When powered this police strobe light circuit, produces the recognizable strobe light illumination that can be seen in police cars.
To arrive at the desired effect two pieces of lights were implemented (in our scenario: LEDs), which are activated alternately. Whenever a set is running, the corresponding LED turns on and off three times. Subsequently the other group is active and quite the same. The procedure is sustained indefinitely.
This effect is comparable to strobe lights that at times are used in the dance halls.
Let's learn how the circuit works
The circuit employs a 555 that features as clock decade counter 4017B. Changing the values of the resistors and capacitor attached to the timer may be used to change the clock speed. Although the values presented initiate the circuit to perform pretty well.
The 4017B delivers sequentially in each of its outputs a high signal level. If only outputs 0, is well identified 2, 4, 5, 7, 9 are connected.
This is done to produce flashing of the diode whenever each group of LEDs is connected.
See that the outputs 1,3,6 and 8 are not associated and the time necessary to create the display LEDs off.
The first group of LEDs connected to the outputs 0, 2 and 4, and the second group is connected to the outputs 5, 7, 9.
List of components for police strobe light circuit
IC2: 4017B decade counter
Q1 = Q2: 2N2222 or 8050
D1 = D2 = D3 = D4 = D5 = D6 1N4007 diodes
D7 to D18: RED 5mm LEDs
R1: 1K resistor
R2: 22K resistor
R3 to R10: 470 ohm
C2: 0.01uF ceramic discThe circuit is powered by a 12VDC supply or a battery of the same voltage as the cars (B +).