| 摘要 |
An amplifier includes a differential amplifier which is supplied with a small amplitude signal in a normal condition and a large amplitude signal in an abnormal condition. Resistors and diodes jointly act to judge whether the differential amplifier issues a small or large amplitude signal. A small amplitude signal is amplified by a small amplitude signal-amplifying section and a large amplitude signal is amplified by a large amplitude signal-amplifying section. The large amplitude signal-amplifying section is supplied with a first source voltage B2. The small amplitude signal-amplifying section is impressed with a second source voltage B1. An output signal of the amplifier is supplied to a load A through an output terminal common to the small amplitude signal-amplifying section and large amplitude signal-amplifying section. The first and second source voltages B2, B1 are chosen to have the following relationship: B2>B1. |
