An electric blanket is a blanket that contains integrated electrical heating wires. Types include underblankets, overblankets, throws, and duvets. An electric underblanket is placed above the mattress and below the bottom bed sheet. This is the most common type in the UK and Commonwealth countries, where it is known by default as an "electric blanket"; in the U.S. and Canada, where it is less common, it is called an electric heated mattress pad. An electric overblanket is placed above the top bed sheet, and is the most common type in the U.S. and Canada, where it is called an "electric blanket". Electric blankets usually have a control unit that adjusts the amount of heat the blanket produces by pulsing current at different intervals. Blankets for two-person beds often have separate controls for each side of the bed. The electric blanket may be used to pre-heat the bed before use or to keep the occupant warm while in bed. Electric blankets use between 15 and 115 watts in general. Some modern "low voltage" electric blankets have thin carbon fiber wires and work on 12 to 24 volts. Mechanism Much like heating pads, electric blankets use an insulated wire or heating element inserted into a fabric that heats when it is plugged in. The temperature control unit, located between the blanket and the electrical outlet, manages the amount of current entering into the heat elements in the blanket. Some modern electric blankets use carbon fiber elements that are less bulky and conspicuous than older heating wires. Carbon fiber is also used as the heating element in many high-end heated car seats. Blankets can be purchased with rheostats that regulate the heat. With signal line type It is used in temperature controller electric blankets which have a thermostat that regulates the temperature. The core of the wire is made of glass fiber or polyester wire. Flexible electrical heating alloy wire is wrapped around it. Outside is covered with a heat-sensitive layer. Then a copper alloy signal wire is wrapped around the outside of the heat-sensitive layer. Outside the copper signal wire is coated with a heat-resistant resin. When the temperature at any point on the electric blanket exceeds a predetermined value, the heat-sensitive layer on the corresponding electric heating wire is changed from an insulator to a good conductor, so that the control circuit is turned on and the electric blanket is disconnected