将一台黑白电视机稍加改装能做多种物理演示实验 ,现介绍如下。实验一、演示热电子发射现象图 1改装 :打开电视机后盖 ,断开显像管原灯丝电压 (3、 4脚为灯丝 ) ,改用低压电源单独向灯丝供电 (12 V档交直流均可 ) ,如图 1所示。演示 :1.接通电视机电源 ,当 K断开时 ,电视机有声 A few black-and-white TVs can be modified to do a variety of physical demonstration experiments, as described below. Experiment 1. Demonstrate the phenomenon of hot electron emission. Fig. 1 Modification: Turn on the back cover of the TV and disconnect the original filament voltage of the picture tube (3, 4 feet for the filament), and use the low voltage power supply to supply the filament alone (AC and DC in the 12 V range) ,As shown in Figure 1. Demo : 1. Turn on TV power, when K is disconnected, the TV has sound