Abstract
In order to detect the change of mean value of AC voltage, smoothing circuit is generally used. However, the response time of the circuite is long, because of having large time constant compared with period of input signal.
A circuit is designed in order to detect the change of mean value of AC voltage as quickly as possible, that is, the DC output of the circuite is obtained within a period of one cycle of input signal. This circuit is constituted of a integrating circuit and a holding circuit where the charge of the integrating condenser is transfered quickly to holding the condenser using SCR. This circuit is scarcely affected by the noise in the signal to the circuit, since it has integrating function.
From experimental results of the circuit detecting the change of commercial frequency voltage, it is shown that this circuit has satisfactory performance in accuracy and responsibility.
