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    Police Car Lights With LEDs

    Uploaded by

    tim schroder
    This circuit simulates the flashing lights of British police cars by using a square wave oscillator and decade counter to alternately pulse two blue LEDs. The oscillator frequency is adjustable for the best effect. The counter outputs are diode ORed to produce double pulses that are differentiated by capacitors and resistors into short pulses to enhance the flashing illusion. A bright 6V battery provides long life for the bright LEDs.

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    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    Police Car Lights With LEDs

    Uploaded by

    tim schroder
    38 views1 page
    This circuit simulates the flashing lights of British police cars by using a square wave oscillator and decade counter to alternately pulse two blue LEDs. The oscillator frequency is adjustable for the best effect. The counter outputs are diode ORed to produce double pulses that are differentiated by capacitors and resistors into short pulses to enhance the flashing illusion. A bright 6V battery provides long life for the bright LEDs.

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    Police Car Lights with LEDs

    Original Title

    Police Car Lights with LEDs

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    This circuit simulates the flashing lights of British police cars by using a square wave oscillator and decade counter to alternately pulse two blue LEDs. The oscillator frequency is adjustable for the best effect. The counter outputs are diode ORed to produce double pulses that are differentiated by capacitors and resistors into short pulses to enhance the flashing illusion. A bright 6V battery provides long life for the bright LEDs.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    38 views1 page

    Police Car Lights With LEDs

    Uploaded by

    tim schroder
    This circuit simulates the flashing lights of British police cars by using a square wave oscillator and decade counter to alternately pulse two blue LEDs. The oscillator frequency is adjustable for the best effect. The counter outputs are diode ORed to produce double pulses that are differentiated by capacitors and resistors into short pulses to enhance the flashing illusion. A bright 6V battery provides long life for the bright LEDs.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 1

    Police Car Lights with LEDs

    his circuit is used to simulate the police car lights by alternating flashing strobes seen on British police cars. The
    IC1a forms a square wave oscillator having adjustable frequency with VR1 to give the best effect.
    This square wave is buffered by IC1b and in turn drives the decade counter IC2. Outputs from the counter
    Q0/Q2 and Q7/Q9 are in turn diode ORed to give alternating double pulses.
    C2 and C3 with R3 and R5 differentiate the pulse time in conjuction with the output drivers IC1c and IC1f. This
    produces a short pulse (30 ms) which enhances the flashing effect and adds to the illusion. The output drivers in
    turn drive a pair of hyperbright blue leds D5 and D6.
    It is worth spending a little extra on using realy bright leds if the best effect is to be obtained. A 6 V camera
    battery or four AAA cells gives a long life in a small package. In use adjust VR1 to give the best effect.
    Article sent by Ian Johnson (Sw) at contact@elec-
    troschematics.com, thanks.

    Police Car Lights circuit diagram

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