| 摘要 |
PURPOSE:To prevent an abnormal operation of a circuit and to reduce noise. CONSTITUTION:This device is provided with an airtight case 1 which houses a printed circuit board 5 in it and a cooling fan 8 which blows the outside air against the airtight case 1. The fan 8 is located outside the airtight case 1, therefore the outside air and dust are prevented from entering the airtight case 1 and no dust is collected on the printed circuit board 5 in the airtight case 1. Dust cannot enter the airtight case 1, and also the resonance of the case due to the sound of wind is prevented. |
