| 摘要 |
PURPOSE:To prevent occurrence of the distortion for the output waveform even with increment of the input signal by connecting the diode between the emitter and the base of the 1st-step transistor so that the base side may feature the negative pole. CONSTITUTION:When large signal Va is supplied to input terminal (a) and the output-step waveform of coutput transistor TrQ4 is clipped, feedback voltage (v) is clipped. Thus the base input of TrQ1 increases but signal (v) does not increase. And accordingly, capacitor C2 is charged with the current of (Va-v)/R5 in the positive half cycle. In the negative half cycle, TrQ1 is turned off but with diode D2 turned on. Thus the charge of capacitor C2 is discharged with the current of (Va-v)/R5. As a result, the DC voltage across capacitor C2 has no increment and also the DC voltage of TrQ1 emitter has no increment with no change of DC voltage V2 of the output step. Thus the clip waveform of the output can be formed symmetric up and down, preventing occurrence of the distortion. |
