Light switch circuit with luminous indicator

The circuit of the light-off switch with light-emitting indication is shown in Figure 1. When the switch S is turned on, the 220V alternating current
is reduced by the resistor R to limit the current and the bulb E is added to both ends of the light-emitting diode I and ED, so that I and ED are energized and emit light. To make it easier to find
the switch at night . This means that the current flowing through E is very small, about 2mA. It can be considered that no power is consumed and the lamp will not
light up. Taiwan ES, the light bulb iE Qian Zhiwei shines, at this time I.Fm goes out. If S, I, and FD do not emit light, and if the filament of bulb
E is not burnt out, then there is a power outage.