题干

如图所示是由基本逻辑电路构成的一个公路路灯自动控制电路,图中虚线框内M是一只光敏电阻(受光照时电阻会变小),虚线框N中使用的是门电路。如果要想提高此逻辑电路在黄昏时的灵敏度,可适当调节可变电阻R来实现,下列叙述正确的是

A:N为与门电路,适当增大R可提高黄昏时的灵敏度

B:N为非门电路,适当增大R可提高黄昏时的灵敏度

C:N为与门电路,适当减小R可提高黄昏时的灵敏度

D:N为非门电路,适当减小R可提高黄昏时的灵敏度

上一题 下一题 0.0难度 选择题 更新时间:2019-01-31 11:31:15

答案(点此获取答案解析)

D

同类题1

阅读理解

    Everybody should have some level of first aid ability, because accidents and medical emergencies can happen anywhere at any time. St John First Aid courses give you the knowledge and confidence to provide effective first aid whenever it's needed.

First Aid Level 1

    Ideal(理想的) for anyone who wants to learn basic first aid or needs to renew their first aid qualification. Courses can be held at St John or your workplace.

Fee: $162(includes GST)

Duration(持续时间): Eight hours

First Aid Level 2

    Includes all course content from First Aid Level One, plus an additional half day. Ideal for special first aiders, health and safety managers and anyone who needs a first aid qualification.

Fee: $235(includes GST)

Duration: 12 hours

Pre-Hospital Emergency Care (PHEC)

    Advanced training for first aiders who already hold unit standards 6400 and 6402. Ideal for people who require advanced first aid skills or a pre-hospital emergency care (PHEC) qualification for their work.

Fee: $635(includes GST)

Duration: Three days

Child First Aid

    Ideal for parents, grandparents and other family caregivers. A recognized qualification for childcare workers.

Fee: $65(includes GST)

Duration: Four hours

Outdoor First Aid

    First aid response for accidents and medical emergencies in the wilderness. For groups of eight or more.

Duration: One to two days depending on experience

Sports First Aid

    First aid response for common sporting injuries and medical emergencies. Includes ACC injury prevention advice.

Duration: Eight hours.