Police LED Flasher Using 555 Timers

Police LED Flasher Using 555 Timers

There are many types of emergency vehicle lights that installed on police cars, fire engines, ambulances, etc. This post presents circuit for blinking alternately the two red LEDs and two blue LEDs to imitate the flashing police lights. Circuit is based on two 555 timers which works at different frequency.


1.Power supply (9V) 1
2.555 timer2
3.270Ω resistor1
4.1MΩ resistor2
5.1μF electrolytic capacitor1
6.100μF electrolytic capacitor1
7.10nF ceramic capacitor2
8.100nF ceramic capacitor1
9.Red LED2
10.Blue LED2

Circuit diagram

The values of R1 resistor and C2 capacitor affects the frequency of switching between red and blue LEDs. The blinking rate of the LEDs is affected by values of R3 resistor and C4 capacitor.

Police LED Flasher Using 555 Timers (Circuit Diagram)

Designed circuit

Circuit is designed on a breadboard.

Police LED Flasher Using 555 Timers (Designed Circuit)

Leave a Comment

Cancel reply

Your email address will not be published.