\[P_{DC,A}=V_{CC}I_{CQ},\qquad \eta_A\leq50\%\quad\text{（本页采用变压器耦合 A 类模型）}\]
\[P_{out}=\frac{V_{out,rms}^2}{R_L},\quad P_{DC,B}=\frac{V_{CC}}{R_L}\langle|v_o|\rangle,\quad P_{DC,AB}\approx P_{DC,B}+2V_{CC}I_Q\]
\[V_D=\max\!\left(0,V_{BE}-\frac{V_{BB}}{2}\right),\quad I_Q\approx\max\!\left(0,\frac{V_{BB}-2V_{BE}}{2R_E}\right)\]
取 \(V_{BE}=0.70\text{ V}\)、\(R_E=1.0\,\Omega\)。B 类仅在未失真正弦输出时满足 \(\eta_B=(\pi/4)(V_p/V_{CC})\le78.5\%\)；AB 类在大信号时才逐渐接近该效率。