Subelement G: Transmitters— Topic 52: Amplifiers-2
Question 3-52G1
Element 3 (GROL)The class B amplifier output is present for what portion of the input cycle?
Explanation
A Class B amplifier is defined by its operating characteristic where the output device (transistor or vacuum tube) conducts for exactly one-half of the input signal's cycle. This corresponds to 180 degrees of the input waveform.
This mode of operation allows Class B amplifiers to achieve greater efficiency than Class A amplifiers, which conduct for the full 360 degrees. However, because a single Class B amplifier only processes half the signal, two such amplifiers are typically used in a "push-pull" configuration to reproduce the entire input waveform accurately, with each device handling one 180-degree half-cycle.
Options A (360 degrees) describes a Class A amplifier. Option B (greater than 180 degrees and less than 360 degrees) describes a Class AB amplifier. Option C (less than 180 degrees) describes a Class C amplifier.
Related Questions
3-51G5 What class of amplifier is distinguished by the bias being set well beyond cutoff?3-51G6 Which class of amplifier has an operating angle of more than 180 degrees but less than 360 degrees when driven by a sine wave signal?3-52G2 What input-amplitude parameter is most valuable in evaluating the signal-handling capability of a Class A amplifier?3-52G3 The class C amplifier output is present for what portion of the input cycle?3-52G4 What is the approximate DC input power to a Class AB RF power amplifier stage in an unmodulated carrier transmitter when the PEP output power is 500 watts?