How many classes of amplifier operations are there?

The correct answer is that there are four classes of amplifier operations. These classifications are primarily based on the conduction angle of the active devices within the amplifier and how they operate during the input signal cycle.

The four main classes are:

1. Class A: In this class, the amplifier's active devices conduct for the entire 360 degrees of the input signal cycle. This allows for linear signal amplification but tends to be inefficient due to constant current flow even without an input signal.

2. Class B: Class B amplifiers conduct for half (180 degrees) of the input cycle. They use complementary pairs of transistors (one for each half of the waveform), which increases efficiency but can introduce distortion at the crossover point between the two conducting devices.

3. Class AB: This is a hybrid between Class A and Class B amplifiers. In Class AB, the devices conduct slightly more than half of the cycle to reduce crossover distortion, providing a balance between efficiency and linearity.

4. Class C: Class C amplifiers conduct for less than half of the input signal cycle. This design is highly efficient and is often used in applications like RF transmission, where distortion can be tolerated.

Understanding the four classes of amplifier operations