| 摘要 |
PURPOSE:To expand the life of the titled device and to attain highly accurate detection with a simple constitution without using a reed switch mechanism. CONSTITUTION:A coil L1 is formed on a position corresponding to the reference position of a substance 1 to be detected. When the substance 1 to be detected starts to move and then crosses ad passes a coil L2, the coil L2 generates AC current by its electromagnetic induction. When the positive polarity side of the AC current is rectified, extracted and sent to the gate of a thyristor S1 as the 1st trigger signal, the thyristor S1 is turned on and then held at its state. When the substance 1 to be detected moves, crosses and passes the coil L3, the coil L3 generates AC current similarly to the preceding case. The negative polarity side of the AC current is rectified, extracted and then sent to the thyristor S1 at the 2nd trigger signal. Consequently, the thyristor S1 is turned off and then held at the OFF state. Thus, the thyristor S1 is turned on and off by detecting the arrival of the substance 1 to be detected at the positions L2, L3. When the substance 1 to be detected is located on the intermediate position between the positions L2, L3, the thyristor S1 is held at the ON or OFF state turned in the preceding stage. |
