| 摘要 |
PURPOSE:To prevent a wasteful power consumption due to the forgetting of the disconnection of the power source of a TV receiver, by detecting a video wave for the TV receiver, and disconnecting the power source of the receiver automatically when no transmission of the wave continues for a time exceeding a prescribed time. CONSTITUTION:When a TV broadcast is completed, no synchronizing signal 120 is outputted any more, and it goes to an L level. Thereby, a 60 frequency demultiplier 20 and a 4 frequency demultiplier 21 are reset-released, and simultaneously, the signal of around 60Hz of the output 130 of a vertical oscillation circuit 13 is inputted to the 60 frequency demultiplier 20 via an amplifier 15, and the frequency demultiplier 20 starts to count. And after around one minute from the start of the count of the frequency demultiplier 20, the output 200 of the frequency demultiplier 20 can be obtained. The one minute signal of the output signal 200 is inputted to the 4 frequency demultiplier 21, and after four minutes, the four minute signal of the output 201 of the frequency demultiplier 21 is inputted to an OR gate 17 on one side consisting of an R-SFF, As a result, the output of a NOR gate 18 consisting of the other side of the R-SFF goes to an (H) level, and a driving transistor 24 for a relay 25 is cut off, and a dedicated power source 700 for the TV receiver is disconnected.
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