Can anyone help provide the working principle of the LED night light, thank you!

LED (Light Emitting Diode), light-emitting diode, is a solid-state semiconductor device that can directly convert electricity into light. The heart of an LED is a semiconductor wafer with one end attached to a bracket, one end is the negative pole, and the other end is connected to the positive pole of the power supply, so that the entire wafer is encapsulated by epoxy resin. A semiconductor wafer is made up of three parts, one is a P-type semiconductor, in which holes dominate, and the other end is an N-type semiconductor, where electrons are the mainstay, and in the middle are usually quantum wells with 1 to 5 cycles.

When an electric current passes through the wire on the wafer, the electrons and holes are pushed towards the quantum well, where the electrons recombine with the holes, and then emit energy in the form of photons, which is the principle of LED luminescence. The wavelength of light, which is the color of light, is determined by the material that forms the P-N junction.

When you say color change, you mean full-color LED lights!

The main working principle of full-color LED is: it is a three-color mixing of red, green and blue to achieve seven color changes, using the pulse width modulation of the output waveform, that is, adjusting the duty cycle of LED lamp conduction, and using the visual inertia of the human eye to achieve the effect of gradient in the case of fast scanning speed.

The simplest way is also to copy the circuit for LED lights.

The four rectifier diodes should be 4007, rectifying the AC 220V into DC 220V, and then the electrolytic capacitor and the polyester capacitor are connected in parallel at the output end of the rectifier bridge to do power filtering, and the two resistors should be used for current limiting, connected to 6 LEDs, so that the LEDs emit light.