荧光电平管是一种分段式的荧光显示管,它有灯丝(直热式阴极),栅极和阳极(如图1)。阳极被分成若干段,分别给予引出。灯丝通常加数伏交流电压,灯丝发热后,发射电子,电子穿过栅极(通常加+12～+20伏电压)飞向阳极。阳极分成若干段,其上涂有荧光物质,当电子打上去时,会发出绿色荧光。但是,只有加高电压(即+12～+20伏)的那些阳极段,才会有电子打上去发出荧光,如果没有电压加到那些阳极段它们就不发光。荧光电平 Fluorescent level tube is a segmented fluorescent tube, it has a filament (direct thermal cathode), the grid and the anode (Figure 1). The anode is divided into several sections, respectively, to give leads. Filaments usually add a few volts of AC voltage. After the filament heats up, it emits electrons that travel through the gate (usually +12 to +20 volts) toward the anode. The anode is divided into sections, coated with a fluorescent substance that emits green fluorescence when the electrons hit it. However, only those anode segments that are energized (ie, +12 to +20 volts) will have electrons that fluoresce and will not emit light if no voltage is applied to those anode segments. Fluorescence level