sorry but i must ask this as it is important.. WhaT is class-D,A,AB Guru?
Like the guy said, you could look it up.
I'll get you started, though:
- Class A: "Single-ended" amplifier; a single amplifying device (transistor, vacuum tube, MOSFET) conducts throughout the AC cycle. Can be highly linear (= low distortion) but inefficient (wastes power) because current flows throughout the cycle.
- Class B: Two amplifying devices operating in "push-pull" mode, where each device only conducts 180° of each cycle (one device amplifies the positive half, the other device the negative half of each cycle). Eliminates distortion due to even-order harmonics and is much more efficient than class A.
- Class AB: A class B amp where a small amount of overlap is allowed between the push-pull devices (conduction is slightly more than 180°) to reduce "crossover" distortion.
- Class C: A highly efficient mode of operation used in RF (radio frequency) only, where the amplifier is tuned to a specific frequency using a resonant tank circuit and produces a series of pulses that are converted into a sine wave at the output. Not usable for audio.
- Class D: An amplifier that uses PWM (pulse-width modulation) or "chopping" to achieve very high efficiency (90% or more) by driving the output stage with high-frequency pulses (significantly higher than the highest frequency to be amplified) of varying widths. The PWM frequency is removed at the output, leaving only the amplified audio wave. Capable not only of high efficiency but surprisingly low distortion. Used extensively in automobile audio amps.
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