Search results
Results from the WOW.Com Content Network
A temperature coefficient describes the relative change of a physical property that is associated with a given change in temperature. For a property R that changes when the temperature changes by dT , the temperature coefficient α is defined by the following equation:
A positive-temperature-coefficient heating element (PTC heating element), or self-regulating heater, is an electrical resistance heater whose resistance increases significantly with temperature. The name self-regulating heater comes from the tendency of such heating elements to maintain a constant temperature when supplied by a given voltage.
in which α is a positive coefficient called the thermal diffusivity of the medium. In addition to other physical phenomena, this equation describes the flow of heat in a homogeneous and isotropic medium, with u ( x , y , z , t ) being the temperature at the point ( x , y , z ) and time t .
In thermochemistry, a thermochemical equation is a balanced chemical equation that represents the energy changes from a system to its surroundings.One such equation involves the enthalpy change, which is denoted with In variable form, a thermochemical equation would appear similar to the following:
Quantity (common name/s) (Common) symbol/s Defining equation SI unit Dimension Temperature gradient: No standard symbol K⋅m −1: ΘL −1: Thermal conduction rate, thermal current, thermal/heat flux, thermal power transfer
In crystal oscillators for temperature compensation, medical equipment temperature control, and industrial automation, silicon PTC thermistors display a nearly linear positive temperature coefficient (0.7%/°C). A linearization resistor can be added if further linearization is needed. [23]
A ceramic heater as a consumer product is a space heater that generates heat using a heating element of ceramic with a positive temperature coefficient (PTC). [1] [2] [failed verification] Ceramic heaters are usually portable and typically used for heating a room or small office, and are of similar utility to metal-element fan heaters.
For example, if the change is an increase in temperature at constant volume, with no phase change and no chemical change, then the temperature of the body rises and its pressure increases. The quantity of heat transferred, Δ Q , divided by the observed temperature change, Δ T , is the body's heat capacity at constant volume: