How to Make a Police Flasher Without IC | Simple DIY LED Flasher Circuit

Introduction.

Want to create a police-style flashing light circuit without using any ICs like 555 or CD4017? You’re in the right place! This project shows you how to build a basic police flasher using only transistors, resistors, capacitors, and LEDs.

Materials for the Project

2X BC557 TRANSISTORS
2X BC547 TRANSISTORS
4X RED LEDs 4X BLUE LEDs
8X 100 OHM RESISTORS
6X 10K RESISTORS
2X 47K RESISTORS
2X 10uF CAPACITORS
2X 22uF CAPACITORS
VERO BOARD

Download Circuit Diagram

Working Principle

This is a transistor-based astable multivibrator circuit. It creates an alternating blinking effect using:

Two NPN transistors that switch ON and OFF alternately.
Two electrolytic capacitors are connected across the base of each transistor.
When one transistor is ON, the other remains OFF—this toggling causes the connected red and blue LEDs to flash alternately, just like a police siren light.

Tips

You can use RGB LEDs for more variety.
Try using 3V or 5V power (but recalculate resistor values accordingly).
For better effect, increase the number of LEDs on each side using transistors with higher current ratings (like BD139)

Final Thoughts

This no-IC police flasher is perfect for:

School electronics projects
Learning transistor basics
Toy modification
Arduino-less light effects

You’ve just built a police light flasher without any ICs—all with simple components and basic electronics knowledge. Let us know in the comments how your build went!