| 摘要 |
In a push-pull power amplifier which amplifies an audio-frequency signal supplied thereto and supplies its output signal to a load, a pair of output transistors constituting the push-pull circuit are alternately turned on and off according to the polarity of the input signal. In the power amplifier, current flowing through the current path leading from a DC power source to each of the output transistors includes many harmonic components besides its fundamental wave component. These harmonic components of current are introduced through a stray magnetic field into the signal path in the power amplifier thereby producing distortion of the signal supplied to the load. To prevent this signal distortion, the signal path of the audio-frequency signal is magnetically coupled to the current paths from the DC power source, so that the harmonic components of current flowing through the current paths can be supplied to the signal path with the phase and the signal level which cancel the harmonic components of current introduced into the signal path through the stray magnetic field thereby minimizing distortion of the amplifier output signal.
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