| 摘要 |
PURPOSE:To simplify the amplitude control, by connecting a variable resistor to an input side of the 1st and the 2nd PMOS transistors(TR) amplifying input pulse trains of opposite phase relation respectively. CONSTITUTION:The 1st and the 2nd amplifiers are formed with PMOS TRs 1, 3 and resistors 5-8 and NMOS TRs 2, 4 are connected in series with both TRs. The TR2 is set off when the TR1 is turned on and the TR4 is set off when the TR3 is turned on. The variable resistors 5, 8 control the amplification factor of the 1st and the 2nd amplifying circuits for the adjustment of the outputted amplitude. Then inverted and non-inverting pulse input signals impressed to input terminals 10, 11 are push-pull-amplified at the 1st and the 2nd amplifying circuits and drive a speaker 9. |
