| 摘要 |
PURPOSE:To make easy the switching of reception sensitivity, corresponding to the status of electromagnetic wave reception producing difference at night and day, by switching the stop sensitivity of the automatic channel selector for receivers with on/off signal of a light switch for car. CONSTITUTION:The automatic channel selector for receiver consisting of an antenna 1, tuning circuit 4 and amplifying circuit 5 is provided with a stop sensitivity switching circuit 2 consisting of a capacitor C1 and a resistance R1. This stop sensitivity switching circuit 2 is inserted to a reception circuit with ground with a good electromagnetic wave reception at night to decrease the sansitivity with lower level of antenna input VO. Further, a switching transistor 6 is connected to the stop sensitivity switching circuit 2. By controlling the transistor 6 with a light switch 7 which is connected to a car light 8 and a battery VB, the switching to a low sensitivity at night strong in the electric field and a high sensitivity at day, can easily be made. |
