| 摘要 |
PURPOSE:To set the DC output voltage perfectly at zero, by floating a positive/ negative power supply from an earth in terms of DC and having a 100% DC feedback factor without giving any time constant to a feedback loop. CONSTITUTION:A positive/negative power supply (+ or -VCC) supplied to a circuit floats from an earth in terms of DC, and the junction between a positive power supply +VCC and a negative power supply -VCC is earthed via a capacitor CB having sufficiently large capacity. The DC output voltage (output offset voltage) is stabilized since the DC feedback factor is set at 100%. Furthermore no DC current flows to resistances Rf, Rg and Ri respectively since the power supply + or -VCC has DC floating from the earth. Thus it is possible to set the DC output voltage perfectly at zero. The offset voltage of an input differential amplifier emerges at a gate of the input side and then cut by an input coupling capacitor Ci. |
