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发表于 2010-3-11 00:26:32
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回复【15楼】gzhuli 咕唧霖
回复【14楼】rainbow 老陈
原作者的这张图就是测的笔记本电脑的功耗,好像有用啊!
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如果电源有主动PFC,那种还是能得出比较接近的数值的。
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谢谢!
下面这个有没有看过它的实用性。
PowerBox: The Safe AC Power Meter
文中写道:
The primary inspiration for our project was the EnerJar(也就是罐头瓶的那个)
Hardware was used to bring voltage levels into the appropriate range for the Mega32 internal ADC. In software, the Mega32 was used to sample the voltage levels at a frequency of 1 KHz and perform the appropriate calculations in real time. The software also handles interacting with the computer and controlling the relay switch.
The Mega32 ADC channels are multiplexed and not simultaneous. An external simultaneous ADC chip could have been used to sample current and voltage at the same time, resulting in slightly more accuracy. However, to save costs, the extra hardware was not used. The internal Mega32 ADC was switched in software to take one sample after the other. This was deemed good enough for our purposes.
Fixed point (20:12) was used instead of floating point to speed up multiplication and division operations. The Mega32 hardware performed floating point multiplication operations much slower than integer multiplication operations. Therefore, some accuracy was traded for speed.
原文网址:http://instruct1.cit.cornell.edu/courses/ee476/FinalProjects/s2008/cj72_xg37/cj72_xg37/index.html
保存的网页:点击此处下载 ourdev_537715.mht(文件大小:570K) (原文件名:PowerBox The Safe AC Power Meter.mht) |
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