| 摘要 |
PURPOSE:To obtain a detecting circuit which confirms the presence of a human body, etc., likewise a thermopile and a thermistor porometer by adding adequate circuits to a pyroelectric detector. CONSTITUTION:The pyroelectric detector 1 performs differential responding operation to obtain detection output as shown by (a) when a man passes through its detection area. For example, A is a signal generated when the man enters the detection area and B is a signal generated when the man exits from the detection area. A comparator 3 has two positive and negative threshold values, which have the absolute values less than said signals A and B and greater than a noise. A judging circuit 4 generates a set signal S and a reset signal R according to whether the output of the comparator 3 is plus or minus and a figure 5 shows a flip-flop set and reset by the set signals S and reset signal R. Therefore, the flip-flop 5 generates an output while the man is in the detection area. The circuit between the detector 1 and flip-flop 5 performs the same operation as a thermopile, etc., when detecting the presence or absence of a man. |
