一种研究粉末电致发光(EL)器件频率特性的新方法

A NEW METHOD FOR STUDYING FREQUENCY CHARACTERISTICS OF POWDER EL DEVICES

提出了一种简单的研究粉末电致发光(EL)器件频率特性的新方法.用这种方法可以使用最少和最一般的设备条件很方便地测量粉末EL器件的有功电流、无功电流、损耗角和发光效率等重要参量及其随频率的变化特性.也可用来简单快速地测量介质和电容器的损耗特性. 试验并论证了方法的合理性,可行性及其物理依据.分析了方法的系统误差及随机误差.

A new method of studying frequency characteristics of powder EL devices is reported. The method is based on the principles as follows. For a RC parallel circuit, at frequency f1:Where I1, the total current, and I1c,L1R,I1R are the capacitive current and conductive current, respectively. Similarly, when the frequency is raised to f2:For an ideal RC parellel circuit, the values of capacitance and resistance arc independent of frequency. For this reason,From (1) , (2) , (3) and ( 4 ) , the dependences can be derived as follows: According to ( 5 ) and (6) , I1 and I2 are measured, I1C and IIR can be obtained.For a real RC parallel circuit, the values of capacitance and resistance are dependent on frequency.But when a suitable small AAAAAAAAAf(AAAAAAf = f2-f1) is taken, it can be considered that the values of R and C are constant in the region of AAAAAAAAAAf. Therefore, (5 ) and (6) are available.A powder EL device operated under AC voltage can be considered as a RC parallel circuit including conductive current IR and capacitive current IC. Thus above principles can be used for measuring loss current, no-loss current, loss angle, efficiency and their dependences on frequency in powder EL devices.The results of measurement confirm that the new method is reasonable.The error is analyzed.