In a Class A amplifier, what percentage of the time does the amplifying device conduct?

A Class A amplifier is biased so that its output current flows during the entire 360-degree cycle of the input signal. Because there is never a time when the transistor or tube is completely turned off, the amplifying device conducts 100% of the time. This continuous conduction means Class A amplifiers offer excellent linearity and very low distortion, making them ideal for high-fidelity audio and sensitive RF receiving stages. However, this comes at the cost of poor efficiency, as power is constantly being consumed and dissipated as heat even when no signal is present. Other options describe different amplifier classes. For example, a Class B amplifier conducts for exactly 50% of the cycle, Class AB conducts for more than 50% but less than 100%, and Class C conducts for less than 50% of the time.