| 摘要 |
PURPOSE:To perform an operation with a low source voltage by clamping an input signal without shifting the level of a clamping voltage, and attenuating the amplitude of the input signal. CONSTITUTION:Forward voltages between the bases and emitters of transistors 7-10 are assumed as VBE7-VBE10, respectively. When the voltage of a constant voltage source 3 is set at 1V to generate the clamping voltage of 1V, all the voltages at points A-C are set at 1Vs since it is VBE7 VBE9 and VBE8 VBE 10. And since both DC voltages at the points B and C are 1Vs, the clamping voltage at an output signal terminal 6 also goes to 1V, which is not decided by the raio of the resistance values of resistors 4 and 5. Thus, since no change occurs in the setting voltage value of the constant voltage source 3 even when the attenuation quantity of input signal amplitude is set at any value and also, the voltage at the point A does not depend on the attenuation quantity, the operation with the low source voltage can be performed. |
