| 摘要 |
PURPOSE:To ensure the synchronization between the light transmitter and the light receiver in a simple constitution by driving the luminous element at the specific phase time of the AC power source and then giving triggering to the switching element in the specific gate period via the light reception signal. CONSTITUTION:Projector 1 connected to the AC power source forms a separately excited oscillator. And PVT19 receives application of the divided voltage of the full-wave rectified voltage of the AC voltage caused by resistance 17 and 22 in the form of the gate voltage and furthermore the voltage featuring the shifted phase with the level under the fixed value in comparison with the gate voltage in the form of the anode voltage via constant voltage diode 24 of the parallel connection plus capacitor 23. As a result, PUT19 triggers in the fixed phase period of the AC power source, and luminous element 21 is driven by the discharge of capacitor 23. The light emitted from element 21 is received at photo detector 41 of receiver 3 to be changed into the trigger signal. And thus the similar separately excited oscillator circuit 6 of the receiver triggers switching SCR73 for the gate period during which transistor 68 of circuit 6 is turned off only at the specific phase time of the similar AC power source, thus exciting relay 71. As a result, the synchronous action is secured between the light transmitter and receiver in a simple constitution omitting the synchronous signal line. |
