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 like a Police Style Strobe light. Whenever a group of LEDs is activated, its LEDs turn on and off three times at specific time intervals. LEDs are red for one group and blue for the other group.

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

Because its a simple circuit and easy to make. So you can't change the current because as you will change the current quantity st-robing will also change. We recommended 9 volts of current for this circuit anyhow you can give 12 volts of current.

Police Style Strobe Light Circuit 

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

Caution 

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 a transistor to control the power otherwise your ICs may damage.

Components for the circuit

2 Pieces 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

Schematic

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