| 摘要 |
PURPOSE:To eliminate distortion near a clip voltage by having a second transistor, for which emitters are commonly connected mutually with a first transistor, a differential pair is formed and the output of a differential amplifier is impressed to a base, and obtaining a signal output from the output of an emitter follower. CONSTITUTION:When an input voltage VI is higher in comparison with a clip voltage Vr and the condition of a signal output Vo>Vr is provided, the base potential of a transistor Q2, which constitutes a differential amplifier 1, is decreased only by A(Vo-Vr). Accordingly, when a gain A is large at a certain degree, the transistor Q2 is turned off only by slight potential difference (Vo-Vr) and the input voltage VI is fetched through the emitter follower of a transistor Q1 to an output terminal P. On the other hand, when the input voltage VI is decreased and the condition of VophiVr is obtained, the transistor Q2 is turned on and a voltage follower is formed by the transistor Q2 and differential amplifier 1. Even when the VI is further decreased, the fixed clip voltage Vr is outputted to the output Vo. Thus, the ditortion near the clip voltage is eliminated. |
