| 摘要 |
A circuit for automatically activating defrosting systems of a vehicle's front and rear windscreens may comprise a programmable microchip 5, a timer switch 4 and a temperature sensing switch 3. The timer switch 4 may be preset to activate the defrosting systems before a driver is due to begin a journey, and the temperature sensing switch 3 may be used to ensure that the defrosting systems are only activated when ambient temperature is below a predetermined level. When a preset time is reached, timer switch 4 may close and, if ambient temperature is below the predetermined level, temperature sensing switch 3 may also be closed. With both switches closed, the microchip 5 may provide a voltage output 6 to activate the windscreen defrosting systems for a predetermined duration. |
