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Flashing Police Lights Circuit

This Police Style Strobe Light Circuit using 555 timer ICs shows the familiar lights used on police cars. To achieve this Police Style Strobe Light effect, two groups of LEDs are used. Each group has four LEDs and they turn on and off alternately with like Police Style Strobe light. Whenever a group of LEDs activated, its LEDs turn on and off three times with specific time interval. LEDs are red for one group and blue for the other group.

Flashing Police Lights Circuit

This Police Style Strobe Light circuit uses two timer 555 ICs. When circuit is turned on 1st IC genrates pulses and then clock to 2nd IC. When 2nd IC is active it generates also 3 pulses and then clock to 1st IC. You can change the speed of the clock, changing the resistor and capacitor values connected to the timer ic 555. We have chosen the values of the components as best operating. 

Because its simple circuit and easy to make. So you cant change the current because as you will change the current quantity st-robing will also change. We recommended 9 volts current for this circuit anyhow you can give 12 volts current.

Police Style Strobe Light Circuit 

Flashing Police Lights Circuit

In the above circuit we have used two groups of LEDs and Each group of LEDs have two LEDs. So in this way you can increase and decrease the no of LEDs as you want to connect. 


Police Style Strobe Light Circuit is operating using 555 ICs and these ICs can operate a limited amp and current. So to add more than 8 LEDs you should use transistor to control the power other wise your ICs may damaged.

Components for the circuit

2 Piece of timer ic555

2 piece of 1m(1000k) resistor

1 piece of capacitor 2.2uf ( change capacitor to change the speed)

1 piece of pf capacitor 104

2 LEDs RED color

2 LEDs blue color

Circuit Diagram for IC 555 and 4017 IC


Circuit Diagram for IC 555 and 4017 IC

Components List

  • 1x – NE555 Bipolar Timer
  • 1x – 4017 Decoded Decade
  • 6x – 1N4148 Diode
  • 1x – 1K Resistor (1/4W)
  • 1x – 22K Resistor (1/4W)
  • 2x – 4.7K Resistor (1/4W)
  • 6x – 470 Resistor (1/4W)
  • 1x – 2.2 F Electrolytic Capacitor (16V)
  • 2x – LED (Blue)
  • 2x – LED (Red)
  • 2x – BC547 NPN Transistor
  • 1x – 9V Voltage Battery