Dimmable desk lamp circuit

The desk lamp is a kind of local lighting fixture, which is the first choice for study lighting in the study room. Desk lamps are divided into writing desk lamps, dimming desk lamps and craft desk lamps.
    Dimmable desk lamps can change the brightness of the bulb as needed to protect eyesight and save electricity. The picture shown is the actual picture.

The Sl branch and the resistor R in the dimming circuit are connected in series to reduce the voltage, which can change the brightness of the bulb. The S2 branch is connected in series with a 400V diode
to reduce the power supply voltage by half to reduce the brightness of the bulb.
    For example, if the light bulb is low, when the switch S3 is closed, a 4F capacitor is connected in series to the 100W incandescent lamp circuit, and after the voltage is reduced, it can emit
15W light; when S4 is closed, the circuit is connected through, and the bulb is ioow.