Electronic toss circuit

jacky February 28, 2010 22 Comments


The circuit given here can be used for tossing head or tail. There are many games in which a tossing is required to start and this circuit can be used in all such instances.

The circuit uses two ICs NE 555 timer (IC1) and 74LS76 dual JK flip flop (IC2).The IC 1 is wired as an astable multi vibrator operating at 10Hz.The output of IC1 is inverted by using the transistor Q1.The collector of Q1 is connected to the pin 1 of IC2 via the push button switch S1.The IC2 is wired in toggle mode. When push button S1 is pressed the output pins 14 and 15 of IC2 starts toggling in state. The LEDs connected to these pins also toggles (Since the frequency of toggling is 10Hz, we feel both LEDs glowing).When push button S1 is released either one of the LED remains ON indicating the head or tail.

Circuit diagram with Parts list.



  • The circuit can be powered from 5 V DC.
  • Switch S1 is a push button switch.
  • The ICs must be mounted on holders.
  • The circuit can be assembled on a general purpose PCB.
  • April 4, 2015

    Use IC 7473 instead of IC 7476.The out will come easily and better.

  • October 7, 2013

    The basic problem I experienced with this circuit was instability and spurious clocking of the 7476 with the push button in its present position.
    I found the input to the 7476 was acting like an aerial.
    A practical modification to this circuit would be to move the push button switch to the output of the 555
    This really does stabilise the input to the 7476 because the transistor, BC548 buffers the input to the 7476 with no spurious clocking at all.

  • February 22, 2013


    February 20, 2013

    i am doing this project,
    i dont getting 5v battery…..
    wt to do?

    • seetharaman
      August 28, 2013

      Avinash use 6 volt battery with 1no 1N4002 diode in series in the positive line it will become 5.3 volts, should be ok for the ICs operation.

    January 31, 2013

    Hey guyz,
    what will be the cost to making this ckt?

  • July 23, 2012

    Can it be use by multimedia

  • JIMMY GEEK 1969
    November 12, 2011


    November 12, 2011


    November 12, 2011

    NICE CIRCUIT!!!!!!!!!!

  • Ayush
    October 17, 2011

    Nice Circuit. Just 1 question.. Why do we need to invert the output from NE555? Wont NE555 provide a positive output?

  • seetharaman
    August 10, 2011

    Hi Arun sorry for the miss, pin no3 is output of IC.

  • arun
    August 9, 2011

    From which terminal of NE555 R3 is taken??

  • Seetharaman
    June 8, 2011

    Hi Bari To invert the pulse from NE555 IC. The input requirement for 74LS76 should be positive going to respond, the negative going pulse of IC 555 is inverted for 74LS76 to respond.

  • bari
    June 8, 2011

    what is the role of BC548 in this electronic circuit?

  • vaidehi
    January 15, 2011

    its a vry usful & gud design…..on which i scored 10/10 in board exam

  • teja
    September 24, 2010

    its a outstanding design…well,i want a ckt design of a “motion sensor”…

  • siddhant
    October 15, 2009

    m not getting what i want i want a electronic toss circuit which uses only 1 IC 7404 a hex inverter

  • December 2, 2008

    Тема ну просто пиздец.
    Неужели ничего поактуальней не нашлось?

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