Based on the form of dielectric barrier discharge （DBD）

two plasma jets were designed and produced. One plasma jet’s inner electrode was bared

and the other’s inner electrode was covered with quartz glass. The characteristics of two different plasma jets with mid-frequency sinusoidal power were measured. The Lissajous figures

images and optical spectrum of DBD were acquired

when Ar was inlet. The discharge power and electron excitation temperature were investigated through Lissajous figures and optical spectrum

respectively. The experimental results were shown that

when under the same applied voltage

the electron excitation temperature didn’t change with the Ar flow rate. Through investigating the two plasma jets’electricity and optical characteristics

it was found that

compared to the inner electrode covered with quartz glass plasma jet

the bare inner electrode plasma jet had bigger discharge power and higher electron excitation temperature.