Delayed lights-out pull switch circuit (1)

It is a novel delayed light-off pull switch.
When turning on the light, it is the same as an ordinary pull switch. Pull the light to turn on.
When turning off the
light, it is different from the ordinary pull switch. When you need to turn off the light, pull the switch. The light will not go out immediately, but the light will turn on. The brightness
decreases and it takes a while to turn off. It is suitable for locking when going out at night or when going to bed.
    When S is turned on on the stage, the positive half cycle of the alternating current passes through VD1 and VD1, causing the thyristor VT to pass through. At the same time, both ends of the capacitor C are also
filled with charges. At this time, the positive half cycle of the alternating current supplies power to bulb E through VT , and the negative half cycle supplies power to bulb F through diode VD2, so bulb F is powered by umbrella voltage at this time. When setting the lamp, open the cover s and the capacitor c will be discharged through the resistor R. This discharge current can maintain VT to continue to conduct, so there is still a positive half-cycle current flowing through the bulb E.䉉 Since s cuts off the VD2 power supply circuit of the negative 'l# cycle, the bulb is in a half-voltage power supply state, and E emits dim light. About imln later, the capacitor C is discharged, and when the alternating current VT crosses zero, j is cut off, and the light E is completely extinguished.