| 摘要 |
PURPOSE:To obtain a device for preventing close watching to be recognized securely by a viewer by providing a sensor detecting the viewer to access a television receiver. CONSTITUTION:A pressure sensor B is installed in front of the television receiver A. In this pressure sensor, the resistance is stepped to be changed by pressuring or switching operation is produced. An alarm means is operated in response to the output signal of the pressure sensor B. When the pressure sensor B goes to 1 in its level, the level is applied to a transistor(TR) Q2 with a preset time delay by a timer circuit Ts. When this voltage is impressed to the base of the TRQ2, the TRQ2 is turned on, the base voltage of the TRQ1 is decreased and turned off. Its output is set to a voltage decided by resistors R1, R3 and it is applied to a terminal 24 via a diode D<3> to bring the potential of the terminal 24 7.4V. Thus, the chrominance signal from terminals 26-28 are biased to the black level and the video of a color picture tube 7 is, e.g., erased. |
