaction score
9
Trophy points
1,288
Activity points
0
Did you check the simulator in the link given by shivaram.....
 

mdkmahesh

Member level 1
Joined
Apr 6, 2011
Messages
40
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Location
chennai
Activity points
1,558
ya. In my project i have to connect my potential transformer output to input of an amplifier which is in common mode now and i am planing to change it to differential mode,what will happen if i changed the mode of operation?
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top