问题
问答题 简答题
什么是PWM技术?
答案
参考答案:
PWM脉宽调制技术,是对逆变电路开关器件的通断进行控制,使输出端得到一系列脉幅值相等而宽度不等的脉冲,用这些脉冲来代替正弦波或所需要的波形。
什么是PWM技术?
参考答案:
PWM脉宽调制技术,是对逆变电路开关器件的通断进行控制,使输出端得到一系列脉幅值相等而宽度不等的脉冲,用这些脉冲来代替正弦波或所需要的波形。
阅读理解。 | ||
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1. Alice plays the drums well, she can _____ to join the School Art Festival. | ||
A. call 8850-6789 B. write an e-mail C. write a letter | ||
2. Who can be in the School Festival? | ||
A. Michelle (she can draw pictures) B. Nike (he can play tennis) C. Gina (she can speak English) | ||
3. Ann is in the School Festival. She may give a show on _____. | ||
A. December 20th B. January 4th C. January 2nd | ||
4. We can't buy _____ at School Things Store. | ||
A. baseballs B. onion C. pencils | ||
5. How much are two notebooks and a volleyball at School Things Store? | ||
A. ¥15 B. ¥17 C. ¥19 |