In the circuit, I have connected 3 RGB LEDs in series. After giving power supply these RGB LEDs start blinking in a sequence manner and the voltage across the LED also varies as it changes the color. As the Base of the TIP122 NPN transistor connected in series with the RGB LEDs so each time the RGB LED blinks a small electric pulse fed to the base of the transistor. When the positive pulse received at the base of the NPN transistor, the transistor turns on and the current can flow Collector to the Emitter of the transistor. When the transistor turns on, the 12v LED strip connected with the Collector of the transistor also turns on. Thus the 12v LED strip also starts blinking with the RGB LED.