Class A and B Power Amplifiers — Lessson 1

This lesson covers the concept power amplifiers. It explains why power amplifiers are needed, their requirements, and the different classes of power amplifiers, including class A, Class B, and Class C. The lesson also discusses the role of power amplifiers in transmitting signals, the importance of efficiency, and the impact of distortion. It further delves into the concept of frequency reuse in cell phone networks and the stringent power control requirements in CDMA systems. The lesson concludes with a detailed analysis of the efficiency of class A and B amplifiers.

Video Highlights

00:24 - Introduction to power amplifiers
08:11 - Efficiency and importance of linearity of the power amplifier
16:31 - Discussion on different architectures of power amplifiers
19:58 - Class A amplifiers and their efficiency
36:40 - Class B amplifiers and their efficiency

Key Takeaways

- Power amplifiers are crucial in transmitting signals, with their main requirement being to pump out as much energy as possible.
- Efficiency and linearity are two significant concerns in power amplifier design.
- In cell phone networks, power control is crucial to prevent interference with other communications.
- Class A, B, and C power amplifiers have different efficiencies and operational times. Class A is always on, Class B is on 50% of the time, and Class C is on less than 50% of the time.
- The efficiency of class A is at max 50 percent, while class B and C have better efficiencies.