| 摘要 |
PURPOSE:To eliminate a latch phenomenon without any decrease in sensitivity by coupling one output terminal of a pyroelectric sensor with the output of an amplifier and coupling the other terminal with the minus input of the amplifier circuit. CONSTITUTION:One output terminal of the pyroelectric sensor 1 is coupled with the output of the amplifier circuit 2 and the other output terminal is coupled with the minus input of the amplifier circuit 2, so that the pyroelectric sensor becomes a negative feedback element. Therefore, an impedance resistance value or transient resistance value decreases greatly below a static resistance value and current amplification becomes possible, so a current flows all the time. A latch phenomenon is therefore eliminated and the need for a mechanical chopper which cuts off infrared rays intermittently is eliminated, so that the system is reduced in size and cost. |
