Power Amplifiers Study Guide

Flashcards based on a Power Amplifiers study guide covering Classes A, B, AB, and C, efficiency, and component configurations.

Efficiency

The ratio of output signal power to total power, or more specifically, the ratio of the power delivered to the load to the power from the dc power supply.

Class A Power Amplifiers

A type of large-signal amplifier that operates in the linear region at all times.

Power Gain

The ratio of power delivered to a load ($P_{out}$) to the input signal power ($P_{in}$); for example, delivering $5\,W$ to a load with an input signal power of $100\,mW$ results in a gain of $50$.

Quiescent current

The factor upon which the peak current that a class A power amplifier can deliver to a load depends.

Complementary symmetry transistors

A pair of transistors (typically one npn and one pnp) used in a class B push-pull amplifier with no transformer coupling and required in class AB amplifiers.

Darlington transistors

Transistors that can be used to increase the input resistance of a class AB amplifier.

Class B conduction cycle

A mode of operation where each transistor conducts for only half of the input cycle ($180^{\circ}$), rather than the entire input cycle.

Class C power dissipation

The power dissipation level of a class C amplifier, which is normally very low.

Class C conduction

A condition where the transistor conducts for only a small portion of the input cycle.

Class B transistor bias

The biasing state of transistors in a class B amplifier, which is set at cutoff.

Class A Q-point

The operating point that should ideally be centered on the load line for a class A amplifier.