DETECTOR CIRCUIT

PROBLEM TO BE SOLVED: To provide a detector circuit capable of setting a time constant by the charging and discharging of a capacitor to a different value. SOLUTION: Time constant for the current turned back by a current mirror from a transistor P4 on the side of the transistor Q8 of a comparator composed of the transistors Q6 and Q8 and made to flow to the transistor P5 is decided by a capacitor C2 for deciding the time constant. Also, by utilizing the current turned back by the current mirror from the transistor P3 on the side of the transistor Q6 and made to flow to the transistor P2, the capacitor C1 for control is charged, the comparator composed of the transistor P6 and P8 with the capacitor C1 for the control is controlled and level of the current flowing to the comparator composed of the transistors Q6 and Q8 is changed. Thus, a current level is separately set through charging and discharging to the capacitor C2 for deciding the time constant.