Supply Voltage :3 - 4 .5 V PCB size: 88 * 25mm PCB thickness: 1.0mm Circuit: The kit mainly by the clock generation circuit and decimal counter circuit constitute By NE555 core self-excited multivibrator power through R2, R1, VR1 to charge the capacitor C2, when C2 just start charging, U1's pin 2 is low, so the output end of the 3 foot was high power by R2, R1, VR1 C2 charges to 2/3 of the supply voltage, the output level of 3 feet from high to low, U1 internal discharge tube is turned on, capacitor C2 via VR1, R1, U1 pin 7 discharge , less than 1/3 of the supply voltage until the voltage across C2, U1's level of 3 feet from the low to high level. C1 again charging, so the cycle formed oscillation. The charging time is: 0.695 (R2 + R1 + VR1) C2 discharge time: 0.695 (VR1 + R1) C2, regulator VR1 can be controlled oscillator output frequency, U1 clock oscillation signal constantly applied to the U2 to pin 14, U2's 10 output terminal 10 is connected with LED, when U2's 10 output terminal to produce a high level in the clock signal under the action of rotation, D1 - D10 are sequentially lit, thereby forming a flowing light effect. Adjust VR1 to adjust the flow rate of the LED lights.