Patent ID: 7019262

Claim:
An electric blanket comprising: a substrate ( 11 ) made of cotton cloth; a heating member ( 12 ) mounted on the substrate ( 11 ), the heating member including a fiber ( 121 ), a heating wire ( 122 ) wound around the fiber, an inner silicon rubber insulating layer ( 123 ) covering the fiber and the heating wire, and an outer silicon rubber insulating layer ( 124 ) covering the inner silicon rubber insulating layer; a plurality of digital temperature sensors ( 15 ) mounted to the heating member ( 12 ) at a plurality of positions for detecting temperature of the heating member ( 12 ) at the positions and sending signals relating to the temperature of the heating member at the positions and indicating the positions; a temperature protection switch ( 16 ) electrically connected in series to the heating member ( 12 ); an electromagnetic radiation interference filter ( 27 ) electrically connected to an AC power source; a DC power supply circuit ( 22 ) electrically connected to the electromagnetic radiation interference filter ( 27 ) for converting AC power source into a DC power supply; a display ( 20 ) for displaying at least temperature of the electric blanket; a zero-cross detector (R 8 ) electrically connected to the DC power supply circuit; a triac ( 23 ) electrically connected to the heating member ( 12 ); and a central processing unit ( 21 ) electrically connected to the digital temperature sensors ( 15 ), the electromagnetic radiation interference filter ( 27 ), the DC power supply circuit ( 22 ), the zero-cross detector (R 8 ), the triac ( 23 ), and the display ( 20 ); the central processing unit ( 21 ) receiving and processing the signals from the digital temperature sensors and a feedback signal from the temperature protection switch ( 16 ) to control temperature of the electric blanket.