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alarm timer circuit schematic

Timer with Alarm Circuit

This simple alarm timer circuit is made with 4060 which has an integrated oscillator with a good stability with a relatively wide frequency range. In the circuit diagram the oscillator frequency is set by the RC network that is connected at pins 9, 10 and 11.

When the timer with alarm circuit is connected with S1, the pulse from R4 and C2 common point will reset the counter and will start the counting. When it reaches 14 bit, the 13 pin passes in state H and the auto oscillating buzzer is powered by the control transistor T1.

The time interval is adjusted with P1. In order to get intervals ranging from one minute to two hours we should do a proper sizing of the oscillator components:

  • 1 to 30 minutes: C1=220nF; P1=500KΩ
  • 1 to 60 minutes: C1=470nf; P1=500KΩ
  • 1 to 120 minutes: C1=470nF; P1=1MΩ

The power supply of the timer alarm is from a 9V battery. D1 led does not does not affect the operation of the circuit and was included only to show that it works. So, R3 and D1 are optional components.

S1 can be a tilt-sensitive switch with mercury if that will be used as a kitchen clock. With the buzzer on the power consumption of the timer alarm will be around 10 mA.

Timer Alarm circuit diagram

alarm timer circuit schematic

Components values

P1 = 500kΩ (* read the list above)
R1 = 2.2MΩ
R2 = 18kΩ
R3 = R5 = 1kΩ
R4 = 1MΩ
C1 = 220nF (* read the list above)
C2 = 10nF
T1 = BC547
IC1 = 4060

9 Comments

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  • midium

    Hi, very stupid question from a very stupid (about electronic) guy.
    When the counter ends and the Buzzer is powered, does this generate a constant beep or does it beep in a on/off alike mode?

    I’m asking as otherwise I was thinking to introduce an a-stable 555 circuit between the T1 and the Buzzer to achieve this. Is this the right solution in case?

    Cheers,
    Matteo

  • simontsui88hotmail-com

    Hi P. Marian,

    Thanks for your information posted in this page. Recently my 14-yr son searching for a circuit which can control the TV to turn off after some time. He found this page and I help to replace the buzzer to a relay with 2 LED indicating the “TV” is on and off.

    I would like to thank you for your valuable information. Hope this can bring my son’s interest on circuit/design.

    Thank you once again.

    Here I attached our design for you.

    Simon (from Hong Kong)

  • Ryan Parrish

    Hello, I would like to have a motor run while the timer is running should I connect it on the C1 leg?

    Ryan

  • Emil

    how about if i want to place a seven segment to show the time . is it applicable with this schematic?

  • Mark

    Any chance to have a ready to use PCB layout for this project?

  • Paresh Maghodiya

    This is best project for me.

  • student

    is the alarm working? can i use audio amplifier for the output of the sound?]

    i need project for my subject
    REPLY ASAP!

  • SUBHASISH MUNDLE

    I have understood (if not wrong) that the above suggested circuit cannot be used for different timings (unless one changes as suggested) why not you suggest to use selector switch with combination (with exact values)of C & R so that it will be really useful for house wives? Presently it looks like – some one has to go on experimenting with R & C?

    • Pulak Ranjan Das

      You are right about this kind of circuit. And electronic expert can do it right away but housewives cannot be able to do this.

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