Search results
Results from the WOW.Com Content Network
A positive temperature coefficient (PTC) refers to materials that experience an increase in electrical resistance when their temperature is raised. Materials which have useful engineering applications usually show a relatively rapid increase with temperature, i.e. a higher coefficient.
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 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]
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 .
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.
The coefficients of the differential quantities are intensive quantities (temperature, pressure, chemical potential). Each pair in the equation are known as a conjugate pair with respect to the internal energy.
The first term has a negative temperature coefficient; the second term has a positive temperature coefficient (from its ). By an appropriate choice of N {\displaystyle N} and R 1 {\displaystyle R1} and R 2 {\displaystyle R2} , these temperature coefficients can be made to cancel, giving an output voltage that is nearly independent of temperature.
Thermodynamic temperature is a quantity defined in thermodynamics as distinct from kinetic theory or statistical mechanics.. Historically, thermodynamic temperature was defined by Lord Kelvin in terms of a macroscopic relation between thermodynamic work and heat transfer as defined in thermodynamics, but the kelvin was redefined by international agreement in 2019 in terms of phenomena that are ...