| 摘要 |
PURPOSE:To realize a two-wire type ultrasonic level meter whose supply energy is limited by charging the driving energy of a transmitter-receiver and sending the charged energy to the transmitter-recevier intermittently. CONSTITUTION:When a transmitter 13 sends out no ultrasonic pulse, a capacitor 24 is charged with a current Ir from an external power source 19 through a current limiting circuit 23. When an ultrasonic wave pulse is sent out, the power charged in a capacitor 24 is used to average a consumed current, so that a load current IL conducting through transmission lines L1 and L2 never varies. Therefore, the supply energy is limited and the ultrasonic level meter is realized even if it is a two-wire type. |
