Features 1、SELF EXCITED MULTIVIBRATOR: This kit is mainly composed of a clock generation circuit and a decimal counter circuit, and a self excited multivibrator with NE555 as the core 2、CHARGE CAPACITOR C1: The power supply charges the capacitor C1 through R2, R3, and R4. When C1 just starts to charge, the 2 pin of NE555 is still at a low level, so the output pin 3 is high. When the power is charged to C1 through R2, R3, R4 when it reaches 2/3 of the power supply voltage, the level of pin 3 of the output terminal changes from high to low 3、CYCLE FORMS OSCILLATION: NE555 internal discharge tube is turned on, capacitor C1 is discharged through R4, R3, NE555 pin 7 until the voltage across C1 is lower than 1/3 of the power supply voltage, NE555 pin 3 level changes from low to high again. C1 is charged again, and this cycle forms an oscillation 4、ADJUST R4 TO CONTROL OUTPUT FREQUENCY: The charging time is 0.695 (R2+R3+R4) C1, and the discharging time is 0.695 (R4+R3) C1. Adjusting R4 can control the output frequency of the oscillator, and also adjust the flow speed of the LED light 5、WATER LAMP EFFECT: The clock oscillation signal of NE555 is continuously added to the 14 pins of CD4017, and 10 LEDs are connected to the 10 output terminals of CD4017. When the 10 output terminals of CD4017 generate high level in turn under the action of the clock signal, then D1‑D10 are sequentially lit to form a water lamp effect Specification Item Type: Water Flowing Light Power Supply Voltage: 2.5-14.5V PCB Size: Approx. 54 x 21mm / 2.13 x 0.83in PCB Thickness: Approx. 1.6mm / 0.06in Package List 1 x Water Flowing Light Kit(19Pcs)