Mini Flasher

Last Updated on October 8, 2025

Multipurpose Mini Flasher is designed by using timer IC LM555 and two LEDs, these two LEDs are glows alternatively according to the timer IC output. By variable Resistor used in this circuit we can adjust the blinking speed of LEDs.

This Mini Flasher circuit works like astable multivibrator and gives continuous square pulse output. This circuit can operate by using 6 volt to 10 volt power source, here we used battery in schematic (you can use any power source which provides less than 400 mA).

Circuit Diagram

Components Required (BOM)

1	C1	10uf/16v	CP_Radial_D4.0mm_P2.00mm	1
2	C2	0.1u	C_Disc_D3.8mm_W2.6mm_P2.50mm	1
3	R1	1K	R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal	1
4	R2	3.3K	R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal	1
5	R3	220R	R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal	1
6	R4	10R	R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal	1
7	D1	LED Red	LED_D5.0mm	1
8	D2	LED Blue	LED_D5.0mm	1
9	D3	1N4007	D_DO-41_SOD81_P10.16mm_Horizontal	1
10	U1	NE555P	DIP-8_W7.62mm	1
11	RV1	100K	Potentiometer_Piher_PT-6-V_Vertical_Hole	1
12	J1	Bat_6V	TerminalBlock_Altech_AK300-2_P5.00mm	1

Construction & Working

For an experiment here we constructed this circuit on a PCB and all components involved in this prototype are THT elements. After Printed Circuit Board Assembly, apply power supply to the board and then timer IC LM555 starts to oscillate Square pulse, duty cycle of the pulse is depends on the value of RV1 and C1. By varying RV1 we can get different range of duty cycle.

At the output terminal two LEDs are connected through R3 Resistor and these two connected in antiparallel way. Hence for both positive and negative cycle output LEDs will glow alternatively.