Here's The schematic shown below is a simplest LED flasher circuit. The circuit is using three LEDs which will start blinking or flashing when we provide 9 volt to the circuit. The circuit is so simple it uses a self flashing LED (LED 1) to make all LEDs flash. Self flashing LEDs have a built in circuit to make
them flash and they are also very cheap now a days. Most self blinking LEDs operate from 3.5V to 9V but it is better to confirm from the seller or manufacturer to be sure. LED 2 and LED 3 are general LEDs of any colour.