| 摘要 |
PURPOSE:To prevent the destruction of active element so that excessive voltage can not be fed to the active element for amplifying, by connecting the diode at the both ends of the high frequency block coil at the output side in opposite direction as the polarity of bias supply power source. CONSTITUTION:The high frequency block coil RFC 5 is inserted between the amplifying active element 1 in the amplifying circuit and the output bias supply power source Vcc. The diode 6 is connected across RFC 5 in the opposite direction as the polarity of the bias supply power source Vcc. With this constitution, when the operation of the amplifying circuit is in interrupting state, the counterelectromotive force produced across RFC5 at the output side is absorbed with the diode 6, allowing to avoid excessive voltage to the active element 1, and the worst case condition of the destruction of the active element 1 can be avoided. Accordingly, the life of the active element 1 can be made longer. |
