ZnS:Mn

Cu powder direct-current electroluminescent(DCEL) devices show wonderful characteristics under alternating-current (AC) voltage operation. The brightness of several tens of foot-1ambert can be obtained easily at no V and 50 Hz

which is two orders of magnitude brighter than that of conventional ZnS:Cu

C1 powder ACEL devices under the same circumstances.This signifies a great achievement in the field of ACEL phosphors.This paper reports the dependences of current-voltage(

I-V

)

brightness-voltage (

B-V

) and brightness-current (

B-I

) of DCEL devices as a new kind of ACEL devices. The empirical formulae of above dependences are presented. On the basis of the experimental results

it is confirmed that there are three areas for the load of DCEL devices at AC operation depending on excited conditions. In higher voltage and lower frequency area

DCEL device appears to be a resistive load; in lower voltage and higher frequency area

it appears to be a capacitive load

and between the above mentioned areas

it appears to be a mixed load. The extent of the voltage and frequency for each load area depends on the forming and aging processes. The further forming and aging result in the enhancement of properties of capacitive load and the expansion of all of load areas into high voltage and low frequency area.