Question
Question: In a common-base amplifier, the phase difference between the input signal voltage and output voltage...
In a common-base amplifier, the phase difference between the input signal voltage and output voltage is:
(A) 4π
(B) π
(C) 0
(D) 2π
Solution
To answer this question, we need to use the relation between the input signal voltage and the output signal voltage. Then, on comparing them, we will get the required value of the phase difference between them.
Complete step-by-step solution
The term common base amplifier means that the bipolar junction transistor used in this amplifier circuit must have the base common to the input and the output terminals.
So the input is applied between the emitter and the base terminals, while the output is taken between the collector and the base terminals.
Now, a common base amplifier is used for amplifying the given input voltage in the same phase as that of the input voltage. So the output voltage is just the magnified form of the input voltage. Since both of the input signal voltage and the output voltage are in the same phase, so the phase difference between the two is equal to zero.
Thus, the phase difference between the input signal voltage and the output voltage in a common base amplifier is equal to zero.
Hence, the correct answer is option C.
Note
An amplifier is of three types, based on the configuration of the transistor used. Since the transistor can have three different configurations depending upon the common terminal, so the types of amplifiers are; common emitter, common base, and common collector. A common base amplifier has no phase difference between input and output voltage, which makes it the best voltage amplifier. A common emitter amplifier, on the other hand, has the input and the output voltages opposite in phase.