Led Flasher Type of Police Circuit Diagram

This is the simple Led Flasher Type of Police Circuit Diagram. LED flasher same as that used in the police car, where the pace at which the lights flash is well paced and there is a sequence on each side. This type of flasher is also called strobe light or stroboscopic light. I began to develop a project to be published here, but by coincidence I ended up finding a circuit, easy to build and giving effect was wanting.

The electronic circuit flasher police is a Russian site, as the Russians have their own markup for semiconductor like this project, which uses KT815 transistors, for sure you will not find these transistors in a Western store, but of course are the replacements, in this case BD135.

Led Flasher Type of Police Circuit Diagram

Flasher LED Police type



This circuit is a classic of electronics, a flip-flop circuit, "astable multivibrators", this circuit is used for common flasher, but in this case two of this circuit were coupled to give the desired effect. The circuit flasher is so simple that can be done by a novice, as we see in the image below of the author, it was made on a standard printed circuit board.

How does the flasher Police

The flasher consists of two astable multivibrators, a leading astable formed by VT1 and VT2 transistors that generate the strobe and VT3 eVT4 transistors that have created short pulses to VT1 and VT2. The master oscillator is switched alternately strobe generator and the operating frequency of the generator is determined by the capacitors C1 and C4 and resistors R5, R6, R8 and R9.

You can use the trimpot R7 and R10 resistors to change the frequency of multivibrators, changing the frequency of blinking of the LEDs. The power transistors VT1 and VT3 and resistors R1 and R2 depend on the power of the LEDs used in the circuit.

Have the circuit power supply can be made with voltages 6-9 V, and its consumption is very low, enabling the use of batteries or battery. You can also change the operating voltage to 12 volts, just change some circuit resistors or put a 7809 regulator in input voltage.

Flasher LED type Police

I will give the most common equivalent found, the VT1 and VT2 transistors can be replaced by medium power transistors BD135, BD137 or BD139. The VT3 transistor can be replaced by transistors average power transistors BD136, BD138 or BD140.

But the transistor VT4 can be replaced by transistor 2sa611, BC556 or 2N4058 and other BCs of life. Below the video of the flasher police, the circuit can also be used for security systems, emergency flashing, holiday lighting, etc.


You can use higher power LEDs in this circuit since modify the resistors R1 and R2.