The self-regulating heater is an electric heater that tries to keep the temperature constant regardless of how the surrounding conditions change. It is the material in the heater itself that regulates the temperature. The heater does not require regulator electronics, temperature sensors, overheating protection, etc. The temperature to be held by the heater is decided when the material and heater are produced. This can be fine tuned by changing the voltage to the heater. Self-regulating heaters are made of materials with strong positive temperature (PTC) temperatures, ie the resistivity of the material increases rapidly with increasing temperature. Such materials include ceramic PTC stones. and PTC rubber.
Video Self-regulating heater
Ceramic type
Ceramic PTC heater is made of small ceramic pieces pressed between two metal plates. Compartment constraints cause them to get strong PTC effects. The typical temperature of ceramic stone is 140-250 Â ° C (284-482 Â ° F). Ceramic stones actually have Negative temperature coefficient (NTC) properties at low temperatures that make them slow to heat up.
Maps Self-regulating heater
Rubber type
PTC rubber heaters are made of a special type of rubber that conducts electricity, but only to the specified temperature on the PTC rubber production. The typical design temperature is between 0-80Ã, Â ° C (32-176Ã, Â ° F). The rubber resistivity increases exponentially with temperature for all temperatures up to the design temperature. Therefore, it has strong PTC properties for all temperatures and heats up rapidly. Above this temperature the rubber is an electrical insulator and stops generating heat. This makes the heater self-limiting. Rubber sheets are thin and flexible and can be shaped for various shapes and sizes.
Operation
When the voltage applied to the PTC electric heater flows through the material and the resistivity of the material causes it to heat up (P (T) = U2a R (T)). As it heats up, the resistivity increases rapidly and the power (heat) generated decreases. At the same time heat is transferred from the heater to the embedded object, and its surroundings. Eventually the amount of heat generated in equilibrium by the amount of heat carried and radiated away from the heater. The heater reaches the equilibrium temperature and stays there. The exponential PTC property of the material ensures that the equilibrium temperature is almost insensitive to changes in ambient temperature.
References
Source of the article : Wikipedia
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