Zero-power resistance refers to the extremely low power consumption of the PTC thermistor when measuring the PTC thermistor value at a certain temperature, so that the resistance change of the PTC thermistor due to its power consumption can be ignored. Excluding. The rated zero power resistance refers to the zero power resistance measured at an ambient temperature of 25 °C.
Curie temperature Tc
For PTC thermistor applications, the temperature at which the resistance value begins to increase steeply is important, which we define as the Curie temperature. The resistance of the PTC thermistor corresponding to the Curie temperature is RTc = 2*Rmin.
Temperature coefficient α
The temperature coefficient of a PTC thermistor is defined as the relative change in resistance caused by temperature changes. The greater the temperature coefficient, the more sensitive the PTC thermistor reacts to temperature changes. α = (lgR2-lgR1)/lge(T2-T1)
Rated voltage VN
The rated voltage is the supply voltage below the maximum operating voltage Vmax. Usually Vmax = VN + 15%
Breakdown voltage VD
The breakdown voltage is the highest voltage withstand capability of the PTC thermistor. The PTC thermistor will fail breakdown above the breakdown voltage.
Surface temperature Tsurf
The surface temperature Tsurf refers to the temperature of the surface of the PTC thermistor when the PTC thermistor is in a state of thermal equilibrium with a predetermined voltage and with the surrounding environment for a long time.
Operating current Ik
The current flowing through the PTC thermistor is sufficient to cause the PTC thermistor to rise above the Curie temperature, which is called the operating current. The minimum value of the operating current is called the minimum operating current.
No action current INk
The current flowing through the PTC thermistor is insufficient to cause the PTC thermistor to rise above the Curie temperature, which is called a non-operating current. The maximum value of the non-operating current is called the maximum non-operating current.
Usually, there are certain restrictions on smart portable projectors in 2 aspects:
1. Size: Usually the size is the size of a mobile phone.
2. Battery life: It is required to have at least 1-2 hours or more of battery life without power connection. In addition, its general weight will not exceed 0.2Kg, and some do not even need fan cooling or ultra-small silent fan cooling. Can be carried with you (it can be put into a pocket, the screen can be projected to 40-50 inches or more, so sometimes we also call it a pico projector or a pocket projector.)
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