PTC Thermistor Working Principle
PTC thermistor (Positive Temperature Coefficient Thermistor) is a temperature-sensitive semiconductor resistor. Once it exceeds a certain temperature (Curie temperature), its resistance value increases almost stepwise with the increase of temperature. The temperature change of the positive temperature coefficient thermistor can be obtained by the current flowing through the PTC thermistor, or by the external heat input or the combination of the two.
Ceramic materials are usually used as excellent insulators with high resistance. Ceramic PTC is made of barium titanate and doped with other polycrystalline ceramic materials, which has low resistance and semiconductivity. It is achieved by purposefully doping a material with higher chemical valence as the lattice element of the crystal: a part of barium ions or titanate ions in the crystal lattice is replaced by higher valence ions. Therefore, a certain number of free electrons are obtained.
Then, let's look at the reason for PTC thermistoreffect, in other words, the reason for the step increase in resistance value. The material structure is composed of many small crystallites, and the potential is formed on the grain boundary, which prevents the electrons from crossing the boundary into the adjacent area, thus resulting in high resistance. This effect is offset at low temperatures: the high dielectric constant and spontaneous polarization at the grain boundary hinder the formation of barriers and allow electrons to flow freely at low temperatures. At high temperatures, this effect greatly reduces the dielectric constant and polarization, leading to a substantial increase in the barrier and resistance, showing a strong PTC effect.
PTC is a kind of semiconductor heating ceramic. When the external temperature decreases, the resistance value of PTC decreases, and the calorific value increases correspondingly. PTC thermistor working principleis as follows: once it exceeds a certain temperature (Curie temperature), the resistance increases of positive temperature coefficient resistor with the increase of temperature almost in a step-by-step manner. The temperature change of PTC thermistor types body can be obtained by the current flowing through it, or by the external input heat or the combination of the two. Ceramic materials are usually used as excellent insulators with high resistance, PTC ceramics are based on barium titanate and doped with other polycrystalline ceramic materials, which have low resistance and semiconductivity. It is achieved by purposely doping a kind of material with higher chemical value as the lattice element of the crystal: in the lattice, part of barium ions or titanate ions are replaced by higher valence ions. Therefore, a certain number of free electrons are obtained.
As one of industrial sensor suppliers, we will do our best to meet all the needs of customers.
在线联系供应商
Other supplier products
 |
Disposable Medical Body Probe | Details Material: the medical temperature probeis made of a high-precision medical chip/silicone cable/mono audio plug Applicable temperature rang... |
 |
School Fire Monitor Temperature Sensor | Details Material: NTC glass-sealed thermistor/plastic cable tie/Teflon wire Applicable temperature range：-30~150℃ Output signal: analog signal... |
 |
Epoxy Thermistor | Epoxy Thermistor Details Material: Semiconductor ceramics/epoxy Applicable temperature range：-40~125℃ Output signal: analog signal output Adva... |
 |
Charging Pile Temperature Sensor TPS200724-11 | Specification: TPS200724-11 Details Material: NTC glass-sealed thermistor / high-temperature Teflon wire / PVDF heat shrinkable film Applica... |
 |
Motor Temeperature Sensor | Motor Temp Sensor Specification: TPS190629-11-C Details Material: National standard copper nutshell, high-temperature injection mold Applicable te... |
Same products
 |
contact displacement sensor DET-200A for Vallur power | 卖方: Dongfang Yoyik Engineering Co., Ltd | |
 |
rpm measurement sensor D521.12 for Akrimota power | 卖方: Dongfang Yoyik Engineering Co., Ltd | |
 |
SENSOR CZ891 for Banyuasin power | 卖方: Dongfang Yoyik Engineering Co., Ltd | |
 |
China made sensor SZCB-01-B01 for power plant | 卖方: DONGFANG YOYIK (DEYANG) ENGNIEERING CO; LTD | "China made sensor SZCB-01-B01 for power plant Dongfang Yoyik has advanced technology and equipme... |
 |
China manufacturer sensor TD-2-50.0 for power generation | 卖方: DONGFANG YOYIK (DEYANG) ENGNIEERING CO; LTD | "China manufacturer sensor TD-2-50.0 for power generation Is to use the generator sets of profess... |
