Question

A condition, where two signal applied in differential inputs are of the same phase, frequency and amplified, is called
1. Common baud
2. Common mode
3. Common signal
4. Common input

Answer 1

Correct Answer - Option 2 : Common mode

In common mode, two signals applied in differential inputs are of the same phase, frequency, and amplified.

Common mode:

• A common-mode signal is one that drives both inputs of a differential amplifier equally
• The common-mode signal is interference, static and other kinds of undesirable pickup etc

Application:

• The transistors in the differential amplifier are chosen to be closely matched
• If both the transistors were matched in all respects then the balanced output would be theoretically zero
• This is the important characteristic of a differential amplifier
• It discriminates against common-mode input signals i.e. it refuses to amplify the common-mode signals