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在评估电气设备和家用电器的能源效率时,长期测量和记录功耗是很有帮助的。为了获得“实际”(非电抗)功率的有意义读数,电表对负载电抗和非线性必须是不灵敏的。 本电路利用了一对对称的晶体管倍增器来直接计算实际电源和市电电压的4象限乘积(参见附图)。所得的结果是平均值,并变换成适合直接连接到标准PC机通信口的可变频率光隔离RS—232兼容脉冲输出。PC通信口硬件把每个脉冲解释为有效(虽然是无意义的)字符的“起始位”。然后,在PC机上运行的简单软件可以监视字符接收的频率,作为一种功耗的精确量度。 在观看该电路的一个透视图时,请
Long-term measurement and recording of power consumption can be helpful in assessing the energy efficiency of electrical equipment and appliances. In order to obtain a meaningful reading of “real” (non-reactance) power, the meter must be insensitive to load reactance and non-linearity. This circuit uses a pair of symmetrical transistor multipliers to directly calculate the 4-quadrant product of the actual power supply and mains voltage (see the figure). The results obtained are averaged and converted to variable frequency optically isolated RS-232 compatible pulse outputs for direct connection to a standard PC communication port. The PC port hardware interprets each pulse as a valid (albeit meaningless) “start bit” of the character. Then simple software running on a PC can monitor the frequency of character reception as an accurate measure of power consumption. When looking at a perspective of the circuit, please