Abstract: A viewing distance sensor for television receiver which cannot influence the remote infra-red control function over other electronic equipment positioned in the vicinity of a television receiver and also cannot be influenced by the infra-red signals transmitted from other electronic equipment. An infra-red signal is transmitted from the infra-red signal transmitter where a viewer is positioned within a viewable distance from the front of television receiver, whereby false operation caused by the infra-red signal from other equipment can be avoided. Also, an inhibiting control signal is applied to the screen controller of a television set where infra-red signals transmitted from other electronic equipments are received by the infra-red receiver in the television receiver, whereby false operation of the viewing distance sensor can be further avoided.

Abstract: A switching mode power supply circuit designed to apply an operating power to the load when a relay connected to the remote control part is driven. The switch of the relay is connected to the base of the switching transistor, and the secondary winding of the transformer for making the electric power flow to the base of the switching transistor is connected to the terminals fixed on each side of the switch of the relay through the base current supply and absorption parts, respectively. Thereby, the base current of the switching transistor is varied in accordance with the driving state of the relay. The switching mode power supply circuit is operated stably regardless of the state where the operating power is applied only to the remote control part or the state where the operating power is applied to both the remote control part and the load.

Abstract: There is provided a circuit for displaying selection of a channel in television sets. In the circuit, the output voltage from a saw tooth generator generating a saw tooth wave by a horizontal pulse signal is compared with reference voltages applied to the respective connection points of the registers at the operational amplifiers and, thereby, a color bar is generated on a television screen when low level signals are output from both the operational amplifiers. The circuit is constructed in such a manner that changes in the width of the color bar on both sides correspond to the change of reference voltages at the connection points which fluctuate according to the output voltages of an automatic fine tuning circuit (AFT).