| 摘要 |
PURPOSE:To make a car audio set burglarproof by configurating a circuit in such a manner that alarm bells are made to sound over when the car audio set is removed. CONSTITUTION:When an ignition switch SW1 is off, and earth wires L4 and L5 and connectors 15 and 16 are connected, an electric current flows in the following sequential order: an electric power source 2, a resistance R7, a diode D4, a connector 16, a pilot lamp PL, a chaisis of the audio set 11, an earth wire L4, a car frame 12, and an earth wire L5. If the earth wires L4 and L5 are disconnected to remove the car audio set, an electric current flows in the following order: an electric power source B2, a buzzer 14, a transistor Q7, and an earth allowing the warning buzzer to sound. |
