PTC thermistor working principle: PTC thermistor (positive temperature coefficient thermistor is a self-recovery fuse) is a semiconductor resistor with temperature sensitivity. Once it exceeds a certain temperature (Curie temperature), its resistance value The increase in temperature is almost a step increase. The temperature change of the PTC thermistor can be obtained by the current flowing through the PTC thermistor, it can also be obtained by the input of heat from the outside or the superposition of the two.
Operation principle of PTC heater: PTC heater adopts PTCR thermosensitive ceramic element, which is composed of several single pieces combined with corrugated heat dissipation aluminum strip and bonded by high temperature adhesive. It has the obvious advantages of small thermal resistance and high heat exchange efficiency. Its biggest feature is its safety, that is, when the fan is blocked, the PTC heater will not actively dissipate heat, and the power will actively drop sharply. At this time, the surface temperature of the heater is limited to the Curie temperature (generally 220 ℃), so as not to cause the "redness" phenomenon on the surface of the electric heating tube heater, eliminating the hidden danger of the incident.
The difference between PTC thermistor and PTC heater:
1. The PTC heating plate has the characteristics of active constant temperature, no temperature control system is needed, and the PTC heating plate can be directly powered on.
2. When the PTC heater is used to heat liquid (such as water), the PTC heater will not be damaged after the liquid is dried.
3. If the PTC heater is used to heat the cool wind, the PTC heater will not be damaged when the air is not supplied.
4. The operation is reliable, and the internal characteristics of the PTC heating plate are used to control the temperature, and the temperature will never be overheated.
5. The operating voltage is very wide: when the operating voltage changes twice, the change in surface temperature is very small.
6. When multiple PTC heaters are used together, they should be connected in parallel, not in series.
7. Different heat dissipation conditions make the heating power of the PTC heater very different.
8. The heating power changes from large to small after being energized, and is finally stable. The stable power is related to the operating conditions. If the operating conditions of the same PTC heater are different, the power may differ by several times. The faster the heat dissipation, the greater the stable power; the higher the PTC surface temperature, the higher the power.
9. The surface temperature of the PTC heating element is controlled by the PTC itself, and can also be controlled by disconnecting the circuit, but it is not possible to control the surface temperature by adjusting the voltage.
10. PTC itself has high reliability and long life, but if it is not installed properly, the product will have unstable power and temperature.